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

“Good” water quality conditions were also found during one or more years at thefollowing stations:• Myakka River near Sarasota (1999, 2000)• Deer Prairie Slough near North Port (1999)• Peace River at Ft. Meade (2000)• Peace River at Arcadia (2000)• Charlie Creek near Gardner (2000)• Horse Creek near Myakka Head (1999)• Horse Creek near Arcadia (1999).The remaining stations and years were characterized as “fair” based on the WQI.EXCEEDANCES OF STATE WATER QUALITY STANDARDSAlthough WQI values are helpful in providing an easily-understandable summary ofgeneral water quality conditions, they are calculated using a limited number ofparameters and must be interpreted with care. A more detailed examination ofmonitoring data, focusing on additional parameters, can also be helpful to identify waterquality issues that may go unnoticed in an analysis based on WQI values alone.The State of Florida has adopted water quality standards (summarized in Ch. 62-302,Florida Administrative Code) for a number of water quality constituents, in order tomaintain productive populations of fish and wildlife and protect human health. In somecases these standards may be exceeded due to natural factors, and exceedances ofthis type should not be interpreted as evidence of degraded water quality. In manycases, however, exceedances of state standards can be linked to specific pollutantdischarges or other human activities that are causing negative water quality impacts.Information on the frequency and magnitude of exceedances can thus be helpful inidentifying sites where water quality may be declining or degraded. Once such sites areidentified, more detailed follow-up studies can be designed and implemented to identifythe cause(s) of the observed exceedances.Specific ConductanceSpecific conductance measures the ability of a water sample to carry an electric current,which depends on the presence of ions in the sample, their total concentration, andother physical and chemical characteristics. Freshly distilled water has a conductivity ofbetween 0.5 and 2 µmhos/cm. The Florida standard for specific conductance in freshsurface waters is 1,275 µmhos/cm, a level set to protect populations of native fish andother aquatic organisms.Exceedances of this standard were observed at four stations during water years 1998-2001:• Joshua Creek at Nocatee (during 1999, 2000 and 2001)• Shell Creek near Punta Gorda (during 2001)• Big Slough Canal near Myakka City (during 1999)• Big Slough Canal near North Port (during 1999).v