CYPRESS FLOWS PROJECT FLOODPLAIN INUNDATION ANALYSIS REPORT MAY 2012 ENVIRONMENTAL FLOWS REGIME AND ANALYSIS RECOMMENDATION REPORT TABLE OF CONTENTS 1 Introduction ........................................................................................................................................................... 1 1.1 Bottomland Hardwood Forests .................................................................................................................... 1 1.1.1 River-Floodplain Ecosystem ..................................................................................................................... 1 1.1.2 Bottomland Hardwood Forest: Composition and Hydroperiod .............................................................. 2 1.2 Hydrology of Bottomland Hardwood Forests .............................................................................................. 3 1.2.1 Natural Overbank Events ......................................................................................................................... 3 1.2.2 Influence of Overbank Events on BLH Tree Recruitment and Species Diversity...................................... 3 1.3 Ecosystem Processes in Floodplain Forests with Variable Flows ................................................................. 5 1.3.1 Ecosystem Benefits of Floodplain Forests ............................................................................................... 5 1.3.2 Floodplain Hydrology and Primary Productivity ...................................................................................... 6 1.3.3 Floodplain Hydrology and Fish and Wildlife Productivity ........................................................................ 7 1.4 Water Development Impacts ....................................................................................................................... 7 1.4.1 Water Development Impacts to River Hydrology .................................................................................... 7 1.4.2 Water Development Impacts to Bottomland Hardwood Forests ............................................................ 8 2 Methods ................................................................................................................................................................ 9 2.1 Scope ............................................................................................................................................................ 9 2.1.1 Geographic Scope .................................................................................................................................... 9 2.1.2 Vegetation Types ................................................................................................................................... 15 2.1.3 Imagery for High Flow Events ................................................................................................................ 17 2.2 Data Processing .......................................................................................................................................... 19 2.2.1 Mapping wetted area ............................................................................................................................ 19 2.3 Regression Analysis .................................................................................................................................... 23 2.4 Time Series Analysis ................................................................................................................................... 26 3 Results ................................................................................................................................................................. 32 3.1 Frequency and duration of inundation for natural systems ...................................................................... 32 3.2 Frequency and duration of inundation for modified system (Big) ............................................................. 32 3.3 Frequency and duration of inundation based on proposed building blocks. 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Bookmark not defined. 4 Discussion ............................................................................................................................................................ 33 4.1 Linking Stream Discharge and Inundation Area within BLH Forests .......................................................... 33 4.2 Historical Flow Regimes ............................................................................................................................. 34 4.3 Holistic Management of Riparian Water Resources .................................................................................. 35 4.4 Recommendations for Future Research .................................................................................................... 36 4.4.1 Ecological Flow Prescriptions ................................................................................................................. 36 4.4.2 Importance of Early Spring Flows .......................................................................................................... 36 4.4.3 Key BLH Habitats as Benchmarks for Determining Regulated Flows ..................................................... 36 i 4.5 Validation of existing recommendations ...................................................... 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References ................................................................................................................................................................... 38 Appendix A Seasonally and Temporally Flooded Forest ............................................................................................. 42 Appendix B Antecedent Hydrology ............................................................................................................................. 43 Appendix C Monitoring Plan ....................................................................................................................................... 47 5.1.3 Biology ................................................................................................................................................... 47 5.1.4 Hydrology ............................................................................................................................................... 47 5.1.5 Water Quality......................................................................................................................................... 47 5.1.6 Geomorphology ..................................................................................................................................... 47 5.1.7 Connectivity ........................................................................................................................................... 47 5.2 Permanent Vegetation Plots ...................................................................................................................... 48 5.2.1 Transect Benchmarks ............................................................................................................................. 48 5.2.2 Tree Strata ............................................................................................................................................. 48 5.2.3 Shrub Strata ........................................................................................................................................... 49 5.2.4 Herb Strata ............................................................................................................................................. 50 5.2.5 Calculations for Vegetation and Microhabitat Features ........................................................................ 50 5.3 Water Quality Monitoring .......................................................................................................................... 50 TABLES Table 1 Riparian Vegetation Types .............................................................................................................................. 15 Table 2 Initial estimates of flows that begin to result in overbank inundation ........................................................... 18 Table 3 Dates for which aerial imagery is available .................................................................................................... 19 Table 4 Big Cypress Creek Study Area Inundated Areas for Wetland Habitat Types .................................................. 21 Table 5 Little Cypress Creek Study Area Inundated Areas for Wetland Habitat Types .............................................. 21 Table 6 Black Cypress Creek Study Area Inundated Areas for Wetland Habitat Types .............................................. 22 Table 7 Upper Caddo Lake Study Area Inundated Areas for Wetland Habitat Types ................................................. 22 Table 8 Percent of Habitat inundated vs. Flow (or Elevation) .................................................................................... 26 FIGURES Figure 1 Overall Cypress-Caddo Flows SRP Project Area: Four Sub-basin