Introduction

Water is a critical resource that affects every aspect of life, from the environment and public health to economic development and social equity. In cities like Atlanta, managing water resources presents a complex set of challenges that require innovative solutions. As one of the largest and fastest-growing US metro regions, Atlanta’s water management faces a range of issues, including growth, drought, flood, water quality, and equity. In response to these challenges, the proposed concept of piloting a new water recycling initiative is a critical step towards a more sustainable water supply. In this article, we will examine the water system in Atlanta and the proposed initiative, as well as our analysis that supports this approach.

System Overview 

Fig 1. A map of the City of Atlanta boundary in relation to the Metro North Georgia Water Planning District

Atlanta’s water system, managed by the Department of Watershed Management (DWM), serves approximately 1.2 million customers over a 379 square-mile area, with water treated from the Chattahoochee River. (City of Atlanta Department of Watershed Management 2019) The City is the center of the sprawling 15-county Metropolitan North Georgia Water Planning District, which spans 95 municipalities and 6 river basins.  In 2022, the region used an estimated 560 million gallons of water per day (Metropolitan North Georgia Water Planning District 2022) 

The system faces a number of significant water management challenges, with urban growth, groundwater conditions, and cycles of drought contributing to physical supply scarcity, while increased rainfall events cause flooding, which in turn contributes to water quality issues in the form of sewer backups and combined sewer overflows. And as Atlanta is a city that is highly segregated by race and income, all these issues are bound up with the affordability of water and sewer services, as well as the spatial distribution of where water system failures occur.

Water Management Challenges

Growth, Drought & Heavy Dependence on Surface Water

The region’s regular cycles of drought worsen the city’s water challenges, especially given its reliance on surface water. 

Water management challenges faced by the City of Atlanta within this system are interconnected, with issues of urbanization and population growth creating a strain on the water supply which is then exacerbated by cycles of drought and lack of access to groundwater. The region is the largest population center in the southeastern United States, and growing fast. Anticipating and preparing for growth is a critical issue for Atlanta’s water management, which has experienced a rapid population increase. In the past two decades, the metro region grew 57% – from 3.6 million in 2001 to 5.7 million by 2019 (Macrotrends, 2023). And due to the region’s yearly average rainfall of at least 50 inches, water conservation isn’t a common practice. The perception of an abundant water supply has led Atlanta residents to be profligate with water.

The region depends on weakened tropical storms for the rainfall they provide. However, storm season does not always deliver and total rainfall year over year varies by as much as 20 inches (40%) (Earthzine 2008). The region is increasingly experiencing record-breaking droughts. (National Weather Service, Rainfall Scorecard Data) Over the past 20 years, there have been four drought periods. The 2007-2009 drought was so severe that it brought national attention to the water resource scarcity in the region (U.S. Drought Monitor, National Drought Mitigation Center) As the climate warms, future droughts will come on more unexpectedly and onset more rapidly, as rainfall drops and temperatures rise, increasing the evapotranspiration of water in the soils.

During recent periods of drought, some of the most striking photographs of the impact show Lake Lanier nearly drained, with boating docks extending down into the mud instead of floating on the surface. Currently, 70 percent of the Metro Water District’s water supply comes from Lake Lanier, and the remaining 30 percent of the water supply comes from Allatoona Lake, plus around 20 small reservoirs scattered across the region (Booth 2022).

The entire region is heavily dependent on surface water and storage reservoirs for its supply because of the Piedmont region’s geologic composition of crystalline rocks, which makes accessing large sources of groundwater infeasible. As it is, groundwater makes up less than 1% of public water supplies.(Renner 2010) So when drought conditions occur and Lake Lanier evaporates, as it did in 2007, Atlanta is forced to try to limit water demand, with no other option to maintain critical water supply levels. 

Fig 2. Drought conditions in Atlanta’s reservoir Lake Lanier in Buford, Georgia in late 2007
(PC: Chris Rank/Bloomberg via Getty Images. )

Fig 3. An inventory map of the surface water resources and treatment infrastructure servicing the Atlanta MSA 

Water Rights

Supply constraints are exacerbated by the tri-state water wars and legal disputes over water rights to Lake Lanier and the Chattahoochee River.

