Dry Well Use for Local, Regional and State
Stormwater and Flood Control Managers
Dry wells can help meet important regulatory guidelines for local, regional and State stormwater and flood control managers in California as follows:
- Regulations of the National Pollutant Discharge Elimination System (NPDES) permit require municipalities, the construction industry, and others to retain a high percentage of stormwater runoff volume for smaller storms (10-year events and less) on-site in order to avoid degradation of aquatic habitat in creeks and rivers. Using Low Impact Development (LID) practices to achieve these goals can be challenging if the soils have a high clay composition (Class C and D). By breaking through the clay layers, a dry well allows stormwater runoff to reach more pervious layers beneath the ground.
- Many California cities, small and large, are struggling to meet the water needs of their communities. The groundwater table is dropping in many regions of the State due to over drought. As a consequence, many communities are looking at stormwater as a potential resource for groundwater augmentation. These cities are investigating ways to incorporate dry wells into their stormwater management systems primarily to address the issue of water shortage.
- Dry wells keep stormwater out of sewers, eliminate the need for curb drains and piping. They can be cost-effective and can be particularly useful in urban areas where space is limited.
- Dry wells can be viewed as a climate change adaptation. Climate change models suggest that the form and amount of precipitation in the Sierras is likely to change from one which is characterized by a high volume of water stored as snow to rain. The dams in California were not constructed to manage this pattern of precipitation. Dry wells might provide an option for capturing rain and runoff to recharge the aquifer.
- Where space is limited and traditional conveyance systems are too expensive to construct, dry wells can help to minimize the risk of localized flooding. A dry well is a simple way to manage stormwater runoff and to reduce localized flooding. For example, dry wells can be installed in a roadside ditch or streetscape.