General

• Region (Map) : .................. Great Plains
• State (Map) ........................ Montana
• County ................................ Lewis and Clark
• Project: ................................ Sun River
• Dam type: ........................... Earthfill
• Location: ............................ 5 mi NW of Augusta
• Watercourse: ......................Willow Creek
• Reservoir: ............................Willow Creek
• Construction Date: ............1907-1911
• National ID Number .......... MT00577
• Hydrologic Unit Code .....

Dimensions

• Crest Elevation of Dam: ...................... 4154.0 ft
• Structural Height of Dam: ....................    93.0 ft
• Crest Length: .........................................  650.0 ft
• Top of Joint Use: .................................        N/A
• Top of Active Conservation: ............. 4142.0 ft
• Top of Inactive Conservation: ...........        N/A
• Spillway Crest: ..................................... 4144.0 ft
• Top of Dead Storage: .......................... 4085.3 ft
• Streambed at Dam Axis : ..................... 4080.0 ft

Hydraulics

• Normal Water Surface Elev: ................4142.0 ft
• Hydraulic Height: .................................... 69.0 ft
• Service Spillway Type:
•    Uncontrolled  Crest    ................................Yes
•    Morning-Glory ............................................ No
•    Crest Length    ........................................ 700 ft
•    Gated      ....................................................... No
•    Capacity at Elev:  4147.0  ft,           10,000  cfs
• Auxiliary Spillway ......................................... No
•     Capacity at Elev.   ................................... 0 cfs
• Outlet Works Capacity at

    Elevation  4142.0 ft.,  .......................... 500 cfs

Hydrology

• Drainage Area: .................................118.3 sq mi
• Hydrometeorological Report               HMR 55

Flood Type: .............................Summer General

• Storm Duration: ....................................... 72 hrs
• Probable Maximum Flood (PMF) Report:
•   Peak Inflow: .............................164,100,000 cfs
•   Inflow Volume: .........................191,400 acre-ft
•   Flow Duration: ...................................... 7 days
•   PMF Routing MWS Elev.: ....................... NA
•   Initial Routing Elev: ...........................4142.0 ft
•   Study Date: ..................................... April 1996