The two-basin solution promises Russian River users a water supply for 30 years, with the potential for a 20-year renewal, and perhaps more if Eel River restoration goals are met.

The mostly wintertime diversions will reduce annual transfers into the Russian River watershed from a current level of about 40,000 acre-feet a year to about 35,000 acre-feet.

The Russian River watershed includes Sonoma and Mendocino counties, and water stored in Lake Mendocino north of Ukiah is released downstream to maintain flows in the Upper Russian River.

A Russian River flood warning is in effect until 6 a.m. Thursday for Guerneville and from unincorporated Healdsburg to Jenner, located at 36 feet above the river or below.