Predicting sediment yield and transport dynamics of a cold climate region watershed in changing climate

• Published in: The Science of the total environment Vol. 625; pp. 1030 - 1045
• Main Authors: Shrestha, Narayan Kumar, Wang, Junye
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2018
• Subjects: agricultural land; Alberta; Athabasca River basin; basins; Climate change; climate models; climatic factors; Cold climate regions; cold zones; hills; land use; meteorological data; monitoring; pollution load; prediction; rivers; sediment transport; sediment yield; Sediment yield and transport; Soil and Water Assessment Tool model; soil formation; stream flow; Swat; topographic slope; uncertainty; watersheds; Alberta; Swat; Climate change; Cold climate regions; Sediment yield and transport; Athabasca River basin
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.12.347

The effects of climate change on sediment yield and transport dynamics in cold climate regions are not well understood or reported. In this study, the Soil and Water Assessment Tool (SWAT) has been built-up, calibrated, and validated against streamflow and sediment load at several monitoring stations in a cold climate region watershed - the Athabasca River Basin (ARB) in Alberta, Canada. The model was then fed with bias-corrected spatial disaggregated high-resolution (~10km) future climate data from three climate models for two emission scenarios (RCP 4.5 and 8.5), and two periods (mid- and end-century). Results show that channel erosion and deposition are the dominant processes over hill slope erosion in the basin. On average, a predicted warmer and wetter future climate has both synergetic and offsetting effects on sediment yield. Changes are sub-region specific and land-use type dependent, thus reflecting a marked spatial and temporal heterogeneity within the basin. Increases on sediment yield in future periods in the agricultural areas are up to 0.94t/ha/yr, and are greater than reported soil formation rates in the region. Similarly, while substantial increases (by more than two fold) in the sediment load transport through the river reaches were obtained, the changes show both temporal and spatial variability, and are closely aligned with the trend of stream flows. We believe that availability of such models and knowledge of the effect of future climatic conditions would help water managers formulate appropriate scenarios to manage such basins in a holistic way. However, significant uncertainties in future sediment yield and transport, as a result of variations in climatic forcing of different climate models, need to be considered in any adaptation measures. [Display omitted] •Climate change impact analysis on erosion and sediment transport of the Athabasca River Basin (ARB) using the SWAT model•Future (mid- and late-century) climate data generated by three climate models for RCP 4.5 and 8.5 emission scenarios•Impacts due to climate change are found to be region specific and land-use type dependent.•Channel erosion and deposition were the dominant processes over hill slope erosion.•Increment on soil erosion rate due to climate change is greater than reported soil formation rates.