Riparian Vegetation and Digitized Channel Variable Changes After Stream Impoundment: The Provo River and Jordanelle Dam

Following stream impoundment, rivers respond via changes in sediment dynamics, channel morphology, and vegetation distribution. Such changes have occurred along the Provo River, Utah, located within the Intermountain West of the U.S. Jordanelle Dam was built on the Provo River in 1992 after the majority of dam construction in the United States and therefore allows for a large-scale GIS analysis using aerial photographs, available before and after construction. To evaluate the effects of the dam, this study examines reach scale channel changes with respect to vegetation distribution and species richness. Post-impoundment, the authors 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. Identifying and understanding the impacts of the Jordanelle Dam on vegetation is necessary for protection of this valued ecosystem as rapid development continues.