Peace and Myakka River Water Quality Summary 2002 - Southwest ...

Chlorophyll-aChlorophyll-a concentrations, which are used to estimate the biomass of algae in thewater column, are among the best indicators of a waterbody’s trophic state. Annualmean chlorophyll-a concentrations in Florida streams are usually at or below 5.5 µg/L.FDEP considers stream water quality to be “impaired” if the annual mean is above 20µg/L.Annual mean chlorophyll-a concentrations greater than 20 µg/L were observed at twostations during the 1998-2001 water years:• Saddle Creek at Structure P-11 (all years)• Peace River at Bartow (1998, 1999).The elevated concentrations at these stations were apparently caused by dischargesfrom Lake Hancock, a hypereutrophic lake that experiences chronic, year-round bloomsof algae and cyanobacteria.Individual observations of chlorophyll-a concentrations greater than 20 µg/L, whichindicated the presence of occasional algal blooms but did not represent a violation ofstate water quality standards, were observed at a number of additional stations:• Peace Creek Canal near Wahneta (1999)• Peace River at Fort Meade (1998, 1999, 2000)• Peace River at Zolfo Springs (1998, 1999, 2000)• Peace River at Arcadia (1998)• Horse Creek near Myakka Head (2000)• Horse Creek near Arcadia (1998)• Myakka River near Sarasota (1999, 2000, 2001).14