University of California Water Resources Center

Based on a combination of field observations and laboratory experiments, we have analyzed the annual and interannual salinity dynamics in a seasonal wetland in the San Joaquin Valley. The field observations, which included direct measurement of both the temporal and spatial variability in water velocities, conductivity, temperature an depth, suggest that the salinity dynamics in the wetland are dominated by advective transport processes which redistribute high salinity waters from the inlet throughout the wetland. As such, evapotranspiration and exchange between the soil column and the water column appear to play secondary roles in the salinity dynamics of the wetland. The conclusion regarding the role of soil column-water column exchange has been reinforced using laboratory experiments combined with numerical analysis, which indicate that the flux of salt between the soil and water columns is small in magnitude.