The City of Atlanta is likewise at the heart of the legal battles between the states of Florida, Georgia, and Alabama over rights to Chattahoochee River water. Critics fault the region’s leaders for ignoring previous calls to plan for population growth and associated increased water demand. The historic 2007 drought was a particularly alarming turning point in this conflict, as Lake Lanier– the main reservoir that provides Georgia’s drinking water supply– was  90 to 121 days away from running completely dry (Goodman, 2007). The effect of this drought was felt downstream as well, as Florida’s then-failing oyster population took an even greater hit.

In 2009, a federal district judge ruled against Georgia, declaring that Georgia was improperly allocating water from Lake Lanier and was then required to reach a water-sharing agreement with Florida and Alabama. This ruling was reversed in 2011 by the Eleventh Circuit Court of Appeals. The appeal led to the Corps determining that it has the discretion to operate Lake Lanier for the purpose of meeting Georgia’s current and future water needs.

Afterward, Florida filed an original jurisdiction action against Georgia in the U.S. Supreme Court in 2013, claiming that Georgia’s irresponsible use of water within the ACF River Basin caused irreparable harm to Apalachicola Bay and effectively Florida’s economy. The U.S. Supreme Court reached a unanimous decision in April 2021 in the case of Florida v. Georgia: Florida failed to provide enough evidence that any harm to the Apalachicola Bay could not be directly attributed to Georgia’s water use.

Partnering with the National Wildlife Federation, Alabama also took Georgia to court over its water usage. In 2017, the Corps updated the ACF Water Control Manual, which had not been updated since 1958. This manual guides the operations of the Corps’ five reservoirs, as well as the dams and navigation locks in the basin to meet Congressionally authorized purposes such as water supply, recreation, and power generation. That same year, Alabama and the National Wildlife Federation filed legal challenges against the court, claiming that the Corps did not follow procedures put forth by the National Environmental Policy Act (NEPA) when revising this manual. However, in August 2021, a federal judge rejected this lawsuit. Alabama has since appealed this decision (Manganiello, 2023).

Flood, Sewer Overflows & Equity Concerns

Climate change leads to heavier storms and more frequent floods while aging stormwater infrastructure still drives in sewer backups and overflows. 

Atlanta has made remarkable progress in addressing water quality, investing in scaling up stormwater infrastructure throughout the city. Over the past two decades through the Clean Water Atlanta program, the DWM has significantly reduced the volume and frequency with which combined sewer systems overflow wastewater onto streets and into rivers and streams. 

Despite these successes, there remains work to be done. A 2018 EPA report notes that more progress is still needed to address water quality issues (Butler et al, 2018), and a study of sewer overflows between 2002-2013 highlights the links between increased hospital visits due to gastrointestinal illness and combined sewer overflow events (Seltenrich, 2022). Combined Sewer Overflows (CSOs) and Sanitary Sewer Overflows (SSOs) spill millions of gallons of sewage into Atlanta creeks and rivers every year.(Butler et al. 2018) And most of sewage overflow events occur in neighborhoods that are majority black and low-income (McCormack 2022).

Going forward, it is likely the region will continue to grow, and both droughts and flood-causing storms will worsen. To cope with what will inevitably become worsening cycles of too little water (drought), followed by too much water (flood), the city of Atlanta needs to invest in both better stormwater and storage infrastructure as well as identify ways to expand its portfolio of sources for drinking water. 

Leveraging Water Recycling

Implementing an extensive, city-wide water recycling program will help diversify the water supply portfolio and meet the growing demand for drinking water in a supply-constrained system. The proposed water recycling initiative would intercept the treated wastewater that has been processed up to less than portable quality and released into the Three Rivers tunnel. Instead of sending this water and discharging it into the Chattahoochee River – or other water bodies– the initiative would collect this partly-treated water locally, store it in wetlands and detention ponds,  and eventually return it to water treatment plants where it would be treated up to drinking water standards. This would create a net positive impact on the urban water cycle, closing the loop, creating a critical new drought-resilience water source, and promoting more sustainable water management practices. This process is similar to what’s being done in  Clayton County where they have been successful in treating wastewater using wetlands and providing a new source of potable water through closed-loop, water recycling. 

