University of Florida

Best Management Practices & Water Resources

For more information contact Samira Daroub.

Background

UF/IFAS researchers at the EREC initiated field lysimeter studies in 1986 that ultimately lead to the development of BMPs for reducing P concentrations and loads in the EAA. From these studies it was determined that fertilizer practices and a combination of improved drainage uniformity and a reduction in drainage pumping could yield significant reductions in P concentrations and loads for all EAA crops. Using the results of these studies, and best professional judgment available at the time, expected reductions in P loading were attached to each BMP. It was hypothesized that P load reductions ranging from 20 to 60% could be realized for individual EAA farms and for the EAA basin as a whole. The BMPs suggested by the UF/IFAS research and others proposed by industry and the SFWMD, were selected by the SFWMD for inclusion into a table of BMP options for EAA growers. The BMP table was part of a regulatory program initiated by the SFWMD to comply with specific requirements of the state mandated Rule 40E-63, F.A.C. Mandatory BMP implementation in the EAA started in January 1995.

In 1992, the UF/IFAS researchers started a wide-scale implementation and BMP efficacy verification project aimed at quantifying the load reductions that could be achieved at the farm level. Ten farms located through out the EAA were selected as being representative of soils, geographic location, crop rotations, and water management philosophies. Best management practice packages were developed for each farm and implemented. Monitoring of farm drainage volumes and total P concentrations of drainage waters began in Water Year 1993 (May 1, 1992 to April 30, 1993). Water quality and BMP implementation data was collected from all ten farms until 2000 when the number of farms monitored by the project was reduced to seven. In January 2002 the number of farms monitored was further reduced to three, however the level of monitoring at these three farms was intensified to collect and analyze hourly drainage water samples for total suspended solids and total, dissolved, and particulate P concentrations.

All indicators of BMP efficacy have shown that consistent and sustained reductions in total P concentrations and loads occurred due to the implementation of BMPs in the EAA. Basin-level numbers presented annually by the SFWMD reinforce the effectiveness of the BMP program, showing a sustained 50% reduction in total P loading from the EAA. In WY 2004, the TP load reduction from the EAA was 64% compared to the pre-BMP baseline period. The three year average load reduction is 55%. Phosphorus concentrations have also been reduced. In WY 2004, P concentrations from the EAA averaged 69 ppb compared to the pre-BMP base period P concentration of 173 ppb. This major and sustainable reduction is directly attributable to the BMP program. Adjusted unit area loads on project farms averaged 0.73 lbs total P/acre after BMP implementation compared to 1.30 lbs total P/acre prior to WY95. This represents a project average reduction in adjusted unit area loads of approximately 44% which approximates the overall EAA basin load reduction.

The implementation of BMPs successfully reduced P loads leaving the EAA, however there were other water quality concerns besides P specified in the The Everglades Forever Act (EFA) of 1994 that required attention of water managers and researchers. The goals of assessing other water quality concerns was to evaluate the constituents that have been previously identified as elements of water quality concern that will likely not be significantly improved by the Storm Water Treatment Areas (STAs) and current Best Management Practices being widely implemented throughout the EAA, and to identify strategies needed to address such parameters. These parameters were identified by the Florida Department of Environmental Protection (FDEP) as specific conductance, particulate P, and the pesticides Atrazine and Ametryn. The Everglades Agricultural Area-Environmental Protection District (EAA-EPD) and the SFWMD are responsible for the monitoring of Atrazine and Ametryn in waters leaving the EAA basin. The UF/IFAS implemented a research project to investigate the specific conductance and particulate P issues in the EAA. These two studies were completed in 2004; summaries of Specific Conductance and Particulate phosphorus technical reports are found on the Technical Report Summary page of this website.

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