RECLAMATION Managing Water in the West Yellowtail Dam & Bighorn Lake Long Term Issues Group Boysen Buffalo Bill Bull Lake YELLOWTAIL DAM, BIGHORN LAKE and AFTERBAY Yellowtail Afterbay Dam Substation Visitor Center Yellowtail Dam YELLOWTAIL DAM, BIGHORN LAKE AND AFTERBAY Yellowtail Unit • Authorization: Flood Control Act of Dec. 22, 1944 (ch.665 Stat. 887) Senate Document 191—USACE/Reclamation plan for Missouri River Basin Development • Project Purposes – Flood Control – Hydropower – Irrigation – Recreation – Fish & Wildlife – Sediment storage Yellowtail Unit Project Purposes- Flood Control (Exclusive flood storage = 259K af), Coordinated with U.S. Army Corps of Engineers Bighorn Canyon National Recreation Area Authorization: Public Law 89-664, October 15, 1966 Purpose “In order to provide for public outdoor recreation use and enjoyment of the proposed Yellowtail Reservoir and lands adjacent thereto in the States of Wyoming and Montana by the people of the United States….” BIGHORN RESERVOIR ALLOCATIONS Dam Crest Maximum Water Surface or Top of Surcharge Elev. 3660.00 (1,381,189 Acre-Feet) Elev. 3660.0 SURCHARGE - 52,829 Acre-Feet Top of Exclusive Flood Elev. 3657.00 (1,328,360 AF) EXCLUSIVE FLOOD CONTROL - 258,331 Acre-Feet Top of Joint Use Elev. 3640.00 (1,070,029 Acre-Feet) JOINT USE - 240,342 Acre-Feet Top of Active Conservation Elev. 3614.00 (829,687 Acre-Feet) Spillway crest Elev. 3593.00 ACTIVE CONSERVATION - 336,103 Acre-Feet FISH WILDLIFE RECREATION AGRICULTURE POWER MUNICIPAL INDUSTRIAL Top of Inactive Elev. 3547.00 (493,584 Acre-Feet) Powerplant Penstock Elev. 3450.00 INACTIVE CONSERVATION - 477,576 Acre-Feet Irrigation Outlet Elev. 3400.00 River Outlet Elev. 3300.0 Top of Dead Elev. 3296.50 (16,008 Acre-Feet) DEAD - 16,008 Acre-Feet Streambed Elev. 3166.0 Record Drought Water Years • Average Bighorn Lake Inflow 1967-2006 2,373 kaf • DPR avg. 1934-1940 Drought: 1,558 kaf • Average Inflow Drought 2000-2006 1,384 kaf • Lowest annual inflow of record 2002 1,030 kaf 4000000 3500000 3000000 2500000 Bighorn Lake Annual Inflow Trend 2000000 1500000 Inflow1000000 acre-feet 500000 0 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 Lake Level Versus Current Safe Launch Levels Bighorn Lake Elevation May 20 - September 5 1997-2006 3650 Recreation periods in red 3640 3630 3620 Horseshoe Bend Safe Boat Launch 3610 Elevation (ft) Elevation 3600 Non-recreation periods in blue 3590 Ok-A-Beh & Barry’s Landing Safe Boat Launch 3580 3570 10/01/1997 02/01/1998 06/01/1998 10/01/1998 02/01/1999 06/01/1999 10/01/1999 02/01/2000 06/01/2000 10/01/2000 02/01/2001 06/01/2001 10/01/2001 02/01/2002 06/01/2002 10/01/2002 02/01/2003 06/01/2003 10/01/2003 02/01/2004 06/01/2004 10/01/2004 02/01/2005 06/01/2005 10/01/2005 02/01/2006 06/01/2006 10/01/2006 Date HORSESHOE BEND RAMP July 27, 2001 July 17, 2002 Lake Elevation 3614.43 Lake Elevation 3588.36 Horseshoe Bend Area AUGUST 31, 2001 3603.00 LAKE ELEVATION View Downstream of Bighorn River at Bighorn Access August 20, 2002 1536 CFS River Flow MFWP estimates fish populations have declined from 7500 fish per mile to as low as 2200 fish per mile as minimum flows have been reduced from 2500 to 1500 cfs. View of Bighorn River at Bighorn Access August 20, 2002 1536 CFS River Flow MFWP estimates fish populations have declined from 7500 fish per mile to as low as 2200 fish per mile as minimum flows have been reduced from 2500 to 1500 cfs. RECLAMATION Managing Water in the West Yellowtail Dam & Bighorn Lake Lovell, Wyoming February 17, 2007 RECLAMATION Managing Water in the West Yellowtail Dam & Bighorn Lake Long Term Issues Group Bighorn River System Long-Term Issues Group Montana: Fish Wildlife & Parks, Department of Natural Resources and Conservation Wyoming: Fish and Game, State Engineer Crow & Northern Cheyenne Tribes Bighorn County Wyoming Bighorn County Montana Congressional Representatives Passionate Public: Friends of Bighorn Lake, Friends of Bighorn River Bighorn River System Long-Term Issues Group Montana: Fish Wildlife & Parks, Department of Natural Resources and Conservation Wyoming: Fish and Game, State Engineer Crow & Northern Cheyenne Tribes Bighorn County Wyoming Bighorn County Montana Congressional Representatives Passionate Public: Friends of Bighorn Lake, Friends of Bighorn River Bighorn River System Long-Term Issues Group Montana: Fish Wildlife & Parks, Department of Natural Resources and Conservation Wyoming: Fish and Game, State Engineer Crow & Northern