Introduction: The Caloosahatchee River is the major source of freshwater to the Caloosahatchee Estuary and southern Charlotte Harbor. Regulatory releases through an artificial connection to Lake Okeechobee and an intricate system of canals within the watershed have drastically altered the timing and quantity of freshwater inflow to this coastal ecosystem. The resulting large fluctuations of salinity in the downstream estuary can adversely impact plant and animal life. The South Florida Water Management District is using a resource-based strategy to establish freshwater inflows that will provide a salinity range suitable for a healthy ecosystem. Because sea grasses and other submerged aquatic plants provide valuable habitat in the Caloosahatchee Estuary, these biotic resources are the focus of our research and management programs.

Summary: The ultimate goal of our research is to identify 1) a freshwater inflow range defined by a minimum and a maximum, 2) a frequency distribution of inflows and 3) a temporal distribution of inflows. Our results address each of these goals in a preliminary manner. Minimum inflows of about 300 cfs during dry periods will maintain Wild Celery in the upper estuary. Discharges greater than 2800 cfs appear detrimental to most biota at any time of the year. Flows in the range of 300 - 800 cfs appear optimal for most biota and a frequency distribution of flows that has a peak in this range should be generally beneficial. We can now begin to consider preliminary management scenarios that result in a freshwater flow regime with these characteristics.

Franklin Lock & Dam (S-79) at head of estuary

Shell Point near mouth of estuary looking up-stream (note grass beds in foreground)

(Click on any image above for full-sized version.)

Related Links

Information on Wild Celery: http://www.npwrc.usgs.gov/resource/literatr/WILDCEL/WILDCEL.HTM (see http://www.npwrc.usgs.gov/resource/plants/wildcel/index.htm) Information on seagrass and links to other sites: http://www.fiu.edu/~seagrass/

Disclaimer for non-USGS materials

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