BASS LAKE WATER LEVEL & STATISTICS
Bass Lake is also known as Crane Valley Reservoir
Topo Map of Bass Lake (size 119K) Boating Information
More Dam Information Water Sample Report Home Page
Lake Water Height
Snow & Stream Flows
As of March 27, 2025 -12' 6" @ 3364' 2"
Elevation (full) 3376' 8"
Seasonal Rainfall (inches)
Graph 2001-2007
Raw data - Excel spread sheet
Lake Level History/Management
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While PG&E owns the Lake, the water level is adjusted for several needs through the year. First of all, farmers need the water downstream. Around 1900, the corporation of ranch owners, Henry Miller and Charles Lux sued to stop the obstruction of the natural flow of water for the San Joaquin River and its branches. The suit resulted in the Miller-Lux Agreement. For Bass Lake this required the Lake's owner to decrease the Lake level to 60% of full by September 15th and 50% by November 1st each year. The Bureau of Water Reclamation monitors this agreement. For the last several years the Bureau has delayed the date of the agreement by 6 weeks allowing Bass Lake to remain fuller for recreation.
To provide flood control, the Lake is not allowed to fill above -10 ft before April 1st. PG&E uses the winter and spring runoff to generate power and limit the lake level below the -10 ft level. On April 1st PG&E places wooden boards in steel guide on top of the spillway to allow the water rise above the -10 level. The Boards are removed after summer when the water level fall below -10 ft. The water level is further managed by generating power to limit the water level from spilling over the top boards, thus wasting the ability to generate power. If the water level increases too rapidly while the boards are in, spillway doors can be used manage the lake level. See pictures of the Dam here.
Typically the Lake fills to within 1-4 ft of full for the summer. Most shallow water docks float at -10 ft and all the dock are floating at about -5 ft. In the summer 2007 we had only about 50% of normal rain fall and the lake still filled so almost all the dock were floating. Only a dozen docks on the very North West side were dry in 2007.