Dataset associated with: The Influence of Knickpoint Development and Channel Incision on Riparian Vegetation in Semi-arid River Corridors

Hydrogeomorphic processes strongly influence riparian vegetation, but few studies have determined the influence of knickpoint development on these processes. We present a dataset of channel geomorphology, flood patterns, and riparian vegetation used in the investigation of the influence of knickpoint development and channel incision on fluvial ecogeomorphic processes on the Fremont River in Utah. We conducted topographic surveys (n = 30 transects) and plot-based vegetation surveys (n = 336) in three 1 km-long reaches with varying proximities to a human-created knickpoint. Geomorphic and ecological data from a fourth reach is also included in this dataset, although it was not used in the analyses and results presented in the associated journal article due to reduced measurements and limited data from that reach. We also developed 1D hydraulic models to assess flood inundation patterns. Our data indicate that knickpoint development affects riparian vegetation composition and abundance through its influence on geomorphic and hydrologic processes. The study reach located just upstream of the knickpoint (R2) had a deeper channel, flooded less frequently, and required higher flows to inundate the floodplain compared to the study reach located 5 km upstream of the knickpoint (R1). Overall mean vegetation abundance (percent cover) was higher in R1 (55.7%) than in R2 (30.1%), and R1 had more occurrences of wet-adapted (facultative wetland and obligate) species than R2 (198 and 79, respectively). Vegetation in the human-created abandoned meander reach near the knickpoint (R4) was predominantly dry-adapted (upland) species. Our dataset indicates that knickpoint development has resulted in channel incision in R2, shifting its vegetation towards more dry-adapted species reminiscent of the surrounding uplands. This work informs natural resource management practices for habitat in riparian ecosystems and can be applied to rivers in drier regions.