Modelling potential impacts of climate change on water and nitrate export from a mid-sized, semiarid watershed in the US Southwest

Abstract

The impacts of climate change on water and nitrogen cycles in arid central Arizona (USA) were investigated by integrating the Second Generation Coupled Global Climate Model (CGCM2) and a widely used, physical process-based model, Soil and Water Assessment Tool (SWAT). With statistically downscaled daily climate data from the CGCM2 as model input, SWAT predicted increased potential evapotranspiration and decreased surface runoff, lateral flow, soil water, and groundwater recharge, which suggests serious consequences for the water cycle in this desert catchment in the future. Specifically, stream discharge is projected to decrease by 31 % in the 2020s, 47 % in the 2050s, and 56 % in the 2080s compared to the mean discharge for the base period (0.73 m 3 /s). A flowduration analysis reveals that the projected reduction of stream discharge in the future is attributable to significant decreases in mid-range and low-flow conditions; however, flood peaks would show a slight increase in the future. The drier and hotter future also will decrease the rate of nitrogen mineralization in the catchment and ultimately, nitrate export from the stream. Since mean mineralization rate would decrease by 15 % in the 2020s, 28 % in the 2050s, and 35 % in the 2080s compared to the based period (9.3 g N ha −1 d −1 ), the combined impact of reduced catchment mineralization and reduced streamflow would predict declining nitrate export: from today's mean value of 30 kg N/d, to 20, 15 and 12 kg N/d by the 2020s, 2050s, and 2080s, respectively.

Effect of Climate Change on Hydrology, Sediment and Nutrient Losses in Two Lowland Catchments in Poland

“…It is obvious that this increase corresponds to water flow augmentation driven by precipitation increase. The opposite results that indicate the contaminants loads are decreasing [17][18][19] are likewise strongly correlated with the flow pattern which is projected to decrease in these particular studies. Mixed nutrients emission response reported by Arheimer et al [20], Records et al [21] and Molina-Navaro et al [22] is an effect of diverse flow changes during the projected periods.…”

Novel water sources restore plant and animal communities along an urban river

“…Conservation and restoration of freshwater habitats must account for annual cycles and habitat use of terrestrial, riparian, and aquatic species (Dudgeon et al, 2006). In Arizona specifically, surface runoff, lateral flow, soil water, and groundwater recharge are expected to decrease significantly with some watershed discharges projected to decrease by 47% in the 2050s (Ye and Grimm, 2013). With respect to plants, one guild of the riparian-zone plant community, cool-season annuals, was unexpectedly sparse at the restored reaches (and abundant elsewhere).…”

Spatial and Temporal Changes in Temperature, Precipitation, and Streamflow in the Miyun Reservoir Basin of China

“…As supported in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5), globally averaged temperature increased 0.85 • C between 1880 and 2012, and each of the last three decades has been successively warmer than any preceding decade since 1850. Global warming modifies the intensity and frequency of precipitation, which influence the hydrological cycle and the transportation and fate of pollutants, with possible adverse impact on the ecological environment [2,3]. Identifying the characteristics of regional climate change and their potential impacts on the natural system, especially at the basin scale, has therefore attracted widespread attentions from both academic circles and government.…”