case study of flood management

Case Studies

In the first phase of the AFPM, a number of case studies on flood management were collected from various regions, based on the experiences of organizations active in flood management. These case studies were essential in formulating the Integrated Flood Management concepts, as they helped to:

Identify the extent to which integrated flood management has been carried out;
Understand shortcoming in flood management practices worldwide;
Extract lessons learned and good practices in flood management;
Catalogue the policy changes required to support IFM; and
Identify the institutional changes required to achieve IFM.

The case studies are presented here for “historical purposes”: having been compiled almost 20 years ago, they are reflecting national situations that might since have developed. As such, the case studies might be used as baseline or reference material for studies that aim to check the improvements in flood management since the beginning of the century.

The Overview Situation Paper on flood management practices extracts the essence of each case study, emphasizes findings and recommendations with relevance to the aspects of Integrated Flood Management and the potential for practices to be replicated in other locations. Download the Overview Situation Paper here .

An official website of the United States government

Here’s how you know

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS

A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. .

Teamwork Approach to Outreach and Engagement Reduces Flood Risk

In 2022, the city of Tulsa, Oklahoma received a Class 1 CRS rating from FEMA, which is the highest possible level.

City of Tulsa, Oklahoma

Tulsa, Oklahoma, has a long history with flood-related disasters and hazard mitigation planning. Decades ago, a George Washington University study identified Tulsa as the most frequently flooded city in the United States. The city was built on the banks of the Arkansas River. It is located within “Tornado Alley,” and it regularly experiences severe storms. The city flooded every few years in the 1960s and 1970s; in 1984, a major flood killed 14 residents, injured nearly 300, and left thousands of damaged or destroyed buildings. Following the 1984 flood, there was a long break without floods which caused concern that when “the big one” hits, the storm will catch people unaware.

Approximately 40 years ago, the city mayor and activist citizens began a new approach to flood risk reduction. This long-standing, strong support from the government and citizens for flood mitigation has allowed for a continuing, voluntary home buyout program. To date, the city has bought out over a thousand homes and paid the homeowners to move to safer locations.

The city has and maintains a citywide master drainage plan and a hazard mitigation plan, both of which are used to track and measure mitigation projects. Tulsa’s hazard mitigation plan also serves as the city’s flood management plan and includes comprehensive watershed management, land use controls, voluntary buyouts and green space that doubles as stormwater detention.

A team dedicated to promoting integrated planning, higher-standard regulations, outreach and education is the key to Tulsa’s floodplain management program and hazard mitigation planning success. Citizen involvement helps encourage sound political leadership and wise long-term actions. For instance, since the 1980s the city has mailed an annual notice to people living in the floodplain to help inform them about flood insurance.

The city has a diverse Program for Public Information Committee as part of their participation in the National Flood Insurance Program’s Community Rating System (CRS). The committee includes members from the government, business community, nonprofits and others. In 2014, the committee coordinated with multiple partners to share flood risk messaging across various platforms. The committee also held workshops to get feedback on the city’s hazard mitigation plan.

The committee attended public events, including a block party, a raft race and the state fair, to stress the importance of hazard mitigation. It also created an interactive website and map for community members to learn more about hazards and flood risk. Tulsa residents can use the Map My House platform to see the geographic extents and impacts of hazards on any address in the city. In 2020, the Flood Insurance Coverage Improvement Plan was integrated into the Program for Public Information Plan, allowing for more outreach messaging coordination.

Today, Tulsa is a national leader in stormwater management and hazard risk reduction. The city continues to build on over 40 years of intensive floodplain management work. City planners prioritize outreach and engagement so that residents know about flood risk and prevention. These outreach efforts have helped Tulsa earn the highest rating in FEMA’s CRS. The CRS Class 1 designation means that Tulsa residents receive a 45% discount on their flood insurance policies. Tulsa is one of only two communities in the nation with Class 1 status.

Key Takeaways

The goal of this outreach and engagement is sustaining mitigation and prevention measures that invest in a community’s future. It is an ongoing journey and may evolve over decades.

Gain public buy-in through ongoing outreach and education efforts, especially during the hazard mitigation planning process . Longtime members of the hazard mitigation committee developed a strong relationship and attended community events together to talk about flood risks and hazard mitigation. They reached out to many stakeholders and community groups. There were multiple voices echoing the same important message.
Long-term political support and regulations are needed . The hazard mitigation team instilled pride with mayors and city leaders over the last 40 years, which helped keep the flood program moving forward. Ann Patton said, “When the water dries out, so does the commitment. It’s a challenge to keep momentum high over the decades it may take to manage water resources.” Political priorities tend to shift, and staff leadership changes over time, but floodplain ordinances that were implemented in the hazard mitigation planning process can outlive any political term.
Don’t rest on your laurels . The city worked hard to reduce risk. The results of a citizen survey indicated that residents feel safer now, which raises concerns that people may not take flood risk seriously anymore. Continued outreach is necessary; it must become part of the city culture.
Apply to the CRS to receive flood insurance benefits with reduced flood risk . When flood risks are reduced, flood insurance premiums should be lower. The CRS allows communities to benefit from their mitigation efforts.

The challenge of unprecedented floods and droughts in risk management

Heidi Kreibich ORCID: orcid.org/0000-0001-6274-3625 1 ,
Anne F. Van Loon ORCID: orcid.org/0000-0003-2308-0392 2 ,
Kai Schröter ORCID: orcid.org/0000-0002-3173-7019 1 , 3 ,
Philip J. Ward ORCID: orcid.org/0000-0001-7702-7859 2 ,
Maurizio Mazzoleni ORCID: orcid.org/0000-0002-0913-9370 2 ,
Nivedita Sairam ORCID: orcid.org/0000-0003-4611-9894 1 ,
Guta Wakbulcho Abeshu ORCID: orcid.org/0000-0001-8775-3678 4 ,
Svetlana Agafonova ORCID: orcid.org/0000-0002-6392-1662 5 ,
Amir AghaKouchak ORCID: orcid.org/0000-0003-4689-8357 6 ,
Hafzullah Aksoy ORCID: orcid.org/0000-0001-5807-5660 7 ,
Camila Alvarez-Garreton ORCID: orcid.org/0000-0002-5381-4863 8 , 9 ,
Blanca Aznar ORCID: orcid.org/0000-0001-6952-0790 10 ,
Laila Balkhi ORCID: orcid.org/0000-0001-8224-3556 11 ,
Marlies H. Barendrecht ORCID: orcid.org/0000-0002-3825-0123 2 ,
Sylvain Biancamaria ORCID: orcid.org/0000-0002-6162-0436 12 ,
Liduin Bos-Burgering ORCID: orcid.org/0000-0002-8372-4519 13 ,
Chris Bradley ORCID: orcid.org/0000-0003-4042-867X 14 ,
Yus Budiyono ORCID: orcid.org/0000-0002-6288-6527 15 ,
Wouter Buytaert ORCID: orcid.org/0000-0001-6994-4454 16 ,
Lucinda Capewell 14 ,
Hayley Carlson 11 ,
Yonca Cavus ORCID: orcid.org/0000-0002-0528-284X 17 , 18 , 19 ,
Anaïs Couasnon ORCID: orcid.org/0000-0001-9372-841X 2 ,
Gemma Coxon ORCID: orcid.org/0000-0002-8837-460X 20 , 21 ,
Ioannis Daliakopoulos ORCID: orcid.org/0000-0001-9333-4963 22 ,
Marleen C. de Ruiter ORCID: orcid.org/0000-0001-5991-8842 2 ,
Claire Delus ORCID: orcid.org/0000-0002-6690-5326 23 ,
Mathilde Erfurt ORCID: orcid.org/0000-0003-1389-451X 19 ,
Giuseppe Esposito ORCID: orcid.org/0000-0001-5638-657X 24 ,
Didier François 23 ,
Frédéric Frappart ORCID: orcid.org/0000-0002-4661-8274 25 ,
Jim Freer 20 , 21 , 26 ,
Natalia Frolova ORCID: orcid.org/0000-0003-3576-285X 5 ,
Animesh K. Gain ORCID: orcid.org/0000-0003-3814-693X 27 , 28 ,
Manolis Grillakis ORCID: orcid.org/0000-0002-4228-1803 29 ,
Jordi Oriol Grima 10 ,
Diego A. Guzmán 30 ,
Laurie S. Huning ORCID: orcid.org/0000-0002-0296-4255 6 , 31 ,
Monica Ionita ORCID: orcid.org/0000-0001-8240-4380 32 , 33 , 34 ,
Maxim Kharlamov ORCID: orcid.org/0000-0002-4439-5193 5 , 35 ,
Dao Nguyen Khoi ORCID: orcid.org/0000-0002-1618-1948 36 ,
Natalie Kieboom ORCID: orcid.org/0000-0001-8497-0204 37 ,
Maria Kireeva ORCID: orcid.org/0000-0002-8285-9761 5 ,
Aristeidis Koutroulis ORCID: orcid.org/0000-0002-2999-7575 38 ,
Waldo Lavado-Casimiro ORCID: orcid.org/0000-0002-0051-0743 39 ,
Hong-Yi Li ORCID: orcid.org/0000-0002-9807-3851 4 ,
María Carmen LLasat ORCID: orcid.org/0000-0001-8720-4193 40 , 41 ,
David Macdonald ORCID: orcid.org/0000-0003-3475-636X 42 ,
Johanna Mård ORCID: orcid.org/0000-0002-8789-7628 43 , 44 ,
Hannah Mathew-Richards 37 ,
Andrew McKenzie ORCID: orcid.org/0000-0001-8723-4325 42 ,
Alfonso Mejia ORCID: orcid.org/0000-0003-3891-1822 45 ,
Eduardo Mario Mendiondo ORCID: orcid.org/0000-0003-2319-2773 46 ,
Marjolein Mens 47 ,
Shifteh Mobini ORCID: orcid.org/0000-0002-3365-7346 48 , 49 ,
Guilherme Samprogna Mohor ORCID: orcid.org/0000-0003-2348-6181 50 ,
Viorica Nagavciuc ORCID: orcid.org/0000-0003-1111-9616 32 , 34 ,
Thanh Ngo-Duc ORCID: orcid.org/0000-0003-1444-7498 51 ,
Thi Thao Nguyen Huynh ORCID: orcid.org/0000-0001-9071-1225 52 ,
Pham Thi Thao Nhi ORCID: orcid.org/0000-0003-4118-8479 36 ,
Olga Petrucci ORCID: orcid.org/0000-0001-6918-1135 24 ,
Hong Quan Nguyen 52 , 53 ,
Pere Quintana-Seguí ORCID: orcid.org/0000-0002-7107-9671 54 ,
Saman Razavi ORCID: orcid.org/0000-0003-1870-5810 11 , 55 , 56 ,
Elena Ridolfi ORCID: orcid.org/0000-0002-4714-2511 57 ,
Jannik Riegel 58 ,
Md Shibly Sadik ORCID: orcid.org/0000-0001-9205-4791 59 ,
Elisa Savelli ORCID: orcid.org/0000-0002-8948-0316 43 , 44 ,
Alexey Sazonov 5 , 35 ,
Sanjib Sharma ORCID: orcid.org/0000-0003-2735-1241 60 ,
Johanna Sörensen ORCID: orcid.org/0000-0002-2312-4917 49 ,
Felipe Augusto Arguello Souza ORCID: orcid.org/0000-0002-2753-9896 46 ,
Kerstin Stahl ORCID: orcid.org/0000-0002-2159-9441 19 ,
Max Steinhausen ORCID: orcid.org/0000-0002-8692-8824 1 ,
Michael Stoelzle ORCID: orcid.org/0000-0003-0021-4351 19 ,
Wiwiana Szalińska ORCID: orcid.org/0000-0001-6828-6963 61 ,
Qiuhong Tang 62 ,
Fuqiang Tian ORCID: orcid.org/0000-0001-9414-7019 63 ,
Tamara Tokarczyk ORCID: orcid.org/0000-0001-5862-6338 61 ,
Carolina Tovar ORCID: orcid.org/0000-0002-8256-9174 64 ,
Thi Van Thu Tran ORCID: orcid.org/0000-0003-1187-3520 52 ,
Marjolein H. J. Van Huijgevoort ORCID: orcid.org/0000-0002-9781-6852 65 ,
Michelle T. H. van Vliet ORCID: orcid.org/0000-0002-2597-8422 66 ,
Sergiy Vorogushyn ORCID: orcid.org/0000-0003-4639-7982 1 ,
Thorsten Wagener ORCID: orcid.org/0000-0003-3881-5849 21 , 50 , 67 ,
Yueling Wang 62 ,
Doris E. Wendt ORCID: orcid.org/0000-0003-2315-7871 67 ,
Elliot Wickham 68 ,
Long Yang ORCID: orcid.org/0000-0002-1872-0175 69 ,
Mauricio Zambrano-Bigiarini ORCID: orcid.org/0000-0002-9536-643X 8 , 9 ,
Günter Blöschl ORCID: orcid.org/0000-0003-2227-8225 70 &
Giuliano Di Baldassarre ORCID: orcid.org/0000-0002-8180-4996 43 , 44 , 71

Nature volume 608 , pages 80–86 ( 2022 ) Cite this article

52k Accesses

125 Citations

962 Altmetric

Metrics details

Natural hazards

Risk management has reduced vulnerability to floods and droughts globally 1 , 2 , yet their impacts are still increasing 3 . An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data 4 , 5 . On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change 3 .

How the USA can benefit from risk-based premiums combined with flood protection

Biases in national and continental flood risk assessments by ignoring spatial dependence

Developing more useful equity measurements for flood-risk management

Observed decreasing trends in the vulnerability to floods and droughts, owing to effective risk management, are encouraging 1 . Globally, human and economic vulnerability dropped by approximately 6.5- and 5-fold, respectively, between the periods 1980–1989 and 2007–2016 (ref. 2 ). However, the impacts of floods and droughts are still severe and increasing in many parts of the world 6 . Climate change will probably lead to a further increase in their impacts owing to projected increases in the frequency and severity of floods and droughts 3 . The economic damage of floods is projected to double globally 7 and that of droughts to triple in Europe 8 , for a mean temperature increase of 2 °C.

The purpose of risk management is to reduce the impact of events through modification of the hazard, exposure and/or vulnerability: according to United Nations (UN) terminology 9 , disaster risk management is the application of disaster risk reduction policies and strategies to prevent new disaster risk, reduce existing disaster risk and manage residual risk, contributing to the strengthening of resilience against, and reduction of, disaster losses. Hazard is a process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation; exposure is the situation of people, infrastructure, housing, production capacities and other tangible human assets located in hazard-prone areas; and vulnerability is the conditions determined by physical, social, economic and environmental factors or processes 10 , 11 , 12 , 13 that increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards. To be effective, risk management needs to be based on a sound understanding of these controlling risk drivers 14 , 15 . Past studies have identified increasing exposure as a primary driver of increasing impacts 3 , 4 , and vulnerability reduction has been identified as key for reduction of impacts 16 , 17 . However, ascertaining the combined effect of the drivers and the overall effectiveness of risk management has been hampered by a lack of empirical data 4 , 5 .

Here we analyse a new dataset of 45 pairs of flood or drought events that occurred in the same area on average 16 years apart (hereinafter referred to as paired events). The data comprise 26 flood and 19 drought paired events across different socioeconomic and hydroclimatic contexts from all continents (Fig. 1a ). We analyse floods and droughts together, because of the similarity of some of the management methods (for example, warning systems, water reservoir infrastructure), the potential for trade-offs in risk reduction between floods and droughts and therefore value for the management communities to learn from each other 18 . The impact, quantified by direct (fatalities, monetary damage), indirect (for example, disruption of traffic or tourism) and intangible impacts (for example, impact on human health or cultural heritage), is considered to be controlled by three drivers: hazard, exposure and vulnerability 3 . These drivers are quantified using a large range of different indices—for example, the standardized precipitation index, the number of houses in the affected area and risk awareness, respectively (Supplementary Table 1 ). These three drivers are considered to be exacerbated by management shortcomings. Hazard may be exacerbated by problems with water management infrastructure such as levees or reservoirs 19 . Exposure and vulnerability may be worsened by suboptimal implementation of non-structural measures such as risk-aware regional planning 20 or early warning 21 , respectively. We analyse management shortcomings and their effect on the three drivers explicitly, as this is the point at which improvements can start—for example, by the introduction of better strategies and policies. Data availability understandably varies among the paired events, and this can introduce inconsistency and subjectivity. The analyses are therefore based on indicators of change, to account for differences between paired events in respect of measured variables, data quality and uncertainty. These indicators of change represent the differences between the first event (baseline) and the second, categorized as large decreases/increases (−2/+2), small decreases/increases (−1/+1) and no change (0) (Supplementary Table 2 ). To minimize the subjectivity and uncertainty of indicator assignment, a quality assurance protocol is implemented and indicators of change with sub-indicators are used.

a , Location of flood and drought paired events ( n = 45). Numbers are paired-event IDs. b , Indicators of change, sorted by impact change. Impact is considered to be controlled by hazard, exposure and vulnerability, which are exacerbated by risk management shortcomings. Maps of the paired events coloured according to drivers and management shortcomings are shown in Extended Data Fig. 1 .

Source data

The majority of paired events show decreases in management shortcomings (71% of paired events; Fig. 1b ), which reflects that societies tend to learn from extreme events 22 . Most cases also show a decrease in vulnerability (80% of paired events) as societies typically reduce their vulnerability after the first event of a pair 21 . The five paired events with a large decrease in impact (dark blue, top left in Fig. 1b ) are associated with decreases or no change of all three drivers.

Drivers of changes in impact

Changes in flood impacts are significantly and positively correlated with changes in hazard ( r = 0.64, P ≤ 0.01), exposure ( r = 0.55, P ≤ 0.01) and vulnerability ( r = 0.60, P ≤ 0.01) (Fig. 2a ), which is in line with risk theory 3 . Although a previous analysis of eight case studies 21 identified vulnerability as a key to reduction of flood impacts, this new, more comprehensive, dataset suggests that changes in hazard, exposure and vulnerability are equally important, given that they correlate equally strongly with changes in flood impact. Changes in drought impacts are significantly correlated with changes in hazard and exposure, but not with changes in vulnerability (Fig. 2c ). This suggests that changes in vulnerability have been less successful in reducing drought impact than flood impact, which is also consistent with those event pairs for which only vulnerability changed (Extended Data Table 1 ). However, quantification of the contribution of individual drivers is difficult with this empirical approach because there are only a limited number of cases in which only one driver changed. There are three cases in which only vulnerability changed between events, two cases in which only hazard changed and no case in which only exposure changed (Extended Data Table 1 ). Additionally, paired events without a change in hazard (0) are analysed in more detail to better understand the role of exposure and vulnerability (Extended Data Fig. 2 ). In all these paired events, a reduction in impact was associated with a reduction in vulnerability, highlighting the importance of vulnerability. In five of these eight cases with a decrease in impact there was also a decrease in exposure, whereas in one case (floods in Jakarta, Indonesia in 2002 and 2007 (ID 18)) there was a large increase in exposure. In the paired event of droughts in California, United States (1987–1992 and 2011–2016, ID 36) an increase in exposure and a reduction in vulnerability increased impact, which points to the more important role of exposure in comparison with vulnerability in this drought case (Extended Data Fig. 2 ).

a , c , Correlation matrix of indicators of change for flood ( a ) and drought ( c ) paired events. Colours of squares indicate Spearman’s rank correlation coefficients and their size, the P value. b , d ,Histograms of indicators of change of flood ( b ) and drought ( d ) stratified by decrease ( n = 15 and n = 5 paired events for flood and drought, respectively) and increase ( n = 5 and n = 8 paired events, respectively) in impact. The asterisk denotes the success stories of Box 1 ; double asterisks denote pairs for which the second event was much more hazardous than the first (that is, 'unprecedented'). Mgmt shortc, management shortcomings.

Generally the changes in drivers are not significantly correlated with each other, with the exception of hazard and exposure in the case of floods ( r = 0.55, P ≤ 0.01) (Fig. 2a ). This finding may be explained by the influence of hazard on the size of the inundation area, and thus on the numbers of people and assets affected, which represent exposure.

The sensitivity analysis suggests that the correlation pattern is robust, as visualized by the colours in Extended Data Fig. 3 . The pattern of P values is also robust for flood cases, although these become less significant for drought because of the smaller sample size (Extended Data Fig. 3 ).

We split the paired events into groups of decreasing and increasing impact to evaluate their drivers separately (Fig. 2b,d ). Overall, the pattern is similar for floods and droughts. Most flood and drought pairs with decreasing impact show either a decrease in hazard (ten pairs, 50%) or no change (eight pairs, 40%). Exceptions are two flood pairs that are success stories of decreased impact despite an increase in hazard, as detailed in Box 1 . The change in exposure of the pairs with decreased impacts (Fig. 2b,d ) ranges from a large decrease to a large increase, whereas vulnerability always decreased. All cases with a large decrease in vulnerability (−2) are associated with a decrease in impacts. Overall, the pattern suggests that a decrease in impacts is mainly caused by a combination of lower hazard and vulnerability, despite an increase in exposure in 25% of cases.

The role of hazard and vulnerability in impact reduction can be exemplified by the pair of riverine floods in Jakarta, Indonesia (ID 4 in Fig. 1 ). The 2007 event had a flood return period of 50 years, whereas it was 30 years for the 2013 event 23 (that is, the hazard of the second event was smaller). Vulnerability had also decreased as a result of improved preparedness resulting from a flood risk mapping initiative and capacity building programmes implemented after the first flood, to improve citizens' emergency response, as well as by an improvement in official emergency management by establishment of the National Disaster Management Agency in 2008. Additionally, exposure was substantially reduced. Whilst the first flood caused 79 fatalities and direct damage of €1.3 billion, the second event caused 38 fatalities and €0.76 billion of direct damage.

Another example is a pair of Central European droughts (ID 9). During the 2003 event, the minimum 3-month Standardized Precipitation Evapotranspiration Index was −1.62 whereas in 2015 it was −1.18—that is, the hazard of the second event was smaller 24 . The vulnerability was also lower in the second event, because the first event had raised public awareness and triggered an improvement in institutional planning. For instance, the European Commission technical guidance on drought management plans 25 was implemented. Many reservoirs were kept filled until the beginning of summer 2015, which alleviated water shortages for various sectors and, in some cities (for example, Bratislava and Bucharest), water was supplied from tanks 26 . Additionally, water use and abstraction restrictions were implemented for non-priority uses including irrigation 26 . The impact was reduced from €17.1 billion to €2.2 billion, despite an increase in exposure because of the larger drought extent affecting almost all of Europe in 2013.

Most flood and drought pairs with an increase in impact also show a larger hazard (11 cases, 85%; Fig. 2b,d ). For six of these paired events (46%), the second event was much more hazardous than the first (hazard indicator-of-change +2), whereas this was never the case for the pairs with decreasing impact. Of those pairs with an increase in impact, 12 (92%) show an increase in exposure and nine (69%) show a small decrease in vulnerability (vulnerability indicator-of-change −1). Overall, the pattern suggests that the increase in impact is mainly caused by a combination of higher hazard and exposure, which is not compensated by a small decrease in vulnerability.

The role of hazard and exposure in increasing impact is illustrated by a pair of pluvial floods in Corigliano-Rossano City, Calabria, Italy (ID 40). This 2015 event was much more hazardous (+2) than that in 2000, with precipitation return periods of more than 100 and 10–20 years, respectively 27 . Also, the 2000 event occurred during the off-season for tourism in September whereas the exposure was much larger in 2015, because the event occurred in August when many tourists were present. Interruption of the peak holiday season caused severe indirect economic damage. Another example is a pair of droughts (ID 33) affecting North Carolina, United States. Between 2007 and 2009, about 65% of the state was affected by what was classified as an exceptional drought, with a composite drought indicator of the US Drought Monitor of 27 months 28 , whereas between 2000 and 2003 only about 30% of the state was affected by an exceptional drought of 24 months 28 . The crop losses in 2007–2009 were about €535 million, whereas they were €497 million in 2000–2003, even though vulnerability had been reduced due to drought early warning and management by the North Carolina Drought Management Council, established in 2003.

Box 1  Success stories of decreased impact despite increased hazard

The dataset includes two cases in which a lower impact was achieved despite a larger hazard of the second event, making these interesting success stories (Fig. 3 ). Both cases are flood paired events, but of different types (that is, pluvial and riverine floods (Table 1 )). These cases have in common that institutional changes and improved flood risk management governance were introduced and high investments in integrated management were undertaken, which led to an effective implementation of structural and non-structural measures, such as improved early warning and emergency response to complement structural measures such as levees (Table 1 ).

Effects of changes in management on drivers

The correlations shown in Fig. 2a,c also shed light on how management affects hazard, exposure and vulnerability and thus, indirectly, impact. For flood paired events, changes in management shortcomings are significantly positively correlated with changes in vulnerability ( r = 0.56, P ≤ 0.01), and both are significantly positively correlated with changes in impact (Fig. 2a ). For drought, however, these correlations are not significant (Fig. 2c ). Thus, achieving decreases in vulnerability, and consequently in impact, by improving risk management (that is, reducing management shortcomings) seems to be more difficult for droughts than for floods. This difficulty may be related to spillover effects—that is, drought measures designed to reduce impacts in one sector can increase impacts in another. For example, irrigation to alleviate drought in agriculture may increase drought impacts on drinking water supply and ecology 29 .

