Background
Many activities such as urban development, agriculture, industry, and regional water management have impacted the waters of the St. Lucie Estuary (SLE) and the Indian River Lagoon (IRL). Numerous activities are currently underway to improve surface water discharges to the SLE and IRL. One of the most visible programs is the development of Best Management Practices (BMPs) for Indian River Area citrus groves. The BMP development process is a voluntary effort to reduce loadings to the SLE and IRL in five areas (water volume, pesticides, nutrients, sediments, and aquatic weeds). Since 1998, the BMP process has produced an extensive BMP manual, initiated a series of workshops and on-farm demonstrations, produced materials to educate the general public on the BMPs and water-related issues, provided training for farm laborers, created a web site with BMP-related materials, and identified areas where further research is necessary.
The driving force behind the BMP effort is the total maximum daily load (TMDL) process that has been initiated for the waters in the SLE/IRL watersheds. TMDLs are defined as the maximum amount of a pollutant that a waterbody can receive and still meet the water quality standards as established by the Clean Water Act of 1972. One of the factors that hinders the TMDL development process is the lack of data on water quality parameters throughout the watershed. Most likely, loadings are not distributed uniformly from groves. Rather, it is likely that grove configuration, soil type, drainage system, and cultural practices all are important factors that affect loadings coming off a particular grove. In order to effectively initiate corrective actions, the temporal and spatial variations of water quality parameters within the watersheds need to be assessed. If the voluntary citrus BMP implementation process is to be successful, growers need to know which problems to address and then select the most appropriate BMPs to resolve the problems.
Objectives
- Track basic water quality parameters by frequent sampling at selected sites within the drainage systems serving citrus groves in the Indian River Citrus Production Area.
- Disseminate results in a timely manner via quarterly newsletters and web site postings so that growers can relate results to grove practices and climatic factors.
- Identify problem areas in the drainage systems that require further study to determine the cause of higher than normal loadings.
Approach & Methodology
A series of water sampling sites have been selected in drainage canals in Martin, St. Lucie, and Indian River Counties where the primary land use is citrus production. The sites are at identifiable locations such as road crossings, structures, etc. in order to facilitate identification by growers and interested parties. Water samples are collected at approximately 2-week intervals throughout most of the year. Project duration will be 3 years, resulting in about 150 samples at each site.
Water samples are collected in sample bottles using a grab sampler extension rod. Samples are stored on ice and transported to the IRREC lab for analysis of total phosphorus, total ortho-phosphorus, copper, nitrate, and ammonia. All tests (except copper) utilize Hach Test-‘N-Tube pre-prepared kits. These kits will allow quick turn-around and reporting of results. Copper is analyzed using Method 3500-CuE (Bathocuproine Method) found in Standard Methods for Examination of Water and Wastewater. In addition to the lab analysis, pH, conductivity, turbidity, and dissolved oxygen are measured in situ at each site during sampling. Water level (canal stage) and accumulated rainfall is also be measured at each site when water samples are obtained.
