Gauge Description:

Southern CA Edison is now posting flow information for the San Joaquin below Shakeflat Creek gauge which is a short ways below Mammoth Pool dam. Click on the "Show List" button and you will see flows in several other river sections in the basin, as well as reservoir surface elevations. Mammoth Pool will spill when the surface elevation reaches about 3,330 feet.

The Millerton DailyReport - pdf shows reservoir storage as of midnight, including percent of capacity, for Mammoth Pool and for other reservoirs in the basin. Mammoth can only spill when it is full, as there are no gates on the dam or spillway.

Flows of 700-800 cfs are low but okay. A flow around 1,500 cfs is considered optimal by many.

Historical flow data related to this reach can be found at these sites:
San Joaquin above Shakeflat: USGS
Mammoth Pool PowerPlant
San Joaquin above Big Creek, has data from before the construction of Mammoth Pool dam.
USGS gauge list for historical records of all gauges past and present in the upper San Joaquin drainage.