The paired floods in the Piura region, Peru (ID 13) illustrate how effective management can reduce vulnerability, and consequently impact. At the Piura river, maximum flows of 3,367 and 2,755 m 3 s −1 were recorded during the 1998 and 2017 events, respectively (that is, hazard showed a small decrease (−1)). Around 2000, the national hydrometeorological service started to issue medium-range weather forecasts that allowed preparations months before the 2017 event. In 2011, the National Institute of Civil Defence and the National Centre for the Estimation, Prevention, and Reduction of Disaster Risk were founded which, together with newly established short-range river flow forecasts, allowed more efficient emergency management of the more recent event. Additionally, non-governmental organizations such as Practical Action had implemented disaster risk-reduction activities, including evacuation exercises and awareness campaigns 30 . All of these improvements in management decreased vulnerability. The impact of the second event was smaller, with 366 fatalities in 1998 compared with 159 in 2017, despite an increase in exposure due to urbanization and population increase.

When the hazard of the second event was larger than that of the first (+1, +2), in 11 out of 18 cases (61%) the impact of the second event was also larger, irrespective of small decreases in vulnerability in eight of these cases (light blue dots/triangles in Fig. 3 ). There are only two paired events in our dataset for which a decrease in impact was achieved despite the second event being more hazardous (highlighted by the green circle in Fig. 3 ). These cases are considered success stories and are further discussed in Box 1 . For the two paired events (ID 21 and 30) for which the only driver that changed was hazard (+1), the impacts did not change (0) (Extended Data Table 1 ). Water retention capacity of 189,881,000 m³ and good irrigation infrastructure with sprinkling machines were apparently sufficient to counteract the slight increase in hazard for the drought paired event in Poland in 2006 and 2015 (ID 21). The improved flood alleviation scheme implemented between the paired flood events (2016 and 2018), protected properties in Birmingham, United Kingdom (ID 30). There are, however, seven cases for which the second event was much more hazardous (+2) than the first (highlighted by the purple ellipse in Fig. 3 )—that is, events of a magnitude that locals had probably not previously experienced. We term these events, subjectively, as unprecedented; almost all had an increased impact despite improvements in management.

Categories are: lower hazard and lower impact, ten cases; higher hazard and higher impact, 11 cases; lower hazard and higher impact, one case; higher hazard and lower impact, two cases. Circles and triangles indicate drought and flood paired events, respectively; their colours indicate change in vulnerability. Green circle highlights success stories ( n = 2) of reduced impact (−1) despite a small increase in hazard (+1). Purple ellipse indicates paired events ( n = 7) with large increase in hazard (+2)—that is, events that were subjectively unprecedented and probably not previously experienced by local residents.

One unprecedented pluvial flood is the 2014 event in the city of Malmö, Sweden (ID 45). This event was much more hazardous than that experienced a few years before, with precipitation return periods on average of 135 and 24 years, respectively, for 6 h duration 31 . The largest 6 h precipitation measured at one of nine stations during the 2014 event corresponded to a return period of 300 years. The combined sewage system present in the more densely populated areas of the city was overwhelmed, leading to extensive basement flooding in 2014 (ref. 31 ). The direct monetary damage was about €66 million as opposed to €6 million in the first event. An unprecedented drought occurred in the Cape Town metropolitan area of South Africa, in 2015–2018 (ID 44). The drought was much longer (4 years) than that experienced previously in 2003–2004 (2 years). Although the Berg River Dam had been added to the city’s water supply system in 2009, and local authorities had developed various strategies for managing water demands (for example, water restrictions, tariff increases, communication campaign), the second event caused a much higher direct impact of about €180 million 32 because the water reserves were reduced to virtually zero.

Even though it is known that vulnerability reduction plays a key role in reducing risk, our paired-event cases reveal that when the hazard of the second event was higher than the first, a reduction in vulnerability alone was often not sufficient to reduce the impact of the second event to less than that of the first. Our analysis of drivers of impact change reveals the importance of reducing hazard, exposure and vulnerability to achieve an effective impact reduction (Fig. 2 ). Although previous studies have attributed a high priority to vulnerability reduction 17 , 21 , the importance of considering all three drivers identified here may reflect the sometimes limited efficiency of management decisions, resulting in unintended consequences. For example, levee construction aiming at reducing hazards may increase exposure through encouraging settlements in floodplains 33 , 34 . Similarly, construction of reservoirs to abate droughts may enhance exposure through encouraging agricultural development and thus increase water demand 35 , 36 .

Events that are much more hazardous than preceding events (termed unprecedented here) seem to be difficult to manage; in almost all the cases considered they led to increased impact (Fig. 3 ). This finding may be related to two factors. First, large infrastructure such as levees and water reservoirs play an important role in risk management. These structures usually have an upper design limit up to which they are effective but, once a threshold is exceeded, they become ineffective. For example, the unprecedented pluvial flood in 2014 in Malmö, Sweden (ID 45) exceeded the capacity of the sewer system 31 and the unprecedented drought in Cape Town (ID 44) exceeded the storage water capacity 37 . This means that infrastructure is effective in preventing damage during events of a previously experienced magnitude, but often fails for unprecedented events. Non-structural measures, such as risk-aware land-use planning, precautionary measures and early warning, can help mitigate the consequences of water infrastructure failure in such situations 21 , but a residual risk will always remain. Second, risk management is usually implemented after large floods and droughts, whereas proactive strategies are rare. Part of the reason for this behaviour is a cognitive bias associated with the rarity and uniqueness of extremes, and the nature of human risk perception, which makes people attach a large subjective probability to those events they have personally experienced 38 .

On the other hand, two case studies were identified in which impact was reduced despite an increase in hazard (Box 1 ). An analysis of these case studies identifies three success factors: (1) effective governance of risk and emergency management, including transnational collaboration such as in the Danube case; (2) high investments in structural and non-structural measures; and (3) improved early warning and real-time control systems such as in the Barcelona case. We believe there is potential for more universal application of these success factors to counteract the current trend of increasing impacts associated with climate change 3 . These factors may also be effective in the management of unprecedented events, provided they are implemented proactively.

The concept of paired events aims at comparing two events of the same hazard type that occurred in the same area 21 to learn from the differences and similarities. This concept is analogous to paired catchment studies, which compare two neighbouring catchments with different vegetation in terms of their water yield 39 . Our study follows the theoretical risk framework that considers impact as a result of three risk components or drivers 3 : hazard, exposure and vulnerability (Extended Data Fig. 4 ). Hazard reflects the intensity of an event, such as a flooded area or drought deficit—for example, measured by the standardized precipitation index. Exposure reflects the number of people and assets in the area affected by the event. Consequently, the change in exposure between events is influenced by changes in the population density and the assets in the affected area (socioeconomic developments), as well as by changes in the size of the affected area (change of hazard). Vulnerability is a complex concept, with an extensive literature from different disciplines on how to define, measure and quantify it 13 , 40 , 41 , 42 . For instance, Weichselgartner 43 lists more than 20 definitions of vulnerability, and frameworks differ quite substantially—for example, in terms of integration of exposure into vulnerability 11 or separating them 3 . Reviews and attempts to converge on the various vulnerability concepts stress that vulnerability is dynamic and that assessments should be conducted for defined human–environment systems at particular places 12 , 44 , 45 . Every vulnerability analysis requires an approach adapted to its specific objectives and scales 46 . The paired event approach allows detailed context and place-based vulnerability assessments that are presented in the paired event reports, as well as comparisons across paired events based on the indicators-of-change. The selection of sub-indicators for the characterization of vulnerability is undertaken with a particular focus on temporal changes at the same place. All three drivers—hazard, exposure and vulnerability—can be reduced by risk-management measures. Hazard can be reduced by structural measures such as levees or reservoirs 19 , exposure by risk-aware regional planning 20 and vulnerability by non-structural measures, such as early warning 21 .

Our comparative analysis is based on a novel dataset of 45 paired events from around the world, of which 26 event pairs are floods and 19 are droughts. The events occurred between 1947 and 2019, and the average period between the two events of a pair is 16 years. The number of paired events is sufficiently large to cover a broad range of hydroclimatic and socioeconomic settings around the world and allows differentiated, context-specific assessments on the basis of detailed in situ observations. Flood events include riverine, pluvial, groundwater and coastal floods 47 , 48 , 49 , 50 . Drought events include meteorological, soil moisture and hydrological (streamflow, groundwater) droughts 51 . The rationale for analysing floods and droughts together is based on their position at the two extremes of the same hydrological cycle, the similarity of some management strategies (for example, warning systems, water reservoir infrastructure), potential trade-offs in the operation of the same infrastructure 52 and more general interactions between these two risks (for example, water supply to illegal settlements that may spur development and therefore flood risk). There may therefore be value in management communities learning from each other 18 .

The dataset comprises: (1) detailed review-style reports about the events and key processes between the events, such as changes in risk management (open access data; Data Availability statement); (2) a key data table that contains the data (qualitative and quantitative) characterizing the indicators for the paired events, extracted from individual reports (open access data); and (3) an overview table providing indicators-of-change between the first and second events (Supplementary Table 3 ). To minimize the elements of subjectivity and uncertainty in the analysis, we (1) used indicators-of-change as opposed to indicators of absolute values, (2) calculated indicators from a set of sub-indicators (Supplementary Table 1 ) and (3) implemented a quality assurance protocol. Commonly, more than one variable was assessed per sub-indicator (for example, flood discharges at more than one stream gauge, or extreme rainfall at several meteorological stations). A combination or selection of the variables was used based on hydrological reasoning on the most relevant piece of information. Special attention was paid to this step during the quality assurance process, drawing on the in-depth expertise on events of one or more of our co-authors. The assignment of values for the indicators-of-change, including quality assurance, was inspired by the Delphi Method 53 that is built on structured discussion and consensus building among experts. The process was driven by a core group (H.K., A.F.V.L., K. Schröter, P.J.W. and G.D.B.) and was undertaken in the following steps: (1) on the basis of the detailed report, a core group member suggested values for all indicators-of-change for a paired event; (2) a second member of the core group reviewed these suggestions; in case of doubt, both core group members rechecked the paired event report and provided a joint suggestion; (3) all suggestions for the indicators-of-change for all paired events were discussed in the core group to improve consistency across paired events; (4) the suggested values of the indicators-of-change were reviewed by the authors of the paired-event report; and finally (5), the complete table of indicators-of-change (Supplementary Table 3 ) was reviewed by all authors to ensure consistency between paired events. Compound events were given special consideration, and the best possible attempt was made to isolate the direct effects of floods and droughts from those of concurrent phenomena on hazard, exposure and impact, based on expert knowledge of the events of one or more of the co-authors. For instance, in the course of this iterative process it became clear that fatalities during drought events were not caused by a lack of water, but by the concurrent heatwave. It was thus decided to omit the sub-indicator ‘fatalities’ in drought impact characterization. The potential biases introduced by compound events were further reduced by the use of the relative indicators-of-change between similar event types with similar importance of concurrent phenomena.

The indicator-of-change of impact is composed of the following sub-indicators: number of fatalities (for floods only), direct economic impact, indirect impact and intangible impact (Supplementary Table 1 ). Flood hazard is composed of the sub-indicators precipitation/weather severity, severity of flood, antecedent conditions (for pluvial and riverine floods only), as well as the following for coastal floods only: tidal level and storm surge. Drought hazard is composed of the duration and severity of drought. Exposure is composed of the two sub-indicators people/area/assets exposed and exposure hotspots. Vulnerability is composed of the four sub-indicators lack of awareness and precaution, lack of preparedness, imperfect official emergency/crisis management and imperfect coping capacity. Indicators-of-change, including sub-indicators, were designed such that consistently positive correlations with impact changes are expected (Supplementary Table 1 ). For instance, a decrease in 'lack of awareness' leads to a decrease in vulnerability and is thus expected to be positively correlated with a decrease in impacts. Management shortcomings are characterized by problems with water management infrastructure and non-structural risk management shortcomings, which means that non-structural measures were not optimally implemented. These sub-indicators were aggregated into indicators-of-change for impact, hazard, exposure, vulnerability and management shortcomings, to enable a consistent comparison between flood and drought paired events. This set of indicators is intended to be as complementary as possible, but overlaps are hard to avoid because of interactions between physical and socioeconomic processes that control flood and drought risk. Although the management shortcoming indicator is primarily related to the planned functioning of risk management measures, and hazard, exposure and vulnerability primarily reflect the concrete effects of measures during specific events, there is some overlap between the management shortcoming indicator and all three drivers. Supplementary Table 1 provides definitions and examples of description or measurement of sub-indicators for flood and drought paired events.

The changes are indicated by −2/2 for large decrease or increase, −1/1 for small decrease or increase and 0 for no change. In the case of quantitative comparisons (for example, precipitation intensities and monetary damage), a change of less than around 50% is usually treated as a small change and above approximately 50% as a large change, but always considering the specific measure and paired events. Supplementary Table 2 provides representative examples from flood and drought paired events showing how differences in quantitative variables and qualitative information between the two events of a pair correspond to the values of the sub-indicators, ranging from large decrease (−2) to large increase (+2). We assume that an event is unprecedented in a subjective way—that is, it has probably not been experienced before—if the second event of a pair is much more hazardous than the first (hazard indicator-of-change +2).

Spearman’s rank correlation coefficients are calculated for impact, drivers and management shortcomings, separated for flood and drought paired events. Despite the measures taken to minimize the subjectivity and uncertainty of indicator assignment, there will always be an element of subjectivity. To address this, we carried out a Monte Carlo analysis (1,000 iterations) to test the sensitivity of the results when randomly selecting 80% of flood and drought paired events. For each subsample correlation, coefficients and P values were calculated to obtain a total of 1,000 correlation and 1,000 P value matrices. The 25th and 75th quantiles of the correlation coefficients and P values were calculated separately (Extended Data Fig. 3 ).

Data availability

The dataset containing the individual paired event reports, the key data table and Supplementary Tables 1 – 3 are openly available via GFZ Data Services ( https://doi.org/10.5880/GFZ.4.4.2022.002 ). Source data are provided with this paper.

Jongman, B. et al. Declining vulnerability to river floods and the global benefits of adaptation. Proc. Natl Acad. Sci. USA 112 , E2271–E2280 (2015).

Article CAS PubMed PubMed Central Google Scholar

Formetta, G. & Feyen, L. Empirical evidence of declining global vulnerability to climate-related hazards. Glob. Environ. Change 57 , 101920 (2019).

Article PubMed PubMed Central Google Scholar

IPCC. Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (eds Field, C.B. et al.) (Cambridge Univ. Press, 2012).

Bouwer, L. M. Have disaster losses increased due to anthropogenic climate change? Bull. Am. Meteorol. Soc. 92 , 39–46 (2011).

Article ADS Google Scholar

Ward, P. J. et al. Natural hazard risk assessments at the global scale. Nat. Hazards Earth Syst. Sci. 20 , 1069–1096 (2020).

Economic Losses, Poverty & Disasters (1998–2017) (UNISDR (United Nations Office for Disaster Risk Reduction) and CRED (Centre for Research on the Epidemiology of Disasters), 2018); https://www.cred.be/unisdr-and-cred-report-economic-losses-poverty-disasters-1998-2017

Dottori, F. et al. Increased human and economic losses from river flooding with anthropogenic warming. Nat. Clim. Change 8 , 781–786 (2018).

Cammalleri, C. et al. Global Warming and Drought Impacts in the EU (Publications Office of the European Union, 2020); https://doi.org/10.2760/597045

Terminology on Disaster Risk Reduction (UNDRR (United Nations Office for Disaster Risk Reduction), 2017); www.undrr.org/terminology

Cutter, S. L., Boruff, B. J. & Shirley, W. L. Social vulnerability to environmental hazards. Soc. Sci. Q. 84 , 242–261 (2003).

Article Google Scholar

Turner, B. L. et al. A framework for vulnerability analysis in sustainability science. Proc. Natl Acad. Sci. USA 100 , 8074–8079 (2003).

Article ADS CAS PubMed PubMed Central Google Scholar

Eakin, H. & Luers, A. L. Assessing the vulnerability of social-environmental systems. Annu. Rev. Environ. Resour. 31 , 365–394 (2006).

Eriksen, S. et al. Adaptation interventions and their effect on vulnerability in developing countries: help, hindrance or irrelevance? World Dev. Rev. 141 , 105383 (2020).

Kreibich, H. et al. Costing natural hazards. Nat. Clim. Change 4 , 303–306 (2014).

De Ruiter, M. C. et al. Why we can no longer ignore consecutive disasters. Earths Future 8 , e2019EF001425 (2020).

Di Baldassarre, G. A. et al. Perspectives on socio-hydrology: capturing feedbacks between physical and social processes. Water Resour. Res. 51 , 4770–4781 (2015).

Mechler, R. & Bouwer, L. M. Understanding trends and projections of disaster losses and climate change: is vulnerability the missing link? Clim. Change 133 , 23–35 (2015).

Ward, P. J. et al. The need to integrate flood and drought disaster risk reduction strategies. Water Secur. 11 , 100070 (2020).

Raikes, J. et al. Pre-disaster planning and preparedness for floods and droughts: a systematic review. Int. J. Disaster Risk Reduct. 38 , 101207 (2019).

Johnson, K. A. et al. A benefit–cost analysis of floodplain land acquisition for US flood damage reduction. Nat. Sustain. 3 , 56–62 (2019).

Kreibich, H. et al. Adaptation to flood risk: results of international paired flood event studies. Earths Future 5 , 953–965 (2017).

Birkland, T. A. Focusing events, mobilization, and agenda setting. J. Public Policy 18 , 53–74 (1998).

Budiyono, Y. et al. River flood risk in Jakarta under scenarios of future change. Nat. Hazards Earth Syst. Sci. 16 , 757–774 (2016).

Ionita, M. et al. The European 2015 drought from a climatological perspective. Hydrol. Earth Syst. Sci. 21 , 1397–1419 (2017).

Drought Management Plan Report (European Commission, 2007); https://ec.europa.eu/environment/water/quantity/pdf/dmp_report.pdf

Van Lanen, H. A. J. et al. Hydrology needed to manage droughts: the 2015 European case. Hydrol. Process. 30 , 3097–3104 (2016).

Petrucci, O. et al. Civil protection and damaging hydrogeological events: comparative analysis of the 2000 and 2015 events in Calabria (southern Italy). Adv. Geosci. 44 , 101–113 (2017).

NDMC (National Drought Mitigation Center) U.S. Drought Monitor https://droughtmonitor.unl.edu (2020).

Garrick, D. E. et al. Managing the cascading risks of droughts: institutional adaptation in transboundary river basins. Earths Future 6 , 809–827 (2018).

French, A. & Mechler, R. Managing El Niño Risks Under Uncertainty in Peru (International Institute for Applied Systems Analysis, 2017); http://pure.iiasa.ac.at/id/eprint/14849/1/French_Mechler_2017_El%20Ni%C3%B1o_Risk_Peru_Report.pdf

Sörensen, J. & Mobini, S. Pluvial, urban flood mechanisms and characteristics—assessment based on insurance claims. J. Hydrol. 555 , 51–67 (2017).

Muller, M. Cape Town’s drought: don’t blame climate change. Nature 559 , 174–176 (2018).

Article ADS CAS PubMed Google Scholar

White, G. F. Human Adjustment to Floods (Univ. of Chicago Press, 1945).

Wenger, C. Better use and management of levees: reducing flood risk in a changing climate. Environ. Rev. 23 , 240–255 (2015).

Kallis, G. Coevolution in water resource development: the vicious cycle of water supply and demand in Athens, Greece. Ecol. Econ. 69 , 796–809 (2010).

Di Baldassarre, G. et al. Water shortages worsened by reservoir effects. Nat. Sustain. 1 , 617–622 (2018).

Savelli, E. et al. Don’t blame the rain: social power and the 2015–2017 drought in Cape Town. J. Hydrol. 594 , 125953 (2021).

Merz, B. et al. Charting unknown waters—on the role of surprise in flood risk assessment and management. Water Resour.Res. 51 , 6399–6416 (2015).

Brown, A. E. et al. A review of paired catchment studies for determining changes in water yield resulting from alterations in vegetation. J. Hydrol. 310 , 28–61 (2005).

Cutter, S. L. & Finch, C. Temporal and spatial changes in social vulnerability to natural hazards. Proc. Natl Acad. Sci. USA 105 , 2301–2306 (2008).

Hinkel, J. ‘‘Indicators of vulnerability and adaptive capacity’’: towards a clarification of the science–policy interface. Glob. Environ. Change 21 , 198–208 (2011).

Tate, E. Social vulnerability indices: a comparative assessment using uncertainty and sensitivity analysis. Nat. Hazards 63 , 325–347 (2012).

Weichselgartner, J. Disaster mitigation: the concept of vulnerability revisited. Disaster Prev. Manage. 10 , 85–94 (2001).

Adger, W. N. Vulnerability. Glob. Environ. Change 16 , 268–281 (2006).

Birkmann, J. Framing vulnerability, risk and societal responses: the MOVE framework. Nat. Hazards 67 , 193–211 (2013).

Thywissen, K. Components of Risk—a Comparative Glossary (UNU-EHS, 2006); http://collections.unu.edu/view/UNU:1869

Tarasova, L. et al. Causative classification of river flood events. Wiley Interdiscip. Rev. Water 6 , e1353 (2019).

Google Scholar

Rosenzweig, B. R. et al. Pluvial flood risk and opportunities for resilience. Wiley Interdiscip. Rev. Water 5 , e1302 (2018).

Ascott, M. J. et al. Improved understanding of spatio‐temporal controls on regional scale groundwater flooding using hydrograph analysis and impulse response functions. Hydrol. Proc. 31 , 4586–4599 (2017).

Danard, M., Munro, A. & Murty, T. Storm surge hazard in Canada. Nat. Hazards 28 , 407–431 (2003).

Tallaksen, L. & Lanen, H. A. J. V. Hydrological Drought. Processes and Estimation Methods for Streamflow and Groundwater (Elsevier, 2004).

Van den Honert, R. C. & McAneney, J. The 2011 Brisbane floods: causes, impacts and implications. Water 3 , 1149–1173 (2011).

Okoli, C. & Pawlowski, S. D. The Delphi method as a research tool: an example, design considerations and applications. Inform. Manage. 42 , 15–29 (2004).

Download references

Acknowledgements

The presented work was developed by the Panta Rhei Working Groups 'Changes in flood risk' and 'Drought in the Anthropocene' within the framework of the Panta Rhei Research Initiative of the International Association of Hydrological Sciences. We thank the Barcelona Cicle de l’Aigua S.A., Barcelona City Council, Environment Agency (United Kingdom), Länsförsäkringar Skåne, Steering Centre for Urban Flood Control Programme in HCMC (Vietnam), VA SYD and the West Berkshire Council (United Kingdom) for data. The work was partly undertaken under the framework of the following projects: Alexander von Humboldt Foundation Professorship endowed by the German Federal Ministry of Education and Research (BMBF); British Geological Survey’s Groundwater Resources Topic (core science funding); C3-RiskMed (no. PID2020-113638RB-C22), financed by the Ministry of Science and Innovation of Spain; Centre for Climate and Resilience Research (no. ANID/FONDAP/15110009); CNES, through the TOSCA GRANT SWHYM; DECIDER (BMBF, no. 01LZ1703G); Deltares research programme on water resources; Dutch Research Council VIDI grant (no. 016.161.324); FLOOD (no. BMBF 01LP1903E), as part of the ClimXtreme Research Network. Funding was provided by the Dutch Ministry of Economic Affairs and Climate; Global Water Futures programme of University of Saskatchewan; GlobalHydroPressure (Water JPI); HUMID project (no. CGL2017-85687-R, AEI/FEDER, UE); HydroSocialExtremes (ERC Consolidator Grant no. 771678); MYRIAD-EU (European Union’s Horizon 2020 research and innovation programme under grant agreement no. 101003276); PerfectSTORM (no. ERC-2020-StG 948601); Project EFA210/16 PIRAGUA, co-founded by ERDF through the POCTEFA 2014–2020 programme of the European Union; Research project nos. ANID/FSEQ210001 and ANID/NSFC190018, funded by the National Research and Development Agency of Chile; SECurITY (Marie Skłodowska-Curie grant agreement no. 787419); SPATE (FWF project I 4776-N, DFG research group FOR 2416); the UK Natural Environment Research Council-funded project Land Management in Lowland Catchments for Integrated Flood Risk Reduction (LANDWISE, grant no. NE/R004668/1); UK NERC grant no. NE/S013210/1 (RAHU) (W.B.); Vietnam National Foundation for Science and Technology Development under grant no. 105.06-2019.20.; and Vietnam National University–HCMC under grant no. C2018-48-01. D.M. and A. McKenzie publish with the permission of the Director, British Geological Survey. The views expressed in this paper are those of the authors and not the organizations for which they work.

Open access funding provided by Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum - GFZ.

Author information

Authors and affiliations.

