Evaluation of the effect of climate and land use changes on hydrologic processes in the Salt River Basin, Missouri, United States.

The impact of climate and land use changes on watershed hydrologic processes is needed by land managers and policy makers to improve future water resources management. The objective of this ongoing study is to assess the combined impacts of climate and land use changes on hydrologic processes including precipitation, streamflow, groundwater flow, and evapotranspiration in the 6, 417 km² Salt River Basin (SRB) in Northeast Missouri. The Soil and Water Assessment Tool (SWAT) was used to characterize hydrology in the SRB under varying future climate and land use scenarios. Model parameters were calibrated using streamflow data at ten USGS stations within the SRB, with model calibration from 2004-2008 and validation from 2009-2013. For future simulation, climate data from 2014-2060 were obtained from Downscaled CMIP5 Climate Projections. Two representative concentration pathways (RCPs) reflecting the range of radiative forcing levels, RCP 8.5 and 4.5 with 20 different model outputs for each RCP, were considered. Statistical downscaling methods, including delta method for temperature and quantile mapping for precipitation, were used to further downscale these data to the climate station level. Two land use scenarios were created with worst-case and best-case scenario and mapped by CLUE-S model to produce 30m × 30m resolution land use maps for the future period. The wide range of combinations of land use and climate change scenarios were examined to indicate possible outcomes useful for local and national agency application within the near (2020-2039) and far (2040-2059) future periods.