The Willow County Water District (Willow) operates two wellfields adjacent to the Russian River which draw underflow from the river. Willow holds two surface water rights: one allows diverting 1 cubic feet per second (cfs) year-round; the other allows diverting 3 cfs from November to June with a required bypass flow of 150 cfs. Willow also purchases water from the Russian River Flood Control & Water Conservation Improvement District (RRFCWCID).
Since 2009, Horizon has assisted Willow with its annual reporting to the State Water Resources Control Board (SWRCB) pursuant to its water rights. This has involved using well log data to calculate the amount of water diverted under its license or permit, or purchased from RRFCWCID. To determine when water is available under the permit, Horizon uses flow records from the nearest U.S. Geological Survey stream gage to determine whether flow is above 150 cfs.
Horizon also assisted Willow with petitions pursuant to its permit and license. These petitions would add various wells as points of diversion, and irrigation as a purpose of use, under both its surface water rights. Horizon coordinated with SWRCB, performed an analysis of historical pumping records, and negotiated updated permit terms. In March 2019, Horizon was informed that Willow had received approval of its petitions from SWRCB.