Development of an integrated ecosystem model to determine effectiveness of potential watershed management projects on improving Old Tampa Bay.
The Tampa Bay estuary has undergone a remarkable ecosystem recovery since the 1980s despite continued population growth within the region. However during this time, the Old Tampa Bay (OTB) segment has lagged behind the rest of the Bay's recovery relative to improvements in overall water quality and seagrass coverage. In 2011, the Tampa Bay Estuary Program, in partnership with the Southwest Florida Water Management District, began development of an integrated set of numerical and empirical modeling approaches to evaluate management actions to improve the ecology of the OTB estuarine segment. The goal was to integrate watershed, hydrodynamic, water/sediment quality, and ecological models (light and biota) to simulate changes in OTB ecology in response to the future implementation of large-scale management actions. The potential management actions evaluated: (1) completely diverting stormwater/freshwater input from a portion of the subwatershed that historically drained to the Gulf of Mexico, (2) diverting 100 percent of the directly discharged advanced wastewater treatment effluent to OTB from the subwatershed, (3) physically altering causeways along road expanses that intersect OTB, (4) reducing stormwater nutrient loads by 25 percent throughout the subwatershed, and (5) various combinations of these actions, as well as, other secondary management actions. The integrated set of models were used to evaluate the net environmental benefits to OTB's water quality (light environment and dissolved oxygen conditions), sediment quality (reduced accumulation of organic-rich sediments), potential expansion of seagrasses, and benthos/nekton habitat suitability. Based upon this evaluation, management actions that produced the greatest simulated improvements relative to costs are being considered for further evaluation in the OTB segment and subwatershed.