The May River is a picturesque, tide-driven estuary located in the heart of the Lowcountry, flowing alongside the historic Town of Bluffton in Beaufort County, South Carolina. Unlike typical rivers, the May has no significant freshwater source at its headwaters, relying instead on the rhythmic, semi-diurnal tides of the Atlantic Ocean (which range from 2.5 to 3 meters) to maintain its flow and ecosystem. This unique environment is the lifeblood of the area, providing crucial habitat for natural resource populations, including Bottlenose Dolphins, Bald Eagles, and various finfish, shrimp, crabs, and, most famously, the highly coveted Bluffton oyster.
A Brief History
The river has been central to human life in the region for millennia:
- Indigenous Roots: For thousands of years, Indigenous people, including the Yemassee, visited the area to fish in the tidal waters, hunt in the forests, and gather oysters on the marsh edges.
- Colonial Era and Antebellum Retreat: European settlers began purchasing land along the river in the 18th century, developing large plantations. During the antebellum period, wealthy plantation owners from the sweltering inland rice plantations, particularly around Savannah, brought their families to the high, breezy bluffs overlooking the river to escape mosquitoes and disease during the summer. The town of Bluffton itself is named for this signature high bank jutting from the river’s edge, and was incorporated in 1852.
- Commerce and Seafood: Throughout the 19th and early 20th centuries, the May River served as the town’s main artery for transportation and commerce, connecting it to Savannah and Charleston via packet ships. Its most economically coveted resource, however, was, and remains, the Eastern oyster. The Bluffton Oyster Company, the last continuously operational oyster shucking facility in South Carolina, has been tied to the river since 1899, with the May River historically supplying nearly 20% of the state’s annual harvest.
- Modern Challenges: Recognising its immense ecological, cultural, and economic value, the May River has been designated as an Outstanding Resource Water (ORW) by the state of South Carolina. However, the town’s rapid population growth and resulting development in the early 2000s led to increased stormwater runoff and rising Fecal Coliform levels, causing nearly one-third of the headwaters to be closed to shellfish harvesting in 2009. This event spurred the creation and continued updating of the May River Watershed Action Plan, demonstrating the community’s commitment to protecting its defining natural feature.
The May River Watershed Action Plan Update & Modeling Report addresses the significant water quality degradation in the May River Headwaters, an area designated as an Outstanding Resource Water (ORW) by the South Carolina Department of Health and Environmental Control (SCDHEC). The primary concern is the sustained elevation of Fecal Coliform (FC) bacteria, which led to the closure of shellfish harvesting beds in this crucial portion of the May River in 2009.
The core issue is directly linked to rapid development within the Town of Bluffton, which saw its population grow dramatically. This growth caused the total impervious surface area in the Headwaters to nearly triple, increasing from 5.78% in the 2002 baseline condition to 15.31% in the 2018 current condition. The total amount of developed land jumped from 10.67% of the Headwaters area in 2002 to 30.72% in 2018. This expansion of impervious surfaces—including roads, buildings, and parking lots —is a key contributor to increased stormwater runoff volume and pollutant loading, which is further exacerbated by the fact that FC bacteria persist in fresh water. The model results showed that higher FC levels correlate strongly with decreased salinity, a direct result of freshwater input from developed and deforested areas.
To refine remediation efforts, a Water Quality (WQ) Model was developed and calibrated using XPSWMM software to compare the 2002 baseline to 2018 current conditions. This modeling identified Rose Dhu Creek and Stoney Creek as the most impervious and high-loading sub-basins.
The report’s purpose is to update the original 2011 Action Plan, which is considered a “living document” that requires revision based on changing land-use conditions and lessons learned from previously implemented projects. While the Town has successfully used grant funding to implement projects, such as the New Riverside Stormwater Pond, post-treatment monitoring did not always show a statistically significant decrease in FC concentrations further downstream. Ongoing Microbial Source Tracking (MST) has identified human, deer, and dog markers and has already resulted in the elimination of five failing septic systems.
The updated plan’s strategies are organized around the “Four Ps”: Partnerships, Policies, Programs, and Projects. Key recommendations include:
- Programs/Monitoring: Expanding Microbial Source Tracking (MST) capabilities and establishing new monitoring locations for both bacteria and water flow.
- Policies: Adopting a new regional Post Construction Stormwater Ordinance and Design Manual to enforce more restrictive requirements, such as reducing overall imperviousness.
- Projects: The report evaluates and proposes Capital Improvement Program (CIP) projects , specifically prioritizing Septic-to-Sewer Conversion Projects and high-impact Stormwater Best Management Practice (BMP) Retrofit Projects.
Ultimately, the core recommendation is to adhere to Better Site Design principles. This strategy focuses on reducing stormwater runoff volume and FC loading by conserving natural areas, decreasing impervious cover, and maximizing stormwater infiltration throughout the May River Headwaters.