Responses of Simulated Low Salinity Habitats to the Uncertainties of Gauged and Ungauged Flows in the Myakka River Estuary in Florida

One of important factors affecting hydrodynamics in a riverine estuary is the hydrologic loading to the estuarine system, including gauged and ungauged freshwater flows. While gauged flows are generally reliable with known confidence intervals through QA/QC processes, the estimation of flow rates from ungauged areas of the watershed usually involves a great deal of uncertainties. Before a sound management decision can be made based on the results of a hydrodynamic model, it is often desirable to investigate the responses of simulated hydrodynamics and salinity transport processes to uncertainties associated with gauged and ungauged flows. This paper presents a sensitivity study examining the responses of simulated low salinity habitats, in terms of water volume and bottom area, to uncertainties of both gauged and ungauged flows in the Myakka River estuary in southwest Florida. The Myakka River is an ideal estuary for conducting this kind of study and comparing the relative importance of gauged and ungauged flows, because almost one half of the Myakka River watershed is ungauged.