Recommended Minimum Flows for the Lower Peace River and Proposed Minimum Flows Lower Shell Creek, Draft Report
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Recommended Minimum Flows for the Lower Peace River and Proposed Minimum Flows Lower Shell Creek, Draft Report November 30, 2020 Recommended Minimum Flows for the Lower Peace River and Proposed Minimum Flows for Lower Shell Creek, Draft Report November 30, 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, PhD, 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 who 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 Eisenbeis, 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 Table of Contents Acronym List Table......................................................................................................... vii Conversion Unit Table ................................................................................................... viii ACKNOWLEDGMENTS ..................................................................................................ix EXECUTIVE SUMMARY ................................................................................................. x CHAPTER 1 - INTRODUCTION ..................................................................................... 1 1.1. Reevaluation of 2010 Lower Peace River Minimum Flows and Development of Recommended Minimum Flows for the Lower Peace River and Proposed Minimum Flows for Lower Shell Creek ........................................................................................ 1 1.2. Legal Directives for Establishment of Minimum Flows and Levels ..................... 4 1.2.1. Relevant Florida Statues and Rules ............................................................ 4 1.2.2. Environmental Values .................................................................................. 5 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 .............................................................................. 8 1.3.4. Low Flow Threshold .................................................................................... 9 1.3.5. Significant Harm and 15% Change Criteria ................................................. 9 1.3.6. Percent-of-flow Method.............................................................................. 10 1.3.7. Adaptive Management ............................................................................... 11 1.4. Vertical Datums ................................................................................................ 12 1.5. Updates Made in Reevaluation of the Minimum Flows .................................... 12 CHAPTER 2 - PHYSICAL AND HYDROLOGIC DESCRIPTION OF THE LOWER PEACE RIVER AND LOWER SHELL CREEK .............................................................. 15 2.1. Peace River and Shell Creek Watersheds ....................................................... 15 2.2. Land Use and Land Cover ............................................................................... 18 2.3. Soils ................................................................................................................. 20 2.4. Bathymetry and Morphometry .......................................................................... 21 2.5. Climate ............................................................................................................. 25 2.6. Tides ................................................................................................................ 27 2.7. Streamflow ....................................................................................................... 28 2.7.1. Mean Annual Flows ................................................................................... 29 2.7.2. Seasonal Flows ......................................................................................... 32 2.8. Hydrogeology and Aquifer Levels .................................................................... 33 ii 2.9. Water Use ........................................................................................................ 35 CHAPTER 3 - WATER QUALITY CHARACTERISTICS ............................................... 39 3.1. Water Quality Classification ............................................................................. 39 3.2. Impaired Waters and Pollutant Load Reduction Goal ...................................... 40 3.2.1. Impaired Waters ........................................................................................ 40 3.2.2. Pollutant Load Reduction Goal ................................................................... 41 3.3. Water Quality Review ....................................................................................... 42 3.3.1 Water Quality Characteristics in the Lower Peace River ............................. 42 3.3.1.1. Salinity .................................................................................................... 44 3.3.1.2. Dissolved Oxygen .................................................................................. 46 3.3.1.3. Chlorophyll ............................................................................................. 48 3.3.1.4. Total Nitrogen, Nitrate+Nitrite, and Total Kjeldahl Nitrogen .................... 50 3.3.1.5. Orthophosphate ...................................................................................... 52 3.3.1.6. Color ....................................................................................................... 54 3.3.2. Relationships between Lower Peace River Flow and Water Quality Constituents ............................................................................................................... 55 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 Color .................................................. 61 3.3.3. Water Quality Characteristics in Lower Shell Creek...................................... 62 3.3.3.1. Salinity .................................................................................................... 64 3.3.3.2. Dissolved Oxygen .................................................................................. 65 3.3.3.3. Chlorophyll ............................................................................................. 67 3.3.3.4. Total Kjeldahl Nitrogen and Orthophosphate ......................................... 68 3.3.3.5. Color .................................................................................................... 70 3.3.4 Relationships between Shell Creek Flow and Water Quality Constituents ... 71 CHAPTER 4 – ECOLOGICAL RESOURCES ............................................................... 72 4.1 Vegetation ........................................................................................................ 72 4.1.1. Shoreline Vegetation ................................................................................. 72 4.1.2. Bottomland Hardwood and Mixed Wetland Forests ................................... 72 4.1.3. Tidal Marshes and Saltmarshes ................................................................ 73 4.1.4. Mangroves ................................................................................................. 73 iii 4.1.5. Seagrasses ................................................................................................ 74 4.2 Fish and Benthic Macroinvertebrates ............................................................... 76 4.2.1 Fish and Planktonic/Nektonic Invertebrates ............................................... 78 4.2.2 Macroinvertebrates in the Lower Peace/Shell System .............................. 81 CHAPTER 5 – FLOW BLOCKS, BASELINE FLOWS, RESOURCES OF CONCERN AND MODELING TOOLS RELEVANT TO MINIMUM FLOWS DEVELOPMENT ......... 84 5.1. Overview .......................................................................................................... 84