EVALUATION OF WATER-QUALITY AND MONITORING IN THE ST LUCIE ESTUARY, FLORIDA

The St. Lucie River and its tributaries form a major estuarine system on the southeast coast of Florida. This system is strongly affected by anthropogenic influences, including controlled releases of freshwater from Lake Okeechobee through the St. Lucie Canal and an extensive art ificial drainage and irrigation system in the watershed. In the presen t study, three years of biweekly water quality monitoring data from th e estuary were examined. The major stresses to the system stem from hi gh variability of the salinity, frequent low dissolved oxygen (DO) eve nts, and light limitation due to high levels of humic substances broug ht into the system with the fresh water. Nutrient levels also are high . Management goals for the system, including improvement of DO and wat er clarity, will require reduction in quantity and variability of fres hwater releases.