Estimating Potential Climate Change Effects on the Upper Neuse Watershed Water Balance Using the SWAT Model

Abstract

Research Impact Statement: The results of this study can aid planning for the RTP's future hydrologic and water supply conditions and expand the knowledge of local impacts of climate change on critical watersheds.ABSTRACT: Climate change poses water resource challenges for many already water stressed watersheds throughout the world. One such watershed is the Upper Neuse Watershed in North Carolina, which serves as a water source for the large and growing Research Triangle Park region. The aim of this study was to quantify possible changes in the watershed's water balance due to climate change. To do this, we used the Soil and Water Assessment Tool (SWAT) model forced with different climate scenarios for baseline, mid-century, and end-century time periods using five different downscaled General Circulation Models. Before running these scenarios, the SWAT model was calibrated and validated using daily streamflow records within the watershed. The study results suggest that, even under a mitigation scenario, precipitation will increase by 7.7% from the baseline to mid-century time period and by 9.8% between the baseline and end-century time period. Over the same periods, evapotranspiration (ET) would decrease by 5.5 and 7.6%, water yield would increase by 25.1% and 33.2%, and soil water would increase by 1.4% and 1.9%. Perhaps most importantly, the model results show, under a high emission scenario, large seasonal differences with ET estimated to decrease by up to 42% and water yield to increase by up to 157% in late summer and fall. Planning for the wetter predicted future and corresponding seasonal changes will be critical for mitigating the impacts of climate change on water resources.(

Assessing Climate Change Effects on Water Balance in a Monsoon Watershed

“…A SWAT weather generator aided in simulating missing and unavailable data for wind velocity, solar radiation, and humidity for future projections [54]. Land cover was assumed not to change significantly as this has been addressed in other studies [10,14].…”

“…Hence, a large decrease in transpiration will result in a decrease in ET. Transpiration plays a key role in the water cycle, especially in our area of study, which is predominantly made up of cultivated crops and forest cover [10]. These results are similar to a Ministry of Environment report in 2018, which predicted the average precipitation in seven major domestic areas compared to the past three decades , projecting a 14.8% increase in the early 21st century (2011-2040), a 17.1% increase by the mid-21st century (2071-2100), and an 11.4% increase by the late 21st century (2071-2100) [86].…”

“…This may be due to the high atmospheric CO 2 concentrations used in the RCP 4.5 and 8.5 scenarios (540 ppm for the MC and 940 ppm for the EC periods with respect to 330 ppm as the baseline). Transpiration decreases as the atmospheric CO 2 concentration increases due to plants having efficient water use [10,[83][84][85]. On the other hand, evaporation depends mainly on temperature and water availability.…”

Assessment of Urbanization-Induced Land-Use Change and Its Impact on Temperature, Evaporation, and Humidity in Central Vietnam

“…Furthermore, the understanding of urbanization development and its effects on regional temperature during thermal-extreme events is especially critical for coastal regions [40]. This scientific basis is also valuable for streamflow assessment within the context of climate change [41,42]. However, several recent study attempts regarding this topic by [7,25,38,39] for the north midlatitude area of Vietnam (Hanoi city) could not help in this case, in which the chosen study area is the low-land coastal region, Central Vietnam.…”

The combined impact of redcedar encroachment and climate change on water resources in the Nebraska Sand Hills

“…Several studies have evaluated the impact of climate change on the hydrological cycle at the watershed scale. Some studies applied different representative concentration pathways (RCPs) scenarios for different climate models under Coupled Model Intercomparison Project 5 (CMIP5) using RCP2.6, RCP4.5, and RCP8.5 (Fant et al, 2017;Ercan et al, 2020;Wang et al, 2020), or consider the impacts of changing CO 2 on hydrological fluxes while applying climate models (Perazzoli et al, 2013;Lee et al, 2018b). Many studies used the Soil Water Assessment Tool (SWAT) with climate models on different scales worldwide (Pandey et al, 2021;Touseef et al, 2021), in the U.S. (Mueller-Warrant et al, 2019;Ercan et al, 2020) and in Nebraska (van Liew et al, 2012;Rehana et al, 2018).…”