Clayton County Constructed Wetland

Fig 4. Clayton County Constructed Wetlands (PC: U.S. Climate Resilience Toolkit)

One of the main inspirations for this intervention is Clayton County’s E.L. Huie Jr. Constructed Treatment Wetlands, which was completed as part of the Clayton County Water Authority (CCWA) 2000 Master Plan (Thomas, 2013). The 100-acre constructed wetlands treat an average of 17.4 MGD of wastewater per day but can treat up to 42 MGD, providing wastewater treatment services for the county’s 250,000 residents (Sewanee Wetland Research Station). Effluent that is released into this system is treated up to potable standards and eventually reclaimed (Miller, 2018). 

The project has been so successful that during the historic 2007 drought that almost dried up the City of Atlanta’s source of drinking water, Clayton County’s water reserves remained at 77%. The county was able to provide supplemental water to the City of Atlanta during this period of physical scarcity (Sewanee Wetland Research Station).

The process begins by pumping treated effluent from nearby wastewater treatment facilities into the wetland through subterranean piping systems. Once the effluent is introduced to the wetland it is able to move throughout the system via gravitational flow, as each of the clay-lined wetland cells are at varying depths. Each wetland cell is filled with multiple species of plants to enhance treatment capacity while also encouraging biodiversity. The entire process takes five days, providing an additional 10 to 20 percent of conventional pollutant removal (Force, 2011). Once treated, the water is piped into CCWA’s Shamrock and Blalock Reservoirs, where it is stored until it is channeled to drinking water treatment facilities for production and distribution (Wastewater Digest, 2004).

Piloting a New Water Recycling Initiative: The Browns Mill Golf Course Site Proposal

While the intention of this intervention is to implement a system of city-wide water recycling initiatives, it’s important to highlight in this proposal how land conversion to urban wetlands might appear on a site-specific basis. For this prototype, the Browns Mill Golf Course was selected as the first example. 

The Browns Mill Golf Course is currently an 18-hole golf course– one of six publicly funded courses in the City of Atlanta– located within the South River watershed. The South River was named one of “America’s Most Endangered Rivers” by American Rivers, highlighting the river’s threat to public health (American River, 2021). Additionally, Entrenchment Creek, which is a neighboring watershed, is the site of nearly half of Atlanta’s CSO events (Seltenrich, 2022). The context of this site is clearly suited for an intervention that reduces flooding while simultaneously improving water quality.

Nearly half of the golf course is within a high flood hazard area (FEMA, 2023)– unsurprisingly, considering that the South River bisects the course. Just across the street from Browns Mill is the South River Water Treatment Plant. The plant is permitted to discharge 48 million gallons of water per day into the Chattahoochee River (Georgia Department of Natural Resource, 2017).

Taking inspiration from the Clayton County Constructed Wetlands, the Browns Mill Golf Course could be designed to accommodate a fraction of the effluent from the South River Water Treatment Plant to be treated to potable standard before piping this water back into the system for drinking water supply. Effectively, the urban wetland will close the loop in this particular water system to provide a resilient supply of water to Atlanta residents.

Fig 5. Constructed wetland site design for the Browns Mill Golf Course

The site design presented above would propose removing nine holes of the 18-hole golf course to convert to a constructed wetland system. The wetland would be roughly 73 acres, with four treatment cells and the capacity to treat an estimated 14 MGD of wastewater piped from the South River Water Treatment Plant. By utilizing existing piping infrastructure, the water could be delivered to one of Atlanta’s drinking water facilities for redistribution.

Expanding the Water Recycling Initiative City-Wide

The browns mill example demonstrates how existing infrastructure can be repurposed and expanded upon throughout the city to accommodate water recycling. Overall, the intention is to implement such urban wetland projects throughout the City of Atlanta to establish city-wide water recycling infrastructure. This could be achieved at a city-wide scale by utilizing existing public infrastructure, such as a public golf course, to address the need for a more resilient water supply. Another example of existing infrastructure that could be expanded and repurposed is the Bellwood Quarry, which currently holds water reserves that could last the city up to 30 days (ATL Parks & Rec, 2023). The Bellwood Quarry currently gets this supply of “raw” water directly from the Chattahoochee. Instead, with integrated water recycling infrastructure, the Bellwood Quarry could store water waiting to be recycled through constructed wetland systems to be treated for potable use. Additionally, at a certain scale, these systems could be used to provide an additional supply of both potable water and nonpotable water as well.

