Upper Colorado River Endangered Fish Recovery Program GREEN RIVER SUBBASIN Floodplain Management Plan FINAL April 2004 Recommended Citation: Valdez, R.A. and P. Nelson. 2004. Green River Subbasin Floodplain Management Plan. Upper Colorado River Endangered Fish Recovery Program, Project Number C-6, Denver, CO. Disclaimer: Opinions and recommendations expressed in this Floodplain Management Plan are those of the authors and do not necessarily reflect the views of any agency, organization, or corporation; or of the Upper Colorado River Endangered Fish Recovery Program. Mention of trade names, commercial products, or firms and businesses does not constitute endorsements or recommendations for use. GREEN RIVER SUBBASIN FLOODPLAIN MANAGEMENT PLAN Prepared by Richard A. Valdez1 and Patrick Nelson2 1 R.A. Valdez & Associates 172 West 1275 South Logan, UT 84321 2 Habitat Restoration Coordinator Upper Colorado River Endangered Fish Recovery Program U.S. Fish and Wildlife Service, 134 Union Boulevard, Lakewood, CO 80228 ___________________________________ Final Upper Colorado River Endangered Fish Recovery Program Project No. C-6 April 2004 Table Of Contents April 2004 TABLE OF CONTENTS EXECUTIVE SUMMARY ..................................................... xi ACKNOWLEDGMENTS ..................................................... xiv 1.0 INTRODUCTION ..................................................... 1-1 1.1 Background .................................................... 1-1 1.2 Goals And Objectives ............................................ 1-1 1.3 Relationship To Recovery ......................................... 1-2 2.0 PLANNING AND DEVELOPMENT ...................................... 2-1 2.1 Planning ....................................................... 2-1 2.2 Plan Development ............................................... 2-2 2.3 Role Of Propagation And Augmentation Program ...................... 2-2 2.4 Role Of Floodplain Model ......................................... 2-3 2.5 Coordination ................................................... 2-4 3.0 SCIENTIFIC BASIS AND UNDERLYING PRINCIPLES ..................... 3-1 3.1 Scientific Basis For Plan .......................................... 3-1 3.2 Underlying Principles Of Plan ...................................... 3-2 3.3 Green River Flow Recommendations ................................ 3-3 3.4 Types Of Floodplains ............................................. 3-7 3.5 Role Of Floodplains .............................................. 3-8 3.6 Nonnative Fish In Floodplains ...................................... 3-9 3.7 Floodplain Management Strategy .................................. 3-10 3.7.1 Floodplain Connection ..................................... 3-13 3.7.2 Larval Entrainment ....................................... 3-14 3.7.3 Sufficient Food Production ................................. 3-15 3.7.4 Suitable Quantity and Quality of Water ........................ 3-15 3.7.5 Reconnection Of Floodplain To Main Channel .................. 3-16 3.7.6 Desiccation To Reset Floodplain ............................. 3-16 4.0 PRIORITIZATION OF REACHES AND SITES ............................. 4-1 4.1 Priority River Reaches ............................................ 4-1 4.2 Priority Floodplain Sites .......................................... 4-5 4.2.1 Split Mountain To Desolation Canyon ......................... 4-6 4.2.2 Labyrinth And Stillwater Canyons ............................. 4-6 4.2.3 Gray Canyon To Labyrinth Canyon ............................ 4-6 iii Table Of Contents April 2004 5.0 REACH OBJECTIVES AND MANAGEMENT ACTIONS .................... 5-1 5.1 Split Mountain To Desolation Canyon ............................... 5-1 5.1.1 Role In Recovery .......................................... 5-1 5.1.2 Objectives And Management Actions .......................... 5-1 5.2 Labyrinth And Stillwater Canyons ................................... 5-8 5.2.1 Role In Recovery .......................................... 5-8 5.2.2 Objectives And Management Actions .......................... 5-8 5.3 Gray Canyon to Labyrinth Canyon .................................. 5-9 5.3.1 Role In Recovery .......................................... 5-9 5.3.2 Objectives And Management Actions ......................... 5-10 6.0 MANAGEMENT OF FLOODPLAIN SITES ................................ 6-1 6.1 Summary Of Past Restoration Actions ............................... 6-1 6.2 Objectives And Management Actions ................................ 6-1 6.2.1 Thunder Ranch ............................................ 6-3 6.2.2 IMC .................................................... 6-5 6.2.3 Stewart Lake ............................................. 6-6 6.2.4 Sportman’s Lake .......................................... 