The impact of station location on water quality characterization in the Loxahatchee National Wildlife Refuge.

Water quality was monitored in the Loxahatchee National Wildlife Refuge based on the Consent Decree (CDN), the Enhanced Refuge (ERN), the four-part Test impacted (FPTIN), and the four-part test unimpacted (FPTUN) networks. Alkalinity, dissolved organic carbon, total organic carbon, dissolved oxygen, total dissolved solids, total suspended solids, turbidity, pH, specific conductivity, calcium, chloride, silicon, sulfate, and total phosphorus (TP) were measured from 2005 through 2009. When the ERN was used, the 10 μg TP L(-1) Consent Decree limit would have been exceeded and would have ranged from a low of 2 months in 2009 to a high of 9 months in 2005. Based on the CDN, the limit exceeded only for 1 month in each year from 2006 through 2008. Based on the FPTIN, the 10 μg TP L(-1) limit would have been exceeded and would have ranged from a low of 1 month in 2007 to a high of 7 months in 2005 and 2008. Based on the CDN, the limit only exceeded for 1 month in each year from 2006 through 2008. Since TP is rapidly removed from canal water intruded into the Refuge marsh, one cannot expect a water quality sampling station located 2 km from the source to reliably detect violations. This may be the primary reason why there have been very few months when TP concentration has exceeded the limit since 1992 or part four of the four-part test annual 15 μg L(-1) limit since 2006.