Caribbean-Florida Water Science Center
Lake Okeechobee Watershed Nutrient Loading
Project Chief: Michael J. Byrne Sr.
Figure 1. Location of regional basins, sub-basins, and monitoring sites in the Lake Okeechobee Watershed Project (LOWP) area. SFWMD, South Florida Water Management District; USGS, U.S. Geologoical Survey.
Lake Okeechobee is a large, shallow lake located in southern-central Florida. With a surface area of 730 square miles, it is the second largest lake within the contiguous United States and has an average depth of 9 feet. Lake Okeechobee is the heart of southern Florida’s water supply and flood control system and is the major source of water for the Everglades.
The general objective of the USGS project was to quantify the nutrient loads, specifically phosphorus and nitrogen, for 15 canals located throughout the LOW project area. The specific objectives of the sub-basin-scale monitoring conducted by the USGS were to: (1) compute loads for phosphorus, nitrogen, and total suspended solids in selected sub-basins with no current load monitoring; (2) characterize spatial distribution of loads across the LOW Project area; (3) establish a baseline of water quality and stream-flow information at the sub-basin level; (4) provide data to cooperators for planning management measures for restoration of Lake Okeechobee; and (5) provide data for evaluating changes in the watershed, particularly the cumulative effect of restoration management measures at the sub-basin level.
The USGS maintained hydrologic gages for the purpose of determining stream flows. The South Florida Water Management District personnel collected weekly water samples near the gages in order to calculate nutrient loads from the canals.
Tributaries east of the Kissimmee River have elevated concentrations of phosphorus. However, tributaries on the western side of the Kissimmee River contribute most of the flow to the river. Variation in nutrient loading from tributaries is controlled by rainfall. Throughout the study, numerous hurricanes followed by a long drought, made it difficult to determine if management decisions improved the water quality of the lake.
Byrne, M.J., Sr., and Wood, M.S., in review, Concentrations and Loads of Nutrients in the Tributaries of the Lake Okeechobee Watershed, South-Central Florida, Water Years 2004–2008: U.S. Geological Survey Data Series 613, 22 p.