Abstract
This report summarizes the work efforts, results and conclusions of a study conducted from June 1992 to July 1993 by Environmental Research & Design, Inc. to inventory and evaluate agricultural activities within the Sebastian and Vero Beach region of the Indian River Lagoon (IRL) Basin. This study specifically addresses agricultural activities in three water control districts located within Indian River County: the Fellsmere Water Control District (FWCD), the Sebastian River Water Control District (SRWCD) and the Indian River Farms Water Control District (IRFWCD).
An identification and inventory of agricultural activities were conducted for each of the three water control districts which included information on the size, location, type of agricultural operations and water quality characteristics. A literature review was conducted of existing information on water quality and measured flow rates in canals and laterals within the drainage basin to provide a historical perspective on water quality.
A six-month water quality monitoring program was conducted at twelve locations within the three water control districts to provide an assessment of current characteristics for water quality and discharge flow rates. This information was used to perform an assessment of loadings of nitrogen, phosphorus and suspended solids from drainage sub-basins within Indian River County to the IRL. Estimates were performed of relative pollutant loadings for both agricultural and non-agricultural land use areas within the three water control districts. These estimates are based upon a pollutant loading model which uses a combination of field measured and literature-based loading rates for land use categories within the three water control districts. Reductions in pollutant loadings are calculated for existing stormwater management facilities and for attenuation during migration through the watershed prior to reaching the IRL. For the purposes of assessing the effectiveness of both structural and non-structural BMPs, and for directing future diagnostic and management efforts, it was decided to apply the model toward the selection of BMPs that could achieve arbitrary reduction targets of 40% and 80% of the total loadings of total nitrogen, total phosphorus and suspended solids from the water control districts.
Work efforts outlined in this proposal primarily address nutrient discharges of nitrogen, phosphorus and suspended solids within contributing drainage basin areas to six primary canals and ultimately into the IRL. The six primary canals evaluated during this project include:
Funding for this study was provided by the Surface Water Improvement and Management (SWIM) Program of the St. Johns River Water Management District (SJRWMD). The SJRWMD provided substantial assistance during this project in the form of maps and exhibits related to agricultural and non-agricultural land use within Indian River County. Much of the information in this report that relates to soil types, identification and quantification of agricultural units within Indian River County, water management and irrigation practices, and fertilization practices was provided by the USDA Soil Conservation Service (SCS) which evaluated these aspects of agricultural practices under a separate contract to the Indian River Lagoon National Estuary Program.
The project team would like to acknowledge the significant assistance provided by our Project Director, Mr. Joel
Steward, with the St. Johns River Water Management District. Mr. Steward was instrumental in directing the
development of the scope of work for this project; assisted in selection of field monitoring locations; and coordinated
review of the final report by the water control districts, Indian River County (Public Works), USDA Soil Conservation
Service, and SJRWMD staff.
Return to Technical Papers