6-9 6.2.5 Bonanza Bridge .......................................... 6-10 6.2.6 Richens/Slaugh/Slaugh .................................... 6-13 6.2.7 Horseshoe Bend .......................................... 6-14 6.2.8 The Stirrup .............................................. 6-16 6.2.9 Baeser Bend ............................................. 6-18 6.2.10 Above-Brennan .......................................... 6-19 6.2.11 Johnson Bottom .......................................... 6-21 6.2.12 Leota Bottom ............................................ 6-24 6.2.13 Wyasket Lake ............................................ 6-26 6.2.14 Sheppard Bottom ......................................... 6-27 6.2.15 Old Charlie Wash ......................................... 6-29 6.2.16 Lamb Property ........................................... 6-32 7.0 PLAN IMPLEMENTATION ............................................. 7-1 7.1 Suitability Of Floodplain Habitat .................................... 7-1 7.2 Implementation ................................................. 7-4 7.3 Monitoring ..................................................... 7-8 7.4 Success Criteria ................................................. 7-9 7.4.1 Achievement Of Management Actions ......................... 7-9 7.4.2 Achievement Of Larval Entrainment And Fish Escapement ........ 7-11 7.5 Uncertainties, Risks, and Contingencies ............................. 7-12 7.6 Research Needs ................................................ 7-15 8.0 RECOMMENDATIONS ................................................ 8-1 iv Table Of Contents April 2004 LITERATURE CITED ..................................................... LC-1 Appendix A: Tables of Floodplain Sites in the Green River Subbasin .................. A-1 Appendix B: Floodplain Model Simulations .......................................B-1 v List Of Tables April 2004 LIST OF TABLES Table Page 3-1 Recommendations for spring peak flows by hydrologic condition for Reach 2 (Yampa River to White River) to benefit endangered fishes in the Green River downstream of Flaming Gorge Dam ................................................... 3-4 4-1 Areas of floodplain inundation in the three priority reaches of the Green River Subbasin at full inundation potential, and at flows of 18,000 cfs and 1,560 cfs ..... 4-4 4-2 Total numbers of razorback sucker larvae potentially entrained in floodplains of each of the three priority reaches of the Green River at full inundation potential and at flows of 18,200 cfs and 1,560 cfs ................................................ 4-4 4-3 Location, acres inundated, and ownership of 16 priority floodplain sites in the Split Mountain to Desolation Canyon reach ...................................... 4-8 5-1 Summary of objectives and management actions for the three priority reaches of the Green River Subbasin ................................................. 5-11 6-1 Acres of inundation at 13,000 cfs and 18,600 cfs and summary of previous actions on 16 floodplain sites in the Split Mountain to Desolation Canyon Reach of the Green River Subbasin ............................................................. 6-2 6-2 Summary of site features, objectives, and management actions for each of the 16 priority floodplains of the Split Mountain to Desolation Canyon reach .................. 6-33 7-1 Summary of acres restored by floodplain type for 16 sites in the Split Mountain to Desolation Canyon reach at 18,600 cfs flows of the Green River at Jensen, Utah .... 7-2 7-2 Floodplain area (acres) needed to meet 30% average annual recruitment for a razorback sucker population of 5,800 adults, based on three levels each of fish density and growth rate ................................................................. 7-4 7-3 Summary of management actions and success criteria for each prioritized floodplain site in the Split Mountain to Desolation Canyon Reach ............................ 7-6 vi List Of Tables April 2004 7-4 Estimated larval entrainment at 80, 90, and 95% mile-to-mile survival rate, and numbers of adults necessary to be produced at each of 14 floodplain sites to achieve 30% recruitment (i.e., 1,740 adults annually) ................................... 7-12 7-5 Summary of estimated costs (x $1,000) by calendar year for Phases I and II of this floodplain management plan ............................................ 7-17 A-1 The top 11 ranked bottomland habitats in the Split Mountain to Desolation Canyon Reach identified by Irving and Burdick (1995) .............................. A-2 A-2 Ranked bottomland habitats in the Labyrinth and Stillwater Canyons Reach identified by Irving and Burdick (1995) .............................................. A-3 A-3 Ranked bottomland habitats in the Gray Canyon