Recommended Minimum Flows For the Chassahowitzka River System Photo: W. Sotera October 30, 2012 Michael G. Heyl, Doug Leeper, Ron Basso Southwest Florida Water Management District Brooksville, Florida 34604-6899 and Marty Kelly (Formerly with Southwest Florida Water Management District) With contributions by Balanced Environmental Management Systems, Inc. ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM ii ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM Recommended Minimum Flows for the Chassahowitzka River System October 30, 2012 Michael G. Heyl, Doug Leeper, Ron Basso Southwest Florida Water Management District Brooksville, Florida 34604-6899 and Marty Kelly (Formerly with Southwest Florida Water Management District) With contributions by Balanced Environmental Management Systems, Inc. Prime Contractor The Southwest Florida Water Management District (District) does not discriminate on the basis of disability. This nondiscrimination policy involves every aspect of the District's functions, including access to and participation in the District's programs and activities. Anyone requiring reasonable accommodation as provided for in the Americans with Disabilities Act should contact the District's Human Resources Bureau Chief, 2379 Broad Street, Brooksville, Florida 34604-6899; telephone (352) 796-7211, ext. 4702 or 1-800-423-1476 (FL only), ext. 4702; TDD (FL only) 1-800-231-6103; or email to [email protected]. iii ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM Acknowledgements We would like to thank several of our colleagues at the Southwest Florida Water Management District for their contributions and useful suggestions concerning the work summarized in this report We are also indebted to District staff who conducted field sampling for the project (Don Hampton, Courtney James, Tammy Hinkle, Jason Hood and Richard Gant) and to Barbara Matrone for her assistance in document production. Sid Flannery provided historical datasets and valuable knowledge about prior District projects related to the Chassahowitzka River. Finally, we would like to thank the many District contractors that contributed to this report. Dynamic Solutions LLC contributed the hydrodynamic modeling utilizing bathymetry data provided by Dr. Ping Wang of the University of South Florida (USF). Ernst Peebles with his staff and students at USF, and Tim MacDonald and his colleagues at Florida Fish and Wildlife Conservation Commission collected and analyzed the fish and invertebrate data. Ernie Estevez of Mote Marine Lab conducted the mollusk surveys and Ernie and Jay Leverone collected benthic samples for enumeration and analysis in addition to enumerating the macrophyte community. Additional analysis of the benthic results was completed by the staff at Janicki Environmental, Inc. Using results from the individuals and organizations identified above, the staff of Balanced Environmental Management Systems (BEM), Inc., including Ken Duffy, Jay Burrell and Kevin Zhu completed the bulk of the initial analyses and much of the writing for this report. The cost of non-District support for the project was approximately $674,700, which was provided by the Coastal Rivers Basin Board and the District Governing Board. iv ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM Conversion Table Metric to U.S. Customary Multiply By To Obtain cubic meters per second 35.31 cubic feet per second (cfs) (m3/s) cubic meters per second 23 million gallons per day (m3/s) (mgd) millimeters (mm) 0.03937 inches (in) centimeter (cm) 0.3937 inches (in) meters (m) 3.281 feet (feet) kilometers (km) 0.6214 statute miles (mi) square meters (m2) 10.76 square feet (feet2) square kilometers (km2) 0.3861 square miles (square miles) hectares (ha) 2.471 acres liters (l) 0.2642 gallons cubic meters (m3) 35.315 cubic feet (feet3) cubic meters (m3) 0.0008110 acre-feet milligrams (mg) 0.00003527 ounces grams (g) 0.03527 ounces kilograms (kg) 2.205 pounds Celsius degrees (oC) 1.8*(oC) + 32 Fahrenheit (oF) U.S. Customary to Metric Multiply By To Obtain inches (in) 25.40 millimeters (mm) inches (in) 2.54 centimeters (cm) feet (feet) 0.3048 meters (m) statute miles (mi) 1.609 kilometers (km) square feet (feet2) 0.0929 square meters (m2) square miles (square 2.590 square kilometers (km2) miles) acres 0.4047 hectares (ha) gallons (gal) 3.785 liters (l) cubic feet (feet3) 0.02831 cubic meters (m3) acre-feet 1233.0 cubic meters (m3) Fahrenheit (oF) 0.5556*(oF-32) Celsius degrees (oC) U.S. Customary to U.S. Customary Multiply By To Obtain acre 43560 square feet (feet2) square miles (square 640 acres miles) cubic feet per second 0.646 million gallons per day (cfs) (mgd) v ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM Table of Contents CHAPTER 1. PURPOSE & BACKGROUND OF MFL ................................................... 1 1.1 Overview and Legislative Direction ..................................................................... 1 1.2 The Flow Regime ................................................................................................ 2 1.3 Defining Significant Harm ................................................................................... 4 1.4 Minimum Evaluation Criteria ............................................................................... 5 1.5 Flow Definitions .................................................................................................. 6 1.6 Summary of the District Approach for Developing Minimum Flows .................... 7 1.6.1 Elements of Minimum Flows ........................................................................ 7 1.7 Content of Remaining Chapters ......................................................................... 8 CHAPTER 2. WATERSHED CHARACTERISTICS – PHYSICAL AND HYDROLOGY 10 2.1 Watershed and Springshed .............................................................................. 10 2.1.1 Land Use/Land Cover ................................................................................ 13 2.2 Climate .............................................................................................................. 14 2.3 Flow and Hydrogeology (Adapted from Wolfe 1990, Knochenmus and Yobbi 2001) 14 2.3.1 Discharge Estimates .................................................................................. 15 2.3.1.1 Discharge from USGS 02310650 ....................................................... 15 2.3.2 Long-Term flow .......................................................................................... 19 2.4 Historical Change in Discharge ........................................................................ 20 2.5 Historical Discharge Measurements ................................................................. 22 2.6 Ungaged Flow Estimates .................................................................................. 23 CHAPTER 3. ESTUARY CHARACTERISTICS ........................................................... 25 3.1 Physical ............................................................................................................ 25 3.1.1 Linear ......................................................................................................... 25 3.1.2 Area / Volume (Adapted from Dynamic Solutions, LLC 2009) .................. 25 3.2 Sea Level Change ............................................................................................ 28 3.3 Bottom Habitats ................................................................................................ 30 3.4 Sediments ......................................................................................................... 34 3.5 Tidal Wetlands and Riparian Habitats .............................................................. 36 CHAPTER 4. TIDE, SALINITY & WATER QUALITY ................................................... 43 4.1 Tide ................................................................................................................... 43 4.2 Salinity – Longitudinal ....................................................................................... 44 4.2.1 Vertical Salinity Variability ......................................................................... 47 4.3 Water Quality .................................................................................................... 48 4.3.1 FDEP Impaired Waters .............................................................................. 48 CHAPTER 5. BIOLOGICAL CHARACTERISTICS ...................................................... 55 5.1 Benthos ............................................................................................................. 55 5.1.1 Descriptive (Adapted from Janicki Environmental 2006, Grabe and Janicki 2008) 55 5.1.2 Relation to Inflow ....................................................................................... 56 5.2 Fish ................................................................................................................... 58 5.2.1 Descriptive (Adapted from Greenwood et al. 2008) .................................. 58 5.2.1.1 Fish Composition ................................................................................ 59 5.2.1.2 Invertebrate Composition ................................................................... 60 5.2.2 Relation to Inflow ....................................................................................... 60 5.2.2.1 Distribution – Plankton Net ................................................................. 61 vi ChassMFL_Final.docx Last Save: 12/11/2012 9:18 AM 5.2.2.2