GFZ German Research Centre for Geosciences, Section Hydrology, Potsdam, Germany

Heidi Kreibich, Kai Schröter, Nivedita Sairam, Max Steinhausen & Sergiy Vorogushyn

Institute for Environmental Studies, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands

Anne F. Van Loon, Philip J. Ward, Maurizio Mazzoleni, Marlies H. Barendrecht, Anaïs Couasnon & Marleen C. de Ruiter

Leichtweiss Institute for Hydraulic Engineering and Water Resources, Division of Hydrology and River basin management, Technische Universität Braunschweig, Braunschweig, Germany

Kai Schröter

Department of Civil and Environmental Engineering, University of Houston, Houston, TX, USA

Guta Wakbulcho Abeshu & Hong-Yi Li

Lomonosov Moscow State University, Moscow, Russia

Svetlana Agafonova, Natalia Frolova, Maxim Kharlamov, Maria Kireeva & Alexey Sazonov

University of California, Irvine, CA, USA

Amir AghaKouchak & Laurie S. Huning

Department of Civil Engineering, Istanbul Technical University, Istanbul, Turkey

Hafzullah Aksoy

Center for Climate and Resilience Research, Santiago, Chile

Camila Alvarez-Garreton & Mauricio Zambrano-Bigiarini

Department of Civil Engineering, Universidad de La Frontera, Temuco, Chile

Operations Department, Barcelona Cicle de l’Aigua S.A, Barcelona, Spain

Blanca Aznar & Jordi Oriol Grima

Global Institute for Water Security, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Laila Balkhi, Hayley Carlson & Saman Razavi

LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, Toulouse, France

Sylvain Biancamaria

Department of Groundwater Management, Deltares, Delft, the Netherlands

Liduin Bos-Burgering

School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK

Chris Bradley & Lucinda Capewell

Agency for the Assessment and Application of Technology, Jakarta, Indonesia

Yus Budiyono

Department of Civil and Environmental Engineering, Imperial College London, London, UK

Wouter Buytaert

Department of Civil Engineering, Beykent University, Istanbul, Turkey

Yonca Cavus

Graduate School, Istanbul Technical University, Istanbul, Turkey

Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany

Yonca Cavus, Mathilde Erfurt, Kerstin Stahl & Michael Stoelzle

Geographical Sciences, University of Bristol, Bristol, UK

Gemma Coxon & Jim Freer

Cabot Institute, University of Bristol, Bristol, UK

Gemma Coxon, Jim Freer & Thorsten Wagener

Department of Agriculture, Hellenic Mediterranean University, Iraklio, Greece

Ioannis Daliakopoulos

Université de Lorraine, LOTERR, Metz, France

Claire Delus & Didier François

CNR-IRPI, Research Institute for Geo-Hydrological Protection, Cosenza, Italy

Giuseppe Esposito & Olga Petrucci

INRAE, Bordeaux Sciences Agro, UMR ISPA, Villenave dʼOrnon, France

Frédéric Frappart

University of Saskatchewan, Centre for Hydrology, Canmore, Alberta, Canada

Environmental Policy and Planning Group, Department of Urban Studies and Planning, Massachusetts Institute of Technology, Cambridge, MA, USA

Animesh K. Gain

Department of Economics, Ca’ Foscari University of Venice, Venice, Italy

Lab of Geophysical-Remote Sensing & Archaeo-environment, Institute for Mediterranean Studies, Foundation for Research and Technology Hellas, Rethymno, Greece

Manolis Grillakis

Pontificia Bolivariana University, Faculty of Civil Engineering, Bucaramanga, Colombia

Diego A. Guzmán

California State University, Long Beach, CA, USA

Laurie S. Huning

Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Palaeoclimate Dynamics Group, Bremerhaven, Germany

Monica Ionita & Viorica Nagavciuc

Emil Racovita Institute of Speleology, Romanian Academy, Cluj-Napoca, Romania

Monica Ionita

Forest Biometrics Laboratory, Faculty of Forestry, Ștefan cel Mare University, Suceava, Romania

Water Problem Institute Russian Academy of Science, Moscow, Russia

Maxim Kharlamov & Alexey Sazonov

Faculty of Environment, University of Science, Ho Chi Minh City, Vietnam

Dao Nguyen Khoi & Pham Thi Thao Nhi

Environment Agency, Bristol, UK

Natalie Kieboom & Hannah Mathew-Richards

School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece

Aristeidis Koutroulis

Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Peru

Waldo Lavado-Casimiro

Department of Applied Physics, University of Barcelona, Barcelona, Spain

María Carmen LLasat

Water Research Institute, University of Barcelona, Barcelona, Spain

British Geological Survey, Wallingford, UK

David Macdonald & Andrew McKenzie

Centre of Natural Hazards and Disaster Science, Uppsala, Sweden

Johanna Mård, Elisa Savelli & Giuliano Di Baldassarre

Department of Earth Sciences, Uppsala University, Uppsala, Sweden

Civil and Environmental Engineering, The Pennsylvania State University, State College, PA, USA

Alfonso Mejia

Escola de Engenharia de Sao Carlos, University of São Paulo, São Paulo, Brasil

Eduardo Mario Mendiondo & Felipe Augusto Arguello Souza

Department of Water Resources & Delta Management, Deltares, Delft, the Netherlands

Marjolein Mens

Trelleborg municipality, Trelleborg, Sweden

Shifteh Mobini

Department of Water Resources Engineering, Lund University, Lund, Sweden

Shifteh Mobini & Johanna Sörensen

University of Potsdam, Institute of Environmental Science and Geography, Potsdam, Germany

Guilherme Samprogna Mohor & Thorsten Wagener

University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi, Vietnam

Thanh Ngo-Duc

Institute for Environment and Resources, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam

Thi Thao Nguyen Huynh, Hong Quan Nguyen & Thi Van Thu Tran

Institute for Circular Economy Development, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam

Hong Quan Nguyen

Observatori de l’Ebre, Ramon Llull University – CSIC, Roquetes, Spain

Pere Quintana-Seguí

School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Saman Razavi

Department of Civil, Geological and Environmental Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Dipartimento di Ingegneria Civile, Edile e Ambientale, Sapienza Università di Roma, Rome, Italy

Elena Ridolfi

University of Applied Sciences, Magdeburg, Germany

Jannik Riegel

Center for Environmental and Geographic Information Services, Dhaka, Bangladesh

Md Shibly Sadik

Earth and Environmental Systems Institute, The Pennsylvania State University, State College, PA, USA

Sanjib Sharma

Institute of Meteorology and Water Management National Research Institute, Warsaw, Poland

Wiwiana Szalińska & Tamara Tokarczyk

Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China

Qiuhong Tang & Yueling Wang

Department of Hydraulic Engineering, Tsinghua University, Beijing, China

Fuqiang Tian

Royal Botanical Gardens Kew, London, UK

Carolina Tovar

KWR Water Research Institute, Nieuwegein, the Netherlands

Marjolein H. J. Van Huijgevoort

Department of Physical Geography, Utrecht University, Utrecht, the Netherlands

Michelle T. H. van Vliet

Civil Engineering, University of Bristol, Bristol, UK

Thorsten Wagener & Doris E. Wendt

School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USA

Elliot Wickham

School of Geography and Ocean Science, Nanjing University, Nanjing, China

Institute of Hydraulic Engineering and Water Resources Management, Technische Universität Wien, Vienna, Austria

Günter Blöschl

Department of Integrated Water Systems and Governance, IHE Delft, Delft, the Netherlands

Giuliano Di Baldassarre

You can also search for this author in PubMed Google Scholar

Contributions

H.K. initiated the study and led the work. H.K., A.F.V.L., K. Schröter, P.J.W. and G.D.B. coordinated data collection, designed the study and undertook analyses. All co-authors contributed data and provided conclusions and a synthesis of their case study (the authors of each paired event report were responsible for their case study). M. Mazzoleni additionally designed the figures, and he and N.S. contributed to the analyses. H.K., G.D.B., P.J.W., A.F.V.L., K. Schröter and G.D.B. wrote the manuscript with valuable contributions from all co-authors.

Corresponding author

Correspondence to Heidi Kreibich .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Peer review

Peer review information.

Nature thanks Elizabeth Tellman, Oliver Wing and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended data fig. 1 location of flood and drought paired events coloured according to their indicators-of-change..

a , Change in hazard; b , change in exposure; c , change in vulnerability and d , change in management shortcomings.

Extended Data Fig. 2 Parallel plot of paired events with the same hazard of both events.

The hazard change is zero for all shown paired events. The lines show how the different combinations of indicators-of-change result in varying changes in impacts. Small offsets within the grey bars of the indicator-of-change values enable the visualization of all lines.

Extended Data Fig. 3 Results of the sensitivity analyses.

a–d Correlation matrix of indicators-of-change for 25th and 75th quantiles of correlation coefficients and p-values, respectively ( a , c ) and 75th and 25th quantiles of correlation coefficients and p-values, respectively ( b , d ) separate for flood and drought paired events. Quantiles of correlation coefficients and p-values were calculated separately; colours of squares indicate Spearman’s rank correlation coefficients; sizes of squares indicates p-values. Fig. 2a, c is added to the right to ease comparison.

Extended Data Fig. 4 Theoretical framework used in this study (adapted from IPCC 3 ).

This theoretical risk framework considers impact as a result of three risk components or drivers: hazard, exposure and vulnerability, which in turn are modified by management.

Supplementary information

Supplementary tables.

Supplementary Tables 1–3.

Source Data Fig. 1.

Source data fig. 2., source data fig. 3., source data extended data fig. 1., source data extended data fig. 2., source data extended data fig. 3., rights and permissions.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Cite this article.

Kreibich, H., Van Loon, A.F., Schröter, K. et al. The challenge of unprecedented floods and droughts in risk management. Nature 608 , 80–86 (2022). https://doi.org/10.1038/s41586-022-04917-5

Download citation

Received : 19 August 2021

Accepted : 30 May 2022

Published : 03 August 2022

Issue Date : 04 August 2022

DOI : https://doi.org/10.1038/s41586-022-04917-5

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

This article is cited by

Associations between a cash voucher intervention, food consumption, and coping strategies in somali food-insecure populations.

Theresa Fang
Yunhee Kang

Agriculture & Food Security (2024)

Limited progress in global reduction of vulnerability to flood impacts over the past two decades

Inga J. Sauer
Benedikt Mester
Christian Otto

Communications Earth & Environment (2024)

Strategic storm flood evacuation planning for large coastal cities enables more effective transfer of elderly populations

Mingfu Guan

Nature Water (2024)

Applying a machine learning-based method for the prediction of suspended sediment concentration in the Red river basin

Son Q. Nguyen
Linh C. Nguyen
Sylvain Ouillon

Modeling Earth Systems and Environment (2024)

Floods have become less deadly: an analysis of global flood fatalities 1975–2022

S. N. Jonkman
L. M. Bouwer

Natural Hazards (2024)

By submitting a comment you agree to abide by our Terms and Community Guidelines . If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Quick links

Explore articles by subject
Guide to authors
Editorial policies

Open Access is an initiative that aims to make scientific research freely available to all. To date our community has made over 100 million downloads. It’s based on principles of collaboration, unobstructed discovery, and, most importantly, scientific progression. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. How? By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers.

We are a community of more than 103,000 authors and editors from 3,291 institutions spanning 160 countries, including Nobel Prize winners and some of the world’s most-cited researchers. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too.

Brief introduction to this section that descibes Open Access especially from an IntechOpen perspective

Want to get in touch? Contact our London head office or media team here

Our team is growing all the time, so we’re always on the lookout for smart people who want to help us reshape the world of scientific publishing.

Home > Books > Flood Risk Management

Flood Management in China: The Huaihe River Basin as a Case Study

Submitted: 16 November 2016 Reviewed: 07 April 2017 Published: 30 August 2017

DOI: 10.5772/intechopen.69047

Cite this chapter

There are two ways to cite this chapter:

From the Edited Volume

Flood Risk Management

Edited by Theodore Hromadka and Prasada Rao

To purchase hard copies of this book, please contact the representative in India: CBS Publishers & Distributors Pvt. Ltd. www.cbspd.com | [email protected]

Chapter metrics overview

2,174 Chapter Downloads

Impact of this chapter

Total Chapter Downloads on intechopen.com

Total Chapter Views on intechopen.com

Overall attention for this chapters

The Huaihe River Basin (HRB) is a transitional river located in the transitional climate zone in China, and it has been frequently hit by big floods and suffered from flood disasters. Flood control and management of the areas are of vital importance of the Huaihe River Basin in its social and economic development. In this chapter, pioneer works of summarizing the flood management have been done for the Huaihe River in China. It first introduces flood and flood disasters of the River basin. In addition, this chapter summarizes achievements in flood control and management. Furthermore, it discusses experiences and enlightenment in flood control and management and draws conclusions for the research.

flood management
flood control
the Huaihe River
transitional river

Author Information

Qian mingkai.

Hydrologic Bureau of Huaihe River Commission, Bengbu, China

*Address all correspondence to: [email protected]

1. Introduction

China is located in eastern Asia. It is impacted by monsoonal climate and the temporal, and therefore, spatial distribution of precipitation is uneven. The terrain in China is high in the west and low in the east with mountains, plateaus, and humps, which account 67% of China’s areas and basins and 33% plains. Special geographical and climatic conditions result in very serious flood and drought disasters in China. Since 1949, great efforts have been made for flood control in China. A series of policies and regulations has been formulated for flood control and management. Furthermore, numerous structural measures such as construction of reservoirs, flood detention areas and lakes, building of dykes, water gates and hydro junctions have been constructed. In addition, non-structural measures of hydrological monitoring system and flood forecasting system have been made for flood control in China.

The Huaihe River Basin (HRB) is located in the transitional climate zone in China ( Figure 1 ), which is known as the transitional river of China [ 1 ]. It has been frequently hit by big floods and suffered from flood disasters, and the frequency of disaster is one time in 10 years on average [ 2 – 5 ]. The critical issue is that about two-third of the middle and downstream of the major rivers are prone to floods, where is inhabited 13% of people of China, 12% of cultivated land area of China, one-sixth of food product of China, and one-fourth of the food as commodity of China. Flood control and management of the areas are of vital importance for the Huaihe River Basin in its social and economic development. Strenuous efforts have been made in fighting against floods; however, there is still a long way to go.

Figure 1.

Location map of the study area.

This chapter is organized as follows: Section 1 introduces general situation of flood management in China and the Huaihe River Basin, Sections 2 and 3 summarize the study area of the Huaihe River Basin. Section 4 presents floods and flood disasters of the River basin and concerns achievements in flood control. Section 5 discusses experiences and enlightenment in flood control and management. Section 6 draws conclusions for the research.

2. Geographical features

The Huaihe River Basin is located in the east China, with the Yellow River in the north and the Yangtze River in the south, and its catchment area is 270,000 km 2 . Starting in the Tongbai Mountains of Henan province, it flows from west to east. The upper reaches of the river are located in Henan and Hubei Provinces, the middle of the river is located in Anhui Province, and the downstream of the river is located in the Jiangsu Province. The length of the trunk stream is about 1000 km. The upper reaches of Huai river flow from the river head to the mouth of Honghe River between Henan and Anhui provinces, and the total length of the upper reaches is 360 km; the middle reaches, from Honghe River to Hongze Lake, are 490 km in length; and the lower reaches have a total length of 150 km. In the lower part of the Huaihe River Basin, there are four major outlets for floods, i.e., the Floodway to the Yangtze River, the Floodway to the Yellow Sea, the Northern Jiangsu Irrigation Canal to the Yellow Sea, and diversion waterway from the Huaihe River to new Yi River, then to the Yellow Sea.

The average annual precipitation of basin is about 875 mm, of which 50–80% precipitation is concentrated in the rainy season (June–September). Located in the north-south climate transition zone, with uneven spatial-temporal distribution of precipitation and the capture of the headwaters of Yellow river into the Huaihe River, Huaihe River flood disasters occurred very frequently. The basin-wide floods hit the Huaihe River in 2003 and 2007 of this century.

Due to the frequent flood disasters in the Huaihe River Basin, the State attaches great importance to harness of the Huaihe River. For nearly half a century, many flood control buildings have been built, including 38 large reservoirs, 21 flood storage areas, 1716 km embankment of grade I, diversion rivers such as Huaihongxinhe canal, Ruhaishuidao canal (floodway to the sea), as well as large lakes such as Hongze Lake. In addition, non-structural measures such as communication systems, hydrological forecasting system, the remote monitoring system of flood control works, remote consultation system, and flood control system have also been built. All these measures have played a positive role in the defence of floods.

3. Outstanding characteristics of the HRB

Compared with other rivers all over the world, the Huaihe River has its own outstanding characteristics:

HRB is located in the transitional zone from southern to northern climate of China, the weather system changes dramatically, and precipitation varies greatly in both space and time. Therefore, it is prone to flood and drought disaster. The average annual precipitation of HRB is 875 mm, the average annual precipitation in the northern area is 600–700 mm, and in the southern area reaches to 1400–1600 mm. The precipitation is concentrated in flood season (from June to September) and accounts for 70% of the annual amount.

The Huaihe River Basin is short of water resources, and water pollution problems have not been effectively solved yet. The total amount of average annual water resources in the Huaihe River Basin is 79.4 billion m 3 , and the average amount of water resources per capita and per mu only accounts for one-fourth and one-fifth of that of China (1 mu =1/15 ha). Water is unevenly distributed in time and space, unmatched with the production and population pattern. River regulation capacity is weak, and development and utilization of water resources are difficult.

The Huaihe River Basin is with flat terrain, where mountainous area is less with poor flood incept and storage condition. It has a broad plain area accounting for two-third of the total area, which has flat terrain and small gradient ratio in the middle-low stream. The total fall-head of the Huaihe River is 200 m (gradient ratio is 0.2‰). In the upstream, the gradient ratio is greater, with a fall-head of 178 m (gradient ratio is 0.5‰), and flood concentrates rapidly. In the middle reach, the gradient ratio and the fall-head of the midstream are 0.03‰ and 16 m, respectively. The river channel is curved and flat, and several parts of the river even have inverse slopes. The floods cannot flow smoothly and freely, which can easily cause flood disaster. In the middle reach, the gradient ratio and the fall-head of the midstream are 0.04‰ and 6 m, respectively.

Historically, with the diversion (capture) of the headwaters of Yellow river into the Huaihe River dramatically changes the natural water system, aggravates flood burden on the one hand, and increases the difficulties in harnessing the Huaihe River on the other hand. Originally, the Huaihe River is a separate river flowing into the East Sea; however, from the end of twelfth century to the middle of nineteenth century, in the 700 years of the Yellow river capture into the Huaihe River, a large number of sediments silted up the middle-low channel of the Huaihe River and made the Huaihe River lose its outlet to the Sea. It changes the natural water system to a great extent and has profound influences. It aggravated flood burden on the one hand and increased the difficulties in harnessing the Huaihe River on the other hand.

The Huaihe River Basin is densely populated, contradictions between human and water are sharp, and coordinated development is difficult. The Huaihe River Basin has a population of 0.178 billion, which accounts for 13% of that of China. Moreover, the Huaihe River Basin is also a main grain production area in China, with a cultivated land area of 0.19 billion mu accounting for 10.5% of the total amount of China; grain yield of the Huaihe River Basin takes up 17% of the total amount of China, and commodity grain of the Huaihe River Basin constitutes 25% of that of China. There are so many trans-boundary rivers that numerous conflicts of interests between different regions occur in terms of drainage and water resources utilization and protection. As a result, water affairs and conflicts are complex, and therefore, it increases the difficulties in river harness and management.

4. Floods and flood disasters

4.1. floods characteristics.

The Huaihe River Basin is located in the transitional zone from southern to northern climate of China, the weather system changes dramatically, and precipitation varies greatly in both space and time. Therefore, it is prone to flood and drought disasters. The average annual precipitation of HRB is 875 mm, the average annual precipitation in the northern area is 600–700 mm, and in the southern area reaches to 1400–1600 mm. The precipitation is concentrated in flood season (from June to September) and accounts for 70% of the annual amount. The maximum records of point rainfall of different durations in the Huaihe River Basin are close to or higher than the corresponding maximum records of China and the world. Extremely large flood peaks caused by such high intensity and extensive coverage rainstorms result in serious flood disasters ( Figure 2 )

Figure 2.

The relationship between catchment area and peak discharge in the Huaihe River Basin, China, and the world.

The magnitude of the maximum floods varies greatly from one area to another over the whole basin, and the important events are given in Table 1 .

Table 1.

The maximum flood discharge for major rivers in HRB (Unit m 3 /s).

4.2. Flood disasters

According to statistics, during the 2256 years from 246 B.C. to 2010, totally 1946 flood and drought disasters had occurred in the Huaihe River Basin, among which, number of flood disaster is 1008, while number of drought disaster is 938, which means disaster almost happens every year. Number of basin-wide flood and drought disasters is 340 (number of flood disaster is 268 and number of drought disaster is 72), and frequency is approximately once every 6.6 years on average. From the diversion (capture) of the Yellow river into the Huaihe River in 1194, flood disasters became more frequently. From the thirteenth century to the nineteenth century, there were 165 flood and drought disasters occurred in the HRB, one time in every 4.2 years on average.

Due to the unique natural features of the HRB, in recent years, large-area flood and drought disasters happen frequently, and local flood and drought disasters happen annually. According to statistics, from 1949 to 2008, average annual flood disaster area of the HRB is 25.29 million mu ( Figure 3 ), among which, number of annual flood disaster area above 30 million mu reaches to 15 accounting for 25% of the number of statistical years; number of annual flood disaster area higher than 40 million mu reaches to 11 accounting for 18.3% of the number of statistical years; and number of annual flood disaster area above 50 million mu reaches to 8 accounting for 13.3% of the number of statistical years. Table 2 shows statistics of flood disasters for three basin-wide floods in the HRB.

Figure 3.

Disaster area in different years in the Huaihe River Basin.

Table 2.

Statistics of flood disasters in 1991, 2003, and 2007 in HRB.

5. Achievements in flood control

Since the foundation of the new China, for the purpose of effectively reacting to flood and drought disasters and reducing losses, under the guidance of “jointly considering storage and discharge of floodwater” principle for harnessing the Huaihe River, with 60-year continuous river harness, tremendous achievements have been made in engineering construction of the Huaihe River harness. Laws and regulations, i.e., “Flood Control Law of The People’s Republic of China,” “Flood Control Regulation of The People’s Republic of China,” “Drought relief regulation of The People’s Republic of China,” and “Administrative regulation for flood storage and detention areas,” have been established, and basin flood prevention and dispatching programs have been improved, and all these play a vital role in reducing flood and drought disasters.

5.1. Structural measures

Overall arrangement: In the upper reaches, carrying out water-soil conservation and constructing reservoirs are important to intercept and store floods. In the middle reaches, taking structural measures to dredge & broaden river course, construct dykes and flood diversion & storage areas to increase channel flood discharge capacity. In the lower reaches, taking structural measures to excavate river channels for enlarging flood discharge capacity. The overall layout of structural measures is shown in Figure 4 .

Figure 4.

Simplification of major water conservancy projects of the Huaihe River.

Water and soil loss have accumulatively been harnessed with an area of 40,000 km 2 .

About 6300 reservoirs have been constructed, with a total storage capacity of 30 billion m 3 , and 40 of them are large reservoirs, with a total storage capacity of 20 billion m 3 and a flood control capacity of 6.2 billion m 3 . Seventeen flood detention areas and large lakes for controlling flood have been constructed, with a total storage capacity of 3.59 billion m 3 and a flood storage capacity of 2.63 billion m 3 . Figure 3 illustrates the major structures in the Huaihe River Basin.

Artificial channels have been constructed with a length of 2100 km. Different types of dikes have been constructed with a length of 50,000 km, and the length of key dike is 11,000 km. River channel discharge capacity has been significantly promoted, channel discharge capacity of the upper mainstream has been enhanced from 2000 to 7000 m 3 /s, channel discharge capacity of the middle mainstream has been enhanced from 5000 to 7000 m 3 /s to 7000 to 13,000 m 3 /s, and channel discharge capacity of the lower mainstream has been enhanced from 8000 to 18,270 m 3 /s. In addition, 1200 sluices have been constructed.

At present, flood control standard of the mainstream in the upstream is once-10-years, and flood control standards of the key flood protection areas and important cities in the middle and lower reaches were promoted to once-100-years. Flood control standards of the important tributaries can reach to once-20-years to once-50-years. Specifically, in the upper mainstream, channel discharge capacity has been enhanced from 2000 to 7000 m 3 /s. In the middle mainstream, channel discharge capacity has been enhanced from 5000–7000 to 7000–13,000 m 3 /s. In the lower mainstream, channel discharge capacity has been enhanced from 8000 to 18,270 m 3 /s.

5.2. Non-structural measures

So far, non-structural measures of flood prevention regulation command system jointly form system mechanism for flood prevention and disaster reduction.

5.2.1. Legal and institutional system for flood control

China has already promulgated laws and regulations concerning water, e.g., water law, flood control law, regulation on river channel, regulation on flood control, etc.

(1) Flood control law

The Law of Flood Control was adopted at the 27th Meeting of the Standing Committee of the Eighth National People’s Congress on August 29, 1997, and promulgated by Order No. 88 of the President of the People’s Republic of China on August 29, 1997. It is the first law on the prevention and control of natural disasters in China. It is also a very important law following the Water Law and the Law of Soil and Water Conservation in water domain in China.