Cheyenne Tribes Bighorn County Wyoming Bighorn County Montana Congressional Representatives Passionate Public: Friends of Bighorn Lake, Friends of Bighorn River National Park Service 3645 3640 3635 3630 3625 3620 3615 3610 3605 3600 3595 Reservoir Elevations (feet) 3590 3585 3580 3575 October November December January February Mar c h April May June July August September NPS Recreation Minimal NPS Recreation Op BIGHORN FLOW RECOMMENDATIONS (MT FW&P) Optimal Flow - 3,500 cfs Target Minimum Flow – 2,500 cfs Preferred Min. Fisheries Flow – 2,000 cfs Absolute Min. Fisheries Flow - 1,500 cfs Rule Curves (Forecast & Reservoir Levels) Reservoir Level Targets Date Revised Criteria Old Criteria _______ Target Elevation Targets Oct 31 3638-3640 3630-3635 (Revised Fall/Winter Inflow Formulas, On Web-Site) Mar 31 3616.7-3620.6 3605-3614 Apr-July Rule Curve July 31 3640 3640 Lake Elev. feet 3600.0 3610.0 3620.0 3630.0 3640.0 3/31 Rule CurveExample 4/7 4/14 Min Fill 28% Fill Min 4/21 4/28 LakeBighorn Rule Curves 5/5 5/12 Medium 5/19 5/26 6/2 6/9 UQ 6/16 6/23 UD 6/30 7/7 Max 7/14 7/21 7/28 Yellowtail Dam Power Generation Modified Criteria vs. Historic 1988-2008 100.0 90.0 80.0 70.0 60.0 50.0 Generation GWH 40.0 Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Modified Criteria Historic Bighorn Lake Elev. Modified Criteria vs. Historic 1988-2008 Averages 3640 3635 3630 3625 3620 3615 3610 Lake Level feet 3605 3600 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Modified Criteria Historic River Release Targets Existing SOP Criteria • Optimum Instream Flow 2,500 cfs • Standard Instream Flow 2,000 cfs • Minimum Instream Flow 1,500 cfs • Absolute Minimum 1,000 cfs Revised Criteria • Prefered Instream Flow 3,500 cfs • Optimum Instream Flow 2,500 cfs • Standard Instream Flow 2,000 cfs • Minimum Instream Flow 1,500 cfs • Absolute Minimum 1,000 cfs (Prefered fishery flow provided by Montana FW&P during issued group meetings.) Bighorn River Flows Revised Criteria vs. Historic Bighorn River Fishery Flows 1988-2008 % of of Time above Fishery Flow Targets 100 80 60 40 20 Percent of Time 0 1300 1500 2000 2500 3500 Historic Modified Criteria Expected Benefits of Revised Operating Criteria Values Compared to Historic Operation Lake Levels January-April 7-8 feet higher May-June 3 feet higher July-December 4-5 feet higher Expected Benefits of Revised Operating Criteria Values Compared to Historic Operation River Flows Improvement in Percent of Time Provided 1500 cfs +8% (met 100% of time for study period) 2000 cfs +5% 2500 cfs +5% 3500 cfs -3% Expected Benefits of Revised Operating Criteria Values Compared to Historic Operation Power Generation Increased Generation GWHs Percent Increase Annual +17.9 2% Dec-Feb - 2.2 -1% July-Aug - 1.8 Expected Benefits of Revised Operating Criteria Values Compared to Historic Operation Flood Control June Slight decrease in peak release rate Decrease in peak reservoir level for most high runoff years Statement of problem • Progressive side channel abandonment • Loss of habitat in side channels – Changes from 1939 to 1974 (from Koch et al 1977): • Vegetated Islands 23.1% • Island Gravel Bars 77.2% • Lateral Gravel Bars 34.0% • Water Area 7.8% – Side channel loss appears to be continuing today (based on field observations) – Side channel loss attributed to the construction of Yellowtail Dam Bighorn River near St. Xavier, MT (#06287000) Klines Channel Bighorn Alliance side channel work salt cedar and Russian olive removal Water dam at head of Side Channel Invasive Russian Olive Salt Cedar holding sediment Slated for Removal What did it look like in Feb 2012? 3,130 CFS Big Horn Lake Sediment Management Study Dan Pridal Omaha District Corps of Engineers Range Line 15 - Station 246853 with 40 Year Future Base Condition 3640 Average Bed for Section 3630 3620 Average Bed Change 3610 3600 3590 Elevation Feet - Original 1982 2000 2007 Base 40 Year 3580 3570 Historical model simulation period from Oct 1965 through July 2007. Observed survey data from Bureau of Reclamation rangeline surveys. 3560 3550 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 Distance - Feet Construct spaced berms to increase travel time and sediment retention within basin. Size and extent to be determined in next design phase. Sediment trap efficiency decreases for higher flow as travel time reduces. Second option to restrict Causeway opening and use as dam. May be WY DOT issues with unequal water elevation for embankment. .