Eight Important Questions City Officials Should Ask About Flood Control in Their City
Yvonne Hunter is a legislative representative for the League. Numerous individuals from the public, private and nonprofit sectors also contributed to this article, and their assistance was invaluable.
1. Is a 100-year flood one that happens once every 100 years? No, a 100-year flood is not a flood that occurs only once every 100 years and thus can be ignored today. Actually, the designation really means a 1 percent chance of flooding in any given year. This translates into a 26 percent chance of flooding over the life of a typical 30-year mortgage. “Yikes” is often the response to this definition.
2. Is your city in a 100-year flood zone? This is one of the most basic items of information needed to make informed decisions about flood management in your city. The Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Maps, which show the 100-year floodplain, are the most commonly used maps to identify flood risk. FEMA uses these maps to determine whether flood insurance is required for federally backed mortgages. However, many FEMA maps are outdated and do not reflect the current hydrology and flood risk. They may not identify all flooding or reflect the impacts of recent floods, increases in rainfall data, changes in hydrology due to development, or erosion or damage to levees. Some FEMA maps are available that identify 200-year and/or 500-year floodplains, as well.
3. If your city has a flood risk, what is its cause? Is potential flooding in your city from a levee break, an overflowing stream or creek, runoff from an alluvial fan, a coastal storm, dam break or a combination of causes? It’s important to know how, where, how deeply and why your city may flood so you can be proactive, plan accordingly and be prepared.
4. If your city is behind a levee, how recently has it been evaluated for reliability? Often you will hear the phrase, “The city is protected by a levee.” Ask what is meant by “protected.” Does it mean the levee is suitable to actually protect the city? Or does it really mean “The city is behind a levee”? Because if the condition of the levee is not suitable for urban development, then your city is not really protected.
5. Do you know how deep the water will be if your city floods? Despite the best planning, floods happen. If your city floods, do you know where and how deep the water will be? Will the water be less than a foot deep if a creek or storm drain overflows? If a levee breaks, will flooding be three, 10 or 20 feet deep? Obviously, the location and depth of flooding will have a significant impact on your emergency response needs, the damage to life, property and the economy of your community, and your city’s ability to re- cover. Knowing the community profile of a potential flood can also help you plan to avoid building in areas with a potential for deep flooding and develop your mitigation measures accordingly.
6. Who manages the flood control infrastructure that protects your city? Is your city the primary flood control agency? Or is it a special district or the county? For example, many cities are served by special flood control agencies that provide countywide flood management services. Similarly, the majority of levees are owned and operated by local reclamation or levee districts, not the city that is behind the levee. It’s important to have a good working relationship with those agencies and to ask about their flood management or levee operation and maintenance program, and emergency response capabilities. For example, ask whether the flood control agency is prepared to vigorously respond to a flood if a levee threatens to fail or a stream or river overflows. Ask if they have backup contracts for emergency flood work and if they have emergency supplies stored in strategic locations.
7. Is your city prepared for a flood emergency? Do you have the resources available for a flood disaster? Are there plans in place to inform the public of a potential flood emergency and evacuate people out of the flood inundation area? Is the city proactive in educating people about the importance of being prepared so they can take individual responsibility, including providing information to non-English-speaking residents, low-income citizens and tourists? Do you have equipment and personnel ready to roll during storms or high water? Is the city prepared to provide sandbags to residents?
8. Does your city follow good planning practices? Does your city have an up-to-date floodplain management ordinance (required by FEMA if your city is in a 100-year floodplain and you want your residents to be eligible for low-cost federal flood insurance)? Do you have policies to review the design of new developments so as to avoid, minimize or mitigate the potential flood impacts? Has your city considered site design criteria for new developments that reduce runoff and increase absorption of water, such as those in the Ahwahnee Water Principles for Resource-Efficient Land Use (see page 16)? Are critical facilities such as hospitals, schools, fire and police stations, and corporation yards located outside the deep flood areas, if possible?
Links to Flood Control Resources
Local Government Commission Water Fact Sheets
Federal Emergency Management Agency (FEMA)
FEMA FloodSmart Info Page
FEMA Flood Hazard Mapping www.fema.gov/plan/prevent/fhm/index.shtm
California Department of Water Resources
State of California Reclamation Board
Department of Water Resources Flood White Paper