Effect of geomorphic channel restoration on streamflow and groundwater in a snowmelt-dominated watershed

Reengineering of stream channels is a common approach used to restore hydrologic function in degraded landscapes, but there has been little published research analyzing its effectiveness. A key challenge for impact assessment is disentangling the effects of restoration from climate variability. Trout Creek, near Lake Tahoe, California, was reengineered to reestablish hydrologic connectivity between the stream and its former floodplain. Gauges located above and below the site, along with groundwater well measurements, were used to analyze prerestoration and postrestoration hydrology. Results show that restoration has a seasonal impact with statistically significant increases in streamflow during the summer recession period and decreased groundwater table depths across a wide range of streamflow conditions. Paired gauges and statistical models that are robust to serial autocorrelation demonstrate a feasible approach for assessing hydrologic restoration in regions where climate patterns lead to substantial within-year and between-years variation in streamflow.