Numerous administrative regulations were promulgated to clarify the responsibilities of responsible parties concerned in the flood control, such as flood Control Regulation of the People’s Republic of China (2005 Revision), Regulation of the People’s Republic of China on the Administration of River Courses, Guidelines for safety and construction of flood detention areas and flood control operation plan, etc., which have played an vital role in flood control and management in China. However, with the rapid socio-economic development, population growth, and acceleration of urbanization, numerous problems and new challenges have risen in terms of flood control, which can be summarized as follows: (a) Lack of legal consciousness on the importance of flood planning and at the same time the approved flood plan was not fully observed or strictly enforced; (b) Flood protection standard was relatively low; (c) There was no effective means for river channels management, e.g., sand excavation; (d) No effective management of flood plains area; and (e) Lack of funds in flood control and infrastructure construction. Therefore, there is an urgent call for specific law on flood control to ensure that necessary measures could be implemented legally.

(2) Institutional Arrangement

(a) Ministry of Water Resources (MWR)

Ministry of Water Resources (MWR), the Chinese Government Department responsible for water administration, was founded in October 1949. In order to clarify the responsibilities among different ministries/departments under the State Council, Ministry of Water Resources was reorganized on July 22, 1988. In accordance with the stipulations of the State Council of the People’s Republic of China, the function and responsibility of the department were summarized as follows:

ensure rational development and utilization of water resources in China,

formulate water resources development strategies, plans, and policies in China,

provide draft legislations,

promulgate water administrative rules and regulations,

undertake integrated water resources management and supervision,

take charge of water resource protection and water conservation,

organize, coordinate, and supervise the work of flood control and drought relief, and be responsible for control of soil and water losses.

(b) Flood control and drought relief commanding headquarters (FCDRH)

The flood control and drought relief commanding system has been constructed at national, river basin, and local levels ( Figure 5 ). On a national level, the General Commander is a vice premier of the State Council. Its members are from administrative leaders of governmental departments and the military, who are responsible for organizing and guiding efforts in flood control and drought relief throughout the whole country [ 6 – 9 ]. In the six major river basins, namely, the Yangtze River, Yellow River, Huai River, Hai River, Songhua River, and Pearl River, Flood Control and Drought Relief Headquarters are constructed, and they take the same responsibility of flood control and drought relief on a river basin level. In local governments that undertake flood and drought tasks, flood control and drought relief commanding headquarters are constructed as part of the local governments.

Figure 5.

Institutional framework of Flood Control and Drought Relief Commanding Headquarters.

The Huaihe River Commission is a river basin authority dispatched by the Ministry of Water Resources of China to exercise water administrative functions in the Huaihe River Basin and Shandong Peninsula, which is responsible for basin design and planning, flood control and drought relief, integrated water resources management, etc.

In accordance with the stipulations of the Ministry of Water Resources(MWR), the Commission is given the following major mandates in Huaihe River Basin (HRB):

It is in charge of making the integrated planning and related professional planning for HRB, such as water resources developing planning, annual water projects construction implementing planning, and so on.

It is in charge of HRB’s water resources management and supervising.

It is in charge of checking the water body acceptance capacity for pollutant, and monitoring the water quality for the water functional areas located in the boundary of provinces.

It is in charge of dealing with routine work of the Huaihe River Flood Control and Drought Relief Headquarters. This includes the organization, coordination, supervision, and direction of flood control for HRB, and execution of operations of flood control and drought prevention for major river basins and key water projects.

It is in charge of building, managing, and operating for important water projects.

It is in charge of enforcing the laws and regulations relative to water administration.

It is in charge of organizing water and soil conservation in HRB, including development of engineering measures for water and soil conservation, and organization of the monitoring and overall prevention and control of soil and water losses.

(d) The local water resources management agency

The local water resources management comprises four levels, i.e., the provincial, prefecture, country, and the village (town). Overall, it has the most of main functions and responsibilities as that of the central government. Specifically, there are also direct legal duties of flood control and drought relief.

5.2.2. The flood forecasting and warning system

(1) The flood monitoring system

Hydrological information and flood forecasting provide basic information for flood control. By 2014, totally 329 hydrological stations (hydrologic information including information of precipitation, water level, and discharge), 220 stage gauging stations, and 2488 rain gauges had been constructed. For those stationary gauging stations, they collect rainfall information using rainfall recorder, water level information using telemetering stage recorder, and discharge information using acoustic doppler current profilers (ADCP) or current meter. In addition, 1489 water quality monitoring stations, 324 moisture stations, and 3024 ground water monitoring stations had been constructed; all of these constitute the hydrological network and also the flooding monitoring system over the Huaihe River Basin. During flood period, with the aid of water information transmission system, 1250 stations (including important hydrological stations, stage gauging stations, and rain gauges) are mandated to collect, transmit, and share hydrological information from single state level to provincial, river basin, and the national levels. It runs at a regular time interval ranging from 6 minutes to 6 hours as stipulated on the basis of the requirement of flood forecasting for the river system [ 2 ].

(2) Information transmission

The hydrological information is transmitted through the national telecommunication system. Most of the hydrological information collected are transmitted using client software of the transmission system. For those river reaches and water projects of special importance, short wave radio stations were established to ensure more effective information transmission. Furthermore, data collection and management have been computerized in the real-time flood forecasts on the state level, the river basin level, the province level, and the municipal level.

(3) Flood forecasting and warning

Flood forecasting and warning were made by hydrological bureau or flood control office, which is the member of the Flood Control and Drought Relief Headquarters (FCDRH) at various levels ranging from municipal level to the country level. Faced with emergence, the FCDRH will issue warning via government at different levels. Before the flood season in every year, annual meeting of FCDRH at different levels is held to ensure preparatory work is well organized. In addition, on a national level, there are about 1000 hydrological stations that conduct river flood forecast as requested, and there are 66 hydrological stations conducting river flood forecast in the Huaihe River Basin. Numerous models, e.g., the Antecedent precipitation index (API) model, the Xinanjiang model, and tank model, have been employed for flood forecasting ( Table 3 ) [ 9 – 13 ]. Most of the hydrological bureau above municipal – level established flood forecasting system in the flood forecasting [ 14 ] ( Figure 6 ). In addition, a new real-time flood forecasting platform FEWS_HUAIHE has also been established for probability forecasting ( Figure 7 ).

Table 3.

Flood forecasting models applied in the Huaihe River Basin.

Figure 6.

Real-time flood monitoring, forecasting, and warning system for the Huaihe River Basin.

Figure 7.

Probability flood forecasting system for the Huaihe River Basin.

(4) Decision support system for flood control

The major flood control measures can be summarized as “upper-stream storage, middle-stream passage, and lower-stream discharge” in accordance with the principle of flood prevention and regulation. Decision support system for flood control was designed for real-time control of structures in the Huaihe River Basin in case that big floods hit the basin ( Figure 8 ). It has the following functions: reservoir regulation ( Figure 9 ), flood bypass regulation ( Figure 10 ), sluice regulation, hydrojunction regulation as well as joint dispatching of hydraulic structures, etc.

Figure 8.

Topological diagram of hydraulic structures for the Huaihe River Basin.

Figure 9.

Interface of flood bypass regulation.

Figure 10.

Interface of reservoir regulation.

(5) Flood disaster assessment system

Flood disaster assessment system is designed for evaluating losses of flood disasters during the whole process in several key flood-prone areas in the Huaihe River Basin. It has the major function of pre-disaster evaluation, real-time evaluation, and post disaster assessment ( Figure 11 ).

Figure 11.

Flood disaster assessment decision support system.

(6) Flood risk mapping

Flood risk mapping identifies flood hazards, assesses flood risks, and partners with provinces and communities to provide accurate flood hazard and risk data to guide them to mitigation actions. Flood risk mapping is an important part of flood regulations and flood insurance requirements. It maintains and updates data through Flood Insurance Rate Maps (FIRMs) and risk assessments. FIRMs include statistical information such as data for river flow, storm tides, hydrologic/hydraulic analyses, and rainfall and topographic surveys ( Figure 12 ).

Figure 12.

Flood risk mapping for a key area in the Huaihe River Basin.

In summary, an integrated system of flood monitoring, forecasting, and warning system, including weather prediction, flood monitoring and forecasting, flood dispatching, and flood control discussion, has been preliminarily established in the Huaibe River Basin ( Figure 13 ), which plays a vital role in basin flood control. However, system for flood risk management, e.g., probability flood forecasting system, flood risk dispatching models for reservoirs and hydro-junction, still stays at a starting stage.

Figure 13.

Integrated system of flood monitoring, forecasting, and warning system.

6. Case study

6.1. flood management for the huaihe basin-wide flood in 2007, 6.1.1. floods in 2007 in the huaihe river basin.

In 2007, a long-time, wide-range, and high-intensity rainfall occurred in the Huaihe basin, in which area average rainfall reached to 465 mm. Influenced by the rainfall, a multi-peak flood appeared in the mainstream of the Huaihe River. Among them, four flood peaks have been found in the upstream of Wangjiaba of Huaihe River, three peaks in the Wangjiaba-Linhuaigang section, two peaks in the Linhuaigang-Huainan section, and one peak in downstream of Huainan.

The water level of the Wangjiaba-Runheji section rose over the guaranteed stage, and the water level of the Runheji-Wangji section rose to a historically high value. According to a preliminary analysis, the return period of the Mid-Huaihe River is about once-in-15-years to once-in-20-years, while that of the downstream is about once-in-25-years.

The fierce flood lasted for a long time, affected 2.5 million hectares crops, and caused a direct economic loss of 15.5 billion Yuan. However, compared with floods in 1991 and 2003, the loss was reduced by 54.3 and 45.7%, respectively. Why did the same magnitude floods make such differences? It is primarily resulted from scientific regulation of the Huaihe River flood.

6.1.2. Flood management

Flood regulation is an important part of the Huaihe River flood Management work. In 2007, all levels and branches of government facing a serious flood situation took many measures comprising of “intercept, discharge, store, divert” in accordance with “the programs for the defenses of the Huaihe River floods.”

(1) Intercept flood with the reservoirs on upstream

In the general flood defense process, the first step is to discharge flood with river channels, and the second step is to intercept water with reservoirs and then to store flood by detention basins. In 2007, the 18 large reservoirs in the Huaihe River upstream, such as Suyahu, Nianyushan, Meishan, and Xianghongdian, totally stored flood with an amount of nearly 2.1 billion cubic meters, which greatly released the flood defense pressure.

Although the reservoir played a significant role in the Huaihe River flood in 2007, in actual operation, it also faced many difficulties. At first, the Suyahu Reservoir and Meishan Reservoir, which are closely related to the flood control and prevention, are facing different levels of safety problems. Reservoir regulations are subject to the safety of reservoir projects, if a reservoir has safety problems, which means that the project itself is prone to the flood, and it cannot intercept flood according to design standards. The second is the difficulty of forecasting. At present, it is difficult to accurately and timely forecast sudden heavy rain in Huaihe Basin for our technology. Third, the provincial conflicts need to be coordinated. Most of the reservoirs in the upstream of the Huaihe River are located in Henan Province. How to weigh the pros and cons has always been a difficult issue.

Suyahu Reservoir regulation is a typical example. The reservoir is located in Henan Province. On July 15, the reservoir water level reached to 54.76 m, over the flood control water level l 2.26 m, and a lot of land was flooded and therefore reservoir operation was facing great pressure. At the same time, as the downstream part of the river exceeded the guaranteed stage, flood situation was very tense. The Flood Control and Drought Relief Headquarter (FCDRH) of Huaihe River, Henan Province, and Anhui Province launched flood consultations repeatedly and regulated Suyahe Reservoir carefully, and finally intercept 500 million cubic meters for downstream on the premise of guaranteeing projects safety, and thus the masses in this reservoir area have paid a heavy price.

(2) Pre-discharge capacity of rivers and lakes

Under normal circumstances, it takes 2 days for the formation of flood peak in mainstream of the Huaihe River from the beginning of rainfall to a flood peak appears. Short-term weather forecasts can basically predict the location and quantity of rainfall. It provides an opportunity to use the project ahead of time. The Bengbu Gate is the important control hydro-junction in the middle reaches of Huaihe River. When rainfall started in upstream and a large flood forecast was reported, the Bengbu Gate opened all 40-hole gates to pre-discharge the water. As a result, when the flood arrived, the water level can be reduced from 17.85 to 16.03 m. The reduction of 1.82 m of water level provided an opportunity to receive the upstream runoff and drainage.

Hongze Lake is the largest lake in the Huaihe Basin, and Sanhe Gate is the largest controlling gate of the lake. On July 4, before the floods arrived at Hongze Lake, the FCDRH of Huaihe River coordinated with the FCDRH of Jiangsu Province and opened Sanhe Gate and began to discharge water. When flood discharge and water level reach to a warning value in the upstream, open Sanhe Gate of Hongze Lake in the lower stream in advance to decrease water level for discharging flood freely. Through analysis and calculation, Sanhe Gate discharged a cumulative capacity of 16.8 billion cubic meters for flood prevention from July 4 to July 31 for totally 28 days and reduced the water level of the lake by 0.2 m, all of which win an advantageous opportunity in flood prevention.

(3) Make full use of detention basins for flood storage

The detention basins are important parts of the Huaihe River flood control system. When large floods occur, the use of the floodplain detention can reduce the flood volume, decrease flood peak, and lower the water level of rivers, which is a major feature of the flood prevention of the Huaihe River. The Mengwa Detention Basin is the first one in the Huaihe Basin. Due to the important location that involves the two provinces, it is scheduled by State Flood Control and Drought Relief Headquarters (FCDRH).

On July 8, the water level raised rapidly due to a heavy rain. The water level of Wangjiaba hydrological station, which is known as the Huaihe River Flood Control barometer and flood weathervane, reached quickly to 29.3 m, the guaranteed stage. At this point, the 18 large reservoirs in Huaihe River upstream were in full load operation, and the flood control capacity was exerted to the most, many rivers exceeded the guaranteed water level, and the dangers of embankment appeared ceaselessly.

Facing the severe situation, the FCDRH promoted the flood emergency response level to grade II on July 9 and to the highest level I on July 10. This is the first time to start the highest level of flood emergency response. In accordance with request of the grade I response, the Mengwa Detention Basin was operated timely when the water level of Wangjiaba of the Huaihe River reached 29.3 m.

However, there are several real problems in storing floodwater, namely the migrant relocation and resettlement, inundated farmland, heavy loss of property, and waste of human and material resources. To operate, or not to operate? That’s the question. At that time, the SFCDRH made an analysis and found that there would be three negative results when not using detention basin or using not properly. At first, inundated farmland in the upstream would be increased to 2530 hectares, with an increased area of 1340 hectares more than the use of the Mengwa Detention Basin. The second is the raising of the Huaihe River water level, which would increase the difficulty of flood prevention and threaten safety of the mainstream embankment. Lastly, probability of the use of the detention basins in downstream would be increased. However, the use of the Mengwa Detention Basin means that more than 3000 people have to be transferred, 12,000 hectares farmland would be flooded, and the part of the infrastructure in the region to be destroyed. After the five consultations by the relevant authorities, it was determined finally that the Mongwa Detention Basin would be opened. According to analysis, the basin had diverted water for 46 hours, stored flood with a volume of 250 million cubic meters, lowered the Wangjiaba water level by 0.2 m, reduced the water level of the downstream of the Zhengyangguan pass by 0.1 m, and has played a significant role in clipping flood peak. Subsequently, the Huaihe River Basin started using nine more detention basins diverted floodwater with a total capacity of 1.5 billion cubic meters. The use of these detention basins shorten the duration of Wangjiaba stage at high level nearly 20 hours.

(4) Divert water with the channels timely

It can relieve the pressure of flood prevention in the main stream by regulating diversion rivers to discharge a part of the flood water. Both Huaihongxinhe canal and Ruhaishuidao canal (canal to the sea) played the role of accelerating flood discharge in the Huaihe River flood prevention in 2007.

Huaihongxinhe canal is an artificial diversion river that passes through Jiangsu and Anhui provinces. In late July, the Huaihe River water level was still high. After soaking in high level water, much more dangerous situation of the embankments appeared. On the one hand, the rescue personnel were tired due to the long struggle; on the other hand, the high temperatures of 38°C caused inconvenience for the rescue team and relocated people. In order to reduce the water level of Huaihe River and relieve the defensive pressure of the downstream from Bengbu city as soon as possible, the FCDRH of the Huaihe River actively coordinated Jiangsu and Anhui provinces for reasonable operation of Huaihongxinhe canal, thereby reducing the dike defense and emergency pressure, and 110,000 metastatic masses returned home 2–4 days ahead of time and returned to a normal production and living order.

6.2. Room for river project in the Huaihe River Basin

6.2.1. development of “room for river” idea in the huaihe river basin.

From 1950 to 1969, there were 10 flood storage areas (total area is 3788 km 2 and flood storage capacity is 10.18 billion m 3 ) and 21 flood bypasses (total area is 1301 km 2 and flood discharge capacity is 1000~3500 m 3 /s when fully open).

The HRB has constructed five flood storage areas (total area is 3300 km 2 , and flood storage capacity is 9.3 billion m 2 ) and totally 21 flood bypasses. These flood diversion and storage areas constitute as part of the flood control engineering system and played important roles in preventing basin-wide floods in the past.

However, there are also outstanding problems, e.g., too many flood bypasses occupy river’s room, evacuation of 1.8 million people is a hard work, etc.

Since mid-1980s to the twentieth century, problems of flood diversion and storage areas have received a great deal of attention, new ideas about the Huaihe harness have progressively formed, i.e., properly reducing number and area of flood diversion and storage areas, enhancing river channel discharge capacity, reducing the probability of using flood bypasses, and reinforcing security construction of people’s safety.

By 2010, number of flood bypasses along the Huaihe mainstream reduced from 21 to 17, of which four flood bypasses were abandoned and returned room to river with an area of 24.3 km 2 , other flood diversion and storage areas returned room to river with an area of 96.4 km 2 by partial dike retreat, and totally returned 120.7 km 2 area to river.

By the plan completion in 2020, only six of the 17 flood bypasses will be preserved, among which two of the them will be abandoned, three of them will be changed to flood storage areas, and five of them will be adjusted to flood protection areas ( Figure 14 ).

Figure 14.

Adjustment of flood detention areas and flood bypass in 2020.

Totally, 230 km 2 will be returned to river, width of river channels will be increased 100~2500 m, and flood discharge capacity will be increased from 800 to 1200 m 3 /s. The operation standard of the preserved flood bypasses will be promoted to once in 10–20 years ( Figure 15 ).

Figure 15.

Achievements after completion of adjustment of flood detention areas and flood bypass.

From the start time of the flood diversion and storage areas construction to now, flood diversion and storage areas have experienced from “conflicts between human & water”, to “co-existence of human & water” and finally to “harmony between human & water”, which also reflects development of idea about “Room for river” in the HRB.

What follows take Jingshanhu flood bypass as a case study.

6.2.2. Room for river: Jingshanhu flood bypass as a case study

Jingshanhu flood bypass is about 4 km long from east to west, and 17 km wide in south-north direction, with an area of 72.0 km 2 . It plays a vital role in raising the flood-diversion capacity and decreasing water levels of Bengbu and Huainan cities.

The major problems before the harness were as follows: (1) The river channel is narrow, river channel for flood discharge is only 500 m wide, and maximum discharge capacity is only 5700 m 3 /s. (2) There are 10,000 people in the Jingshanhu flood bypass and most of them live in the plain area, which involves a large amount of works when carrying out immigration. (3) The flood bypass operates so frequently that it causes serious property losses. (4) The controlling gates of the flood bypass are so inconvenient that it cannot be timely and effectively operated. (5)Reconstruction after disaster involves hard works.

By retreating, reinforcing, and newly constructing dykes with a length of 42 km, constructing one withdrawal sluice and one intake sluice, and security construction, e.g., retreat road construction, reinforcement of Zhuangtai (small villages on raised ground with higher elevation), communication and warning facilities, etc., the chance of flood diversion was promoted from once-in-7-years to once-in-15-years, and it has significant effects.

After the control measures were implemented, the following achievements have been made:

The problems of local people’s security have been solved. There are only 855 people living in the flood-protected villages.

The flood dispatching measures have been strengthened. In 2007, the Huaihe River Basin was hit by a basin-wide large flood event again and the newly-built intake and withdrawal sluices firstly came into use and showed good effects.

The flood passage of the mainstream has been enlarged. After the implementation of dike reconstruction and reinforcement, the width of the dike inside reached to 600 m, and the release discharge of the reaches lower than Zhengyangguan pass in the mainstream can reach to 8000 m 3 /s without using the flood bypass.

Probability of using the flood bypasses has been promoted from once-in-7-years to once-in-15-years.

If inundated, economic losses of peasants have been compensated by our country and it is conductive to resume production.

Table 4 summarizes control measures and achievements of Jingshanhu flood bypass.

Table 4.

Control measures and achievements of Jingshanhu flood bypass.

7. Experiences and enlightenment

China is a flood-prone country, and flood disasters occur frequently. The Chinese Government attaches great importance to flood management and drought relief, and great efforts and achievements have been made with aid of the structural and non-structural measures. However, flooding is still a big issue in China. The ability to control floods needs further improvement of the non-structural measures, including the relevant laws, monitoring networks, warning and forecasting, and social management [ 14 ].

Both the structural and non-structural measures are very important for flood control and management. However, for the over-standard flood cases, the non-structural measures, such as the hydrological monitoring and flood forecasting, become much more important.

Flooding is still a big issue in China. The ability to control floods needs further improvement of the non-structural measures, including the relevant laws, monitoring networks, warning and forecasting, and social management.

7.1. Experiences in flood management

Flood disaster, which occurred suddenly and inevitably, is different from the general emergency disasters. It is determined by the natural conditions of the Huaihe Basin. By review of the Huaihe River flood regulation, it is found that the keys of success are still dependent on the following factors:

The complete flood control structural system is the foundation of flood regulation and management. The standard and quality of the flood control works are directly related to flood management and projects operation. Although the standard of the flood control system in Huaihe Basin is not high enough, it is compounded by a wide range of works with high correlation. Their operation is very flexible, especially the flood regulation of detention basins and diversion channels like Huaihongxinhe canal and Ruhaishuidao canal (floodway to the sea), and plays a vital role in flood control. In future, we should strengthen the construction of structural system for flood prevention and increase the flood control standard appropriately.

Accurate hydrologic forecasting is the prerequisite of the flood regulation. The forecast accuracy and the lead time will directly affect the correctness and timeliness of the flood regulation decision. In recent years, the extreme weather events have increased significantly from global perspective. The sudden strong rainfall is unforeseeable, and it becomes a new issue for flood prevention work. In the future, we should continue to strengthen early warning system, to optimize flood forecasting model, and to improve forecast accuracy and quality. Particularly, there is an urgent call for constructing an ensemble flood forecasting system integrating with numerical weather models, distributed hydrologic models, hydraulic models, and real-time control models.

Scientific analysis and judgment of the flood are the key to flood regulation. Flood regulation should consider all factors as an integrated system, including upstream and the downstream, both sides of river, global and local, flood control and drought relief, as well as economy and society. To balance different interests is a hard nut to crack in decision-making. In future, we need to continue to strengthen the flood management and risk management and to resolve the problems in laws and regulation, mechanism, technology, and other issues.

Advanced technology and perfect plan are the effective support for flood regulation. Huaihe River floods in 2003 and 2007 are not only a test of the flood structural system, but also a full inspection of the Huaihe River non-structural system. All of advanced technology and comprehensive plan of flood monitoring and forecasting, flood control scheduling, emergency management mechanism, and the joint regulation of the flood engineering system play an important role in joint operation of flood control structural system. In future, we should learn from domestic and international flood management experience, promote the application of high technology, constantly improve the flood control, and strive to reduce disaster losses.

7.2. Outlook on flood management in the Huaihe River Basin

In the future, we have to change from flood control to flood management and finally achieve the goal of flood risk management.

Room for River. In terms of river planning and training, it is necessary to make more room for flood and formulate relevant schemes and measures by comprehensive analysis of flood. Based on the structural system comprising of reservoirs, dykes, and flood detention areas, we have to enlarge passageway for small and middle magnitude floods in river harness for the purpose of releasing such kind of floods. To construct flood detention areas to receive extra floods that exceed the river channel capacity aims to solve the big flood issues.

Live with floods. In order to realize harmony between human and nature, first and foremost, an integrated flood control and management system should be well established on an operational level. In addition, in order to achieve a shift from flood control, flood management to flood risk management, there is urgent call for raising awareness of flood risk management both for the leader and the public.

Flood risk management. We do not have to control all floods of different magnitude, and we cannot bear enormous flood disaster risk. We have to avoid risks actively, take preventive measures as high priority, live far from flood disasters, and control flood disaster risk to a certain extend. We have to determine reasonable flood protection standards, and the standards should not be too high or too low. We have to classify function of flood structures in a reasonable way, because flood disaster risks could propagate if function of flood structures is not classified correctly or properly. We have to share risks. Construction of flood structures can absolutely cause risk propagation; therefore, we have to treat risk propagation in a right way and different regions have to share flood risk and construct flood risk compensation mechanism and flood insurance system.

Acknowledgments

The study was financially supported by Non-profit Industry Financial Program of MWR of China (201301066 and 201501007) and National key research and development program of China (2016YFC0402700).

