Coastal Squeeze: Sewer Systems
Charleston’s bacteria pollution problems are not due to septic tanks alone. In August, Tropical Storm Debby caused untreated sewage to overflow from Charleston Water System’s Plum Island Treatment plant releasing 1 million gallons of wastewater containing fecal bacteria and pathogens into Charleston Harbor, where many of us fish, sail, and swim.
Debby wasn’t the first storm to cause this kind of overflow. Sewer overflows happen far too frequently in the tri-County area. The Plum Island sewage treatment plant overflowed 5 times in the past 12 months, and in the past three and a half years local sewer authorities spilled more than 11.5 million gallons of raw sewage into our waterways and communities. Heavy rain storms, floods, King Tides, sea level rise, and aggressive population growth strain local sewer collection and treatment infrastructure. Unless we act, coastal squeeze means the problem will only get worse.
Coastal squeeze occurs when development moves closer and closer to the shoreline while rising sea levels encroach into coastal communities. This reduces the natural buffer between communities and the water, putting pressure on local infrastructure to withstand the impacts of a changing climate. At the same time, coastal ecosystems like native forests, sand dunes, freshwater wetlands, and salt marshes are losing their ability to protect against storms and floods.
A well maintained and operated sewer system is the most resilient way to protect local water quality and public health. However, they too often overflow under pressure from population growth, poor management, increased development, inundation from heavy rain and floods, and a lack of maintenance for aging infrastructure.
Aging Infrastructure and a Growing Population
The Town of Hollywood’s sewer system is a prime example. After years of neglect and deferred maintenance the Town’s sewer system spilled more than 10 million gallons of untreated sewage into a tributary of the Stono River over the course of two months in 2018. The spill closed local oyster beds during the height of harvesting season and triggered oyster recalls throughout our community.
Sewer Overflows all too Familiar in Charleston
Unfortunately the Town’s of Hollywood’s sewer woes are not uncommon. According to South Carolina’s Department of Environmental Services (DES) sanitary sewer overflow data, 13 local sewer authorities reported 185 sanitary sewer overflows (SSOs) since 2021. Based on this data it is estimated that Charleston Water System, which services downtown, Daniel Island, and West Ashley is responsible for 57% of all overflows in the tri-county area in the past 3.5 years.
James Island Creek and West Ashley are overflow hotspots. Two overflows near James Island Creek have occurred since 2019. The first dumped 7,200 gallons of untreated sewage into the already polluted creek, while another spill in early 2023 went undiscovered for months and released an unknown amount of raw sewage directly into the creek.
Between August and September of 2022, heavy rains in West Ashley caused a major sewer overflow, spilling 40,000 gallons of sewage from a manhole on Donahue Drive. During Tropical Storm Debby in August the manhole spilled 150,000 gallons of sewage. Although Charleston Water System plans to improve this infrastructure, those living near overflows are at risk of exposure to pathogens and bacteria until the work is completed.
Overflows occur for a variety of reasons, but locally one of the most common causes is inflow and infiltration of floodwater into cracks and breaks in sewage pipes. During the week of Tropical Storm Debby’s heavy rains local sewer authorities reported 43 overflows that spilled more than 5 million gallons of raw sewage.
The frequency of wet weather overflows highlights the urgent need to upgrade the Lowcoutnry’s sewer systems to prevent overflows and best protect water quality and public health now and for future generations.
Action for Clean Water
In February 2024, Charleston Waterkeeper, represented by the Southern Environmental Law Center (SELC), threatened to sue Charleston Water System if CWS failed to take action to stop its frequent and repeated overflows. While no lawsuit has been filed yet, Charleston Waterkeeper, SELC, and CWS have maintained a dialogue aimed at solving CWS’s overflow problems and the environmental and public health risks they pose.
You can help stop sewage pollution in your local waterways too!
If you see a sewer overflow report to the nearest sewage authority as soon as possible. Here are some helpful numbers:
Berkeley County Water and Sewer: 843-572-4400
Charleston Water System: 843-727-6800
Dorchester County Water & Sewer: 843-832-0075
Mount Pleasant Waterworks: 843-894-9626
North Charleston Sewer District: 843-764-3072
Summerville CPW: 843-871-0810
Talk to your state and local elected officials about sewer overflows and bacteria pollution. Talk to elected board members at your local sewer authority. Ask them to support action that (1) supports smart planning tying growth to the availability of public sewer, (2) upgrades sewage infrastructure to protect public health and water quality, and (3) focuses on solutions that fix inflow and infiltration of flood water into sewer pipes.
Know before you go. Check Charleston Waterkeeper’s Swim Alert data to see where it’s safe to swim.
Want to learn more? Read this…
References
Chester, J. (2024, February 29). Charleston’s sewers sometimes overflow. Now the issue is likely heading to court. Post and Courier. https://www.postandcourier.com/environment/charleston-water-system-lawsuit-overflow-waterkeeper-selc/article_edbf681c-d5a3-11ee-bbb0-b797b29bc1b9.html
Defeo, O., McLachlan, A., Armitage, D., Elliott, M., & Pittman, J. (2021). Sandy beach social–ecological systems at risk: regime shifts, collapses, and governance challenges. In Frontiers in Ecology and the Environment (Vol. 19, Issue 10, pp. 564–573). John Wiley and Sons Inc. https://doi.org/10.1002/fee.2406
Johnson, C. (2021, June 10). SC town with history of sewer leaks may remove pipe that was site of 10-million-gallon spill. Post and Courier. https://www.postandcourier.com/news/sc-town-with-history-of-sewer-leaks-may-remove-pipe-that-was-site-of-10/article_26dad4bc-c948-11eb-b5de-5f81588d5b55.html
Llerna, R. (2022, September 9). Heavy rain leads to sewer overflows in West Ashley, Charleston Water System says. Live 5 WCSC. https://www.live5news.com/2022/09/09/charleston-water-system-heavy-rainfall-leads-sewer-overflows-west-ashley/
Petersen, B. (2019, August 15). Over 7,000 gallons of raw sewage spilled from treatment plant into James Island creek. Post and Courier. https://www.postandcourier.com/news/over-gallons-of-raw-sewage-spilled-from-treatment-%20plant-into/article_3c8f6590-bf7f-11e9-97d6-af8c427f941f.html
SCDES. (n.d.). SSO List. SCDES Online Services. Retrieved August 26, 2024, from https://epermweb.dhec.sc.gov/ncore/external/overflow/list
Stumpf, C. H., Peeler, M. F., Thomas, S., & Noble, R. T. (2010). Loading of fecal indicator bacteria in North Carolina tidal creek headwaters: Hydrographic patterns and terrestrial runoff relationships. Water Research, 44(16). https://www.sciencedirect.com/science/article/abs/pii/S0043135410004720?casa_token=F8m16o7gKvAAAAAA:Qg6mbeU-mvn5uSm5xj2uvKaOPAP2zBzd1GqaZQBUpG3Bb1Z20JY3rS6768Mapn05yO1NlKHeHQSwim Alert. (n.d.). Charleston Waterkeeper. Retrieved August 26, 2024, from https://charlestonwaterkeeper.org/swimalert/
