| Middle Fork Stanislaus River | |
| Source1 Location: | Confluence of Kennedy and Summit Creeks |
| Source1 Coordinates: | 38.2942°N -119.7303°W |
| Source1 Coord Ref: | [1] |
| Mouth Location: | Stanislaus River |
| Mouth Coordinates: | 38.1542°N -120.3575°W |
| Progression: | Stanislaus–San Joaquin |
| Length: | 45.7miles |
| Source1 Elevation: | 6644feet |
| Mouth Elevation: | 1230feet |
| Discharge1 Avg: | 689cuft/s[2] |
| Basin Size: | 332mi2 |
The Middle Fork Stanislaus River is a 45.7miles[3] tributary of the Stanislaus River in the central Sierra Nevada and Stanislaus National Forest of eastern California.
The river begins at the confluence of Kennedy Creek and Summit Creek in the Emigrant Wilderness. It flows initially northwest, receiving the Clark Fork from the right then turning southwest, through a deep canyon to its confluence with the North Fork Stanislaus River, forming the Stanislaus River. The river drains a watershed of 332mi2[4] in Tuolumne County, much of it within the Stanislaus National Forest.
There are four dams on the main stem of the Middle Fork – at Donnells, Beardsley, Beardsley Forebay and Sand Bar Flat. The only significant tributary impoundment is Relief Reservoir, formed by Relief Dam on Summit Creek. Middle Fork water is managed by the Spring Gap–Stanislaus hydroelectric project, owned by Pacific Gas and Electric, and the Tri-Dam project owned by the Oakdale and South San Joaquin irrigation districts.[5] [6]
Tunnels connect the four mainstem reservoirs to take advantage of the hydraulic head created by the Middle Fork's steep drop. The final tunnel, from Sand Bar Flat, enters the main Stanislaus River about 2miles below the mouth of the Middle Fork, at the head of New Melones Lake reservoir. As a result, much of the Middle Fork is dewatered during the drier months.[5]