Special Publication SJ92-SP16 LAKE JESSUP RESTORATION DIAGNOSTIC EVALUATION HATER BUDGET AND NUTRIENT BUDGET Prepared for: ST. JOHNS RIVER WATER MANAGEMENT DISTRICT P.O. Box 1429 Palatka, Florida Prepared By: Douglas H. Keesecker HATER AND AIR RESEARCH, INC. Gainesville, Florida May 1992 File: 91-5057 TABLE OF CONTENTS (Page 1 of 2) Section Page EXECUTIVE SUMMARY i-1 1.0 INTRODUCTION 1-1 1.1 PURPOSE 1-1 1.2 DESCRIPTION OF THE STUDY AREA 1-2 2.0 DATA COMPILATION 2-1 2.1 HISTORICAL DATA 2-1 2.1.1 Previous Studies 2-1 2.1.2 Climatoloqic Data 2-3 2.1.3 Hydrologic Data 2-4 2.1.4 Land Use and Cover Data 2-6 2.1.5 On-site Sewage Disposal System (OSDS) Data 2-8 2.1.6 Wastewater Treatment Plant (WWTP1 Data 2-9 2.1.7 Surface Water Quality Data . 2-10 3.0 WATER BUDGET 3-1 3.1 METHODOLOGY 3-1 3.1.1 Springflow and Upward Leakage 3-2 3.1.2 Direct Precipitation 3-4 3.1.3 Land Surface Runoff 3-4 3.1.4 Shallow Groundwater Inflow 3-6 3.1.5 Septic Tank (OSDS1 Inflows 3-7 3.1.6 Wastewater Treatment Plant Effluent 3-8 3.1.7 Surface Evaporation 3-8 3.1.8 Surface Water Outflows 3-9 3.2 RESULTS - WATER BUDGET 3-10 3.3 DISCUSSION 3-16 3.4 ESTIMATE OF ERROR 3-18 3.4.1 Sprinoflow and Upward Leakage 3-18 3.4.2 Direct Precipitation 3-19 3.4.3 Land Surface Runoff 3-19 3.4.4 Shallow Groundwater Inflow 3-20 3.4.5 Septic Tank (OSDS1 Inflows 3-21 3.4.6 Wastewater Treatment Plant Effluent 3-22 3.4.7 Surface Evaporation 3-22 3.4.8 Surface Water Outflows 3-22 LAKE JESSUP[WP]TOC 052192 TABLE OF CONTENTS (Page 2 of 2) Section Page 4.0 NUTRIENT BUDGETS 4-1 4.1 METHODOLOGY 4-1 4.1.1 Direct Precipitation Loading 4-2 4.1.2 Land Surface Runoff Loading 4-3 4.1.3 Shallow Groundwater Inflow Loading 4-3 4.1.4 Septic Tank Loading 4-4 4.1.5 Wastewater Treatment Plant Loading 4-4 4.1.6 St. Johns River Inflow 4-4 4.1.7 Artesian Inflows 4-5 4.1.8 Nutrient Pool in Lake Waters 4-5 4.1.9 Surface Water Outflow 4-6 4.1.10 Nutrient Pools in Lake Sediments 4-6 4.1.11 Denitrification in Sediments 4-7 4.1.12 Nutrient Exchange with Lake Sediments 4-8 4.2 RESULTS - NUTRIENT BUDGET 4-9 4.2.1 Total Nitrogen Loadings 4-10 4.2.2 Total Phosphorus Loadings 4-11 4.2.3 Lake Jessup Nutrient Pools and Exports 4-12 4.3 NUTRIENT BUDGET DISCUSSION 4-14 4.4 ESTIMATE OF ERROR 4-20 4.4.1 Sprinoflow and Upward Leakage 4-20 4.4.2 Direct Precipitation 4-21 4.4.3 Land Surface Runoff ..... 4-21 4.4.4 Shallow Groundwater Inflow 4-22 4.4.5 Septic Tank (OSDS1 Inflows 4-22 4.4.6 Wastewater Treatment Plant Effluent 4-23 4.4.7 Denitrification 4-23 4.4.8 St. Johns River Loading 4-23 4.4.9 Lake Jessup Nutrient Concentrations 4-23 4.4.10 Lake Jessup Sediment Nutrient Concentrations 4-24 5.0 CONCLUSIONS 5-1 6.0 REFERENCES 6-1 LAKE JESSUP[WP]TOC 052192 LIST OF FIGURES After Figure Page 1.0-1 Location of Lake Jessup in East Central Florida 1-1 1.0-2 Location of Lake Jessup in Seminole County, Florida 1-1 1.2-1 Location of Lake Jessup Watershed Subbasins 1-2 2.1.2-1 Monthly Totals for Sanford Rainfall and Lisbon 2-3 Pan Evaporation in the