Lower Withlacoochee River Environmental Study Phase 1 - Summary of Existing Environmental Data Prepared for Withlacoochee Area Residents, Inc. September 2, 2013 Prepared by Wetland Solutions, Inc. Lower Withlacoochee River Environmental Study Phase 1 - Summary of Existing Environmental Data Prepared for Withlacoochee Area Residents, Inc. September 2, 2013 Prepared by Wetland Solutions, Inc. Lower Withlacoochee River Study Table of Contents Figures ..................................................................................................................................................... ii Tables ......................................................................................................................................................iii Section 1.0 Introduction ........................................................................................................................ 1 Section 2.0 Existing Data ....................................................................................................................... 4 2.1 Watershed ................................................................................................................................... 4 2.1.1 Location ............................................................................................................................... 4 2.1.1.1 Lakes ................................................................................................................................ 4 2.1.1.2 Springs ............................................................................................................................. 4 2.1.1.3 Reservoir .......................................................................................................................... 4 2.1.1.4 Cross-Florida Barge Canal ............................................................................................ 5 2.1.2 Climate ................................................................................................................................. 5 2.1.3 Physiography ...................................................................................................................... 6 2.1.4 Land-Use ............................................................................................................................. 6 2.2 Study Area .................................................................................................................................. 9 2.2.1 Discharge and Stage ......................................................................................................... 10 2.2.2 Water Quality ................................................................................................................... 20 2.2.2.1 Water Quality Assessment Status .............................................................................. 20 2.2.2.2 Water Quality Summary ............................................................................................. 20 2.2.3 Light Attenuation ............................................................................................................. 36 2.2.4 Biological ........................................................................................................................... 36 Section 3.0 Summary and Recommendations ................................................................................. 39 Section 4.0 References.......................................................................................................................... 42 Appendix A ............................................................................................................................................... 43 Appendix B ............................................................................................................................................... 56 i Lower Withlacoochee River Study Table of Exhibits Figures Figure 1-1. Withlacoochee River Watershed identifying the Lower Withlacoochee River Study Area .............................................................................................................................................................. 2 Figure 1-2. Lower Withlacoochee River Study Area ............................................................................. 3 Figure 2-1. Annual Rainfall Summary for Withlacoochee Watershed Counties (Marion, Citrus, Sumter, Hernando, Lake, Pasco, and Polk) with LOESS curve ........................................................... 6 Figure 2-2. 2004 Land Use / Cover Map of the Withlacoochee River Watershed (Southwest Florida Water Management District, 2010) ............................................................................................ 8 Figure 2-3. Land Use / Cover within the Withlacoochee River Watershed (1974, 1990, 1995, and 2004). ............................................................................................................................................................ 9 Figure 2-4. USGS Stage/Discharge Stations within the Lower Withlacoochee River .................... 11 Figure 2-5. USGS daily average discharge estimates in the Lower Withlacoochee River ............. 13 Figure 2-6. LOESS curves (alpha = 0.33) for USGS daily average discharge estimates in the Lower Withlacoochee River.................................................................................................................... 14 Figure 2-7. Discharge Frequency Curves for the USGS daily average discharge estimates in the Lower Withlacoochee River.................................................................................................................... 15 Figure 2-8. USGS daily average stage estimates in the Lower Withlacoochee River ..................... 16 Figure 2-9. Lake Rousseau Bathymetric map (UF IFAS, 2007) .......................................................... 17 Figure 2-10. Mean flow rates (m/s) measured along transects within the Withlacoochee River below the Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). ...................... 18 Figure 2-11. Mean discharge (cfs) measured along transects within the Withlacoochee River below the Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). ...................... 19 Figure 2-12. Mean depth (m) measured along transects within the Withlacoochee River below the Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). .................................. 19 Figure 2-13. Water Quality Stations identified by station type and location within the Lower Withlacoochee River ................................................................................................................................ 22 Figure 2-14. Nitrate concentrations in the vicinity of the Main Boil at Rainbow Spring from 1927- 2012. Average nitrate concentrations have risen by 27 fold since the 1920s (Wetland Solutions, Inc., 2013). .................................................................................................................................................. 30 Figure 2-15. Nitrogen concentration (mg/L) measured along transects within the Withlacoochee River below the Inglis Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). 31 Figure 2-16. Phosphorus concentration (ug/L) measured along transects within the Withlacoochee River below the Inglis Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). ................................................................................................................................... 32 ii Lower Withlacoochee River Study Figure 2-17. Salinity (ppt) and Chlorophyll concentrations (ug/L) measured along transects within the Withlacoochee River below the Inglis Bypass Channel (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). ..................................................................................................................... 32 Figure 2-18. Field parameter measurements collected in the Withlacoochee River downstream of Lake Rousseau from 5/30/2013 to 6/19/2013. ................................................................................... 34 Figure 2-19. Mean light attenuation (m-1) measured along transects within the Withlacoochee River below the Inglis Bypass Channel – August 1998 (Frazer, Hoyer, Notestein, Hale, & Canfield, Jr., 2001). ................................................................................................................................... 36 Figure 2-20. Aquatic plant treatment areas in Lake Rousseau by Fiscal Year under the FWC aquatic plant management program. .................................................................................................... 38 Tables Table 2-1. Percent of Land Use / Cover within the Withlacoochee River Watershed (1974, 1990, 1995, and 2004). .......................................................................................................................................... 9 Table 2-2. USGS Stage/Discharge Stations within the Lower Withlacoochee River ..................... 12 Table 2-3. Water Quality Assessment Report – 2010 (US Environmental Protection Agency, 2010) ........................................................................................................................................................... 20 Table 2-4. Average water quality summary by decade for stations in the Lower Withlacoochee River ..........................................................................................................................................................