AECOM Alberta Flood Recovery Task Force Appendix F – Southern Diversion Scheme Appendix F Southern Diversion Scheme RPT2-2014-07-09-App_F_Highwood_River_Southern_Diversion.Docx AECOM Alberta Flood Recovery Task Force Appendix F – Southern Diversion Scheme Table of Contents page Sign-Off 1. Background ..................................................................................................................................... 1 1.1 Existing Water Courses ....................................................................................................................... 1 1.2 Existing Reservoirs .............................................................................................................................. 1 1.2.1 Twin Valley Reservoir ............................................................................................................. 1 1.2.2 Travers Reservoir ................................................................................................................... 2 1.2.3 Women’s Coulee .................................................................................................................... 3 1.3 History of Flooding ............................................................................................................................... 3 2. Objective .......................................................................................................................................... 5 3. Alternatives ..................................................................................................................................... 6 3.1 Alternative LBR1: Little Bow Diversion ................................................................................................ 6 3.1.1 LBR1: Overview ...................................................................................................................... 6 3.1.2 LBR1: Assumptions ................................................................................................................ 6 3.1.3 LBR1: Technical Analysis/Review .......................................................................................... 6 3.1.3.1 Little Bow Diversion .............................................................................................. 6 3.1.3.2 Existing Reservoirs ............................................................................................... 7 3.1.4 LBR1: Project Impacts ............................................................................................................ 7 3.1.5 LBR1: Conceptual Cost Estimates ......................................................................................... 8 3.2 Alternative LBR2: Little Bow Diversion and Storage ........................................................................... 9 3.2.1 LBR2: Overview ...................................................................................................................... 9 3.2.2 LBR2: Assumptions ................................................................................................................ 9 3.2.3 LBR2: Design Flow ............................................................................................................... 10 3.2.4 LBR2: Conceptual Design .................................................................................................... 10 3.2.4.1 Diversion Channel .............................................................................................. 10 3.2.4.2 Little Bow River Valley ........................................................................................ 10 3.2.4.3 Headworks .......................................................................................................... 11 3.2.4.4 Control Structure Design .................................................................................... 11 3.2.4.5 Dam site LB1 ...................................................................................................... 11 3.2.4.6 Conflicts .............................................................................................................. 12 3.2.5 LBR2: Technical Analysis/Review ........................................................................................ 12 3.2.5.1 Volume Assessments ......................................................................................... 13 3.2.5.2 Peak Flow Assessments .................................................................................... 13 3.2.5.3 Proposed Constructed Diversion........................................................................ 13 3.2.5.4 Little Bow River Storage ..................................................................................... 14 3.2.6 LBR2: Conceptual Cost Estimates ....................................................................................... 14 3.3 Alternative LBR3: Women’s Coulee Diversion and Storage ............................................................. 17 3.3.1 LBR 3: Overview ................................................................................................................... 17 3.3.2 LBR3: Assumptions .............................................................................................................. 17 3.3.3 LBR 3: Technical Analysis/Review ....................................................................................... 17 3.3.3.1 Expanded Women’s Coulee Diversion ............................................................... 17 3.3.3.2 Expanded Women’s Coulee Storage ................................................................. 18 3.3.4 LBR3: Project Impacts .......................................................................................................... 19 3.3.5 LBR3: Cost Estimates........................................................................................................... 19 RPT2-2014-07-09-App_F_Highwood_River_Southern_Diversion.Docx AECOM Alberta Flood Recovery Task Force Appendix F – Southern Diversion Scheme 3.4 Alternative LBR4: Women’s Coulee and Little Bow River Diversion and Storage ............................ 20 3.4.1 LBR4: Overview .................................................................................................................... 20 3.4.2 LBR4: Assumptions .............................................................................................................. 20 3.4.3 LBR4: Technical Analysis/Review ........................................................................................ 20 3.4.4 LBR4: Project Impacts .......................................................................................................... 20 3.4.5 LBR4: Conceptual Cost Estimates ....................................................................................... 21 3.5 Alternative LBR5: Chalcroft Scheme ................................................................................................. 22 3.5.1 LBR5: Overview .................................................................................................................... 22 3.5.2 LBR5: Assumptions .............................................................................................................. 23 3.5.3 LBR5: Technical Analysis/Review ........................................................................................ 23 3.5.3.1 Inlet Design ......................................................................................................... 24 3.5.3.2 Channel Alignment and Section Geometry ........................................................ 24 3.5.3.3 Little Bow River Dams ........................................................................................ 24 3.5.3.4 Frank Lake Reservoir ......................................................................................... 25 3.5.3.5 Roadway Realignment ....................................................................................... 25 3.5.4 LBR5: Project Impacts .......................................................................................................... 25 3.5.5 LBR5: Conceptual Cost Estimates ....................................................................................... 25 3.6 Alternative LBR6: Healy Scheme ...................................................................................................... 26 3.6.1 LBR6: Overview .................................................................................................................... 26 3.6.2 LBR6: Assumptions .............................................................................................................. 27 3.6.3 LBR6: Technical Analysis/Review ........................................................................................ 27 3.6.3.1 General ............................................................................................................... 27 3.6.3.2 Dam Dimensions ................................................................................................ 27 3.6.3.3 Channel Alignment and Section Geometry ........................................................ 28 3.6.3.4 Conduit ............................................................................................................... 28 3.6.4 LBR6: Project Impacts .......................................................................................................... 29 3.6.5 LBR6: Conceptual Cost Estimates ....................................................................................... 29 4. Additional Mitigation Measures ..................................................................................................