The introduction and spread of tamarisk (Tamarix spp.) in the riparian zones adjacent to the Colorado River and many of its tributaries in the southwestern US has contributed to increased stability of many of these river channels over the last century. Recent and expanding efforts to remove tamarisk from riparian zones may contribute to increase channel mobility and bank erosion. A collaborative effort to better understand channel response of the Colorado River to tamarisk removal has involved field surveys as well as GIS analysis of channel change in areas with and without vegetation removal from historic aerial photos. Preliminary results suggest that erosion rates were higher during the time period with higher peak flows regardless of whether or not vegetation was removed, and that erosion rates were greater in sites were vegetation removal occurred. The potential impact of climate change on streamflow in the Upper Colorado River Basin will also be discussed.