The Upper Missouri River headwaters (UMH) basin (36 400 km2 ) depends on its river corridors to support irrigated agriculture and world-class trout fisheries. We evaluated trends (1984–2016) in riparian wetness, an indicator of the riparian condition, in peak irrigation months (June, July and August) for 158 km2 of riparian area across the basin using the Landsat normalized difference wetness index (NDWI). We found that 8 of the 19 riparian reaches across the basin showed a significant drying trend over this period, including all three basin outlet reaches along the Jefferson, Madison and Gallatin rivers. The influence of upstream climate was quantified using per reach random forest regressions. Much of the interannual variability in the NDWI was explained by climate, especially by drought indices and annual precipitation, but the significant temporal drying trends persisted in the NDWI–climate model residuals, indicating that trends were not entirely attributable to climate. Over the same period we documented a basin-wide shift from 9 % of agriculture irrigated with center-pivot irrigation to 50 % irrigated with center-pivot irrigation. Riparian reaches with a drying trend had a greater increase in the total area with center-pivot irrigation (within reach and upstream from the reach) relative to riparian reaches without such a trend (p < 0.05). The drying trend, however, did not extend to river discharge. Over the same period, stream gages (n = 7) showed a positive correlation with riparian wetness (p < 0.05) but no trend in summer river discharge, suggesting that riparian areas may be more sensitive to changes in irrigation return flows relative to river discharge. Identifying trends in riparian vegetation is a critical precursor for enhancing the resiliency of river systems and associated riparian corridors.

Includes data and derivations not publicly available used to create figures and tables for manuscript. This dataset is associated with the following publication: Vanderhoof, M., J. Christensen, and L. Alexander. Influence of multi-decadal land use, irrigation practices and climate on riparian corridors across the Upper Missouri River headwaters basin, Montana. HYDROLOGY AND EARTH SYSTEM SCIENCES. EGS, 23(10): 4269–4292, (2019).

Includes data and derivations not publicly available used to create figures and tables for manuscript. This dataset is associated with the following publication: Vanderhoof, M., J. Christensen, and L. Alexander. Influence of multi-decadal land use, irrigation practices and climate on riparian corridors across the Upper Missouri River headwaters basin, Montana. HYDROLOGY AND EARTH SYSTEM SCIENCES. EGS, 23(10): 4269–4292, (2019).

This dataset represents the extent and spatial distribution of irrigated agricultural lands in the Upper Colorado River Basin for 2007-10. The boundaries in this dataset were modified from data developed by state and local agencies in Colorado, New Mexico, Utah, and Wyoming. The data contain information about the irrigation method used to water the fields and an estimate of the irrigation status of the field for the summer growing seasons between 2007 and 2010. Irrigation method was determined from examination of 1-meter aerial imagery. Irrigation status was estimated from Landsat 5 Thematic Mapper satellite imagery and land cover classification methods.

This dataset represents the extent and spatial distribution of irrigated agricultural lands in the Upper Colorado River Basin for 2007-10. The boundaries in this dataset were modified from data developed by state and local agencies in Colorado, New Mexico, Utah, and Wyoming. The data contain information about the irrigation method used to water the fields and an estimate of the irrigation status of the field for the summer growing seasons between 2007 and 2010. Irrigation method was determined from examination of 1-meter aerial imagery. Irrigation status was estimated from Landsat 5 Thematic Mapper satellite imagery and land cover classification methods.

This tabular data set represents the percent of land cover classes from the 2011 Crop land Data Layer compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the "2011 Crop Land Data Layer" produced by the United States Department of Agriculture (USDA) National Agricultural Statistics Service (NASS, 2012). Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).

This tabular data set represents base flow index (BFI) compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the "Base-flow index grid for the conterminous United States" produced by the United States Geological Survey (Wolock, 2003). Units are percent. Base flow is the component of streamflow that can be attributed to ground-water discharge into streams. The BFI is the ratio of base flow to total flow, expressed as a percentage. Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).

This tabular data set represents the percent of land cover classes from the 2011 Crop land Data Layer compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the "2011 Crop Land Data Layer" produced by the United States Department of Agriculture (USDA) National Agricultural Statistics Service (NASS, 2012). Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).

These data consist of species relative cover, percent cover of dead plant material, percent cover of soil and rock, and a variety of broad - and local- scale environmental variables. These data relate to sample sites along the Colorado River through Grand Canyon between Lees Ferry and river mile 245. The plant and ground cover data included here were originally collected as a part of annual vegetation monitoring by Grand Canyon Monitoring and Research Center. Environmental variables were either recorded in the field or obtained through other data sources. Species and ground cover data were collected in August and September 2014 at 96 randomly selected sample sites that were approximately evenly distributed along the river corridor. The sample sites were distributed among three geomorphic features: channel margins (44), debris fans (28), and sandbars (24).

These data consist of species relative cover, percent cover of dead plant material, percent cover of soil and rock, and a variety of broad - and local- scale environmental variables. These data relate to sample sites along the Colorado River through Grand Canyon between Lees Ferry and river mile 245. The plant and ground cover data included here were originally collected as a part of annual vegetation monitoring by Grand Canyon Monitoring and Research Center. Environmental variables were either recorded in the field or obtained through other data sources. Species and ground cover data were collected in August and September 2014 at 96 randomly selected sample sites that were approximately evenly distributed along the river corridor. The sample sites were distributed among three geomorphic features: channel margins (44), debris fans (28), and sandbars (24).