Candidate Conservation Agreement with Assurances for the False Spike and Texas Fawnsfoot in the Brazos River Basin Developed Cooperatively by: U.S. Fish and Wildlife Service – Southwest Region and Brazos River Authority 2020 1.0 INTRODUCTION ............................................................................................................................................ 1 1.1 BENEFITS OF THIS AGREEMENT ................................................................................................................................ 2 NET CONSERVATION BENEFIT ........................................................................................................................................... 3 1.2 PURPOSE OF THIS AGREEMENT ................................................................................................................................ 4 Species Status Assessment (SSA) .......................................................................................................................... 4 2.0 AUTHORITY ................................................................................................................................................... 5 3.0 COVERED SPECIES ......................................................................................................................................... 5 3.1 FALSE SPIKE ........................................................................................................................................................ 5 3.2 TEXAS FAWNSFOOT .............................................................................................................................................. 9 4.0 THREATS ..................................................................................................................................................... 11 4.1 DEGRADATION, LOSS, AND FRAGMENTATION OF HABITAT .......................................................................................... 11 4.2 WATER QUANTITY .............................................................................................................................................. 11 4.3 WATER QUALITY ................................................................................................................................................ 12 4.4 RUNOFF AND EROSION ........................................................................................................................................ 13 4.5 BARRIERS TO DISPERSAL ...................................................................................................................................... 13 4.6 OVERUTILIZATION ............................................................................................................................................... 13 4.7 EXOTIC SPECIES .................................................................................................................................................. 14 4.8 CLIMATE CHANGE............................................................................................................................................... 14 5.0 COVERED AREA ........................................................................................................................................... 15 6.0 CONSERVATION STRATEGY ......................................................................................................................... 16 7.0 CONSERVATION ZONES .............................................................................................................................. 23 8.0 HYDROLOGIC MODELING ............................................................................................................................ 30 9.0 CONSERVATION MEASURES........................................................................................................................ 35 9.1 DISTRIBUTIONAL FRESHWATER MUSSEL SURVEYS AND HYDROLOGIC MODELING ............................................................ 35 9.1.1 Freshwater Mussel Surveys to Fill Data Gaps ...................................................................................... 35 9.1.2 Additional Hydrologic Modeling .......................................................................................................... 35 9.2 COMMUNICATION / EDUCATION / OUTREACH ......................................................................................................... 35 9.2.1 Coordinate with Agencies through Interagency Workgroup ............................................................... 35 9.2.2 Increase Awareness of Freshwater Mussels and Foster Community Engagement .............................. 36 9.3 ENVIRONMENTAL FLOWS PROTECTION ................................................................................................................... 36 9.3.1 Environmental Flow Management ...................................................................................................... 36 9.3.2 Allen’s Creek Reservoir Management to Support Environmental Flows .............................................. 37 9.3.3 Evaluate Controlled Releases to Minimize Erosion .............................................................................. 39 9.4 AVOIDANCE AND MINIMIZATION ........................................................................................................................... 40 9.5 APPLIED RESEARCH ............................................................................................................................................. 40 9.5.1 Development of a Habitat Quantification Tool .................................................................................... 41 9.5.2 Development of Environmental Flow Methodologies Specific to Freshwater Mussels ........................ 41 9.5.3 Evaluate Reintroduction Techniques and Opportunities ...................................................................... 41 9.5.4 Analyze Physiological Tolerances of Covered Species .......................................................................... 42 9.5.5 Groundwater-Surface Water Interaction Studies ................................................................................ 42 9.6 LONG-TERM MONITORING ................................................................................................................................... 43 9.6.1 Key Mussel Populations ....................................................................................................................... 43 9.6.2 Host Fish Populations ........................................................................................................................... 44 i 9.6.3 Water Quality ...................................................................................................................................... 44 9.6.4 Substrate and Channel Morphology .................................................................................................... 46 9.6.5 Invasive Species Monitoring ................................................................................................................. 47 9.7 SHORT-TERM REFUGIA AND CAPTIVE PROPAGATION ................................................................................................. 47 9.7.1 Contingency Plan for Short-term Refugia ............................................................................................ 47 9.7.2 Captive Propagation ............................................................................................................................ 48 10.0 IMPLEMENTATION TIMELINE ...................................................................................................................... 48 11.0 MONITORING AND REPORTING .................................................................................................................. 50 12.0 ADAPTIVE MANAGEMENT PLAN AND PROGRAM ....................................................................................... 51 13.0 CHANGED AND UNFORESEEN CIRCUMSTANCES ......................................................................................... 53 13.1 CHANGED CIRCUMSTANCES .................................................................................................................................. 53 13.2 UNFORESEEN CIRCUMSTANCES ............................................................................................................................... 55 14.0 COVERED ACTIVITIES .................................................................................................................................. 56 14.1 CCAA RELATED CONSERVATION, RESEARCH, AND MONITORING ACTIVITIES .................................................................... 56 14.2 EXISTING BRA WATER SUPPLY AND DELIVERY ......................................................................................................... 57 15.0 INCIDENTAL TAKE ....................................................................................................................................... 58 LEVEL AND TYPE OF TAKE AND IMPACTS ........................................................................................................................... 60 16.0 REGULATORY ASSURANCES ........................................................................................................................ 61 17.0 AGREEMENT TERM, RESPONSIBILITIES, AMENDMENT AND TERMINATION ................................................ 61 17.1 AGREEMENT TERM ............................................................................................................................................