Proposed Minimum Flows for the Lower Peace River and Lower Shell Creek, Draft Report March 20, 2020 DRAFT Proposed Minimum Flows for the Lower Peace River and Lower Shell Creek, Draft Report March 20, 2020 Yonas Ghile, PhD, PH, Lead Hydrologist XinJian Chen, PhD, PE, Chief Professional Engineer Douglas A. Leeper, MFLs Program Lead Chris Anastasiou, PhD, Chief Water Quality Scientist Kristina Deak, Staff Environmental Scientist Southwest Florida Water Management District 2379 Broad Street Brooksville, Florida 34604-6899 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, services and activities. Anyone requiring reasonable accommodation, or would like information as to the existence and location of accessible services, activities, and facilities, as provided for in the Americans with Disabilities Act, should contact Donna Kaspari, Sr. Performance Management Professional, at 2379 Broad St., Brooksville, FL 34604-6899; telephone (352) 796-7211 or 1-800-423-1476 (FL only), ext. 4706; or email [email protected]. If you are hearing or speech impaired, please contact the agency using the Florida Relay Service, 1-800-955-8771 (TDD) or 1-800-955-8770 (Voice). If requested, appropriate auxiliary aids and services will be provided at any public meeting, forum, or event of the District. In the event of a complaint, please follow the grievance procedure located at WaterMatters.org/ADA. i DRAFT Acknowledgments The authors thank Ron Basso, Mike Bray, Eric DeHaven, Gabe Herrick, Kym Holzwart, Jeanette Lopez, Jordan Miller, Jim Owens, Danielle Rogers, Jennette Seachrist, Randy Smith, Chris Tumminia, Adrienne Vining, Lei Yang and Chris Zajac with the Southwest Florida Water Management District for their contributions and useful suggestions concerning the work summarized in this report. The authors also acknowledge and thank several additional individuals and organizations that contributed to this report, including: HSW Engineering, Inc. for conducting floodplain inundation analysis; Ralph Montgomery for his assistance in providing hydro-biological data and HBMP reports and analyzing the relationships of freshwater inflow with chlorophyll levels; Ping Wang of the University of South Florida for bathymetric data collection; Jan Kool of HydroGeoLogic, Inc. for providing Peace River Integrated Modeling project outputs; Aerial Cartographic of America, Inc., for producing improved LiDAR data; Peter Rubec formerly with the Florida Fish and Wildlife Commission for developing fish habitat suitability information; Janicki Environmental, Inc., for conducting water quality analysis; Lianyuan Zheng for providing boundary conditions data; and staff from the Peace River Manasota Water Supply Authority, the Charlotte Harbor Estuary Program, and the City of Punta Gorda. ii DRAFT TABLE OF CONTENTS EXECUTIVE SUMMARY ................................................................................................ vii CHAPTER 1 - INTRODUCTION ..................................................................................... 1 1.1. Reevaluation of 2010 Lower Peace River Minimum Flows and Development of Proposed Minimum Flows for the Lower Peace River and Lower Shell Creek ............ 1 1.2. Legal Directives for Establishment of Minimum Flows and Levels ..................... 4 1.2.1. Relevant Florida’s Statues and Rules .......................................................... 4 1.2.2. Environmental Values .................................................................................. 6 1.3. Development of Minimum Flows and Levels ...................................................... 6 1.3.1. Flow Definitions and Concepts .................................................................... 7 1.3.2. Baseline Flow Conditions ............................................................................ 8 1.3.3. Building Block Approach .............................................................................. 9 1.3.4. Low Flow Threshold .................................................................................. 10 1.3.5. Significant Harm and 15 Percent Change Criteria ..................................... 10 1.3.6. Percent-of-flow Method.............................................................................. 11 1.3.7. Adaptive Management ............................................................................... 12 1.4. Vertical Datums ................................................................................................ 13 1.5. Updates Made in Reevaluation of the Minimum Flows .................................... 14 CHAPTER 2 - PHYSICAL AND HYDROLGIC DESCRIPTION OF THE LOWER PEACE RIVER AND LOWER SHELL CREEK ........................................................................... 16 2.1. Peace River and Shell Creek Watersheds ....................................................... 16 2.2. Land Use and Land Cover ............................................................................... 20 2.3. Soils ................................................................................................................. 21 2.4. Bathymetry and Morphometry .......................................................................... 22 2.5. Climate ............................................................................................................. 26 2.6. Tides ................................................................................................................ 28 2.7. Streamflow ....................................................................................................... 29 2.7.1. Mean Annual Flows ................................................................................... 30 2.7.2. Seasonal Flows ......................................................................................... 34 2.8. Hydrogeology and Aquifer Levels .................................................................... 35 2.9. Water Use ........................................................................................................ 37 iii DRAFT CHAPTER 3 - WATER QUALITY CHRACTERSTICS .................................................. 41 3.1. Water Quality Classification ............................................................................. 41 3.3.1. Water Quality Characteristics in the Lower Peace River ............................... 44 3.3.1.1. Salinity .................................................................................................... 46 3.3.1.2. Dissolved Oxygen .................................................................................. 47 3.3.1.3. Chlorophyll ............................................................................................. 49 3.3.1.4. Nitrate+nitrite and Total Kjeldahl Nitrogen .............................................. 51 3.3.1.5. Ortho-phosphorus .................................................................................. 53 3.3.1.6. Water Color ............................................................................................ 55 3.3.2. Relationships between Lower Peace River Flow and Water Quality Constituents ............................................................................................................... 56 3.3.2.1. Relationships between Flow and Salinity ............................................... 56 3.3.2.2. Relationships between Flow and Chlorophyll ......................................... 57 3.3.2.3. Relationships between Flow and Dissolved Oxygen .............................. 58 3.3.2.4. Relationships between Flow and Nutrients ............................................ 59 3.3.2.5. Relationships between Flow and Water Color ........................................ 61 3.3.3. Water Quality Characteristics in Lower Shell Creek...................................... 62 3.3.3.1. Salinity .................................................................................................... 63 3.3.3.2. Dissolved Oxygen .................................................................................. 64 3.3.3.3. Chlorophyll ............................................................................................. 66 3.3.3.4. Total Kjeldahl Nitrogen and Ortho-phosphorus ...................................... 67 3.3.4. Relationships between Shell Creek Flow and Water Quality Constituents ... 70 CHAPTER 4 – ECOLOGICAL RESOURCES ............................................................... 71 4.1. Vegetation ........................................................................................................ 71 4.1.1. Shoreline Vegetation ................................................................................. 71 4.1.2. Bottomland Hardwood and Mixed Wetland Forests ................................... 71 4.1.3. Tidal Marshes and Saltmarshes ................................................................ 72 4.1.4. Mangroves ................................................................................................. 73 4.1.5. Seagrasses ................................................................................................ 73 4.2. Fish and Benthic Macroinvertebrates ............................................................... 75 4.2.1. Fish and Planktonic/Nektonic Invertebrates ............................................... 76 iv DRAFT 4.2.2. Macroinvertebrates