1. Huaihe River Commission (HRC). Handbook of Water Resources in the Huai River Basin. Beijing, China: Science Press; 2003. p. 454
2. Huaihe River Commission (HRC). Huaihe River Year Book 2014. Bengbu, China: Huaihe River Press; 2014. p. 386
3. Huaihe River Commission (HRC). The 1991 Huaihe River Storms and Floods. Beijing, China: China Water Publication; 2010. p. 180
4. Huaihe River Commission (HRC). The 2003 Huaihe River Storms and Floods. Beijing, China: China Water Publication; 2006. p. 275
5. Huaihe River Commission (HRC). The 2007 Huaihe River Storms and Floods. Beijing, China: China Water Publication; 2010. p. 306
6. Yan J, Jun X, Gang-sheng W. Simulation of environmental change in response to operation of dams in Huaihe Basin. Water Science and Engineering. 2009; 2 (3):27–36
7. Li ZJ, Bao HJ, Xue CS, Hu YZ, Fang H. Real-time flood forecasting of Huai River with flood diversion and retarding areas. Water Science and Engineering. 2008; 1 (2):10–24
8. Zhen-kun MA, Zi-Wu, B.S. F, Zhang M, Su Y-l. Flood risk control of dams and dykes in middle reach of Huaihe River. Water Science and Engineering. 2014; 1 (7):17–31
9. Xiaotao C. Changes of flood control situation in China & adjustments of flood management strategies. In: Wu, B.S et al., editors. Flood Defence ’2002. New York: Science Press; 2002
10. Jingping E. Report for the National Workshop on Flood Control and Drought Relief Headquarters [Internet]. 2003. Available from: http://www.cws.net-ch/minister/index.asp/2003-01-16
11. Zhitong Z. Report for the National Workshop on Flood Control and Drought Relief Headquarters [Internet]. 2004. Available from: http://www.cws.net-ch/minister/index.asp/2004-02-10
12. Jingping E. Report for the National Workshop on Flood Control and Drought Relief Headquarters [Internet]. 2005. Available from: http://www.mwr.gov.cn/ztbd/2005fbzrhy/20050110/45413.asp
13. Xiaotao C. Large-scale flood control activities in the new era calling the guidance of reasonable theory: One discussion on the flood risk management with Chinese features. Water Resources Development Research. 2001; 2001 (4):1–6
14. Zhang J, Liu Z. Hydrological monitoring and flood management in China. In: Tchiguirinskaia I, Thein K, Hubert P, editors. Frontiers in Flood Research. IAHS Publ; 2006. pp. 93–101

© 2017 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Continue reading from the same book

Edited by Theodore V. Hromadka II

Published: 30 August 2017

By Oscar Sotero Dena Ornelas, Diane Irene Doser, Osca...

1624 downloads

By Saleem Ashraf, Muhammad Luqman, Muhammad Iftikhar,...

2359 downloads

By Ali Arkamose Assani

1294 downloads

Login or signup to the library
my Channels
All Channels
List events
List channels
List collections

Resources on this Collection

Improved Shelters for Responding to Floods in Pakistan Phase 1: Study to Develop a Research Methodology

2007 Floods in South Asia: From Impact to Knowledge

Flood Resistant Housing Low-Cost Disaster-Resistant Housing in Bangladesh

Vietnam shelter: frames to loans

SRI LANKA 2017 / FLOODS AND LANDSLIDES

Kenya 2018 / floods

Collections on this collection.

Flood Resilient Shelter Reconstruction, Retrofitting and Repair Technical Guidelines

Storm Resilient Shelter Case Studies and Reports

Post Disaster Engineering - Reports and Case Studies

You must be logged in to post a comment

INDEX OF NOTATIONS AND ABBREVIATIONS

Introduction, material and methodology, characteristics of the selected case studies, review results and discussion, conclusions, acknowledgements, declaration of competing interest, data availability statement, conflict of interest, addressing sustainable urban flood risk: reviewing the role and scope of theoretical models and policies.

Article contents
Figures & tables
Supplementary Data
Open the PDF for in another window
Guest Access
Cite Icon Cite
Permissions
Search Site

Gabriele Oneto , Maria Canepa; Addressing sustainable urban flood risk: reviewing the role and scope of theoretical models and policies. Water Policy 1 August 2023; 25 (8): 797–814. doi: https://doi.org/10.2166/wp.2023.022

Download citation file:

Ris (Zotero)
Reference Manager

Contemporary adaptation to urban flooding is based on risk management. Urban planners have both an active role in studying cities and a supportive role in helping to define policies. From 33 case studies, this review tries to give insight into how flood risk management fares in confronting international directives on disaster reduction and sustainability, by defining seven sustainability performance criteria. Most studies try to maximize the acceptability and feasibility of implementing solutions in cities (63.6%) and the revision of existing building codes and plans (51.5%), while fewer try to test existing urban practices for weak points (27.3%). Analyses do not fully consider urban habitats as holistic and complex systems, as citizen awareness (27.3%), costs (21.2%), and biodiversity (24.2%) are some of the least recurring and intersecting themes. The main findings should help planners define new lines of action on urban flooding and consider alternative aspects in their frameworks.

Contextuality is the most effective measure for the acceptability of LID solutions.

The sustainability of flood management depends on the scale and objective.

Streamlining the implementation of existing LID solutions should precede new ones.

Conceptual models should bridge the scale gap and empower stakeholders.

New frameworks should cover both physical and socio-economical vulnerabilities.

Geographic Information System

Intergovernmental Panel on Climate Change

Key Performance Indicator

Low-impact Development

Multi-Criteria Decision-Making

Reasons For Concern

Sustainable Development Goals

Flood management is traditionally associated with environmental and hydrological engineering, capitalizing on resistance-based strategies to remove or lower the risk to urban settlements ( Keskitalo, 2013 ). Such approaches mislead the administration in believing that resistance-based solutions can effectively confront future flooding events. Exclusive engineering solutions do not fully take into consideration human life, properties, natural assets, and infrastructure ( Ludwig, 1996 ; Dráb & Říha, 2010 ; Dawson et al., 2011 ). Modern adaptive resilience approaches rely on the recursive processes that can be coupled with engineering systems but are open to different fields of studies and expertise ( Park et al., 2013 ). Risk mapping is usually considered a basic tool for urban flood monitoring and planning, often being the product of hydrological models and hazard maps. As such, several global flood risk assessment models have been developed in the last decade ( Winsemius et al., 2013 ). The Sixth Intergovernmental Panel on Climate Change (IPCC) Assessment Report described adaptation to water-related risks and impacts as the ones that make up most of all documented adaptation practices. The IPCC report configures flooding under the Reasons For Concern (RFC) framework as extreme weather events that impact human health, livelihoods, assets, and ecosystems. As such, numerous guidelines for sustainable development are provided: from decreasing maladaptive actions, to increase in community resilience, and strengthening the acceptability of adaptation strategies.

Contemporary planning for disaster risk reduction aims to envision the consequences of development, using tools such as project cycle management and logical and results-based frameworks. The common mainstream process for sustainable risk management contemplates including socio-economic evaluation when updating construction designs and existing building standards ( Benson et al., 2007 ). As such, modern-day urban development and renovation try to adapt to future scenarios while integrating existing physical and cultural assets. Contemporary policies for urban flooding adaptation and mitigation are being developed side-by-side with international directives, originating from the Sustainable Development Goals (SDGs). Urban planning for contrasting flooding is considered in the third objective (Good Health and Well-being), 11th (Sustainable Cities and Communities), 13th (Climate action), and 15th (Life on Land). Such a broad point of view considers a vaster assortment of stakeholders, distancing from the traditional anthropocentric planning that characterized past practices. Tackling flooding risk often incurs difficulties as management is not always designed for integrated management ( Kreibich et al., 2022 ). A gradual transition in both analytically describing the event and legislating around vulnerability and exposure is taking place. As more socio-economical characteristics are being taken into account to better understand and describe human environments, including both anthropic and natural assets, a shift and redistribution of responsibility is occurring ( Butler & Pidgeon, 2011 ). The 2015 Sendai Framework for Disaster Risk Reduction outlines targets and priorities for action to achieve the reduction of disaster risk and losses in human, environmental, and socio-economical assets. Sustainable disaster risk is addressed by understanding and investing in disaster preparedness, risk reduction, and recovery. Cities should strive to make their citizens the active participants in risk assessment, supporting the overarching social safety net and enhancing the local resilience programmes. Moreover, the Framework envisions a shared ground where government and citizens can collaborate on developing context-specific, long-term, efficient mitigation strategies and governances, as in practices for governing without an enhanced institutional capacity to connect multi-scalar initiatives, adaptation efforts could remain reactive short-term solutions ( Amundsen et al., 2010 ).

The state of the art on urban flooding risk management is currently tackling the phenomenon from different perspectives. While a significant body of literature is being developed regarding the tools for modelling, lowering, and predicting the effects of flooding ( Mosavi et al., 2018 ; Venkataramanan et al., 2020 ; Azizi et al., 2022 ; Casali et al., 2022 ; Perosa et al., 2022 ; Ren et al., 2022 ), there is currently a lack of information regarding investigating integrated policies and practices ( Matczak & Hegger, 2020 ). Growing conscience regarding the need for preserving human habitats and the sustainable development of cities has brought into question the actual integration of conceptual frameworks in urban flood management. Different actors and scales of operation can induce governments to adopt different practices, but often with similar frameworks. Urban planners that tackle urban climate change adaptation are usually positioned in both an operative and supporting role. Firstly, planners operate analysis to understand the mechanisms that make an urban habitat vulnerable to flooding, for example, by studying urban form and using software based on Geographic Information System (GIS). Secondly, planners support administrations in developing tools and policies. Thus, this review is proposed to evaluate the sustainable performance of theoretical modelling and urban policies in tackling urban flooding, to provide insight into how administrations can improve their operative tools and policies regarding sustainable urban flooding. By conducting a systemic review, this study analyses 33 distinct case studies from different areas of the world and at different operative scales. In addition, the study proposes seven sustainable performance criteria deduced from the Sixth IPCC report, the SDG, and the Sendai Framework, to confront the cases. The study proposes to investigate three main topics:

T1. How is urban flooding risk management discussed depending on the scale and main participants?

T2. How are theoretical models and flooding policies addressing sustainable development?

T3. What are the common domains that define sustainable urban flooding risk management?

Addressing these questions would paint a finite picture of the current direction of the literature for effectively contrasting the phenomenon of urban flooding. Furthermore, defining the most common lines of action for reducing flooding risk, across scales and with different objectives, could provide a common ground for developing new frameworks on the matter. The paper is structured as follows. Section 2 covers the planning and identification criteria for the review. Section 3 describes the results of the selected body of literature. Section 4 discusses the defined performance criteria and confronts the selected papers in that regard. Section 5 concludes the paper, giving insight into the most common features, contrasting aspects, limitations, and future research opportunities.

This study is proposed to evaluate the role and scope of theoretical models and policy evaluations in addressing the phenomenon of urban flooding, according to the main international directives on sustainable development, to better understand how the administration could profit from integration in their administrative toolkits. Methodologically, the review is based on a three-step process. We first planned the review by defining the eligibility criteria that will be followed during the starting research phase and the following selection. Secondly, through a database search, we selected a relevant body of literature and gave the opportune screening. Finally, the review is conducted, and the results are discussed and charted. The search was conducted in September 2022.

Papers must be published in journals, peer-review conference papers, or book chapters, and be written in English.

Papers must not be older than 2010, so as to focus only on relevant and recent publications.

Papers must focus on conceptual models or policy analysis for decision-making on adapting to and mitigating urban flooding.

Papers must be related to building and urban design and form, as the analysis will be under scrutiny from an urban planning point of view.

Papers must refer to urban flooding risk as a means to reach the governance goals, independently of the location of the case study but limiting the scope at most at a regional scale, or large area.

Papers applied their methodology to an actual case study, referring to past flooding events as a benchmark.

Diagram showing the selection process of the analyzed body of literature.

To form the first batch of literature for this study, the research was conducted using different search engines to lower the risk of bias. The SCOPUS engine was used to make up the bulk of papers needed for the examination. It was built using the following set of keywords as a search query for title, abstract, and keywords: ‘urban’ AND ‘flood’ AND ‘risk’ OR ‘mitigation’ OR ‘prevention’ OR ‘assessment’ AND ‘mapping’ AND ‘planning’. As filters, we selected as language ‘English’ and for the time of publication ‘after 2010’. This gave 286 results. Starting from this cluster, a second integration was conducted on Google Scholar with the same keyword list as before, resulting in 24,200 publications, of which we considered the first 300 to lower the risk of selecting uninteresting papers ( Haddaway et al., 2015 ). After sifting through duplicates and irrelevant articles, we were left with 489 results.

Next, we limited the search to articles with context to the urban environment that gave explicit mention of planning and policy strategies for mitigating and adapting to urban flooding. We screened the associated keywords for ‘administration’ OR ‘decision’ OR ‘governance’ OR ‘institution’ OR ‘plan’ OR ‘policy’ OR ‘politic’ OR ‘strategy’, resulting in 120 papers. This permitted us to quickly focus on the administrative and disaster assessment side of flood monitoring. We excluded most of the broader and generic research that eluded the scope of our review.

Of the resulting collection, a first focused analysis was conducted by examining the abstracts to understand the main aims of the publications. Papers discussed risk mapping without giving context or direct reference to the administration's needs. Many publications gave no direct interpretation of the urban implications of their data and models. Most of the articles culled from this selection were from a solely technical standpoint focusing on a particular analysis methodology. For instance, papers that focused on machine learning for urban flooding prediction focused on the used methodology, giving no urban planning insights. Similarly for papers on hydrodynamic modelling, cloud computing, satellite, and unmanned drone monitoring. This filter was not explicitly connected to the presence or absence of urban planners from the authors, as even publications made by only environmental engineers and water scientists considered urban morphology. This exclusion brought the total of papers to 66, of which two were not available for consultation past their open-access abstract.

Parallelly, by analyzing the full text, we observed the presence of urban morphology as one of the investigated parameters. This meant having the mean to compare physical vulnerability to social, economic, ecosystem, institutional, and cultural vulnerability. We excluded research that gave no insight into the correlation of urban form to urban flooding. With this filter, we lowered the total of interesting publications to 46 papers.

Finally, we excluded papers that gave no explicit reference to a case study, limiting the review to practical publications. Among the excluded studies we counted international directives (e.g., European proceedings) and theoretical approaches without a specific case study. We concluded the selection of 33 research papers.

After the collection of a selected body of literature of 33 papers, as for the previously enlisted criteria, we carefully examined the literature for acquiring key information. We were interested in highlighting how different administrations are satisfying the need for adapting to urban flooding. The operative strategy was to catalogue the information with different labels so as to better confront it to find possible patterns, selecting a title, authors, year of publication, the field of study, case study location, the case study scope, and case study purpose. Finally, we read through the body of literature for assessing their sustainability performance regarding tackling urban flooding.

Field of study

Network diagram showing the field of studies of the selected body of the literature that tackles urban flooding risk with theoretical models and policies, organized by the publication year.

Case study location

Exposure to climate change and flooding, while being a global hazard, is not equally distributed. Several research centres and groups that are studying the phenomenon are not directly influenced by it and are locating their case studies abroad. We were interested to see if the framework for conducting flooding analysis was dependent on the geographical location.

Case study scale

Network graph, vertically organized by the investigated category, showing the correlation between the field of study, case study location, case study scale, and case study objective.

Case study objective

The research on urban flooding often considers the reasons for a past event or proposes mitigating and adaptation for better answering hazardous events. This is done by funding a study on a flood inventory, or a forecasting methodology. On the operative side, one that is directly affecting the governance process, theoretical models and policies are tools that express a precise intention or the means to interpret the given data. We distinguished between theoretical modelling and policy evaluation. The former was the overwhelming majority (81.8%), while the latter had a minor presence (36.4%). Several cases opted for a hybrid approach, focusing both on the definition of a model and contextualizing it analytically with the local policies (18.2%).

Network graph showing the dependence of performance criteria on the case study objective and scale.

Acceptability and feasibility of implementation

An increasing number of adaptation responses already exist for urban systems, but their effectiveness and implementation feasibility are limited by institutional, financial, and technological access and capacity. By lowering these constraints, appropriate responses across physical, natural, and social infrastructure could take place. Secondly, administrations that are struggling to include mitigation and adaptation solutions into their development programmes and agendas should adopt integrated policies and plans towards efficiency and resilience ( United Nations 2015 ; UNISDR 2015 ; IPCC, 2022 ). Acceptability and feasibility of implementation were the most frequent performance criteria (63.6%). Generally, most of these studies opted to illustrate how a theoretical model could be of use as a governance tool by more effectively using existing resources in an integrated and holistic way.

At the urban scale, theoretical modelling in support of the decision-making process gives the best results when intersecting heterogeneous data are used. In return giving insight on what type of data can be better optimized. This is the case for patterns of hazardous rainfall mapped on urban areas ( da Silva et al., 2021 ), implementation of grey-green solutions ( Wang et al., 2022 ), and blue-green solutions ( Ahmed et al., 2019 ). Moreover, flexibility in model definition greatly opens up possibilities for reuse and ease of application. This is especially efficient in increasing the feasibility of implementation if cities are regarded as complex systems that need to be synthesized ( Koc et al., 2021 ; Ekmekcioğlu et al., 2022 ).

Clear visualization and readability of data are often brought up as keys aspect for easier implementation and acceptance. GIS-based solutions are relevant across scales for user interface platforms, in case of planning and management of local flood-emergency ( Charlotte et al., 2020 ; Yazdani et al., 2022 ), to plan interventions in large areas ( Caprario et al., 2022 ; Wanghe et al., 2022 ), or to select and prioritize critical infrastructure to develop precise mitigation strategies ( Abenayake et al., 2022 ). Among GIS-based applications, graph models have the advantage of accurately representing the complexity of city management; such sensitivity in modelling can proxy for missing indicators, further increasing a model's adaptability ( Liu et al., 2022 ).

At neighbourhood scale, theoretical modelling has the role of validating and verifying architectural and engineering adaptation solutions, in order to prove that a particular low-impact development (LID) solution has relevance in reducing flooding risk locally ( Hua et al., 2020 ) or to confront different designs ( Balsells et al., 2013 ).

Policy evaluation at urban scale is oriented to simplify the implementation of toolkits and planning methodologies to support resilience and sustainability. Interdisciplinarity in urban hydrogeological studies for comprehensive planning could help local resilience in various ways: from assessing the surface conditions of hazardous areas ( Mielby & Henriksen, 2020 ), to limiting indiscriminate urbanization ( Bamrungkhul & Tanaka, 2022 ), to down-scale and up-scale different levels of planning ( Elsharqawy et al., 2022 ).

Other scenarios showed that accessibility and capacity for adaptation strategies can be obtained by integrating both theoretical modelling and policy evaluation. Knowledge of future urban planning scenarios and of local context can help to successfully implement mitigation and adaptation solutions. For example, when proposing adaptive solutions over one-off investments ( Löwe et al., 2017 ), when assessing the capacity of cities to make use of LID solutions by assessing the acceptability of multiple stakeholders ( Koop et al., 2018 ), and by including social, environmental, and technical performance targets for LID solutions ( Zeng et al., 2019 ). Holistic inquiries are relevant when considering secondary planning options, having in mind that citizens' acceptance could influence the efficiency of the implemented strategies ( Kwon et al., 2014 ). At the neighbourhood scale, an integrated approach is meant to allow more contextual-specific efficient, and systematic building-based management of urban space and land use as part of urban planning measures ( Yu et al., 2021 ). At the neighbourhood scale, an integrated approach is meant to allow more contextual-specific efficient, and systematic building-based management of urban space and land use as part of urban planning measures ( Yu et al., 2021 ).

Adaptation costs

Optimization in flood mitigation is often applied considering only risk reduction as the main goal. Recent solutions such as green infrastructures and LID can find it difficult to compete with grey infrastructure. Combining social, economic, and environmental responses as co-benefits allows for comparing strategies according to effective costs and benefits in the long term, strengthening urban and regional development planning. Then, the costs for maintenance and reconstruction of urban infrastructure, including the transportation and energy systems, will increase with climate change, projecting disruption particularly in cities ( United Nations 2015 ; UNISDR 2015 ; Alves et al., 2020 , IPCC, 2022 ). This category was one of the least recurrent (21.2%). We found that studies that cover combined ecosystem-based and structural adaptation approaches often gave no direct insight into the potential lowering of costs for adaptation.

Most cases adopted Multi-Criteria Decision-Making (MCDM) modelling, with supervision from economists. Trade-offs with existing resources and budgets were particularly successful in demonstrating the cost-reduction of mixed grey-green infrastructure ( Hu et al., 2019 ), small-scale, site-specific technologies ( Choi et al., 2021 ), and LID solutions ( Koc et al., 2021 ). A similar budget-oriented investigation has shown to be effective even at a larger scale ( Caprario et al., 2022 ). Finally, the introduction of new indicators, such as the recreational value, has the potential to more appropriately define the benefit of green solutions for citizens ( Skrydstrup et al., 2022 ).

Thematic masterplans can be more accessible to administrators and investors than spatial planning and flood zoning, connecting context-specific vulnerabilities to the whole urban system across scales. These cases are the product of both the theoretical modelling and the policy evaluation. This is the case for locally defined urban-wide interventions, such as renovating large portions of a city's underground water disposal system, and investments, such as the case of urban development in flood-prone areas ( Löwe et al., 2017 ; Bamrungkhul & Tanaka, 2022 ).

Innovation and revisioning of common practices

Traditional and existing practices that do not consider climate change as a critical aspect in mid-long-term planning could be exposed to greater risk and especially in areas prone to flooding. While enhancing water retention and flood risk reduction with land planning is commonly considered a fine solution, revisioning and development of new building codes and standards based on local context are often more effective and more applicable. As such, strengthening disaster preparedness for flooding events must be applied in pre-disaster assessment, prevention, and mitigation, and in post-disaster scenarios with effective response, recovery, rehabilitation, and reconstruction actions ( United Nations 2015 ; UNISDR 2015 , IPCC, 2022 ). This criterion was the second most frequent (51.5%).

Most of the theoretical models were defined at the urban scale. A simple approach in renovating existing administrative toolkits is overriding unreliable processes that could bias the decision recommendation. This can be done just by highlighting the critical limitations of current technologies and imposing a call for renovation ( Choi et al., 2021 ), or by proposing and verifying new flood risk prioritization methodologies ( da Silva et al., 2021 ). A second approach is to identify weaknesses in current spatial planning, firstly by imposing a conservative land use control in flood-prone areas by testing local resilience in various hazardous scenarios ( Mustafa et al., 2018 ), or by using integrated large-scale tools, such as compensation of urban peak runoff by local storage, to limit unregulated urban development ( Akter et al., 2018 ). Afterward, failing links can be patched by redefining building codes based on simulations of building components ( Ghoneim et al., 2022 ) and by allowing combined infrastructural and blue-green ( Miguez & Veról, 2017 ) and LID solutions ( Hua et al., 2020 ). The mobility system is often found as a crucible of critical nodes, and those can be identified by graphs representative of the street network and traffic volume ( Abenayake et al., 2022 ). As a product of modelling, guidelines can inform new building codes across scales and can address different stakeholders.

Policy evaluation exposed the need for more balanced power symmetry between the different fields of studies behind the formulation of planning tools. A dominant engineering resilience discourse could affect the result in a closed decision-making process, weakening proposed solutions ( Vitale & Meijerink, 2021 ). Operatively, this heterogeneity of approach should be obtained both in practitioners, as in trained planners and designers specialized in indigenous conditions and peculiarities ( Anshu & Firduai, 2019 ), and in data analysis based on risk awareness Key Performance Indicators (KPIs) ( Rubinato et al ., 2019 ; Mielby & Henriksen, 2020 ; Elsharqawy et al ., 2022 ). Theoretical modelling informed by local policies is crucial in strengthening land use planning. These are relevant in outputting both short-term measures for minimizing risk and long-term scenarios ( Yu et al ., 2021 ), and in multi-scale analysis, by adopting an ecological urban analysis ( Barbarossa et al ., 2018 ) or by using large-scale flood zoning to provide correspondence to local adaptation solutions ( Löwe et al ., 2017 ).

Reducing maladaptive actions and practices

Current flood mitigation policies are likely to be maladaptive due to unintended consequences that undermine the effectiveness of the interventions in the long term. Isolated practices can quickly cover short-term necessities and distress but they can have negative impacts in the long run. Integrated flood risk management, as a systemic broad approach that envelopes the infrastructure, the technology advance, the management behaviour, and the risk transfer, could increase climatic resilience and flood risk management ( United Nations 2015 ; UNISDR 2015 ; Mai et al., 2020 , IPCC, 2022 ). However, these criteria were not commonly found in the analyzed body of literature (27.3%).

