A few weeks ago I mentioned a plan in Orange County, CA, to capture stormwater by using inflatable dams to slow the flow in a couple of local creeks. The slow-moving water will infiltrate and help replenish the groundwater—the source of much of the county’s drinking water supply—rather than rapidly flowing to the ocean as it usually does. Supplementing the runoff with treated water from wastewater treatment plants, the county hopes to capture 3 billion gallons of water during the rainy season, enough to supply about 25,000 families for a year. The goal is to eventually double the amount captured.
Now a number of groups in nearby Los Angeles County are trying to get support for a similar effort. The plan, which requires voter approval, would add new property taxes and the revenue would fund green infrastructure projects throughout the urban area to help replenish local aquifers. Right now, a county supervisor notes, existing projects capture enough water to supply 1.5 million residents. (Much of this infiltration occurs not through dispersed green infrastructure installations but rather through spreading grounds. See these related articles from Water Efficiency and Stormwater.) New bioswales, rain gardens, and other installations could eventually more than double that amount—enough for a third of the 10 million or so people in LA County. Proponents of the plan are trying to increase support by talking not only about the increased water it would supply, but also about the dangers of the pollutants in untreated stormwater.
The county has a website to explain the plan to voters, which it does without once using—at least on the home page—the words green infrastructure or low impact development. Instead, it emphasizes that the county could save more than 100 billion gallons of water a year that now disappears into the Pacific Ocean.
Does your community have incentives—or mandates—to use green infrastructure to capture stormwater? If so, have you seen a shift in emphasis, from reducing the volume of stormwater runoff and associated pollutants to capturing a usable volume of water?