Lake Thomas A Edison
| Company type | Private |
|---|---|
| Industry | Electric utility |
| Products | Hydroelectric power |
Lake Thomas A Edison—also referred to as Thomas A. Edison Lake or simply Edison Lake—is a man-made reservoir located within the Sierra National Forest in Fresno County, California. It lies in the Sierra Nevada mountain range, close to the Pacific Crest Trail.
This reservoir was created by the construction of the Vermilion Valley Dam (National ID CA00441), which was finalized in 1954. Both the dam and the lake serve as vital elements of the Big Creek Hydroelectric Project infrastructure.
Hydrology
Water from Lake Thomas A Edison flows into Mono Creek, which is a feeder stream to the South Fork of the San Joaquin River. In addition, a portion of the lake’s water is channeled via the Ward Tunnel to Huntington Lake, aiding hydroelectric power generation in the area.
Vermilion Valley Dam
The Vermilion Valley Dam is an earthfill dam extending 4,234 feet in length and rising 167 feet high, with a freeboard of 8 feet. Ownership and operational responsibilities belong to Southern California Edison, a major entity in regional hydroelectric energy production.
Recreation
Situated near the Pacific Crest Trail within Sierra National Forest, Lake Thomas A Edison is central to Vermilion Valley Resort and Vermillion Campground. Visitors engage in activities such as boating, fishing, camping, swimming, kayaking, canoeing, and horseback riding.
Access
Reaching the lake requires approximately three hours of driving from Fresno. The route follows State Route 168 eastward to Huntington Lake, then continues east on Kaiser Pass Road. This road crosses Kaiser Pass at an elevation of , which is closed during winter months. The United States Forest Service recommends that buses, large RVs, and vehicles towing trailers avoid this route.
A ferry service connects Vermilion Valley Resort with the trailhead for the John Muir Wilderness twice daily; however, it was not operational in 2021 due to low water levels. Alternative transportation options can be arranged through Vermilion Valley Resort or by hiking along a trail on the lake’s northern shore. This ferry provides access to both the John Muir Trail and the Pacific Crest Trail.
Nomenclature
The reservoir is named in honor of American inventor Thomas Edison, commemorating the 75th anniversary of his invention of the incandescent light bulb. The dam’s name originates from the valley it submerged, noted for its distinctive reddish soil.