s 627.83 N7bdm 2001 DAM BAIR MANUAL FOR OPERATION AND MAINTENANCE COLLECTION DOCUMENTS STATE L.|KAR^ MONTANA STATE State Water Projects Bureau Water Resources Division Department of Natural Resources and Conservation 48 North Last Chance Gulch P.O. Box 201601 MT Helena, 59620 1601 Initial Publication May 1995 Revised July 2001 « DAM BAIR MANUAL FOR OPERATION AND MAINTENANCE State Water Projects Bureau Water Resources Division Department of Natural Resources and Conservation 48 North Last Chance Gulch P.O. Box 201601 MT Helena, 59620-1601 Initial Publication May 1995 Revised July 2001 Digitized by the Internet Archive 2015 in https://archive.org/details/bairdammanualfor2001 mont 11 TABLE OF CONTENTS PAGE OVERVIEW 1 Map General Location (Figure 3 1) Project Area Map (Figure 2) 4 General Layout Map (Figure 3) 5 Map Monitoring Wells (Figure 4) 6 STATISTICAL INFORMATION 7 OPERATING PROCEDURES 11 Method and Schedule of Operation 1 Drawdown Safe 12 Limits of Appurtenances 12 Dam Operator 13 Storage Determination 14 Weather Monitoring 14 Interaction with Other Dams 15 Emergency 15 INSPECTION AND MONITORING 17 Structural Features Inspection 17 Riprap Inspection 18 Drains 18 Monitoring Wells 19 Seepage Monitoring 19 MAINTENANCE 21 Routine Maintenance 21 Annual Maintenance 22 Record Keeping 22 REFERENCES 25 APPENDICES 27 A. RATING CURVES AND TABLES A1 Table SLOPE STORAGE TABLE -SOUTH SHORE A2 1 . Table 2. SLOPE STORAGE TABLE -DAM A6 Table 3. TOTAL STORAGE TABLE A8 Table 4. SPILLWAY RATING CURVE AND TABLE A1 Table V-NOTCH WEIR RATING TABLE A12 5. B. INSPECTION REPORT FORM B1 2001 i TABLE OF CONTENTS (continued) PAGE C. DISTRIBUTION LIST Cl D. MONITORING WELL LOGS D1 E. TEST PIT LOGS El PROJECT DRAWINGS F. FI 2001 ii OVERVIEW Bair Dam is located in Meagher County approximately three- quarters of a mile northwest of the town of Checkerboard (Figure 1). The reservoir (and dam) is located on and fed by the North Fork Musselshell River (Figure 2). Figure 3 provides a general layout of the dam, spillway and outlet works. Figure 4 shows the location of the monitoring wells and weir. The dam is owned by the Montana Department of Natural Resources and Conservation (DNRC) and is managed by the State Water Projects Bureau (SWPB) of the DNRC. The Upper Musselshell Water Users Association (herein called the “association”) operates and maintains the dam. The earthfill dam was completed in 1939. Bair Dam is 102 feet high and 580 feet long. The dam’s outlet works consists of: a concrete intake structure; a 54-inch reinforced concrete arch conduit; a 48-inch diameter butterfly (operating gate) valve; a 48- inch diameter slide (emergency gate) gate; a control tower; and an outlet structure. The control tower contains the gate operators for the outlet gates. The maximum capacity of the outlet works is 650 cubic feet per second (cfs). The spillway located in the left abutment, is an uncontrolled, rectangular, concrete chute. The spillway has an ogee-shaped crest section at elevation 5,325. The crest is 60 feet wide and tapers to a 20 feet wide chute at the bottom. The maximum capacity of the spillway is 7,880 cfs. dam In October, 2000, a feasibility study to rehabilitate the HKM was completed by Engineering, Inc. The preferred alternative for rehabilitation is to replace the existing spillway and excavate the adjacent slope to eliminate the talus which creeps into the spillway. The new spillway would have a capacity of 14, 000 cfs with the reservoir pool at the dam crest. HKM is currently working 2001 1 on the final design and construction is anticipated to begin in the fall of 2001. Water from the reservoir is primarily used for irrigation water supply. The reservoir is also used for water-based recreation. 2 2001 3 2001 RESERVOIR Dam Map Figure 2. Bair Project 4 2001