The availability of water is the major determinant of vegetation and land use on the High Plains. Well-watered valleys like this one feature irrigated cropland and hay fields, and 
natural and planted stands of cottonwoods, while the surrounding uplands are often bare. But water is becoming increasingly scarce, both as a result of over-utilization of groundwater resources and decreasing mountain runoff and snowmelt in a changing climate, and the vegetation itself is changing in response.
