Learn about personal and community flood risk reduction measures and Flood Factor.
First Street Foundation works to include as many public and community adaptation features as possible into our model. However, because no comprehensive national inventory of adaptation features presently exists, our model may not take into account all such features in your community. You can let our team know about any community adaptation features that might be missing by following the link at the bottom of this article.
Furthermore, personal adaptation features are just that -- personal! As such, personal adaptation features such as raised homes are not included in the calculation. Our flood model is based on the likelihood of water reaching a building footprint, but cannot account for personal adaptations you may have installed at this time.
Personal flood control projects
If a home already has flood reduction measures in place, it may reduce the risk to its structure. Such measures may include:
Elevating your home
Houses can be raised above flood levels by using six-foot tall wooden stilts or concrete blocks. Even if a house doesn’t flood, the driveway and the roads around it still may. It is easier for a new home to be built higher, but existing homes can also be raised. Often, rebuilding happens when FEMA grants money after a disaster like Hurricane Harvey. These grants can often cover the majority of the cost for rebuilding. The median price of elevating a home is $130,000. Please note, an important first step is to contact the local zoning and building departments prior to making any improvements.
Rain garden installation
A rain garden is a garden in a depressed area of a landscape that is designed to temporarily hold and soak in rainwater. Rain gardens reduce runoff from roofs, streets, and/or driveways. The amount of gallons of rainwater that a rain garden can hold depends on the square footage of the catchment area and the depth of the rain garden. In general, rain gardens are typically built to hold 1 inch of rainwater. The cost of rain gardens varies depending on whether you do it yourself or hire a contractor; costs can range from $5 - $45 per square foot. Some communities offer incentives to support the installation of rain gardens. Check your local government website to learn more.
Rain garden in front of someone’s home (photo courtesy of Candace Stoughton, August 2010)
Community flood control projects
Communities thrive near water because they learn how to live with water. There are many different ways communities have been able to create flood reduction measures, including:
Levees are man made structures that are located along rivers, streams, creeks, and tributaries as well as lakes and along the coast. Levees are embankments that are typically made of earthen materials such as clay and other soils that are impervious. These structures work to protect surrounding areas from certain levels of flooding; once this level is exceeded levees can overflow. Levees are built parallel to waterways to keep them from flooding the land. Land behind levees are still subject to flooding from waterways as these structures can fail or overflow depending on the flood scenario.
Seawalls are structures located parallel to shorelines that are built to protect the land behind them from storm surge and wave action. Seawalls are made of concrete, masonry, or sheet pile and are typically placed in the transition zone from beach to mainland. Seawalls vary in height depending on the estimated height of storm surge they are designed to protect against. Seawalls typically reach at least to the height of the mainland elevation and include sections of freeboard above the mainland elevation to protect against waves overtopping. These structures vary in length and the number of properties they protect; individuals can build a seawall to protect their property, or cities can build a seawall that stretches across miles of properties such. Examples of public seawalls include those built in Virginia Beach, Stamford, and Galveston.
Construction of the 17th Street Levee - Washington D.C.
Galveston Seawall - Galveston, Texas
Pump stations work to reduce tidal flooding and flooding from stormwater. A pump station reduces the amount of standing water in low lying areas. Pump stations can also be used in tandem with levees and other flood barriers to provide extra capacity to move water that floods the dry side during storm events out of communities. They are placed in areas where water cannot be moved by gravity; the energy from the pump station is needed to move the water out of these areas. Pump stations are connected to drainage systems in order to quickly and efficiently remove water from drainage pipes so that the system is not overwhelmed and does not flood.
Pump station at the West Closure Complex - Belle Chase, Louisiana
Dams provide flood control and also serve many other purposes: water storage, recreation, navigation, electricity l generation, and irrigation. Flood control dams keep floodwaters impounded and either release floodwaters in controlled amounts downstream to the river below, or, store or divert water for other uses. According to the National Inventory of Dams, there are over 90,000 dams in the U.S. and roughly 18% of these dams are used explicitly for flood control. The average age of dams is 56 years old.
Folsom Dam - California
If you know of any projects that you believe Flood Factor is not currently taking into account, please help the team by providing any level of detail you can here. The adaptation database contains 23,000 features today. We know there are more projects to include, and value your input!