Impacts of rainfall and air temperature variations due to climate change upon hydrological characteristics: a case study

Rainfall and air temperature variations resulting from climate change are important driving forces to change hydrologic processes in watershed ecosystems. This study investigated the impacts of past and future rainfall and air temperature variations upon water discharge, water outflow (from the watershed outlet), and evaporative loss in the Lower Yazoo River Watershed (LYRW), Mississippi, USA using the HSPF model. Four future climate change (i.e., rainfall and air temperature change) scenarios, namely the CSIROMK35A1B, HADCM3B2, CSIROMK2B2, and MIROC32A1B scenarios, were used as input data to perform simulations in this study. Results showed that monthly variations of water discharge, evaporative loss, and water outflow were primarily due to the monthly fluctuations of rainfall rather than air temperature. On average, for all of the four scenarios, a 6.4% decrease in rainfall amount resulted in, respectively, 11.8 and 10.3% decreases in water outflow and evaporative loss. Our study demonstrated that rainfall had profound impacts upon water outflow and evaporative loss. In light of this predicted future decrease in water outflow, water resource conservation practices such as reducing ground and surface water usages that help to prevent streams from drying are vitally important in mitigating climate change impacts on stream flow in the LYRW. doi: 10.2166/wcc.2015.101 Ying Ouyang (corresponding author) USDA Forest Service, Southern Research Station, 100 Stone Blvd., Thompson Hall, Room 309, Starkville, MS 39762, USA E-mail: [email protected] Jia-En Zhang Department of Ecology, South China Agricultural University, Wushan Road, Tianhe, Guangzhou, China Yide Li Research Institute for Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China Prem Parajuli Department of Agricultural and Biological Engineering, Mississippi State University, Mail box 9632, Starkville, MS 39762 USA Gary Feng Crop Science Research Laboratory, USDA-ARS, 810 Hwy 12 East, Starkville, MS 39762 USA