Vicinity of Lake Jessup, 1/80 to 12/90 2.1.2-2 Average Monthly Lake Jessup Evaporation, Sanford Rainfall, 2-3 and Lisbon Pan Evaporation, January 1980 to December 1990 2.1.2-3 Average Monthly Urban Evapotranspiration, Natural 2-4 Evapotranspiration, and Adjusted Urban-Natural Average, January 1980 to December 1990 2.1.3-1 Location of USGS Stream and Lake Gaging Stations in the 2-4 Vicinity of Lake Jessup 2.1.3-2 Lake Jessup Stage and Estimated Stage of St. Johns River 2-5 at the Mouth of Lake Jessup 2.1.6-1 Location of Waste Water Treatment Plants in the 2-10 Lake Jessup Watershed 2.1.7-1 Location of Surface Water Quality Stations in the 2-10 Lake Jessup Watershed 3.2-1 Schematic Diagram of Lake Jessup Water Budget Components 3-10 with Average Annual Flows (acre-ft/yr) and Volumes (acre-ft) 3.2-1 Comparison of Average Subbasin Net Inflows and Direct Lake 3-11 Inflows and Outflows to Lake Jessup 3.2-2 Contribution of Individual Annual Inflows to Annual Total 3-12 Inflow into Lake Jessup 3.2-3 Annual Totals and Period of Record Annual Averages of 3-12 Individual Inflows to Lake Jessup 3.2-4 Monthly Totals of Individual Inflows to Lake Jessup for the 3-13 Period 1/80 to 12/90 3.2-5 Monthly "Total Infiltration, Precipitation, Evaporation and 3-13 Bank Seepage to Lake Jessup 3.2-6 Contribution of Annual Direct Evaporation and Annual 3-14 Lake Jessup Outflow to St. Johns River LAKE JESSUP[WP]LOF 052192 LIST OF FIGURES After Figure Page 3.2-7 Annual Totals and Period of Record Annual Averages of 3-14 Individual Outflows from Lake Jessup and Annual Average Lake Volume 3.2-8 Monthly Totals of Individual Outflows from Lake Jessup 3-15 and Monthly Average Lake Volume 3.2-9 Lake Jessup Total Annual Inflows and Outflows 3-15 3.2-10 Lake Jessup Total Monthly Inflows and Total Monthly Outflows 3-15 3.2-11 Average Monthly Total Inflow, Total Outflow and Average 3-16 Lake Jessup Volume, 1/80 to 12/90 4.1.10-1 Lake Jessup Sediment Sampling Locations Compiled from 4-6 the SJRWMD Water Quality Data Base 4.2-1 Schematic Diagram of Lake Jessup Nutrient Budget 4-9 Components with Average Annual Fluxes (tons N,P/yr) and Pools (tons N,P) 4.2.1-1 Relative Contribution of Total Nitrogen Sources to Annual 4-10 Total Nitrogen Loadings to Lake Jessup 4.2.1-2 Lake Jessup Annual Total Loadings from Total Nitrogen 4-11 Sources 4.2.2-1 Relative Contribution of Total Phosphorus Sources to Annual 4-11 Total Phosphorus Loadings into Lake Jessup 4.2.2-2 Lake Jessup Annual Total Loadings from Total Phosphorus 4-12 Sources 4.2.3-1 Lake Jessup Monthly Water Quality Values Used in Nutrient 4-12 Budget Calculations 4.2.3-2 Annual Total Nitrogen Exports from Lake Jessup for Period 4-13 of Record, 1/80 to 12/90 4.2.3-3 Relative Contribution of Total Nitrogen Exports to Annual 4-13 Total Nitrogen Export 4.2.3-4 Lake Jessup Annual Total Nitrogen Loadings and Exports for 4-13 Period of Record, 1/80 to 12/90 4.2.3-5 Lake Jessup Annual Total Phosphorus Loadings and Exports 4-13 4.2.3-6 Annual Average