TOWARD RESTORATION OF SPRING WATER QUALITY AND IMPLEMENTATION OF AGRICULTURAL BEST MANAGEMENT PRACTICES IN NORTHERN FLORIDA

Several large karstic springs in northern Florida have impaired water quality due to elevated nitrate-N concentrations from agricultural land uses. As part of an interagency springs restoration effort in the Santa Fe River Basin to address nitrogen losses from agriculture, the Florida Department of Environmental Protection (DEP) has conducted quarterly monitoring during the past four years from 20 wells, four springs, and three river sites in a 185-mi2 area that includes agricultural activities. During the monitoring period, the Florida Department of Agriculture’s Office of Agricultural Water Policy (OAWP) has received commitments to implement best management practices (BMPs) on most commercial agricultural lands in the study area (approximately 34,000 acres). These cover practices on irrigated and non-irrigated cropland, pasture land, and dairies. Water samples collected for major ions, nutrients, nitrate isotopes, and selected pesticides have provided data from baseline and post-implementation conditions. Data for nitrate isotopes, K, Cl, and Br show that elevated nitrate-N concentrations in groundwater, springs, and river water are mostly due to inorganic fertilizer losses. Of 13 monitoring wells located adjacent to and or downgradient from farms implementing agricultural BMPs, nitrate-N trends over time have significantly increased in 5 wells, significantly decreased in 4 wells, and remained the same in 4 other wells. To date, nitrate-N concentrations have not decreased in springs or river water samples after 4 years of monitoring. OAWP continues to work with farmers, making BMP implementation assurance site visits and providing support for more advanced farming tools to further reduce nitrogen losses.