Build Resiliency to Drought
Fragile local water supplies are being stressed by decreased precipitation associated with climate change in some areas of the country. When a storm event does occur, rain falling on roofs, parking lots, streets, and other hard surfaces runs directly into city storm drains or water bodies. Communities are losing valuable water that could be used or stored for use when it is needed most.
On this page:
This page contains technical information and references for state and local government officials working in the field of stormwater management.
Installing green infrastructure such as rain gardens and green streets can help replenish local groundwater reserves. These infiltration-based practices and others located in parking lots, along streets, and near buildings can allow rainwater to slowly soak into the ground as it would in a natural setting. While some of the water will evaporate or be soaked up by plants, enough will be stored to make a difference. See: Rain Garden Resources and Green Street Handbook
Reduce the need for imported water.
- On individual properties, rainwater harvesting techniques such as rain barrels and cisterns can reduce demand for potable water. By using stored rainwater to irrigate landscaping in public parks, schools or municipal buildings, or for non-potable uses such as toilet flushing and cooling system make-up cities can eliminate the need to purchase water from out of town. A recent study estimates that by instituting a combination of stormwater capture, water efficiency and water harvesting programs, California could save 4.5 trillion gallons of water a year – more than is needed to irrigate all of it’s orchards, nuts, berries, vineyards and tomatoes.
- Rain barrels, cisterns, and other rainwater harvesting techniques on individual properties can reduce demand for potable water. Eliminate the need to purchase water from out of town by using the stored rainwater:
- to irrigate landscaping in public parks, schools, and municipal buildings; or
- for nonpotable uses such as toilet flushing and cooling system makeup.
Recharge groundwater, recharge your wallet.
- EPA recently conducted an analysis of the value of groundwater recharge that could be achieved through small storm retention alternatives for new development and redevelopment. The study found that stormwater retention requirements applied nationwide in areas that do not already have state or local requirements could lead to replenishment of groundwater reserves and stream flow. The value of encouraging groundwater recharge in these areas was estimated at more than $50 million. See: Green Infrastructure and Ground Water Impacts
The analysis also estimates the value of encouraging groundwater recharge in these areas at more than $50 million. See: More information on how green infrastructure can increase rates of groundwater recharge.
Make the most of rainwater when it is available through capture and use, as well as storing it for later within deep groundwater reserves.
- Prioritize areas in your community to locate infiltration-based green infrastructure practices such rain gardens, planter boxes, and bioswales. Your priorities will depend on local soils, slope, and current land use. Proper siting of green infrastructure should be considered to protect groundwater supplies. For example, avoid infiltrating large quantities of water in contamination hot spots or on steep slopes. See: Learn more about Green Infrastructure Practices
- Consider incentives or local requirements to encourage on-site rainwater harvesting. In Tucson, Arizona, city officials passed a commercial rainwater harvesting ordinance requiring facilities to meet 50 percent of their landscape irrigation demands using harvested rainwater. Covered facilities also must prepare a water harvesting plan and water budget, meter outdoor water use, and use irrigation controls that respond to current soil moisture conditions. See: Tucson, Arizona’s Commercial Rainwater Harvesting Ordinance (PDF)(6 pp, 3.5 K, About PDF) .
- Consider including green infrastructure as part of long-range water planning efforts if your area is dependent on groundwater supplies for drinking water and irrigation. Milwaukee, Wisconsin used a University of Wisconsin-Madison model to help inform a regional green infrastructure plan. It showed that approximately 4 billion gallons of stormwater per year could be infiltrated in the area by combining porous pavement and bioretention practices.
Arid Green Infrastructure for Water Control and Conservation: State of the Science and Research Needs for Arid/Semi-Arid Regions — This page provides an abstract and link to an EPA literature review of current green infrastructure practices that may benefit drier regions of the country and an overview of additional research.
Commercial Rainwater Harvesting Ordinance (PDF) (6 pp, 3.5 K, About PDF) —In October 2008, the city of Tucson adopted the first commercial rainwater harvesting ordinance in the country. It requires facilities to use harvested rainwater to meet 50 percent of their landscaping demand.
Pima County Regional Flood Control District – Water Harvesting —This page provides "How to Harvest Rainwater" and other resources about rainwater capture and reuse.
University of Arizona – Center for Climate Adaptation Science and Solutions—This website is a practitioner network and clearinghouse for southwest regional adaptation resources, research, and tools.
The Untapped Potential of California’s Water Supply: Efficiency, Reuse, and Stormwater Exit—This article discusses a study by the Natural Resources Defense Council and Pacific Institute. Their statewide analysis examined the potential results achievable from a combination of improved efficiency in agricultural and urban water use, water reuse and recycling, and increased capturing of local rainwater were combined.
Shuster, W.D., R. Gehring, and J. Gerken. 2007. Prospects for enhanced groundwater recharge via infiltration of urban storm water runoff: A case study. Journal of Soil and Water Conservation 62(3):129-137. Exit.
Dussaillant, A. R., C. H. Wu, and K. W. Potter. 2004. Richards equation model of a rain garden. Journal of Hydrologic Engineering 9(3):219–225. Exit.
Swann, L. 2008. The Use of Living Shorelines to Mitigate the Effects of Storm Events on Dauphin Island, Alabama, USA (PDF). (12 pp, 1.2 K, About PDF) Exit Retrieved July 1, 2014.
Pacific Institute and Natural Resources Defense Council. 2014. The Untapped Potential of California’s Water Supply. Exit Retrieved July, 1, 2014.
Devinny, J. S., S. Kamieniecki, and M. Stenstrom. 2005. Alternative Approaches to Stormwater Quality Control, USC Center for Sustainable Cities, University of Southern California, Los Angeles, CA (PDF).(95 pp, 1.2 K, About PDF) Exit.
Milwaukee Metropolitan Sewerage District. Green Infrastructure Benefits and Costs: MMSD Regional Green Infrastructure Plan (PDF). (14 pp, 1MB, About PDF) Exit Retrieved October 26, 2015.