Creating an Oxbow in a Channelized Creek to Improve Water Quality and Wildlife Habitat

Delaney Creek is a highly disturbed, channelized creek that drains a 16-square mile area of industrial, residential, and agricultural areas in southern Hillsborough County, Florida. In order to improve on the poor water quality and wildlife habitat in the creek, the Hillsborough County Stormwater Department and the Surface Water Improvement and Management (SWIM) section of the Southwest Florida Water Management District joined forces to fund the design and implementation of the proposed Delaney Creek improvements. The project site is a 10.6-acre parcel including approximately 3.11 acres of channelized jurisdictional wetlands hydrologically connected by tidal fluctuations. The wetlands have the characteristics of an oligohaline marsh, supporting a mixture of true marine species and some typical freshwater species. Preliminary studies indicated that while the water quality in the creek was "fair," the creek had high levels of total suspended solids. The main objectives for the project were to maximize the residence time to reduce the amounts of total suspended solids in the creek flows, to preserve as much of the upland habitat as possible, to maximize the available wetland habitat, and to reduce downstream flooding. The project objectives were accomplished by constructing an oxbow shaped system on line with the main channel of the creek. The majority of the trees on the site were preserved on an island created in the center of the wetland.