Abstract
Management questions concerning the effects of freshwater discharge to the Caloosahatchee River Estuary (CRE) have centered on both quantity and quality of drainage from its natural watershed and the artificial connection to Lake Okeechobee. Here we evaluate the response of nutrient concentrations and other water quality parameters, including light attenuation, within different regions of the CRE from 2009 – 2018. The data from three different long-term monitoring programs were stratified by location, discharge rate and the predominate source of the water, i.e., when flow was either from the C-43 basin or from the lake. The results of this analysis clearly show that water quality along the CRE was influenced greatly by freshwater discharges. Seven of nine parameters were statistically higher in concentration in one or more regions of the estuary when the C-43 basin was the predominant source of the water. The proportional increase in concentration of most parameters with discharge and the strong longitudinal gradient with most parameters decreasing in concentration with increasing distance down estuary was strong evidence that the freshwater end-member was the dominant source of the nutrients and other water quality constituents.