Natural Security: Clayton County, Georgia
Withstanding Drought with Wetlands and Water Reuse
Challenge
In recent years the Southeastern United States has faced major water supply challenges. Communities throughout the region have seen water supply reservoirs drop dramatically, falling below 50 percent capacity in some cases. A region historically blessed with abundant water is now facing shortages due to growing populations, rapid development, mismanagement and extended droughts. Development has brought acres of roofs and parking lots that turn rainfall into polluted runoff where once it was allowed to soak into the ground and recharge water supplies. Inefficient irrigation and wasteful water use in homes and businesses throughout the region force ever larger withdrawals from rivers, aquifers and reservoirs. Communities are now faced with the pressing question of how to ensure a clean, reliable water supply for current and future generations.
Approach
Amidst the bleak water supply realities that have faced the region in recent years, one bright spot has been Clayton County, Georgia. Located south of Atlanta, the county’s reservoirs have remained near capacity even in record drought conditions. The Clayton County Water Authority (CCWA) uses an innovative water recycling wetland system to bolster water supply and has undertaken a number of water quality and efficiency initiatives. The use of recycled wastewater provides a consistent drought-resistant supply of water, while the wetlands gradually release water over time, reducing vulnerability to droughts.
Clayton County’s wetland systems consist of a series of interconnected, shallow ponds filled with native vegetation. Wastewater is first processed in an advanced treatment facility and then discharged to the constructed wetlands which remove remaining pollutants such as excess nutrients like nitrogen and phosphorus. The first section of wetlands was completed in 2003, and additional sections will be completed in 2010 and 2012.
In addition to investing in water reuse, Clayton County has taken a number of steps to protect its water supply from drought and contamination. In order to improve efficiency and avoid unnecessary waste, CCWA has undertaken a successful leak detection program and provided incentives for customers to install water efficient fixtures and appliances. The county has also worked to reduce stormwater pollution in order protect the small streams that recharge water supply reservoirs.
Benefits
Clayton County’s investment has clearly demonstrated the value of wetlands and water recycling over the past several years. During one of the worst droughts of the past 50 years, CCWA’s reservoirs maintained at least a 230 day supply while the Atlanta area at one point had only a 90 day supply of water in its main reservoir, Lake Lanier. The county is nonetheless continuing to expand the capacity of its water reclamation system. When the final sections are completed, the entire system will be able to produce over 28 million gallons of water per day (mgd). The wetland system is also more cost effective than conventional alternatives. Building a wastewater treatment system using constructed wetlands costs about $5.00 per gallon of capacity compared to roughly $10.00 per gallon of capacity for a conventional advanced treatment facility.
The wetlands provide a number of benefits to the community aside from a drought-resistant water supply. They attract a wide range of wildlife and provide habitat for 130 species of birds. Four thousand acres of protected forest land are available for public recreation, including fishing, hunting and hiking. A wetland center and nearby trails serve as educational facilities and host the annual Wetland and Watershed Festival as well as elementary school field trips. Over 20,000 people visit the wetlands annually including international visitors from as far away as Australia.
Adapting to a Changing Climate
Climate projections suggest that the dry conditions of past years offer a glimpse into what the future could hold for the southeastern U.S. Warmer temperatures and declining summer precipitation will lead to worsening droughts and water shortages. If that is the case, Clayton County’s water supply system has clearly demonstrated that it is able to meet the challenge. As neighboring communities went dry in recent years, CCWA continued to provide a safe and consistent supply of water and was able to avoid the water restrictions that other communities experienced. There are two key elements of Clayton County’s water system that make it well adapted to more arid and unpredictable weather patterns. Recycled wastewater is a drought-resistant supply that may decrease slightly during droughts, but will never disappear completely. The use of a wetland system also helps buffer against drought because wetlands release water gradually, delaying the effects of drought. The combination of reuse and treatment wetlands will ensure a continuous inflow and gradual release of treated water to the county’s water supply reservoirs. Even in a changing climate, Clayton County will be able to withstand extended droughts and continue to provide clean water to homes and businesses.
