Prepare for Drought

Green infrastructure can help communities prepare for drought by infiltrating water where it falls—which replenishes groundwater reserves—and harvesting rainwater, which allows for reuse. This relieves stress on local water supplies and reduces the need to import potable water. As the climate changes, fragile local water supplies are being stressed by decreased precipitation in some areas of the country, making green infrastructure increasingly important.

When a storm event occurs, rain falling on roofs, parking lots, streets, and other hard surfaces may run directly into city storm drains or water bodies. Green infrastructure can help prevent communities from losing valuable water that could be used or stored for when it is needed most. Overburdened and underserved communities with fewer resources and communities with environmental justice concerns may be less likely to have drought-ready infrastructure and are more at risk of negative effects. Visit EPA's page on green infrastructure and environmental justice to learn more.

Explore the sections below to learn how green infrastructure can help communities improve resiliency to drought and find resources for community-based organizations, municipalities, state governmental officials, and tribes implementing green infrastructure.

On this page:

• Using Green Infrastructure for Drought Preparation
• Resources
• References

Using Green Infrastructure for Drought Preparation

Installing green infrastructure, such as rain gardens with native plants and green streets (pdf), can help replenish local groundwater reserves. Using these and other infiltration-based practices 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 is stored to make a difference. Choose low-water-use or drought-tolerant plant species to limit the need for supplemental watering. Additionally, rainwater harvesting through rain barrels, cisterns, and other methods creates a reserve and increases available water sources for non-potable uses during drought.

Reduce the Need for Imported Water

On individual properties, rainwater harvesting techniques like 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 reduce the need to purchase water from out of town.

It is important to be aware of and follow any local ordinances that may have requirements for harvesting methods. The Office of Energy Efficiency and Renewable Energy's map of rainwater harvesting regulations includes ordinances by state.

A recent study (pdf) 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 (13.7 million acre-feet per year)—more than is needed to irrigate all of its orchards, nuts, berries, vineyards, and tomatoes.¹

Recharge Groundwater, Recharge Your Wallet

Groundwater recharge involves retaining or redirecting stormwater to replenish groundwater resources stored in aquifers. EPA conducted an analysis of the value of groundwater recharge that could be achieved through small stormwater retention alternatives for new development and redevelopment. The study found (pdf) that stormwater retention requirements applied nationwide in areas that do not already have state or local requirements could lead to replenished groundwater reserves and stream flow. The highest values of encouraging groundwater recharge were in Colorado, Florida, and Texas, estimated at more than $50 million per state.

Resources

Guides and Fact Sheets:

• Green Streets Handbook (pdf) — This EPA handbook provides information, examples, and considerations for looking to install green streets to address runoff and infiltrate stormwater.
• Incorporating Green Infrastructure into Roadway Projects in Sante Fe — This report demonstrates the application of long-term stormwater planning for addressing regulatory obligations and addressing challenges for community roadway projects.
• Rain Garden Resources — A list of resources curated by EPA to help design and develop effective rain gardens and spread awareness of their importance.
• Rainwater Harvesting Rules — This EPA website outlines several Region 8 rain harvesting rules by state.
• WaterSense What to Plant — This EPA website provides a searchable table of plant lists for across the United States and tips for water efficient landscaping.
• Pima County Regional Flood Control District – Water Harvesting — This page provides "How to Harvest Rainwater" and other resources about rainwater capture and reuse.

Reports and Studies:

• Arid Green Infrastructure for Water Control and Conservation: State of the Science and Research Needs for Arid/Semi-Arid Regions — This webpage provides an abstract of and link to an EPA literature review of current green infrastructure types that may benefit drier regions of the country, as well as an overview of additional research.
• Green Infrastructure Barriers and Opportunities in Phoenix, Arizona (pdf) — This EPA report evaluates local codes and ordinances that create barriers to and opportunities for implementing green infrastructure.
• Enhanced Aquifer Recharge of Stormwater in the United States: State of the Science Review — This EPA report is a summary and synthesis of scientific and technical literature on enhanced aquifer recharge (EAR) using stormwater. It is based on a search and screening of published literature conducted during summer and fall 2020. The goal is to summarize the current state-of-the-science of information, leading to best practices for EAR using stormwater.
• McFarland, A.R., L. Larsen, K. Yeshitela, A.N. Engida, and N.G. Love. (2019). Guide for using green infrastructure in urban environments for stormwater management. Environmental Science: Water Research & Technology, 5:643–659. Retrieved May 5, 2023.
• Morash, J., A. Wright, C. LeBleu, A. Meded, R. Kessler, E. Brantley, and J. Howe. (2019). Increasing sustainability of residential areas using rain gardens to improve pollutant capture, biodiversity and ecosystem resilience. Sustainability, 11(12), 3269. Retrieved May 5, 2023.
• Shuster, W.D., R.A. Darner, L.A. Schifman, and D.L. Herrmann. (2017). Factors Contributing to the Hydrologic Effectiveness of a Rain Garden Network (Cincinnati OH USA). Infrastructures, 2(3), 11. Retrieved May 5, 2023.
• The Untapped Potential of California's Water Supply: Efficiency, Reuse, and Stormwater — 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.

Webinars:

• Regional Reflections on Green Infrastructure and Nature-Based Solutions: Southwest — This webinar, hosted by the American Association for the Advancement of Science's Center for Scientific Evidence in Public Issues (AAAS EPI Center), EPA, and the White House discusses green infrastructure and nature-based solution across the Southwest, including how to mitigate drought with green infrastructure.

References

1. Gleick, P., H. Cooley, K. Poole, and E. Osann. (2014). The Untapped Potential of California's Water Supply: Efficiency, Reuse, and Stormwater—Issue Brief (pdf). Retrieved February 23, 2023.