Grassland Water District

Site Description

Los Banos Creek conveys a mixed drainage return flow and may contain returns flows from agricultural lands such as the San Luis Water District and CCID, local feedlots and the City of Los Banos. The Los Banos Creek also conveys flood water generated from the hill South of Los Banos and from Garzas Creek Southwest of the City of Gustine. These flows can reach as high as 1,500 cfs. Los Banos Creek also conveys surface runoff from unincorporated land in the watershed below Hwy I5 as well as from operational spills from San Luis Reservoir and the O’Neill Forebay. Wetlands draining into Los Banos Creek include those supplied by the Volta Wasteway, Garzas Creek and the Main Canal. Because of the variety of drainage conveyed by Los Banos Creek there is normally flow year-around with flows up to 150 cfs that are discharged into Mud Slough between where Hwy 140 crosses over it and Mud Slough’s confluence with the San Joaquin River. Because of the large fluctuation in stage at the gauging station both a bubbler transducer and a SONTEK SL transducer were deployed at the site. Flows are estimated both by rating table and by direct product of SONTEK velocity and channel cross section, corrected for a rating calibration factor.