Theoretical models that focus on analyzing maladaptive practices and interpreting weaknesses in the adaptation strategies lean mostly on the urban scale, leveraging urban morphology for defining operative measures. Some research opted to analyze why LID solutions were not performing as well as previous estimates envisioned. Coupled systems, i.e., integrating grey infrastructure with LID and green solutions, perform better in the long term, albeit showing slightly lower performance to the most extreme events than traditional grey infrastructure. Generally, coupled systems with decentralization seem to provide the best performance in a trade-off among economic costs, hydraulic reliability, and technological and operational resilience ( Wang et al., 2022 ). Because it is difficult to measure the negative impact of grey infrastructure and the positive benefits of green solutions to the environment, planners typically underestimate both by a large margin. Grey infrastructure usually possesses better protection standards in reducing inundation risks associated with the low return period events but has a high level of negative impact on ecology and such negative impact is very difficult to quantify ( Hu et al., 2019 ). Spatial planning has proven detrimental for allocating mitigation and adaptation solutions when coming from analyses not holistically conducted. Urban density needs to be modelled not exclusively from a physical point of view, especially in large urban-natural areas, where rapid urbanization takes place ( Mansur et al., 2016 ), or in cities with degraded soils ( Mustafa et al., 2018 ), and with overexposed public assets that needed to be relocated ( Ghoneim et al., 2022 ).

At the regional level, the main criticism of flood risk management policies was their given nature as a reactive practice. Hence, a more proactive approach that includes the integration of land use planning and flood management is strongly recommended by some ( Rubinato et al., 2019 ; Elsharqawy et al., 2022 ). On top of this, some research stated how solutions like water storage reservoirs were offered as innovative, but remained the task of hydraulic engineers, thereby limiting the interactions with and input from other potential actors who have access to it only through external export remarks. In this regard, authorities are exposed to not being correctly equipped to integrate environmental issues with old expertise and responsibilities ( Vitale & Meijerink, 2021 ). On the end of the spectrum, others featured, through examples, the apathy and laxity of local authorities in urban management and governance practices. This corresponded, again, to flawed land use planning and weak environmental protection, undermining the effectiveness of any solution aimed at making cities resilient ( Anshu & Firduai, 2019 ).

Citizen awareness and empowerment

Reducing the risk areas can be achieved by directly involving the stakeholders as the active part in the planning process, requiring an all-of-society engagement and partnership. A common approach is devoting a share of damage prevention to citizens, which need to be aware of not only the risk of flooding and its potential consequences, but also of the possibility, effectiveness, and cost of private precautionary measures ( Grothmann & Reusswig, 2006 ). In practice, awareness of policies and measures on climate change mitigation, adaptation, impact reduction and more importantly strengthening early warning systems can lower the vulnerability and loss of lives. A more direct approach is the concept of citizen science, where the citizens act as living, direct sensors that could inform the community at large via data mining systems or direct opinion-oriented strategies. Finally, in contrast to traditional planning, the absence of risk diagrams does not imply the absence of risks within a region. Research that eludes human sensible vulnerability and adaptation behavior incurs the risk of bias ( United Nations 2015 ; UNISDR 2015 ; Njue et al., 2019 ; IPCC, 2022 ). Similarly, to the 4.4 criteria, citizen awareness and empowerment wasn't usually a discussed topic (27.3%).

Regarding theoretical modelling, city level is the main scale of analysis. Empowerment can be obtained in flood modelling by revisioning the weights that are put on human assets. This can be done by involving citizens in the weighting process for MCDM analyses and assessment ( Koop et al., 2018 ; Charlotte et al., 2020 ; da Silva et al. , 2021 ). Inhabitants bring a very peculiar and refined sensitivity to flooding, otherwise unobtainable ( Akter et al., 2018 ). If not directly confronted for participation and coordination at neighbourhood scale, citizens could prove distrusting and fall off model predictions ( Ahmed et al., 2019 ), resulting in lost opportunities to enrich models with data that reflects investments desires in small private properties ( Barbarossa et al., 2018 ).

Policies at the regional scale address the governance in regard to land use, but proactively by using early warning systems and water-sensitive urban design engagement. Communities need to be involved and communicate their specific interests, while stakeholders have the role of providing a better understanding of what causes pluvial and fluvial flooding in urban areas, identifying different techniques to be incorporated within urban planning ( Rubinato et al., 2019 ; Elsharqawy et al., 2022 ).

Human life and well-being

Flooding risk is often associated with marginalized communities, peripheral urban areas, and lower income areas. Flooding damage to critical infrastructure usually cascades into risks to safety and well-being of already weakened neighbourhoods. Addressing water services, from runoff retention to stormwater disposal, can lead to promoting human health and well-being while limiting exposure. This phenomenon is accentuated by the uneven distribution of physical assets or intrinsic frailty of urban morphology ( United Nations 2015 ; UNISDR 2015 ; De Risi et al., 2020 ; IPCC, 2022 ). This theme was originally thought to be a matter mostly of policy analysis. Interestingly, only theoretical modelling tackled anthropic well-being as a direct objective. While we observed a horizontal interest regarding human welfare and exposure reduction, it was never explicitly stated as one of the main focal points. Our impression is that risk to human life is not out of the spotlight, rather is a given topic and not to be put on the discussion. Overall, human well-being was the least common topic (18.2%, 6 papers).

In theoretical modelling, people's vulnerability and exposure are the core weights of the analyses at both urban and regional scales. The introduction of social KPIs can proxy for ecological and economic variables. In dense urban contexts where the deterioration of natural capital is a prime criticality, ‘human welfare’ can help us to better understand the sustainability of new blue-green infrastructure ( Ahmed et al., 2019 ). ‘Community resilience’ can help in LID integration in residential and commercial areas ( Koc et al., 2021 ). Introducing social KPI can make traditional risk mapping more sensitive to local characteristics, especially in homogeneous morphological areas at various scales that usually do not represent the real perceived flooding risk ( Mansur et al., 2016 ; Caprario et al., 2022 ; Liu et al., 2022 ). Apart from KPI, modelling on people's vulnerability can be appropriate for a particular category of people, such as hospital patients, that need special care in case of flooding events. In the case of hospital patients, an emergency transportation model based on the street network was developed in the case of evacuation to nearby urban facilities ( Yazdani et al., 2022 ).

Biodiversity and ecosystem services

Urban restoration and development can easily affect biodiversity and ecosystem services, which in turn influence anthropic services. There is substantial literature supporting the positive psychological and physiological effects on human health of exposure to greenness and natural environment. A conservative natural resources management while integrating these resources in traditional planning could productively contribute to risk reduction and to lowering recovery time ( United Nations 2015 ; UNISDR 2015 ; Sutton-Grier & Sandifer, 2019 ; IPCC, 2022 ). Biodiversity was mostly discussed at the regional scale, while the fewer cases that focused on the urban scale viewed biodiversity as a means to simplify and streamline adaptation, without direct concern for the natural stakeholders. This criterion was the third less frequent (24.2%).

The relationship between urban and natural systems can be analyzed by theoretical models in different ways. One approach, in spatial planning, is to appropriately weigh built-up areas and green areas to give the latter more relevance, by adopting specific ecological KPI, such as greenhouse gas emissions and groundwater recharge potential. This facilitates the preservation and enrichment of the inmost ecosystem values, balancing man-made and natural features ( Barbarossa et al., 2018 ; Ahmed et al., 2019 ; Koc et al., 2021 ). At the regional scale, not considering ecologic services could severely underestimate the role that ecosystems play in modulating both the hazardous events and the condition for vulnerability, undermining the mitigation strategies. This is the case for large green areas, such as the Amazon Delta Estuary ( Mansur et al., 2016 ), regional urban watershed management, and the Sponge Cities ( Wanghe et al., 2022 ), regional parks development ( Ghoneim et al., 2022 ).

Amidst the policy analyses, water management can be a way to help foster biodiversity if ecosystem services are taken into account while planning. Stakeholders with strong environmental emphasis can account for the prosperity of natural life, and are especially important for city mitigation strategies and infrastructure development ( Rubinato et al., 2019 ; Elsharqawy et al., 2022 ).

This study illustrates and gives insight into how new theoretical models, policies and practices for urban flood risk management could be developed for effectively reducing the increasing risk derived from climate change. Seven sustainability performance criteria were defined from interpreting the directives and findings of the Sixth IPCC, the SDG, and the 2015 Sendai Framework. Each criterion followed a path of inquiry to understand how current research is following international objectives, what works best, and what is still lacking.

We defined several correlations between the field of study of the analyses, the scale, the objective, and the sustainable performance criteria. We applied the Pearson's Coefficient with Boolean values for each analyzed variable. Regional scale is strongly correlated ( ρ = 0.7536) to ecology, while urban flooding analysis is a topic that is rarely discussed from an ecological perspective ( ρ = −0.6196). Generally, the two scales of analysis are mutually exclusive ( ρ = −0.7536), indicating a difficulty in dialogue at different levels. Among the field of studies, most variables show no strong correlations, meaning an overall homogeneity. A moderate direct correlation between economy, climate, and IT ( ρ = 0.5601, ρ = 0.5316) shows that they are usually tied, while economy bears a correlation to humanities and political science. The only moderate correlation that comes from the objective is the opposing trend from theoretical modelling and policy evaluations ( ρ = −0.6124), as most studies do not use a hybrid approach in analyzing risk management. From the sustainable performance, a moderate negative correlation exists between implementation feasibilities and humanities ( ρ = −0.3983), showing a possible example of missing expertise in tackling human acceptability. Moreover, a moderate negative trend is shown in biodiversity and urban scale ( ρ = −0.4014), as most ecological analyses are conducted at a larger scale ( ρ = 0.4581). Operating at a lower scale could be insightful for addressing biodiversity in a more holistic manner. Finally, the reduction of maladaptive practices is mostly not a matter of theoretical modelling ( ρ = −0.4743) and not put side by side with the feasibility of implementation ( ρ = −0.5610), potentially being limited to just economic analysis ( ρ = 0.4841).

The limitations are as follows. The results come from searching papers that explicitly express a correlation to urban design. A different selection could give an alternative meaning to the same sustainability criteria. Moreover, the synthesis of the international directives is intentionally overlapping, but it could provide misinterpretations. A different set of criteria, or reports, could influence the perception of sustainable urban flooding risk.

Acceptability and feasibility of implementation are the main goals for conceptual frameworks that tackle urban flooding risk (63.6%). Mitigation and adaptation strategies are already being developed and effective measures exist. Instead of developing or optimizing new LID or green solutions, administrators should focus on streamlining and simplifying the adaptation process of existing solutions in development agendas.

For implementing LID and green solutions in urbanized contexts, administrators should give appropriate criteria to socio-economic aspects and to the environmental response so as to increase their appeal, as this influences their overall effectiveness.

LID and resilience-based solutions are usually the most competitive designs in term of sustainability and long-term efficiency, while traditional resistance-based solutions could still be considered the better solution against extreme phenomena.

Clearness and openness of data should be prioritized while tackling data representation, given that a fairer state-of-the-art picture could help different stakeholders understand and participate in designing and verifying the mitigation solutions. GIS-based models are the most common for data visualization, proving to be effective and flexible. Citizens should be brought closer to the development of new tools for tackling urban flooding, as their actions, role and opinions are critical for both acquiring data and accepting the adaptation solutions.

Land use planning is often the most effective solution for flood risk reduction, in both developed areas and where scarcity of resources is critical. Flood zoning should be prioritized over other solutions, even green ones, as a common administrative framework can actively produce linear long-term stability. Developing new models that innovate on existing building codes and urban planning should be one of the main objectives.

While most of the theoretical models are developed at the urban scale, there is often a lack of contextuality coming from the difficulties of tying together problems coming from different scales. Policies should aim to ease dialogue at different levels and conceptual frameworks should be oriented in operating both at large and micro scale. Integrating hydrological modelling, MCDM criteria, and graph theory could bridge the gap of scale by adopting context-specific parameters.

The development of a theoretical model and urban policy should always be oriented to a holistic approach, where physical vulnerabilities are put side-by-side with social, economic, environmental, and cultural vulnerabilities. A more balanced power symmetry between different fields of study should be achieved when formulating planning tools.

Biodiversity is still in most cases used as a means for increasing the likeability and feasibility of implementation of green solutions. While the benefits of living alongside a natural environment is recognized, natural and animal stakeholders don't appear as a main objective in most models and policies. Administrations that opt to not consider ecosystem services should follow a strictly conservative approach while trying to be more inclusive of natural stakeholders as cities become more sustainable and liveable.

The research by G.O. is funded by the PNRR PhD programme. The research by M.C. takes place within the framework of the RTDA-PON Green Research.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.

Affiliations

ISSN 1366-7017 EISSN 1996-9759
Open Access
Collections
Subscriptions
Subscribe to Open
Editorial Services
Rights and Permissions
Sign Up for Our Mailing List
IWA Publishing
Republic – Export Building, Units 1.04 & 1.05
1 Clove Crescent
London, E14 2BA, UK
Telephone: +44 208 054 8208
Fax: +44 207 654 5555
IWAPublishing.com
IWA-network.org
IWA-connect.org
Cookie Policy
Terms & Conditions
Get Adobe Acrobat Reader

This Feature Is Available To Subscribers Only

Paper Information

Paper Submission

Journal Information

About This Journal
Editorial Board
Current Issue
Author Guidelines

Architecture Research

p-ISSN: 2168-507X e-ISSN: 2168-5088

2012; 2(6): 115-121

doi: 10.5923/j.arch.20120206.01

Urban Flood Management – A Case Study of Chennai City

Ar. K. Lavanya

Crescent School of Architecture, B.S.Abdur Rahman University, Chennai, 600073, India

In the recent decades, Indian cities are witnessing devastating floods more often due to heavy rainfall, cyclones, etc., Though Tamil Nadu is not under flood risk prone zone as mapped by meteorological department (New Delhi), within the local body there are few low-lying areas which are susceptible to inundation which also depends mainly on the developments near major drainage systems, encroachment of water bodies, inability of major canals to carry heavy rains, overflowing reservoirs. Chennai, one of the fast growing metros is likely affected by the lack of drainage mainly due to uncontrolled developments of concrete spaces, encroachment of major drainage channels, shrinking of marshlands, etc,. Though Urbanization, the vital factor of response for the flood risks is coupled with the climatic variability and ecological imbalances. The paper discusses causative factors responsible for flood risks in Chennai, the immediate need for proper flood risk reduction and management strategies.

Keywords: Urban Flood, Flood Management, Flood Risk, Chennai Flood

Cite this paper: Ar. K. Lavanya, "Urban Flood Management – A Case Study of Chennai City", Architecture Research , Vol. 2 No. 6, 2012, pp. 115-121. doi: 10.5923/j.arch.20120206.01.

Article Outline

1. prologue of chennai, 1.1. growth of chennai city, 2. history of chennai floods, 2.1. causes of chennai floods ( table 1 ), 2.2. direct factors, 2.2.1. increase in rainfall, 2.2.2. urbanization, 2.2.3. topography, 2.3. indirect factors, 2.3.1. inadequate and poor drainage systems, 2.3.2. solid waste disposal & vehicle parking on roads, 3. master plan & flood mitigation in chennai – a quick review, 4. findings & recommendations, 5. sequence of actions to hurl out from the flood hazard (both structurally & non-structurally).

Evaluation of urban flood adaptability based on the InVEST model and GIS: A case study of New York City, USA

Original Paper
Published: 08 May 2024

Cite this article

Song Yao ORCID: orcid.org/0000-0002-7579-8585 1 , 2 ,
Guoping Huang 3 &
Zihan Chen 4

23 Accesses

Explore all metrics

Flood risk has become a serious challenge for many cities, including New York City (NYC). Evaluating urban flood adaptability evaluation is crucial for regulating storm and rain risks. In this study, we proposed an integrated framework based on the Integrated Valuation of Ecosystem Services (InVEST) model and Geographic Information System (GIS). First, the InVEST model was used to assess the water yield, soil conservation, and water quality purification in NYC. Second, the entropy weighting method was employed to determine the weights of indicators for computing the flood adaptability evaluation (FAE). Third, a spatial correlation of FAE was conducted and finally delineated the flood adaptability zones in GIS. The results show that: (1) The spatial distribution of FAE was uneven, high in the surrounding area and low in the center. (2) The Moran's I for FAE was 0.644, showing an overall positive spatial relationship of FAE. High-scoring clusters were located in the southeastern area while low-scoring clusters were in the northern, central, and southwestern areas. (3) The FAE in NYC can be divided into five categories: the lower-adapted zone (0.22–0.27), low-adapted zone (0.28–0.31), medium-adapted zone (0.32–0.36), high-adapted zone (0.37–0.43) and higher-adapted zone (0.44–0.50). These results of the study can provide evidence and recommendations for flood risk management in NYC and other cities worldwide.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Flooding trends and their impacts on coastal communities of Western Cape Province, South Africa

Can geomorphic flood descriptors coupled with machine learning models enhance in quantifying flood risks over data-scarce catchments? Development of a hybrid framework for Ganga basin (India)

Coastal Flood Induced Salinity Intrusion Risk Assessment Using a Spatial Multi-criteria Approach in the South-Western Bangladesh

Data availability statement.

All the data used for the study appear in Sect. 2.2 of the submitted article.

Adikari Y, Osti R, Noro T (2010) Flood-related disaster vulnerability: an impending crisis of megacities in Asia. J Flood Risk Manag 3:185–191. https://doi.org/10.1111/j.1753-318X.2010.01068.x

Article Google Scholar

Allen RG, Pruitt WO, Raes D et al (2005) Estimating evaporation from bare soil and the crop coefficient for the initial period using common soils information. J Irrig Drain Eng 131:14–23. https://doi.org/10.1061/(ASCE)0733-9437(2005)131:1(14)

Anselin L (1995) Local indicators of spatial association—LISA. Geogr Anal 27:93–115. https://doi.org/10.1111/j.1538-4632.1995.tb00338.x

Arup (2023) Arup GlobalSponge Cities Snapshot. https://www.arup.com/perspectives/publications/research/section/global-sponge-cities-snapshot . Accessed on 19 March 2023

Atlanta Regional Commission (2016) Edition of the Georgia Stormwater Management Manual Volumes 1 & 2. https://atlantaregional.org/natural-resources/water/georgia-stormwater-management-manual/ . Accessed on 19 March 2023

Boruff BJ (2009) Environmental hazards: assessing risk and reducing disasters, 5th Edition – By Keith Smith and David N. Petley. Geogr Res 47:454–455. https://doi.org/10.1111/j.1745-5871.2009.00611.x

Boulange J, Hanasaki N, Yamazaki D, Pokhrel Y (2021) Role of dams in reducing global flood exposure under climate change. Nat Commun 12:417. https://doi.org/10.1038/s41467-020-20704-0

Article CAS Google Scholar

Cabrera JS, Lee HS (2020) Flood risk assessment for Davao Oriental in the Philippines using geographic information system-based multi-criteria analysis and the maximum entropy model. J Flood Risk Manag 13:e12607. https://doi.org/10.1111/jfr3.12607

Cai S, Fan J, Yang W (2021) Flooding risk assessment and analysis based on GIS and the TFN-AHP method: a case study of Chongqing, China. Atmosphere 12:623. https://doi.org/10.3390/atmos12050623

Chen Y, Zhou H, Zhang H et al (2015) Urban flood risk warning under rapid urbanization. Environ Res 139:3–10. https://doi.org/10.1016/j.envres.2015.02.028

Chen Z, Mo C, Chen R, Peng B (2022) Assessment and zoning of rain and flood adaptability in the construction demonstration area of Sponge City in Changde City. J Natl Resources 37:2195–2208. https://doi.org/10.31497/zrzyxb.20220818 . ( in Chinese )

Diniz-Filho JAF, Bini LM, Hawkins BA (2003) Spatial autocorrelation and red herrings in geographical ecology. Glob Ecol Biogeogr 12:53–64. https://doi.org/10.1046/j.1466-822X.2003.00322.x

District of Columbia, Department of Environment (2020) Stormwater Management Guide Book. https://doee.dc.gov/swguidebook . Accessed on 19 March 2023

Donohue RJ, Roderick ML, McVicar TR (2012) Roots, storms and soil pores: Incorporating key ecohydrological processes into Budyko’s hydrological model. J Hydrol 436–437:35–50. https://doi.org/10.1016/j.jhydrol.2012.02.033

FAO Soils Portal (2008) Harmonized World Soil Database v1.2. https://www.fao.org/soils-portal/data-hub/soil-maps-and-databases/harmonized-world-soil-database-v12/en/ . Accessed on 19 March 2023

Feng Z, Jin X, Chen T, Wu J (2021) Understanding trade-offs and synergies of ecosystem services to support the decision-making in the Beijing–Tianjin–Hebei region. Land Use Policy 106:105446. https://doi.org/10.1016/j.landusepol.2021.105446

Fletcher TD, Shuster W, Hunt WF et al (2015) SUDS, LID, BMPs, WSUD and more: the evolution and application of terminology surrounding urban drainage. Urban Water J 12:525–542. https://doi.org/10.1080/1573062X.2014.916314

Getis A, Ord JK (2010) The analysis of spatial association by use of distance statistics. Geogr Anal 24:189–206. https://doi.org/10.1111/j.1538-4632.1992.tb00261.x

Goyen AG, Lees SJ, Phillips BC (2012) Analysis of allotment based storage, infiltration and reuse drainage strategies to minimize urbanization effects. Glob Solut Urban Drain 1:17. https://doi.org/10.1061/40644(2002)42

Hallegatte S, Vogt-Schilb A, Bangalore M, Rozenberg J (2017) Unbreakable. World Bank, Washington, DC

Google Scholar

Hammond MJ, Chen AS, Djordjević S et al (2015) Urban flood impact assessment: a state-of-the-art review. Urban Water J 12:14–29. https://doi.org/10.1080/1573062X.2013.857421

Hong H, Panahi M, Shirzadi A et al (2018) Flood susceptibility assessment in Hengfeng area coupling adaptive neuro-fuzzy inference system with genetic algorithm and differential evolution. Sci Total Environ 621:1124–1141. https://doi.org/10.1016/j.scitotenv.2017.10.114

Hu S, Cao M, Liu Q, Zhang T, Qiu H, Liu W, Song J (2014) Comparison of soil conservation functions of InVEST model from different perspectives. Geogr Res 33:2393–2406. https://doi.org/10.11821/dlyj201412016 . ( in Chinese )

Ji J, Chen J (2022) Urban flood resilience assessment using RAGA-PP and KL-TOPSIS model based on PSR framework: a case study of Jiangsu province, China. Water Sci Technol 86:3264–3280. https://doi.org/10.2166/wst.2022.404

Jun C, Ban Y, Li S (2014) Open access to Earth land-cover map. Nature 514:434–434. https://doi.org/10.1038/514434c

Lehner B, Grill G (2013) Global river hydrography and network routing: baseline data and new approaches to study the world’s large river systems. Hydrol Process 27:2171–2186. https://doi.org/10.1002/hyp.9740

Li T, Liu K, Hu S, Bao Y (2014) Evaluation of ecological benefits of soil loss and soil conservation in Qinling Mountains based on InVEST model. Resources Environ the Yangtze River Basin 23:1242–1250. https://doi.org/10.11870/cjlyzyyhj201409009 . ( in Chinese )

Li Q, Wang F, Yu Y et al (2019) Comprehensive performance evaluation of LID practices for the sponge city construction: a case study in Guangxi, China. J Environ Manage 231:10–20. https://doi.org/10.1016/j.jenvman.2018.10.024

Luu C, Von Meding J, Mojtahedi M (2019) Analyzing Vietnam’s national disaster loss database for flood risk assessment using multiple linear regression-TOPSIS. Int J Disaster Risk Reduct 40:101153. https://doi.org/10.1016/j.ijdrr.2019.101153

Lyu H-M, Sun W-J, Shen S-L, Arulrajah A (2018) Flood risk assessment in metro systems of mega-cities using a GIS-based modeling approach. Sci Total Environ 626:1012–1025. https://doi.org/10.1016/j.scitotenv.2018.01.138

Ministry of Water Resources of the People's Republic of China (2018) Announcement of the Ministry of Water Resources on Approving the Issuance of Three Water Conservancy Industry Standards, including the "Guidelines for the Calculation of Soil Loss in Production and Construction Projects". http://www.gov.cn/zhengce/zhengceku/2018-12/31/content_5440136.htm . Accessed on 19 March 2023

Mitchell G (2005) Mapping hazard from urban non-point pollution: a screening model to support sustainable urban drainage planning. J Environ Manage 74:1–9. https://doi.org/10.1016/j.jenvman.2004.08.002

Mojaddadi H, Pradhan B, Nampak H et al (2017) Ensemble machine-learning-based geospatial approach for flood risk assessment using multi-sensor remote-sensing data and GIS. Geomat Nat Haz Risk 8:1080–1102. https://doi.org/10.1080/19475705.2017.1294113

Morison PJ, Brown RR (2011) Understanding the nature of publics and local policy commitment to Water Sensitive Urban Design. Landsc Urban Plan 99:83–92. https://doi.org/10.1016/j.landurbplan.2010.08.019

National Earth System Science Data Center (2023). http://www.geodata.cn/ . Accessed on 19 March 2023).

