STREAMFLOW AND RIPARIAN GROUNDWATER RESPONSE TO BEAVER DAM ANALOGS IN VERNON CREEK, UTAH

In collaboration with Utah’s Watershed Restoration Initiative and its partners, the Utah Geological Survey is evaluating the hydrologic and ecological impacts of environmental restoration efforts across the state. To counter stream and riparian zone degradation, beaver dam analogs (BDAs), a low tech, process-based restoration method, are being implemented throughout Utah. BDAs reconnect stream channels with floodplains, enhance wildlife and riparian habitat, restore ecosystem function, and improve water quality. However, downstream water users have raised concerns about the potential impact of BDAs on streamflow timing and quantity. To address these concerns, we designed a controlled study of 35 BDAs on Vernon Creek, a second-order stream in the Sheeprock Mountains Sage Grouse Management Area in Tooele County, Utah. Prior to BDA installation, we monitored experimental reaches for three years to characterize baseline response of groundwater to climate variation. We established continuous riparian groundwater elevation and stream stage monitoring at two reaches with BDAs installed and two control reaches along the stream. Monitoring continued for two years after BDA installation. Preliminary analysis shows that groundwater elevations in the adjacent riparian zone increased immediately after BDA installation and have persisted on average relative to the control reaches. Additionally, we observed no significant change in streamflow compared to the control reaches. Further analysis will examine whether increased riparian groundwater elevation translates to higher baseflow. These results provide a quantitative assessment of the impact of stream restoration on shallow groundwater systems. Our findings will help future BDA monitoring projects proactively navigate water rights issues and local water users’ expectations by providing data on potential hydrologic changes and optimal project timing.