Current Water Storage Levels

Designated water year: Normal as of April 1, 2012

Daily Reservoir Operation Status

The Sonoma County Water Agency (Water Agency) is the local cost-sharing partner for Lake Mendocino and Lake Sonoma, and determines the amount of water to be released when the lake levels are in the water supply pools. The US Army Corps of Engineers determines the amount of water to be released when the lake levels are above the water supply pools and in the flood control pools.

The Russian River is a managed river system with reservoir releases controlling river flows, especially throughout most of the summer and fall. When tributary stream flows are low, the Water Agency releases water stored in the reservoirs to supplement the natural flows in the Russian River to provide adequate flows for water supply, recreation and aquatic habitat. A release from a reservoir can be categorized as being of ‘pass-through water’ or ‘stored water’. The term ‘project water’ is often used instead of stored water and is used to describe water that is present because of the dam and reservoir project. Pass-through water is water flowing into the reservoir that is not stored in, but passes through, the reservoir. Project water releases to supplement the natural flows in the Russian River and Dry Creek are necessary to meet mandatory minimum streamflow requirements that exist for both of these watercourses.

*Note each day after March 1, the Water Supply Pool in Lake Mendocino is allowed to encroach into the Flood Control Pool, thus resulting in changing Water Supply and Flood Control pool numbers.

Current status of reservoir and river operations:

Last Update: 05/05/2012 @ 10:00am	Operational Control	Agency is Releasing Project Water to Meet Instream Flow Requirements
Lake Mendocino	SCWA	NO
Lake Sonoma	USACE	YES
Lower Russian River (Dry Creek to Hacienda Bridge)	-	NO

Monthly Summary Data

Reservoir Levels and Releases

Last Update: 05/05/012 @ 10:00am	Water Supply Pool Capacity (acre-feet)	Current Water Supply Pool Storage (acre-feet)	Water Supply Storage % Full	Reservoir Release (cfs)	Required Minimum Instream Flow (cfs)	Instream Flow Regulatory Region
Lake Mendocino	102,600	89,874	83.7	83	125	Upper Russian River
Lake Sonoma	245,000	247,238	101.0	83	75	Lower Dry Creek

*cfs—cubic feet per second

Russian River Flow Data

Last Update: 05/05/2012@ 10:00am	Flow (cfs)	Required Minimum Instream Flow (cfs)	Instream Flow Regulatory Region
Hacienda Bridge	710	70	Lower Russian River

*cfs—cubic feet per second

PG&E Potter Valley Project Data

Last Update:
05/05/2012 @ 10:00am

Water Supply Pool Capacity
(acre-feet)

Current Water Supply Pool Storage
(acre-feet)

Water Supply Storage
% Full

Reservoir Release
(cfs)

Cumulative Inflow as of Oct 1^st
(acre-feet)

Lake Pillsbury

(Eel River Watershed)

74,981

70,002

93.3

341

201.521

Last Update:

05/05/2012 @ 10:00am

Reservoir Release to Eel River

(cfs)

Potter Valley Project Diversion

(cfs)

Lake Van Arsdale

316

*cfs—cubic feet per second

Real-time Data for Potter Valley Project

Disclaimer: The above data is based on provisional data that is subject to revision.