New York Division of Engineering (2016) New York State Stormwater Management Design Manual. https://www.dec.ny.gov/chemical/29072.html . Accessed on 19 March 2023

Nguyen TT, Ngo HH, Guo W et al (2019) Implementation of a specific urban water management: Sponge City. Sci Total Environ 652:147–162. https://doi.org/10.1016/j.scitotenv.2018.10.168

NYC Emergency Management (2014) NYC'S Risk Landscape: A Guide to Hazard Mitigation. https://a860-gpp.nyc.gov/concern/nyc_government_publications/9306sz780 . Accessed on 19 March 2023

NYC Environmental Protection (2017) The Bluebelt Program. https://www.nyc.gov/site/dep/water/the-bluebelt-program.page . Accessed on 19 March 2023

NYC Environmental Protection (2022) NYC green infrastructure 2021 annual report. https://a860-gpp.nyc.gov/concern/parent/bv73c3028/file_sets/qr46r355g . Accessed on 19 March 2023

NYC Open Data (2013). https://opendata.cityofnewyork.us/ . Accessed on 19 March 2023).

Pour SH, Wahab AKA, Shahid S et al (2020) Low impact development techniques to mitigate the impacts of climate-change-induced urban floods: Current trends, issues and challenges. Sustain Cities Soc 62:102373. https://doi.org/10.1016/j.scs.2020.102373

Pyke C, Warren MP, Johnson T et al (2011) Assessment of low impact development for managing stormwater with changing precipitation due to climate change. Landsc Urban Plan 103:166–173. https://doi.org/10.1016/j.landurbplan.2011.07.006

Rao E, Xiao Y, Ouyang Z, Zheng H (2013) Spatial characteristics of soil conservation service and its impact factors in Hainan Island. Acta Ecol Sin 33:746–755. https://doi.org/10.5846/stxb201203240400 . ( in Chinese )

Rufat S, Botzen WJW (2022) Drivers and dimensions of flood risk perceptions: revealing an implicit selection bias and lessons for communication policies. Glob Environ Chang 73:102465. https://doi.org/10.1016/j.gloenvcha.2022.102465

Shangguan W, Hengl T, Mendes de Jesus J et al (2017) Mapping the global depth to bedrock for land surface modeling. J Adv Model Syst 9:65–88. https://doi.org/10.1002/2016MS000686

Shao Z, Fu H, Li D et al (2019) Remote sensing monitoring of multi-scale watersheds impermeability for urban hydrological evaluation. Remote Sens Environ 232:111338. https://doi.org/10.1016/j.rse.2019.111338

Sharp R, Tallis H T, Ricketts T et al. (2018) InVEST 3.12.0 User’s Guide. https://naturalcapitalproject.stanford.edu/software/invest . Accessed on 26 November 2022

Souissi D, Zouhri L, Hammami S et al (2020) GIS-based MCDM: AHP modeling for flood susceptibility mapping of arid areas, southeastern Tunisia. Geocarto Int 35:991–1017. https://doi.org/10.1080/10106049.2019.1566405

Stefanidis S, Stathis D (2013) Assessment of flood hazard based on natural and anthropogenic factors using analytic hierarchy process (AHP). Nat Hazards 68:569–585. https://doi.org/10.1007/s11069-013-0639-5

Sun S, Zhai J, Li Y et al (2020) Urban waterlogging risk assessment in well-developed region of Eastern China. Phys Chem Earth Parts a/b/c 115:102824. https://doi.org/10.1016/j.pce.2019.102824

Tayyab M, Zhang J, Hussain M et al (2021) GIS-based urban flood resilience assessment using urban flood resilience model: a case study of Peshawar City, Khyber Pakhtunkhwa, Pakistan. Remote Sens 13:1864. https://doi.org/10.3390/rs13101864

Tellman B, Sullivan JA, Kuhn C et al (2021) Satellite imaging reveals increased proportion of population exposed to floods. Nature 596:80–86. https://doi.org/10.1038/s41586-021-03695-w

The Minnesota Stormwater Steering Committee (2013) The Minnesota Stormwater Manual. https://stormwater.pca.state.mn.us/index.php?title=Main_Page . Accessed on 19 March 2023

Thorne CR, Lawson EC, Ozawa C et al (2018) Overcoming uncertainty and barriers to adoption of Blue-Green Infrastructure for urban flood risk management. J Flood Risk Manag 11:S960–S972. https://doi.org/10.1111/jfr3.12218

UNDRR (2020) The Human Cost of Disasters: An Overview of the Last 20 Years (2000–2019). https://www.undrr.org/publication/human-cost-disasters-overview-last-20-years-2000-2019 . Accessed on 13 March 2023

Voyde E, Fassman E, Simcock R (2010) Hydrology of an extensive living roof under sub-tropical climate conditions in Auckland, New Zealand. J Hydrol 394:384–395. https://doi.org/10.1016/j.jhydrol.2010.09.013

Wang H, Ding L, Cheng X, Li N (2015a) Hydrological control index system of urban stormwater management in the United States and its referential significance. J Hydraul Eng 46:1261–1271. https://doi.org/10.1038/s41586-021-03695-w . ( in Chinese )

Wang Z, Lai C, Chen X et al (2015b) Flood hazard risk assessment model based on random forest. J Hydrol 527:1130–1141. https://doi.org/10.1016/j.jhydrol.2015.06.008

Wang Y, Meng F, Liu H et al (2019) Assessing catchment scale flood resilience of urban areas using a grid cell based metric. Water Res 163:114852. https://doi.org/10.1016/j.watres.2019.114852

Wang M, Fang Y, Sweetapple C (2021) Assessing flood resilience of urban drainage system based on a ‘do-nothing’ benchmark. J Environ Manage 288:112472. https://doi.org/10.1016/j.jenvman.2021.112472

Ward PJ, Jongman B, Weiland FS et al (2013) Assessing flood risk at the global scale: model setup, results, and sensitivity. Environ Res Lett 8:044019. https://doi.org/10.1088/1748-9326/8/4/044019

Willems P (2013) Revision of urban drainage design rules after assessment of climate change impacts on precipitation extremes at Uccle, Belgium. J Hydrol 496:166–177. https://doi.org/10.1016/j.jhydrol.2013.05.037

Williams JR, Arnold JG (1997) A system of erosion—sediment yield models. Soil Technol 11:43–55. https://doi.org/10.1016/S0933-3630(96)00114-6

Winsemius HC, Van Beek LPH, Jongman B et al (2013) A framework for global river flood risk assessments. Hydrol Earth Syst Sci 17:1871–1892. https://doi.org/10.5194/hess-17-1871-2013

Wisconsin Department of Natural Resources (2017) Non-Agricultural Revisions to Chapter NR 151, Runoff Management Rule. https://dnr.wi.gov/topic/stormwater/documents/NR151_non-ag_FS.pdf . Accessed on 19 March 2023

Wu Z, Liu X, Liu B, Chu J, Pneg L (2013) Risk assessment of nitrogen and phosphorus loads in hainan island based on InVEST Model. J Trop Crops 34:1791–1797. https://doi.org/10.3969/j.issn.1000-2561.2013.09.029(inChinese)

Xia H, Yuan S, Prishchepov AV (2023) Spatial-temporal heterogeneity of ecosystem service interactions and their social-ecological drivers: implications for spatial planning and management. Resour Conserv Recycl 189:106767. https://doi.org/10.1016/j.resconrec.2022.106767

Xu X, Liu W, Scanlon BR et al (2013) Local and global factors controlling water-energy balances within the Budyko framework. Geophys Res Lett 40:6123–6129. https://doi.org/10.1002/2013GL058324

Xu H, Ma C, Lian J et al (2018) Urban flooding risk assessment based on an integrated k-means cluster algorithm and improved entropy weight method in the region of Haikou, China. J Hydrol 563:975–986. https://doi.org/10.1016/j.jhydrol.2018.06.060

Yang W, Xu K, Lian J et al (2018) Integrated flood vulnerability assessment approach based on TOPSIS and Shannon entropy methods. Ecol Ind 89:269–280. https://doi.org/10.1016/j.ecolind.2018.02.015

Yu K, Li D, Yuan H, Fu W, Qiao Q, Wang S (2015) “Sponge City”: theory and practice. Urban Plan 39:26–36. https://doi.org/10.1181/cpr20150605a . ( in Chinese )

Zhang C, Li W, Zhang B, Liu M (2012) Water Yield of Xitiaoxi River basin based on InVEST Modeling. J Resources Ecol 3:50–54. https://doi.org/10.5814/j.issn.1674-764x.2012.01.008

Zhang K, Shalehy MH, Ezaz GT et al (2022) An integrated flood risk assessment approach based on coupled hydrological-hydraulic modeling and bottom-up hazard vulnerability analysis. Environ Model Softw 148:105279. https://doi.org/10.1016/j.envsoft.2021.105279

Zhao Y, Gong Z, Wang W, Luo K (2014) The comprehensive risk evaluation on rainstorm and flood disaster losses in China mainland from 2004 to 2009: based on the triangular gray correlation theory. Nat Hazards 71:1001–1016. https://doi.org/10.1007/s11069-013-0698-7

Zomer RJ, Xu J, Trabucco A (2022) Version 3 of the global aridity index and potential evapotranspiration database. Sci Data 9:409. https://doi.org/10.1038/s41597-022-01493-1

Download references

Acknowledgements

This research was supported by the National Natural Science Foundation of China (Grant No. 51878593).

This research was funded by the National Natural Science Foundation of China (Grant No. 51878593).

Author information

Authors and affiliations.

College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China

Department of Regional and Urban Planning, Zhejiang University, Hangzhou, 310058, China

Spatial Sciences Institute, USC Dana and David Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, 90089, USA

Guoping Huang

George School, Newtown, PA, 18940, USA

You can also search for this author in PubMed Google Scholar

Contributions

Conceptualization, Song Yao and Zihan Chen; data curation, Song Yao; formal analysis, Song Yao and Zihan Chen; funding acquisition, Guoping Huang; methodology, Song Yao; resources, Guoping Huang; software, Song Yao; supervision, Guoping Huang; validation, Song Yao; visualization, Song Yao; writing—original draft preparation, Song Yao and Zihan Chen; writing—review and editing, Song Yao. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Guoping Huang .

Ethics declarations

Conflict of interest.

The authors declare no conflicts of interest.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 35 KB)

Rights and permissions.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Yao, S., Huang, G. & Chen, Z. Evaluation of urban flood adaptability based on the InVEST model and GIS: A case study of New York City, USA. Nat Hazards (2024). https://doi.org/10.1007/s11069-024-06632-y

Download citation

Received : 24 July 2023

Accepted : 15 April 2024

Published : 08 May 2024

DOI : https://doi.org/10.1007/s11069-024-06632-y

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

Flood adaptability
InVEST model
Water yield
Soil conservation
Water quality purification
New York City
Find a journal
Publish with us
Track your research

Future Strategies

State Case Studies

Federal Review

Management Goals

Holistic Approach to Coastal FRM

CONTENTS ≡

CONTENTS ✕

Coastal Management Program

Shoreline regulations, floodplain management, wetland management, building codes, community planning, stormwater and runoff management, erosion management, climate adaptation initiatives, state management capacity, alternatives to structural mitigation, long-term planning, balance of mitigation and disaster recovery, holistic management approach, new york coastal flood risk management case study.

Policies and Programs

The New York Coastal Management Program , established in 1982, is housed within the New York Department of State’s Office of Planning, Development, and Community Infrastructure . Much of the program’s legislative authority is drawn from the state Waterfront Revitalization of Coastal Areas and Inland Waterways law as well as the Coastal Erosion Hazard Areas law . The program pursues goals related to coastal resources protection and development, local waterfront revitalization, coordination of major activities affecting coastal resources, public awareness of coastal issues, and federal consistency with state coastal management policies. Within New York, the Department of State administers the program and coordinates its implementation in cooperation with the state Department of Environmental Conservation as well as other state agencies.

Coastal program boundaries extend along the coast of Long Island, New York City, Hudson River estuary, both Great Lakes that border New York, and the Niagara River. Specific landward boundaries of the coastal program vary by region and locality due to initial delineation proposals from local government agencies. All barrier and coastal islands on Long Island are included within program boundaries along with areas 1,000 feet landward of the shoreline, extending further in some cases. The New York City program boundary generally extends 500 to 1,000 feet inland from the shoreline, with select areas along major tributaries also extending further. Within the Hudson River Valley the landward boundary is generally 1,000 feet but may extend up to 10,000 feet in areas that possess high aesthetic, agricultural, or recreational value. In the Great Lakes region the boundary is also generally 1,000 feet, though urbanized areas or transportation infrastructure parallel to shore limit the boundary to 500 feet or less in some cases.

Coastal management program consistency reviews require federal actions in the state coastal zone to be consistent with the enforceable policies of the state program or the policies of an approved local waterfront revitalization program. The program also contains provisions to ensure consistency of state actions in coastal areas. Of the 44 coastal management program enforceable policies in New York, seven specifically address flooding and erosion hazards. These policies touch on a number of aspects of coastal flood risk management including the siting of buildings in coastal areas to minimize risk to property and human lives, protection of natural features that mitigate coastal flood risk, construction of erosion control structures to to meet long-term needs, prevention of flood level increases due to coastal activities or development, prevention of coastal mining or dredging from interfering with natural coastal processes, use of public funds for erosion protection structures, and use of non-structural mitigation measures when possible. Additional enforceable policies address coastal development, fish and wildlife resources, public access, recreation, historic and scenic resources, agricultural lands, energy and ice management, water and air resources, and wetlands management.

At the state level, aspects of New York’s Environmental Conservation Law , Local Waterfront Revitalization Program , and State Environmental Quality Review permitting program influence coastal zoning and development decisions. Article 34 of the Environmental Conservation Law requires the identification of coastal erosion hazard areas and rates of recession of coastal lands. Shoreline setbacks must then be implemented at a distance that is sufficient to minimize damage from erosion. Article 36 of the Environmental Conservation Law , the state Flood Plain Management Act, also addresses coastal hazards, requiring walled and roofed buildings to be sited landward of mean high tide and prohibiting mobile homes within coastal high hazard areas, among other restrictions. Article 15, Water Resources Law , regulates the placement of coastal structures such as docks or piers and also addresses the placement of fill in coastal areas. Together these elements of the Environmental Conservation Law provide much of the legal basis for zoning decisions that can affect coastal flood risk at the municipal and local level.

Participation in the Local Waterfront Revitalization Program can also influence a local government’s coastal zoning decisions. In the process of preparing and adopting a revitalization program, local governments provide a more specific implementation of the state Coastal Management Program, taking advantage of local regulatory powers such as zoning ordinances and site plan review. Upon approval of a Local Waterfront Revitalization Program, state actions must then be consistent with the local program. In this way the enforceable policies of the Coastal Management Program, including those that relate to coastal flooding and erosion, are incorporated into local zoning decisions. Elements of enforceable policies are also incorporated into environmental permitting through the State Environmental Quality Review Program, which requires state agencies and local governments to prepare an environmental impact statement for any action that may have a significant impact on the environment. If an action in a coastal area requires the preparation of an impact statement, it must also be determined that the action is consistent with any relevant coastal enforceable policies. Consistency reviews must also be applied to NYS SEQRA type 1 actions as well as unlisted actions.

Floodplain management activities within New York are primarily conducted through the National Flood Insurance Program . Any regulations developed by the state must be at a minimum as strict as those prescribed by FEMA. Beyond the state level communities may adopt more restrictive floodplain management regulations. Within the state, local communities largely regulate development within federally designated Special Flood Hazard Areas, with state assistance provided by the New York State Department of Environmental Conservation. Local development permits govern private development within floodplains as well as development by a county, city, town, village, school district, or public improvement district, as specified in the state Environmental Conservation Law.

State standards for floodplain development permits in all designated special flood hazard areas require adequate anchorage and use of flood resistant material for all new construction and substantial improvement to existing structures. Utilities must also be designed in a manner that minimizes or eliminates risk of damage or failure during flood events. In areas where base flood elevation data exists, new construction or substantially improved residential structures must have the lowest floor at two feet above the BFE, including basements and cellars. Nonresidential structures may employ floodproofing to provide protection. Any enclosed areas below the base flood elevation must be designed to allow for the equalization of hydrostatic forces on exterior walls during a flood event. If no base flood elevation has been determined, new construction or substantially improved residential structures must be elevated above grade to the depth specified on the corresponding flood insurance rate map or two feet if no number is specified, with nonresidential structures again able to employ floodproofing measures. All state agency activities, whether directly undertaken, funded, or approved by an agency, must also be evaluated in terms of significant environmental impacts under the State Environmental Quality Review program, which includes a substantial increase in flooding as a criteria of significance. An environmental impact statement must be prepared if it is determined that an action may have a potential significant adverse impact.

All structures must be located landward of mean high tide levels within coastal high hazard areas, and all new construction or substantially improved structures must be elevated on pilings or columns so that the bottom of the lowest horizontal structural member of the lowest flood is elevated to or above the BFE. Pilings or column foundations must be adequately anchored, and fill is prohibited for use as a structural support for any new structure or substantial improvement. Space below the lowest floor may not contain obstructions to flood flows or otherwise be enclosed with non-breakaway walls. Any such space below the lowest structural floor may not be used for human habitation. New development or substantial improvement to structures must also not affect sand dunes in any way that increases potential flood damages.

The New York State Department of Environmental Conservation is also responsible for wetland management within the state. Statutory authority for wetland regulations stems from the Tidal Wetlands Act and Freshwater Wetlands Act , part of the larger state Environmental Conservation Law . Wetlands and wetland regulations are divided into either tidal or freshwater, and wetlands are further classified within each category. State wetland inventories containing information on delineated areas and classifications are made available for public use as part of the state wetland mapping program. Activities within wetland areas are regulated through a permit system.

Tidal wetlands regulations are designed to allow uses of wetlands that are compatible with the preservation, protection, and enhancement of ecological values including flood protection and storm control. Development restrictions require that all buildings and structures in excess of 100 square feet be located a minimum of 75 feet landward from tidal wetland edges, with less stringent setbacks in place for buildings located within New York City. Similar setback requirements exist for impervious surfaces exceeding 500 square feet. On-site sewage systems must have a setback of at least 100 feet, and a minimum of two feet of soil must be between the bottom of a system and the seasonal high groundwater level.

Permit standards for activities within tidal wetlands require that any proposed activity be compatible with the overall state policy of preserving and protecting tidal wetlands, and as such any activity may not cause any undue adverse impact on the ecological value of an affected wetland area or any adjoining areas. Standards also require that any activity within tidal wetlands be compatible with public health and welfare, be reasonable and necessary, and take into account both alternative actions and the necessity of water access or dependence for the proposed action. The state also publishes compatible use guidelines for activities within wetlands based on wetland type. If any activity is presumed to be incompatible with state tidal wetland use guidelines, an applicant must overcome the presumption of incompatible use and demonstrate that the activity is compatible with the preservation, protection, and enhancement of wetland values. If a use is specifically listed as incompatible within guidelines the use is then prohibited. Permitted activities in areas adjacent to tidal wetlands must also be compatible with public health and welfare, have no undue adverse impact on wetland ecological values, and comply with use guidelines.

State flood-resistant construction requirements are listed in the International Residential Code as adopted by New York State . Regulations apply to new residential buildings and structures located fully or partially within flood hazard areas as well as any substantially improved or restored structures within flood hazard areas. Construction requirements are based on the design flood elevation, which at a minimum must be the higher of either the peak elevation of a 1% annual chance flood event or the elevation of the design flood event as adopted on community flood hazard maps. Structures within flood hazard areas must generally be designed and anchored to resist the flood forces associated with the design flood elevation, and methods and practices to minimize flood damage must also be employed.

For the purposes of determining appropriate structural elevations, the lowest floor of a structure is defined as the lowest floor of any enclosed area, including basements. Within flood hazard areas not subject to high-velocity wave action, structures must have the lowest floor elevated to two feet above the base flood elevation or design flood elevation, whichever is higher. Utility systems must also be elevated to this standard. If no depth number is specified structures must be elevated not less than three feet above the highest adjacent grade. Any enclosed area below the design flood elevation must be used only for building access, parking, or storage and must contain flood openings sufficient to equalize hydrostatic forces on exterior walls.

For buildings and structures located in coastal high-hazard areas, including both V zones and Coastal A zones, the lowest floor must be elevated so that the lowest horizontal structural members are elevated to either the base flood elevation plus two feet or the design flood elevation, whichever is higher. Any walls below the design flood elevation must be designed to break away without causing damage to the elevated portion of the building, and again may be used only for parking, building access, or storage. Structures must be elevated using adequately anchored pilings or columns, with select exceptions in Coastal A zones. The use of fill for structural support and any construction of basement floors below grade are prohibited. New buildings and any substantially improved structures in coastal high-hazard areas must be located landward of the mean high tide, and any alteration of sand dunes must not result in any increased potential for flood damage in surrounding areas.

Planning at the state level is guided by the State Smart Growth Public Infrastructure Policy Act , an article within the larger Environmental Conservation Law. The act outlines criteria for public infrastructure projects that are either approved, directly undertaken, or financed by state infrastructure agencies. Among these criteria is a requirement that future public infrastructure projects mitigate future climate risk due to sea level rise, storm surge, or flood events based on available data or predictions of future extreme weather conditions. This and other criteria must be met to a practicable extent, and if deemed impracticable an agency must provide a detailed statement of justification.

The Office of Planning, Development, and Community Infrastructure within the Department of State administers several programs involved in community planning. The New York Rising Community Reconstruction Program provides recovery and resiliency planning assistance to communities affected by severe storm events, including hurricanes Sandy and Irene. The program is operated through the Governor’s Office of Storm Recovery and involves collaborations between state teams and community members to develop reconstruction plans and strategies to increase physical, economic, and social resilience, often including elements related to mitigating future flood risk. State Waterfront Revitalization Programs are also involved in community redevelopment planning. These programs establish land and water use policies and identify revitalization projects at a local level to allow for sustainable use of coastal resources, including planning for coastal flood risk resilience. Local Waterfront Revitalization Programs can also be a conduit for technical assistance and grant funding to facilitate climate change adaptation through the New York State Environmental Protection Fund grant program , a permanent fund addressing a broad range of environmental and community development needs.

The majority of stormwater regulations in New York focus on water quality issues as part of the State Pollutant Discharge Elimination System , a state program that has been approved by the EPA as part of the National Pollutant Discharge Elimination System . The program regulates point source discharges to both groundwater and surface waters and also conducts permitting for stormwater runoff from industrial activities, municipal sewer systems in urbanized areas, and construction activities. The program is administered by the state Department of Environmental Conservation.

While water quality is the focus of stormwater programs within the state, the state stormwater design manual lists best practices that include measures to reduce overbank flooding in order to maintain pre-development peak discharge rates for two and ten-year frequency storm events following development. The design manual also addresses risks due to potential floodplain expansion following development as well as green infrastructure strategies. These green infrastructure strategies are presented as a means to meet runoff reduction standards, which require that post-development conditions replicate pre-development hydrology. Stormwater projects, like all activities undertaken, funded, or approved by state agencies, are also under the purview of the State Environmental Quality Review Act , which requires preparation of an environmental impact statement if a project is likely to cause a significant increase in flood risk.

Coastal erosion in New York is managed within designated coastal erosion hazard areas. Areas are designated as per requirements of the state Coastal Erosion Hazard Areas Act , part of the larger state Environmental Conservation Law. Regulatory programs within identified hazard areas are administered by the state Department of Environmental Conservation. Programs may also be established at a local level if minimum state standards and criteria are met. The objectives of the program, as outlined in the state administrative code, are to ensure that activities in coastal areas subject to flooding minimize or prevent damage to property and natural features, that structures are placed at a safe distance from hazard areas to prevent premature damage to both structures and natural features, that public investment likely to encourage development within erosion hazard areas is restricted, and that publicly financed structures are only used when necessary and effective. Sections of the state administrative code also describe the erosion protection functions of natural protective features in order to guide the review of permit applications.

Coastal erosion management permits are required for any regulated activity conducted within a designated coastal erosion hazard area. Coastal erosion management permit standards require that any proposed activity be reasonable and necessary, with consideration of proposed alternatives, and that an activity will not likely lead to a measurable increase in erosion at the proposed site or other locations. Standards also require activities to prevent or minimize adverse effects to natural protective features, existing erosion protection structures, or natural resources such as fish and wildlife habitat.

Regulations within structural hazard areas allow for placement of movable structures, with construction restrictions, if a permit has been granted. Construction or placement of nonmovable structures is prohibited. Any public utility systems within structural hazard areas also require a coastal erosion management permit. Additional restrictions on regulated activities are present within natural protective feature areas, including nearshore areas, beaches, bluffs, primary dunes, and secondary dunes. Construction of erosion protection structures is allowed within such areas provided the structure meets permitting requirements and is designed to prevent or minimize damage to property and natural features in a cost-effective manner. Structures must be designed to control erosion on site for a minimum of 30 years.

New York has put forth several climate adaptation measures at the state level, led primarily by the state Department of Environmental Conservation. Sea-level rise projections for threatened coastal areas are currently published within the state administrative code, a recommendation from the previously convened NYS Sea Level Rise Task Force . The projections formally establish sea-level rise levels throughout Long Island, New York City, and the Hudson River, providing information based on five risk scenarios and extending out to 2100. The Department of Environmental Conservation has also formally acknowledged its role in climate change adaptation through Commissioner’s Policy 49: Climate Change and DEC Action . The policy outlines methods by which climate change considerations may be integrated into current DEC activities and programs, including making greenhouse gas reductions a primary goal, creating specific mitigation objectives for existing and future programs, incorporating adaptation strategies into programs and activities, considering climate change implications in daily department activities, and identifying specific actions to further climate change goals and objectives as part of annual planning processes. The policy goes on to establish mitigation and adaptation objectives as well as departmental responsibilities and implementation procedures.

