Milles Lake Dam in Twisp, Washington, stands as a vital structure for fish and wildlife conservation and irrigation purposes.
Wind
Humidity
Completed in 1950, this earth dam boasts a hydraulic height of 13 feet and a structural height of 11 feet, providing a crucial 24-acre-feet of storage capacity for the surrounding area. Situated on the Unnamed Tributary of the Twisp River, the dam serves as a key feature within the Okanogan County landscape, regulated and inspected by the Washington Department of Ecology to ensure its safety and functionality.
With a Hazard Potential rated as High and a Condition Assessment deemed Satisfactory during the last inspection in June 2021, Milles Lake Dam remains a significant contributor to the region's water resource management. Its location in the Congressional District 04 of Washington underlines its importance within the state's infrastructure. As a state-regulated and state-permitted dam, it plays a crucial role in maintaining the ecological balance of the area, serving as a lifeline for the local fish and wildlife populations while also supporting agricultural activities through irrigation provisions. The dam's capacity to store 20 acre-feet of water under normal conditions highlights its essential role in sustaining the surrounding environment.
Year Completed |
1950 |
Dam Length |
1150 |
River Or Stream |
Unnamed Tr. -Twisp R. |
Primary Dam Type |
Earth |
Surface Area |
27 |
Hydraulic Height |
13 |
Drainage Area |
1.32 |
Nid Storage |
24 |
Structural Height |
11 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
13 |
Twisp River Near Twisp
|
1780cfs |
Methow River At Twisp
|
6560cfs |
Methow River At Winthrop
|
4510cfs |
Chewuch River At Winthrop
|
587cfs |
Methow River Above Goat Creek Near Mazama
|
3110cfs |
Okanogan River At Malott
|
2420cfs |
| Location | Reservations | Toilets |
|---|---|---|
Tent camping
|
||
Campbell Lake - WDFW
|
||
Pearrygin Lake State Park
|
||
Blackpine Lake
|
||
Black Pine Lake Campground
|
||
Cougar Lake Campground
|
Private Land Boundary To Okanogan Nf Boundary
Lake Chelan-Sawtooth Wilderness Boundary To Okanogan Nf Boundary
Confluence Of South Fork Wolf Creek To Lake Chelan-Sawtooth Wilderness Boundary
Lake Chelan-Sawtooth Wilderness Boundary To Private Land Boundary Near Lime Creek In Se1/4 Of Sec 18, T33N, R20E
Pasayten Wilderness Boundary To Okanogan Nf Boundary