BCI Engineers and Scientists

The SWFWMD contracted BCI to concentrate on water quality Best Management Practice (BMP) development for lakes located within the Lake Wales Ridge that were threatened by stormwater non-point source pollution. Lakes included in this work were Menzi, Marie, Gordon, Isis, McCoy, Clay, June-in-Winter, and Tulane. The District had previously inventoried outfalls and made preliminary assessments of stormwater impacts on the lakes.

BCI’s tasks included developing pollutant load estimates for the above referenced sub-basins/stormwater outfalls, prioritizing the outfalls based on pollutant loads to the lakes, and developing alternative BMPs to remove stormwater load to the lakes with the management objective of keeping the lakes off of the impaired waters list.

BCI used land-use-based Event Mean Concentration pollutant loadings to fairly and cost-effectively prioritize the critical outfalls. Directly connected imperviousness was reviewed carefully due to the preponderance of Type A hydrologic soil group soils and the associated pollutant mass load that is generated from these areas.

Concept BMPs to remove as much nutrient load as possible were drawn schematically in GIS and included such measures as swales, exfiltration trenches, sedimentation inlets and ditch blocks. These BMPs are to be located in urbanized, scenic areas; therefore, aesthetics, footprint minimization and working with the natural surroundings weighed heavily in the design optimization process.

Much of the proposed BMP construction activity is sited in existing governmental lands to help eliminate land procurement costs and to facilitate local municipalities and FDOT to participate in the project. To date, the Lake Menzie project has been fully implemented and the stormwater retrofit was constructed at a cost of $180,000. Currently the Lake Clay stormwater retrofit, which will be a public/private partnership, is on hold while project easements are finalized. Priority drainage sub-basins vary from two acres to approximately 50 acres in size, depending on the imperviousness and associated pollutant load intensity.