The 2014 Community Risk and Resiliency Act (CRRA) forms the basis for a number of climate adaptation initiatives within New York from a legislative standpoint. The previously mentioned sea-level rise projections were a product of the CRRA, as the act amended the state Environmental Conservation Law to include a requirement that the DEC adopt science-based projections. The CRRA also amended additional sections of the Environmental Conservation Law to require applicants for identified funding and permitting programs to demonstrate that risk due to sea-level rise, storm surge, and flooding have been considered in project design and requires the DEC to incorporate similar considerations into facility-siting regulations. The sea-level rise, storm surge, and flood risk mitigation components of the Smart Growth Public Infrastructure Policy Act are also tied to the CRRA. The CRRA also directs the Department of State and Department of Conservation to develop model local laws that consider data-based future risk due to sea-level rise, storm surge, and flooding as well as guidance on the use of natural resources and natural processes to enhance community resilience to such hazards.

Elements of Policy Goals/Management Principles

State management capacity is bolstered by the New York Coastal Management Program’s federal consistency review process, which requires that federal activities within the state coastal zone be consistent with the program’s enforceable policies. The New York program has 44 enforceable policies in total, with 7 specifically addressing flood and erosion hazards.
Local governments can implement the state Coastal Management Program at a smaller scale through the Local Waterfront Revitalization Program, extending the influence of state program goals and enforceable policies.
The enforceable policies of the state coastal management program address the protection of natural features that mitigate coastal flood risk and the use of non-structural mitigation measures where feasible.
Shoreline setbacks must be established within identified coastal erosion hazard areas, and setbacks must be at a distance sufficient to minimize damage from erosion considering the rate of recession of coastal lands.
Floodplain management regulations require that any new development or substantial improvement to structures in coastal areas not affect sand dunes in any way that might increase potential flood damages.
Wetland management regulations require that structures be located a minimum of 75 feet landward from the edges of tidal wetlands, preserving natural flood risk mitigation functions.
Sections of the state administrative code related to erosion management include descriptions of the erosion protection functions of natural features to guide permit applications, and permit standards require that erosion management activities prevent or minimize adverse impacts on natural protective features.
The state stormwater management design manual includes information on green infrastructure strategies, which are presented as a means to meet runoff reduction standards and maintain pre-development hydrology for project areas.
The state building code requires structures not subject to wave action to have the lowest floor elevated a minimum of one foot above the base flood elevation. This rule applies to the lowest horizontal structural members of structures that are subject to wave action.
State regulations require that erosion protection structures in coastal areas be designed to control erosion on site for a minimum of 30 years.
Public infrastructure projects approved, undertaken, or financed by state agencies must account for and mitigate risk due to future climate risk factors such as sea-level rise, storm surge, and flood events. Mitigation efforts must be based on available data as well as projections of future conditions.
The state has published sea-level rise projections for threatened coastal areas within the state administrative code, formally establishing risk based on five scenarios and extending to 2100.
Commissioner’s Policy 49: Climate Change and DEC Action identifies ways that climate change considerations could be incorporated into current state programs and activities and defines departmental responsibilities and procedures for implementing the climate adaptation goals of the policy.
The state Community Risk and Resiliency Act formally establishes a number of climate adaptation initiatives within the state, including the requirement that the state Department of Environmental Conservation adopt science-based sea-level rise projections and that applicants to funding and permitting programs demonstrate that climate risk has been incorporated into the siting of facilities.
The enforceable policies of the state coastal management program address the siting of buildings in coastal areas to reduce risk and well as restrictions on the use of public funds for erosion protection structures.
One of the objectives of the state erosion management program as described in the state administrative code is to restrict public investment that could encourage development within coastal erosion hazard areas. An additional objective is to use publicly financed erosion control structures only when necessary and effective.
The New York Rising Community Reconstruction program works to develop reconstruction plans and strategies to increase coastal community resilience following severe storm events, often involving the mitigation of future flood risk.
The New York Coastal Management Program lists coordination of major activities affecting coastal resources as one of the program goals, and multiple state agencies are involved in implementing the program’s broad suite of enforceable policies.
If an action requires preparation of an environmental impact statement as part of the State Environmental Quality Review Program it must also be consistent with the enforceable policies of the state coastal program, including policies related to coastal hazards.
State wetland regulations are based on the preservation, protection, and enhancement of ecological values as opposed to acreage, with flood control and storm protection listed among the functions provided.
The State Environmental Quality Review Program includes the potential for a substantial increase in flooding as a criteria of significance, which then triggers the preparation on an environmental impact statement for state agency activities.
State Waterfront Revitalization Programs establish land and water use policies that incorporate coastal resilience into revitalization projects and community redevelopment planning.

View the other State Coastal Flood Risk Management Case Studies:

A man wading in the middle of a pool of muddy water and pointing at something, while several other people are seen standing off to the side.

Kenya’s devastating floods expose decades of poor urban planning and bad land management

Consultant in Hydrology and Water Resources, Kenya citizen, Visiting Research Fellow, King's College London

Disclosure statement

Sean Avery is affiliated with: Hydrological Society of Kenya, Water Resource Associates, Kings College London, University of Gent

King's College London provides funding as a member of The Conversation UK.

View all partners

Floods in Kenya killed at least 169 people between March and April 2024. The most catastrophic of these deaths occurred after a flash flood swept through a rural village killing 42 people . Death and destruction have also occurred in the capital, Nairobi, a stark reminder of the persistent failure to keep abreast of the city’s rapid urbanisation needs. Sean Avery , who has undertaken numerous flood and drainage studies throughout Africa, unpacks the problems and potential solutions.

Are floods in Kenya causing more damage? If so, why?

Floods are the natural consequence of storm rainfall and have an important ecological role . They inundate flood plains where silts settle, riverbed aquifers are recharged and nutrients are gathered. Annual rainfall in Kenya varies from 2,000mm in the western region to less than 250mm in the drylands covering over 80% of Kenya. But storm rainfalls are widespread. This means that floods can occur in any part of the country.

The impact of floods has become more severe due to a number of factors.

The first is how much water runs off. In rural areas, changes to the landscape have meant that there’s been an increase in the amount of storm runoff generated from rainfall. This is because the natural state of the land has been altered through settlement, roads, deforestation, livestock grazing and cultivation. As a result, a greater proportion of rainfall runs off. This runoff is more rapid and erosive, and less water infiltrates to replenish groundwater stores.

The East African Flood Model , a standard drainage design tool, demonstrates that by reducing a forested catchment into a field for livestock pasture, for instance, the peak flood magnitude can increase 20-fold. This form of catchment degradation leads to landslides, dams can breach, and road culverts and irrigation intakes are regularly washed away.

Land degradation in sub-Saharan rangelands is omnipresent, with over 90% rangeland degradation reported in Kenya’s northern drylands . Kenyan research has recorded dramatic increases in stormwater runoff due to overgrazing.

Second, human pressure in urban areas – including encroachment into riparian zones and loss of natural flood storage buffers through the destruction of wetlands – has increased flood risks. Riparian zones are areas bordering rivers and other bodies of water.

By 2050, half of Kenya’s population will live in urban areas. Green space is progressively being filled with buildings and pavements. A large proportion of urban population lives in tin-roofed slums and informal settlements lacking adequate drainage infrastructure. As a result, almost all of the storm rainfall is translated into rapid and sometimes catastrophic flooding.

Third, flood risks are worse for people who have settled in vacant land which is often in low-lying areas and within flood plains. In these areas, inundation by flood waters is inevitable.

Fourth, Nairobi’s persistent water supply shortages have led to a proliferation of boreholes whose over-abstraction has resulted in a dramatic decline in the underground water table’s levels. This leads to aquifer compression, which is compounded by the weight of buildings. The result is ground level subsidence , which creates low spots where stormwater floods collect.

What should be done to minimise the risks?

Rural areas require a different set of solutions.

Natural watercourses throughout Kenya are being scoured out by larger floods due to land use pressures. These watercourses are expanding and riparian vegetation cover is disappearing. The flood plains need space to regenerate the natural vegetation cover as this attenuates floods, reducing the force of runoff and erosion.

There are existing laws to protect riverbanks, and livestock movements in these areas must also be controlled. Any building or informal settlement within riparian areas is illegal and would otherwise be exposed to the dangers of floods. Enforcement is a challenge, however, as these areas are favoured by human activities and often these people are among the poorest.

Urban areas have a host of particular challenges that need to be addressed.

Take Nairobi, Kenya’s capital city. The physical planning process is hindered by corruption . Inappropriate and unsafe developments proliferate alongside inadequate water supply, wastewater and solid waste disposal infrastructure. Sewage effluent is often discharged into stormwater drains, even in high-class areas of the city. And there is little control of development in the growing urban centres bordering Nairobi, with transport corridors being congested. Throughout the country, laws that protect riparian zones are flouted.

None of this is sustainable.

Each municipality is obliged to provide infrastructure that includes an effective engineered stormwater drainage network. And in parallel, wastewater and solid wastes must be separately managed.

The typical stormwater drainage network comprises adequately sized earth and lined channels, and pipes and culverts that convey the stormwater to the nearest watercourse. Constant maintenance is essential, especially before the onset of rains, to avoid blockage by garbage and other human activities.

Modern-day urban flood mitigation measures include the provision of flood storage basins. Unfortunately this is impossible in Nairobi where developments are built right up to the edge of watercourses. Constrained channels thereby cause upstream flooding as there is nowhere else for the water to go.

Attempts have been made to reverse urban riparian zone encroachments , but these efforts faltered due to legal repercussions. To this day, unscrupulous developers encroach with impunity .

It’s essential that the authorities demarcate riparian boundaries and set aside buffer zones that cannot be “developed”.

Urbanisation
Deforestation
Groundwater
Water catchment
East Africa
Sub-Saharan Africa
Climate crisis

Events and Communications Coordinator

Assistant Editor - 1 year cadetship

Executive Dean, Faculty of Health

Lecturer/Senior Lecturer, Earth System Science (School of Science)

Sydney Horizon Educators (Identified)

0 Shopping Cart

Banbury Flood Management Scheme

Banbury is a historic market town located in Oxfordshire, England. It is situated on the banks of the River Cherwell (a tributary of the River Thames), near the northeastern edge of the Cotswolds. Banbury is approximately 64 miles (103 kilometres) northwest of London and 22 miles (35 kilometres) north of Oxford, the county town of Oxfordshire.

Why was the Banbury flood management scheme required?

Banbury has been affected by flooding of the River Cherwell numerous times. The 1998 flood led to the closure of the railway station and caused £12.5 million in damage. There was further flooding in 2007.

What is the Banbury flood management strategy?

In 2012, an innovative project was completed to construct a flood storage reservoir north of the town at an investment of £18.5 million. The scheme involved building a 3-kilometre-long and 4.5-metre-high embankment, paralleling the M40 motorway, to form a 3 million cubic meters storage basin. The purpose of the reservoir is to regulate the flow of surplus rainwater into the river, using specially engineered outlets to discharge the water slowly. When heavy rainfall occurs, the surplus water accumulates in the storage reservoir. This water is then gradually released into the River Cherwell over the following days, mitigating any sudden influx that could potentially escalate the town’s flood risk.

The key features of the scheme included:

Raising the A361
Constructing a floodwall around motorsport company Prodrive
Constructing new pumping stations to transfer water

Banbury Flood Control Structure

A biodiversity Action Plan (BAP) habitat with ponds, trees and hedgerows
Constructing 4.5m high embankments using soil taken from the borrow area, which is now a small reservoir used for storing water that would otherwise have caused the River Cherwell to flood

What issues resulted from the scheme?

Social issues

The A361 is no longer affected by flooding, reducing transport disruption for local people.
The new green areas and footpaths have improved the quality of life for local people.
Reduced anxiety in local communities as the risk of flooding has been reduced.

Economic issues

The cost of the scheme was £18.5 million.
The benefits are estimated at over £100 million.
441 houses and 73 commercial properties are protected from flooding.
Property values have increased as they are no longer at risk of flooding.

Environmental issues

Around 100,000 tonnes of earth were required to make the embankment resulting in some habitat destruction.
The Biodiversity Action Plan (BAP) has resulted in planting trees and hedgerows and constructing ponds.
The BAP has created new ponds, trees and hedgerow habitats.
Part of the floodplain will be left to flood if river levels get too high.
The reservoir provides a temporary habitat for waterbirds.
The concrete apertures are unnatural in the landscape .

Premium Resources

Please support internet geography.

If you've found the resources on this page useful please consider making a secure donation via PayPal to support the development of the site. The site is self-funded and your support is really appreciated.

Changing rates of rainforest deforestation

Topic home, next topic page, share this:.

Click to share on Twitter (Opens in new window)
Click to share on Facebook (Opens in new window)
Click to share on Pinterest (Opens in new window)
Click to email a link to a friend (Opens in new window)
Click to share on WhatsApp (Opens in new window)
Click to print (Opens in new window)

If you've found the resources on this site useful please consider making a secure donation via PayPal to support the development of the site. The site is self-funded and your support is really appreciated.

Search Internet Geography

Latest Blog Entries

Pin It on Pinterest

Click to share
Print Friendly

IMAGES

Flood Risk Management: A Strategic Approach
Ppt on Floods
Flood project case study rk
Disaster Management Case Study Of Flood Prone Areas
CASE STUDY AQA GCSE Geog Boscastle flood management
flooding case study

VIDEO

Flood Hazard Assessment
My flood experience
CAWASA Water Webinar Series 2024 Episode #3: Flood Case Study by Greg Archibald
Members' Business: Flood Management
Design flood for safety of a structure using Gumbel's method
Cockermouth flood defences

COMMENTS

Kerala flood case study
River Flooding and Management; Rivers - Hard Engineering; Rivers - Soft Engineering; Case Study - Ganges/Brahmaputra River Basin; The Great Floods of 2000; ... Kerala flood case study Kerala. Kerala is a state on the southwestern Malabar Coast of India. The state has the 13th largest population in India. Kerala, which lies in the tropical ...
Case Studies
The case studies are presented here for "historical purposes": having been compiled almost 20 years ago, they are reflecting national situations that might since have developed. As such, the case studies might be used as baseline or reference material for studies that aim to check the improvements in flood management since the beginning of ...
Lessons from case studies of flood resilience: Institutions and built
This section presents the review of each case study about risk of flooding, history and current standing of flood management systems, and their institutional framework affecting the flood management processes. ... Reviewing the flood management policies in the three case study regions reveals differences in approaches to confronting a common ...
FEMA Case Study Library
Community Wind Shelters: Background and Research. Because of the rising frequency of extreme weather, the Federal Emergency Management Agency (FEMA) strongly encourages homeowners and communities to build safe rooms to FEMA standards. Community shelters have been consistently needed due to the increased risk posed by strong winds and flying ...
A review of the flood management: from flood control to flood
Flood management is widely recognized as an effective way to reduce the adverse consequences, and a more resilient and sustainable flood management approach has been the goal in recent studies. This study used a detailed bibliometric analysis of keywords, terms and timelines in the research field of the flood research.
'A low and watery place': A case study of flood history and sustainable
This case study illustrates how specific flood events served as catalysts for two local groups' bottom-up involvement in flood risk management in the village. Both the Parish Flood Team and the Community Flood Group were set up as a response to flood events that were considered 'meaningful' by the local community. What this case study also ...
Cost-benefit analysis of flood mitigation measures: a case study
This paper shows a detailed, advanced procedure to implement cost-benefit analyses (CBAs) in order to assess the effectiveness of flood mitigation measures. The town of Lodi (North of Italy) has been selected as a case study for the research work, as it was hit by a large flood in 2002 for which several data are available. In order to compute the benefits, in terms of avoided damage with the ...
GIS-Based Urban Flood Risk Assessment and Management—A Case Study of
Urban floods are very destructive and have significant socioeconomic repercussions in regions with a common flooding prevalence. Various researchers have laid down numerous approaches for analyzing the evolution of floods and their consequences. One primary goal of such approaches is to identify the areas vulnerable to floods for risk reduction and management purposes. The present paper ...
Flood Resilient Plan for Urban Area: A Case Study
Flood modelling for a data-scare semi-arid region using 1-D hydrodynamic model: A case study of Navsari Region. Modeling Earth Systems and Environment, 8, 1-11. Google Scholar Mugume, S. N., & Butler, D. (2017). Evaluation of functional resilience in urban drainage and flood management systems using a global analysis approach.
Case study: Diagnosing China's prevailing urban flooding—Causes
Second, there are no floodplain delineation and flood hazard zoning to coordinate the riverine flood management with urban flood controls on the floodplain (F. Zhang et al., 2012), no comprehensive river basin-wide or regional flood management guidance to integrate urban flood prevention schemes inside river drainage basins. Last but not least ...
Teamwork Approach to Outreach and Engagement Reduces Flood Risk
Solution. Approximately 40 years ago, the city mayor and activist citizens began a new approach to flood risk reduction. This long-standing, strong support from the government and citizens for flood mitigation has allowed for a continuing, voluntary home buyout program. To date, the city has bought out over a thousand homes and paid the ...
The challenge of unprecedented floods and droughts in risk management
An analysis of these case studies identifies three success factors: (1) effective governance of risk and emergency management, including transnational collaboration such as in the Danube case; (2 ...
Flood Management in China: The Huaihe River Basin as a Case Study
The Huaihe River Basin (HRB) is a transitional river located in the transitional climate zone in China, and it has been frequently hit by big floods and suffered from flood disasters. Flood control and management of the areas are of vital importance of the Huaihe River Basin in its social and economic development. In this chapter, pioneer works of summarizing the flood management have been ...
Sponge City Program (SCP) and Urban Flood Management (UFM)—The Case of
Flood management is a complex issue in Chinese cities that exhibit high populations and have undergone rapid urbanization. Urban flood management (UFM) approaches can be used to mitigate urban flood risk. To address urban issues of poor water quality and urban surface flooding, the Sponge City Program (SCP) was initiated in 2013 in China. The SCP aims to provide an opportunity for Chinese ...
Natural flood management: Opportunities to implement nature‐based
4 CASE STUDY EXAMPLES ANALYZED. In this section, we discuss three examples of natural flood risk management from the scientific and gray literature. These studies were not originally designed or analyzed with the conditions discussed in Section 3 in mind, and so we explore the opportunities with the information presented in the three selected ...
Flood Resilient Shelter Case Studies and Reports
This Collection contains reports and case studies relative to contexts of flood disaster response. The main topics are centered around how those who have been affected by floods can follow certain guidelines from various countries. The collection contains resources from multiple continents which is a way of enchaining mutually beneficial knowledge.
Addressing sustainable urban flood risk: reviewing the role and scope
Urban planners have both an active role in studying cities and a supportive role in helping to define policies. From 33 case studies, this review tries to give insight into how flood risk management fares in confronting international directives on disaster reduction and sustainability, by defining seven sustainability performance criteria.
Optimal floodgate operation for river flood management: The case study
The focus is here on the flood management in a complex river network. The case study is the the Brenta and Bacchiglione river network nearby (and through) the historical city of Padova (Veneto Region, Italy), which comprises several natural and man-made channels.
Urban Flood Management
The highest per capita solid waste generation in India is in Chennai (0.6kg/day) 3. Majority of solid wastes are dumped in a mixed form in low lying areas & in open areas by Chennai Corporation. The Attitude of people is appalling causing the pile of solid wastes in the vicinity of the residential areas itself.
Flood management case study
Learn about and revise river management, and hard and soft engineering strategies to prevent flooding, with GCSE Bitesize Geography (AQA). ... River management - AQA Flood management case study ...
Evaluation of urban flood adaptability based on the InVEST ...
Flood risk has become a serious challenge for many cities, including New York City (NYC). Evaluating urban flood adaptability evaluation is crucial for regulating storm and rain risks. In this study, we proposed an integrated framework based on the Integrated Valuation of Ecosystem Services (InVEST) model and Geographic Information System (GIS). First, the InVEST model was used to assess the ...
New York Coastal Flood Risk Management Case Study
Of the 44 coastal management program enforceable policies in New York, seven specifically address flooding and erosion hazards. These policies touch on a number of aspects of coastal flood risk management including the siting of buildings in coastal areas to minimize risk to property and human lives, protection of natural features that mitigate ...
Flood Management Scheme
The Great Floods of 2000; Kerala flood case study; Rocks, Resources and Scenery. Geological time is on a different time to human time; Rock Types and the Rock Cycle; ... In 2008 a flood management scheme for Boscastle was completed. The solution included both soft and hard engineering strategies.
Disaster Management in Flash Floods in Leh (Ladakh): A Case Study
Results: 234 persons died and over 800 were reported missing. Almost half of the people who died were local residents (49.6%) and foreigners (10.2%). Age-wise analysis of the deaths shows that the majority of deaths were reported in the age group of 25-50 years, accounting for 44.4% of deaths, followed by the 11-25-year age group with 22.2% ...
Cumulative sedimentation hazard map of urban areas subject to
In the past decades, flood hazard maps have been widely used in flood risk management using qualitative, ... a brief overview of the characteristics of hyperconcentrated flash floods in the Loess Plateau of China and presents a case study of hyperconcentrated flash flood in Suide County in July 2016.
Kenya's devastating floods expose decades of poor urban planning and
Published: May 1, 2024 5:17am EDT. Floods in Kenya killed at least 169 people between March and April 2024. The most catastrophic of these deaths occurred after a flash flood swept through a rural ...
Development of an Integrated Urban Flood Model and Its ...
Urban floods caused by extreme rainstorm events have increased in recent decades, particularly in concave-down bridge zones. To simulate urban flooding processes accurately, an integrated urban flood model (IUFM) was constructed by coupling a distributed urban surface runoff model based on the cellular automata framework (CA-DUSRM), a widely used pipe convergence module in the storm water ...
Quantifying and improving flood resilience of urban drainage systems
For evaluating the efficiency of the proposed framework, it is applied to a real-world case study of improving resilience of the UDS in the eastern part of Tehran metropolitan area. Three scenarios for flood management are proposed based on the Low Impact Development (LID) practices which are simulated using the Storm Water Management Model (SWMM).
An Integrated Bayesian Network and Geographic Information System ...
Flooding poses severe ecological and environmental threats, necessitating comprehensive risk assessments to inform sustainable management practices. This study proposes an innovative approach that integrates Bayesian networks (BNs) and geographic information systems (GIS) for flood disaster risk assessment and ecological monitoring.
Banbury Flood Management Scheme
The Great Floods of 2000; Kerala flood case study; Rocks, Resources and Scenery. Geological time is on a different time to human time; Rock Types and the Rock Cycle; ... Why was the Banbury flood management scheme required? Banbury has been affected by flooding of the River Cherwell numerous times. The 1998 flood led to the closure of the ...

Case Studies

Teamwork Approach to Outreach and Engagement Reduces Flood Risk

City of Tulsa, Oklahoma

Key Takeaways

Related Documents and Links

The challenge of unprecedented floods and droughts in risk management

Similar content being viewed by others

How the USA can benefit from risk-based premiums combined with flood protection

Biases in national and continental flood risk assessments by ignoring spatial dependence

Developing more useful equity measurements for flood-risk management

Source data

Drivers of changes in impact

Box 1 Success stories of decreased impact despite increased hazard

Effects of changes in management on drivers

Data availability

Acknowledgements

Author information

Contributions

Corresponding author

Ethics declarations

Peer review

Additional information

Extended data figures and tables

Extended Data Fig. 2 Parallel plot of paired events with the same hazard of both events.

Extended Data Fig. 3 Results of the sensitivity analyses.

Extended Data Fig. 4 Theoretical framework used in this study (adapted from IPCC 3 ).

Supplementary information

Source Data Fig. 1.

About this article

Share this article

This article is cited by

Limited progress in global reduction of vulnerability to flood impacts over the past two decades

Strategic storm flood evacuation planning for large coastal cities enables more effective transfer of elderly populations

Applying a machine learning-based method for the prediction of suspended sediment concentration in the Red river basin

Floods have become less deadly: an analysis of global flood fatalities 1975–2022

Quick links

Flood Management in China: The Huaihe River Basin as a Case Study

Flood Risk Management

Author Information

1. Introduction

Figure 1.

2. Geographical features

3. Outstanding characteristics of the HRB

4. Floods and flood disasters

Figure 2.

Table 1.

4.2. Flood disasters

Figure 3.

Table 2.

5. Achievements in flood control

5.1. Structural measures

Figure 4.

5.2. Non-structural measures

5.2.1. Legal and institutional system for flood control

Figure 5.

5.2.2. The flood forecasting and warning system

Table 3.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

Figure 11.

Figure 12.

Figure 13.

6. Case study

6.1.2. Flood management

6.2. Room for river project in the Huaihe River Basin

Figure 14.

Figure 15.

6.2.2. Room for river: Jingshanhu flood bypass as a case study

Table 4.

7. Experiences and enlightenment

7.1. Experiences in flood management

7.2. Outlook on flood management in the Huaihe River Basin

Acknowledgments

Continue reading from the same book

You are here

Resources on this Collection

Improved Shelters for Responding to Floods in Pakistan Phase 1: Study to Develop a Research Methodology

Box 1  Success stories of decreased impact despite increased hazard