SPATIAL AND TEMPORAL VARIABILITY OF HYDRAULIC PROPERTIES IN THE RUSSIAN RIVER STREAMBED CENTRAL SONOMA COUNTY, CA

Temporal and spatial variations of flux and vertical hydraulic conductivity (Kv) were measured in the Russian River streambed in Sonoma County, California. In-situ vertical hydraulic conductivity and flux measurements were made using a modified seepage meter equipped with piezometers. Three different streambed locations (near bank, midpoint, and thalweg) were sampled at five different sample locales in a 20-km reach of the Russian River. Vertical hydraulic conductivity of the streambed ranged from 8.55x10^-5 cm/sec to 1.52x10^-1 cm/sec. Significantly (p<0.05) higher values of Kv were found near the banks of the Russian River, and Kv increased (30% to an order of magnitude) after the winter storm season (March 04). Flux varied from -240 to 600 cm/day, which indicates both gaining and losing reaches of the stream occur in our study area. These findings will assist the Sonoma County Water Agency in managing water needs for the citizens of Sonoma County.