Stream impoundment: comprehensive riverine effects on the Provo River, Utah

This study focused on the geomorphological, ecological, and sedimentological impacts of the Jordanelle Dam Provo River, Utah. This particular study site provides a unique opportunity because the Jordanelle dam was put in place in 1992 and a large scale restoration project was completed in 2008, allowing for high resolution imagery and observations prior to dam placement and restoration. To monitor these effects, we established cross section study sites along the Provo River, with 5 above the dam and 5 below the dam. At each cross section, we measured baseline channel morphology characteristics via surveying and sediment size distribution via sediment collection and lab grain size analysis processing. We also inventoried vegetation characteristics along the river to monitor differences upstream and downstream of the dam. This data, combined with analysis of historical imagery and current high resolution imagery, enables us to identify geomorphic changes over time and evaluate the impacts of those changes on the post-engineered river system as it applies to current and future watershed management. Post-impoundment, we find that channels downstream of the dam have become more stable, allowing for vegetation colonization, as exhibited in land cover changes from bare soil to grass. This results in greater species richness owing to colonization of a more stable riparian zone, ultimately changing habitat conditions. Grain size increases below the dam, which is a known dam impact. This data is particularly important as Utah faces climate change and population growth, both of which stress water availability, and has the potential to inform and improve watershed management practices to result in both a healthy fluvial system and a sustainable water resource.