EPD conducts studies that inform regulatory determinations and permitting decisions that meet federal and state law. EPD is not a research institution, nor does it publish studies for purely academic purposes.
The Georgia EPD conducted a field study of the Laurel View River to evaluate existing water quality conditions and the river's capacity to receive treated wastewater discharges. The study concluded that a permitted discharge at the evaluated levels would have a de minimis impact on the river's water quality while remaining protective of environmental standards.
The study supports the idea that as coastal communities grow, reliance on large numbers of septic systems can increase nutrient loading to groundwater and nearby waterways. A centralized MBR wastewater treatment system is one approach communities use to reduce those cumulative impacts by collecting wastewater in one location, treating it to a much higher standard, and allowing for monitoring, reuse opportunities, and regulated discharge.
The State of Georgia’s Coastal Georgia Regional Water Plan explicitly recognizes that coastal rivers, estuaries, and tidal marshes depend on adequate freshwater inflows to maintain salinity balance, dissolved oxygen levels, nutrient cycling, and overall ecosystem function. The Plan further acknowledges that estuarine conditions are influenced not only by natural hydrology but also by regulated municipal and industrial withdrawals and return flows. Through its surface water quality and assimilative capacity analyses, the Plan explicitly evaluates permitted municipal and industrial wastewater discharges as managed freshwater inputs that must meet water quality standards while supporting tidal rivers and estuarine systems. The Plan also notes that during low‑flow conditions, regulated return flows may comprise a substantial portion of freshwater entering downstream tidal and estuarine waters, underscoring the importance of high‑quality treated discharges in sustaining coastal ecosystems.
In 2023, the Georgia Department of Natural Resources released its Coastal Georgia Ecosystem Report Card, highlighting the current health and condition of the region's ecosystems. This year’s report scored a “B,” or moderately good health, slightly down from last year’s ‘A minus.'
“This drop in scores is likely due to estuary salinity changes caused by decreased rainfall in locations where DNR biologist sample blue crabs,” Jan Mackinnon said. “While these sampling locations stay the same, the blue crabs migrate to different parts of the estuary seeking favorable salinity and water conditions.”
(Adult blue crabs are euryhaline, meaning they can tolerate a massive salinity range from 0 to over 60 PSU (Practical Salinity Units). However, a peer-reviewed study on blue crab salinity tolerance published in Science of the Total Environment indicates that their optimal metabolic baseline is around 10 to 25 PSU.)
The study looked at how thousands of septic systems in Bryan County may affect groundwater and nearby waterways as the area continues to grow. Researchers found that while septic systems can work well when properly designed and maintained, large numbers of them in one area can, over time, contribute nutrients such as nitrogen to groundwater and surface waters. These nutrients can harm water quality, increase algae growth, and impact wetlands and rivers. The study suggests that as population growth continues, relying heavily on septic systems may create greater environmental risks and that centralized wastewater treatment systems can provide more consistent monitoring and treatment of wastewater.
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