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Historically, the Dona Bay watershed (in Sarasota County, Florida) encompassed approximately 10,000 acres, whereas, currently, the watershed includes almost 48,000 acres. The fivefold expansion in area is the direct result of the channelization of the historical Cow Pen Slough by a series of deeply incised canals. This diversion of a significant portion of the Myakka River Watershed into the Dona Bay watershed has quadrupled the freshwater flows to Dona Bay and altered its estuarine ecology, including the decline of oyster populations during the wet season; however, water cannot presently be diverted back to the Myakka River due to flooding concerns. ENTRIX censused Sarasota County-owned lands located within the Dona Bay Watershed to evaluate the re-establishment of the historical floodplain wetland system of Cow Pen Slough and the Cow Pen Slough-Myakka River connection, the potential for storage of freshwater for public water supply, and the avenues to increase water quality in the estuary. The proposed Watershed Management Plan included the restoration of 310 acres of floodplain wetlands and the creation/restoration of 115 acres of freshwater marsh; the potential yield of 15 million gallons/day of public water supply; stormwater load reductions of 38-57% for N, 56-70% for P, and 82-88% for TSS; increased estuarine salinity of 10 ppt; and decreased freshwater runoff into the Dona Bay estuary by 41%. Sarasota County is currently undertaking Phase 1 of the Dona Bay Watershed Management Plan, which includes the restoration of 180 acres of floodplain wetland and the construction of a conveyance corridor between Cow Pen Slough Canal and a future public supply reservoir. Team members included Kimley-Horn and Associates (Master Plan and Phase 1), Post Buckley Schuh & Jernigan, Mote Marine, and EarthBalance. |