Success of Agricultural Best Management Practices in Reducing Phosphorus Loads to the Everglades.

A portion of the northern Everglades in south Florida was drained at the beginning of the 20^th century for agricultural and urban purposes, becoming what is known today as the Everglades Agricultural Area (EAA). Concerns about the quality of drainage water leaving the EAA basin prompted the Florida legislature to adopt the Everglades Regulatory program, part of the Everglades Forever Act. A mandatory Best Management Practices (BMP) program was implemented on EAA farms in 1995 as required by the Everglades Forever Act to reduce phosphorus (P) loads from drainage waters that enter the Everglades ecosystem. A system of BMP “equivalents” was developed by assigning points to BMPs implemented. The BMPs are divided into three basic categories consisting of water management, nutrient management, and sediment controls.  Since its inception, the BMP program in the EAA has been very successful in meeting and exceeding the 25% required P load reduction. In water year 2012, the basin released water with a concentration of 93 parts per billion and 63 metric tons of P achieving a 71% total P load reduction compared to a base level. There are, however, spatial and temporal differences in BMP performance in the EAA sub basins. Some of the factors affecting the performance are related to water management and cropping practices. New innovative research is being conducted to evaluate the impact of floating aquatic vegetation on water quality and sediment accumulation rates and characteristics in farm canals to be able to reduce P loads further.