Water quality and source of freshwater discharge to the Caloosahatchee Estuary, Florida

The Caloosahatchee River has two major sources of freshwater: one from its watershed and the other via an artificial connection to Lake Okeechobee. Th e contribution of each source to the freshwater discharge reaching the down stream estuary varies and either may dominate. Routine monitoring data were analyzed to determine the effects of total river discharge and source of d ischarge (river basin, lake) on water quality in the downstream estuary. Pa rameters examined were: color, total suspended solids, light attenuation, c hlorophyll a, and total and dissolved inorganic nitrogen and phosphorus. In general, the concentrations of color, and total and dissolved inorganic ni trogen increased, and total suspended solids decreased, as total discharge increased. When the river basin was the major source, the concentrations of nutrients (excepting ammonia) and color in the estuary were relatively hig her than when the lake was the major source. Light attenuation was greater when the river basin dominated freshwater discharge to the estuary. The ana lysis indicates that water quality in the downstream estuary changes as a f unction of both total discharge and source of discharge. Relative to discha rge from the river basin, releases from Lake Okeechobee do not detectably i ncrease concentrations of nutrients, color, or TSS in the estuary.