California Northern Sierra Precipitation
8-Station Index, July 29, 2015
The average of eight precipitation stations serves as a wetness index for the Sacramento River hydrologic region.
It provides a representative sample of the region's major watersheds:
the upper Sacramento, Feather, Yuba, and American rivers, which produce inflow to some of California's largest reservoirs - the source of much of our water supply. The eight stations are:
Blue Canyon, Brush Creek Ranger Station, Mineral, Mount Shasta City, Pacific House,
Quincy Ranger Station, Shasta Dam, Sierraville Ranger Station.
Seasonal runoff forecasts are based on many more measurements than this index, including snowpack and prior streamflow. The seasonal forecasts are a more accurate measure of water supply.