Optional Sectoral Module STORMWATER AND FLOOD PLAIN MANAGEMENT In a resilient city, the flow of rainwater through the city is managed by natural and impervious areas, conduits, and constructed and natural channels to downstream areas. Local government develops sustainable management systems and infrastructure to prevent impacts and reduce social, economic, and environmental risks and vulnerabilities from flooding (coordinated, robust, and inclusive). Stormwater systems are the local infrastructure for managing rainwater while flood plain management deals with flood flows from major rivers crossing the urban area. Urban development and climate change may increase the city’s vulnerability over time due to increasing frequency (or intensity) of flood events and increasing solids and contamination. A resilient city develops nonstructural and structural measures to increase resilience (robust). Nonstructural measures include institutional capacity for regulation and management prevention through flood alerts, zoning, and long-term programs to mitigate dispersed impacts in the city (coordinated and redundant). Structural measures are investments in reducing existing risk and vulnerability that requires structural interventions (robust). In the implementation of the measures, a resilient city needs a responsible institution to assure the operation, maintenance, and financial management of stormwater and flood management infrastructure (coordinated). This institution needs cost recovery for the services and investments and a strategic plan of action, review of investments, and public participation (reflective). Prepared 2018 1 APPLICABLE RELATIONSHIP TO RESILIENCE TOPIC GUIDING QUESTION RESILIENCE QUALITY QUALITY System Is there a stormwater and Robust; Stormwater and flood management Capacity flood management system Inclusive systems are needed to ensure that in the city? Does it cover all rainwater and water flows from major urban areas? rivers are drained efficiently and protect inhabitants from flooding. Public utilities do not often serve informal settlements, putting them at higher disaster risk than the general public. Institutional Who manages the stormwa- Coordinated Close coordination among water, Capacity ter and flood management sanitation, solids and drainage system in the city? Is there utilities, and flood management can a utility for stormwater? Is facilitate planning for future demand there another institution for and accelerate response in case of flood management? Are all disruption. providers in urban services well coordinated in terms of management, planning, and emergency response? Institutional Is there a periodic Reflective Regular assessment of the stormwater Capacity assessment and update of the and flood management systems are measures and investments in necessary to ensure that the system the stormwater system? reflects new conditions and addresses potential vulnerabilities. Institutional Is there public participation Inclusive When plans are developed in Capacity on stormwater and flood consultation with affected communities management decision- and civil society groups, solutions are making? Is there a more robust because they include the consultation process and nuanced needs of affected communities communication of decisions? and the general public. Institutional Does the city monitor rainfall, Reflective Monitoring changes in the city’s Capacity runoff, solids, and water stormwater drainage system allows for quality in the urban area? informed capacity management and Is there updated drainage design. It can also serve to highlight survey information available potential vulnerabilities. along with topography? Is the data updated regularly? 2 Regulations Does the city have a master Robust Enforced planning regulations can help plan or regulatory framework prevent unauthorized development for managing land use and in the city, especially in flood plains urban growth? Is stormwater or other areas at high risk for urban and flood plain management flooding. included in this plan? Are the regulations effective and enforceable? Regulations Is there a regulatory Robust Regulations are needed to control the framework to control the impacts of increasing urbanization impact of urbanization on the from source water areas to downstream stormwater system? Does it public networks in the city. address peak flows, solids, and water quality? Are the regulations enforceable? Regulations Do land use policies and Robust; Risk-based land use policies and planning regulations Reflective regulations for flooding events should incorporate flood plain be integrated in land use planning to information? What reduce exposure. proportion of the population is in the 100-year flood plain? Are policies and regulations enforceable? Regulations Are there incentives for Robust New construction with green environmental certification infrastructure such as water reuse, for new developments and drainage control, and energy efficiency regeneration in the city? help to minimize the impact of new development on the city’s ecosystem. Planning Is there a stormwater master Robust; Experience of current seasonal rain/ plan for the city? Does the Reflective stormwater variations and forecasted plan cover all urban areas? impacts of climate change on rainfall What is the return period levels should inform the design of the used for the major drainage city’s drainage system. Climate change works design? Is there an projections allow the city to improve the emergency plan for floods design and capacity of existing drainage above the designed time of and water retention infrastructure, as recurrence? well as make necessary flood protection investments to accommodate changes in rainfall patterns. 3 Finance Do stormwater services Robust Cost recovery for flood management achieve cost recovery for implies a sustainable management investments, operations, and where revenues from stormwater maintenance? Is there a tax services recover operational expenses or tariff for stormwater? Is it at the very minimum. economically sustainable? Risk Is the city’s drainage system Reflective The knowledge of flood impacts is the Identification currently able to cope with first step to develop solutions for the seasonal increase in rain/ system. The impacts are distributed stormwater? Is there an in space and vary with frequency. Risk assessment of stormwater assessments identify the city’s current flooding locations and and future vulnerabilities by examining frequency in the city? Is there historical data and/or future scenarios an assessment of damages? Is through modeling. The relevance of risk there an assessment of solids assessments depends on them being and water quality impacts? regularly updated to appropriately reflect levels of vulnerability and exposure. Preparedness Is there a flood alert system Robust Early warning systems are essential for populations that occupy to facilitating public safety during a flood plains in the city? Is disaster event by giving residents time there an emergency plan to evacuate or protect themselves developed for hazard areas? before impact. Program Is there a program to Robust; Minor stormwater floods are distributed eliminate stormwater Inclusive in small areas usually due to drainage flooding at minor drainage capacity constraints. The elimination of points in the city? What has these frequent occurrences is a way of been the perception of this improving the overall quality of life for program by citizens? the population. Program Is there an evaluation of Robust A resilient city minimizes sewage interconnections between in stormwater through separate sewage and stormwater stormwater networks in order to networks (i.e., contamination improve water quality and reduce of stormwater networks environmental impact. For combined by sewage)? Is there a systems, the focus should be on program to eliminate this decreasing the spill of contaminated contamination? Does the city water. have combined networks? How frequent is the spillage of contaminated flow? 4 Program Is there a program for water Robust Water quality is contaminated by quality improvement of sewage and overland flow in urban major drainage in the city? areas along with solids dumped in What is the time frame of the the network. Improving water quality program? Is the program fully of major drainage is important for funded? improving environment sustainability in urban areas. Program Is there a program for the Robust Informal settlement may occur along recovery of degraded areas steep slopes, exacerbating erosion and caused by erosion and posing a risk to the urban ecosystem sedimentation or solids and the settlers. deposits? What is the timeframe of the program? Is the program fully funded? Program Is there a program to reduce Robust In urban areas, there are many sources the contamination of of groundwater contamination. There groundwater? What is the is a need to develop regulation and timeframe of the program? Is contain the existing sources together the program fully funded? with enforcement for minimizing the contamination. Program Is there a capacity-building Reflective All departments in the city should program for stormwater be able to manage risks of disasters utility personnel, design and (including flooding) for their areas of planning professionals, and responsibility. Community members are the community? often the first respondents in a disaster and can be even more effective if they are organized and coordinated with other emergency response agencies. • Tucci, Carlos. 2009. Integrated Urban Water Management in Large Cities: A Practical Tool for Assessing Key Water Management Issues in the Large Cities of the Developing World. 5