Volusia County’s Blue Spring is a first-magnitude spring not currently achieving its minimum flows and levels (MFLs). As part of the recovery strategy for meeting MFLs, the St. Johns River Water Management District (SJRWMD) is working with the West Volusia Water Suppliers (WVWS) to identify and implement projects that will help to increase flows at the Spring. The B&H Excavation Site, about 0.5-mile northeast of Blue Spring, was identified as a potential recharge site that could achieve SJRWMD and WVWS goals. The site is an active mine covering about 60 acres that was excavated to approximately 40 to 50 feet below natural grade. The west side of the property borders an existing 10-inch force main owned by Florida Department of Transportation that conveys stormwater discharge from Mill Lake to the St. Johns River.
Jones Edmunds worked with SJRWMD and WVWS to evaluate the feasibility of using the B&H Excavation Site for a recharge of between 2 to 5 million gallons per day (MGD) to benefit Blue Spring while not adversely impacting water quality at the spring. The project’s water quality target is 0.35 milligrams per liter (mg/L) nitrate at the point of discharge from the treatment system and before recharge. Jones Edmunds developed site layouts and evaluated the following three treatment options: biosorption activated media (BAM) filter; infiltrating wetlands; and BAM and infiltrating wetlands combination.
The results of our study show that a recharge project on this site project is economically, environmentally, and technically feasible. The geotechnical data collected along with groundwater modeling performed as part of the preliminary engineering report provided valuable information for understanding the site’s hydrogeological behavior. Our analysis indicates that the site can be engineered to meet the design goals specified by SJRWMD and WVWS while not adversely impacting water quality at the spring. Our groundwater modeling indicates that recharge of 2 MGD of reclaimed water at the project site will result in an additional 1.7 MGD of flow at the spring. The long-term average flow at Blue Spring is about 101.5 MGD. This project could restore almost 2% of the spring flow for a cost less than $10M – a high level of cost-effectiveness that would receive favorable consideration for SJRWMD cost share funding.
We recommended a combined system using biosorptive activated media (BAM) and infiltrating wetlands as the preferred alternative for the following reasons:
– The BAM and wetland combined system strikes a balance in cost and benefits to the environment.
– The BAM and wetland hybrid are expected to have lower operating and maintenance costs relative to full buildout using either BAM or wetlands.
– Achieving the full BAM buildout would require significant site work and may require import of fill material resulting in higher capital costs.
– The WVWS identified an ability to supply 2 MGD of reclaimed water to the site. Wetlands are incorporated as a natural system benefit and can serve as an educational park area for the community.
In August, the Volusia Aquifer Recharge project load tests were approved at the County Council meeting.