Total Nitrogen in Lake Jessup Sediments 4-14 4.2.3-7 Annual Average Total Phosphorus in Lake Jessup Sediments 4-14 LAKE JESSUP[WP]LOF 052192 LIST OF TABLES After Table Page 2.1.2-1 Period of Record Monthly Means for Rainfall, Pan 2-3 Evaporation, Evapotranspiration, Lake-Pan Evaporation Coefficients and Lake Evaporation, January 1980 to December 1990 2.1.3-1 Selected USGS Gaging Stations in the Lake Jessup Watershed 2-4 and Vicinity 2.1.3-2 Depth-Area-Volume Relationship for Lake Jessup 2-5 2.1.3-3 Runoff Coefficients for Subbasins GEESOLD and Howell 2-5 Calculated from Existing Hydrologic Data 2.1.4-1 Subbasin.Land Use Analyses for Composite Hydrologic 2-6 Characteristics 2.1.4-2 Determination of Land Use Based Runoff Nutrient Loading 2-7 Concentrations for the Lake Jessup Watershed 2.1.5-1 Estimated Distribution of Septic Tanks in the Lake Jessup 2-9 Watershed 2.1.6-1 Wastewater Treatment Plants that Discharge Within 2-9 Lake Jessup Watershed 2.1.6-2 Determination of Average Nitrogen and Phosphorus Effluent 2-10 Concentrations from Winter Springs and Casselberry Waste Water Treatment Plants 2.1.7-1 Summary of Surface Water Quality Data for Stations in the 2-10 Lake Jessup Watershed 3.1-1 Summary of Subbasins and Lake Constants and Characteristics 3-2 Used in the Water Budget Calculations 3.2-1 Inputs and Outputs to the Lake Jessup Annual Water Budget 3-10 from Artesian Sources and Meteorological sources and Sinks for the Years 1980 through 1990 with Monthly and Annual Means and Extremes 3.2-2 Inputs to the Lake Jessup Annual Water Budget from 3-11 Watershed Subbasins for the Years 1980 through 1990 with Monthly and Annual means and Extremes 3.2-3 Summary of Subbasin Net Annual Inflow to Lake Jessup with 3-11 Annual and Monthly Means and Extremes 3.2-4 Annual Inflow and Outflow Volumes and Percent Contribution 3-12 for Components of the Lake Jessup Water Budget with Period of Record Monthly and Annual Means and Extremes LAKE JESSUP[WP]LOT 052192 LIST OF TABLES After Table Page 4.1-1 Subbasin Characteristics and Nutrient Concentrations for 4-2 the Different Components of the Nutrient Budget 4.1.10-1 Summary of Mean Sediment Physical and Chemical 4-6 Characteristics for Lake Jessup 4.1.11-1 Estimates of Denitrification Rates in Sediments 4-8 4.2-1 Nitrogen Budget Summaries for Lake Jessup for the 4-10 Years 1980 through 1990 with Period of Record Monthly and Annual Means and Extremes 4.2-2 Phosphorus Budget Summaries for Lake Jessup for the 4-11 Years 1980 through 1990 with Period of Record Monthly and Annual Means and Extremes 4.2-3 Lake Jessup Water and Sediment Exchange Summaries for 4-12 the Years 1980 through 1990 with Period of Record Monthly and Annual Means and Extremes LAKE JESSUP[WP] LOT 052192 EXECUTIVE SUMMARY EXECUTIVE SUMMARY Lake Jessup is a large, shallow lake with an average stage (for years 1980 through 1990) of 1.86 feet National Geodetic Vertical Datum (NGVD) that lies near the center of Seminole County in east-central Florida.