Fig 6. Demonstrates the site suitability criteria for water recycling infrastructure for the City of Atlanta

Despite being a replicable solution for water recycling, the success of each proposed facility largely hinges upon certain suitability criteria associated with the geography and the “public view” of the site. Our study determined these criteria using our understanding of our case studies on the Clayton County Constructed Wetland, which was completed as part of the Clayton County Water Resource Management Plan of 2000. Coupled with mathematical weights assigned by the decision maker (on a case-by-case basis), combining these criteria informs the selection and subsequent prioritization of intervention for various sites. It is important to note that our proposal recognizes the political friction that can arise due to such proposals. As a result of this, we consider that the political expediency criterion would be assigned the maximum weight in most cases, owing to how this criterion interacts with other criteria and has the potential to cancel projects entirely if they are not politically feasible.

 Besides the suitability criteria for individual sites, our study also estimated the direct and indirect synergies that would arise as a result of scaling our proposed intervention to multiple sites across the city. In the short term, we expect infrastructural synergies in the form of stormwater pipe connections would significantly reduce the cost of routing stormwater catchment in water recycling facilities. This effect would be further strengthened by sites that are at a favorable elevation for the point of stormwater entry into the site. Indirectly, we expect the cost savings to encourage other wholesale water customers in the region to express interest in adopting water recycling to meet their irrigation needs. Extrapolating further, the growth of a culture of water resource sustainability must be explored to modify water usage behavior across user groups. It is important to note here that even though the most favorable scenario surrounding sustainable water resource use seems feasible to reach within a reasonable time frame, the rate at which Atlanta reaches this scenario is a function of all of the suitability criteria – instead of considering political expediency exclusively.

Challenges and Considerations

Expanding the water recycling initiative city-wide presents several challenges and considerations that must be addressed to ensure its success. One major concern is ensuring the safety and quality of the recycled water. To address this, rigorous testing and monitoring programs must be established to ensure that the water meets all applicable health and safety standards. 

Additionally, addressing concerns and objections from local communities and stakeholders is critical to gaining support for the initiative. Effective communication and education efforts will be necessary to build understanding and trust in the safety and effectiveness of the initiative. 

Fortunately, Atlanta would not be the first in the United States to attempt this PR feat. One example where this was successfully accomplished is in the Orange County Water District (OCWD) in California, which since 2008 has pioneered a wastewater treatment facility that recycles wastewater, mixes the recycled water with the rest of the groundwater supply, and returns it to the drinking supply.(Monks, 2015) 

The process works by rerouting a proportion of the 1.3 billion gallons of wastewater generated in Southern California each day into a three-step treatment involving microfiltration, reverse osmosis, and UV light treatment. Mixing the output of the Orange County Water District’s wastewater treatment facility with the main groundwater supply is a measure taken to reassure the public about the safety of the recycled water, but it is largely unnecessary in terms of the water’s quality.(Monks 2015) The wetlands in the Clayton County facility can be seen as serving much the same purpose – although it carries additional benefits in terms of filtration and generating new habitats for birds and wildlife.

The Orange County system was initially met with public skepticism, but a comprehensive PR and education campaign helped to gain public acceptance. By highlighting the safety of the water and its ability to reduce demand on traditional water sources, the program was able to gain widespread support from the community. 

Conclusion

In conclusion, the proposed water recycling initiative near the South River Water Reclamation Center is an essential step toward addressing Atlanta’s most significant water-related challenges. By expanding the initiative citywide and incorporating green infrastructure like wetlands, the city can create a more sustainable and diversified water supply. A cost-benefit analysis supports the proposal, as the long-term benefits would far outweigh the initial investment. By focusing on water recycling, Atlanta can ensure that it meets its growing demand for drinking water while promoting a more equitable and sustainable future for all its residents.

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