Assessing Climate Change Effects on Water Balance in a Monsoon Watershed

Abstract

Understanding the changes on future water resources resulting from climate variations will assist in developing effective management strategies for a river basin. Our area of interest is the Osan watershed in South Korea, where the summer monsoon contributes approximately 60–70% of the annual runoff and precipitation for the country. We determined the effects that future climatic changes have on this area. To accomplish this, we made use of global climate models (GCMs). A total of 10 GCMs were downscaled with the help of climate information production tools. Coupled with the GCMs and the Soil and Water Assessment (SWAT) model, three periods were used to assess these climate impacts. The baseline, mid-century (MC), and end-century (EC) periods include 1993–2018, 2046–2065, and 2081–2099, respectively. The entire process was performed using two scenarios (4.5 and 8.5) from the representative concentration pathways (RCPs). Some of the statistical metrics used for model calibration and validation were p-factor, r-factor, percent bias, root-mean-square error (RMSE), and Nash–Sutcliffe model efficiency. Their respective values were 0.88, 0.88, 8.3, 0.91, and 0.91 for calibration, and 1.16, 0.85, 7.9, 0.88, and 0.87 for validation. For the MC and EC periods under both scenarios, we projected an increase in temperature and precipitation of approximately 2–5 °C and 15–30%, respectively. A predicted rise in precipitation, surface flow, lateral flow, and water yield were noted for the month of June. Subsequently, a decline in July followed during the summer monsoon season. Summer monsoon rains will fluctuate more sharply, with heavy rainfall in June, lower rainfall in July, and more rain in the late summer, leading to the possibility of both flooding and drought within a given period. Annual precipitation, surface flow, lateral flow, and water yield will increase whereas evapotranspiration would decrease in both periods under both scenarios during the summer monsoon period, which will lead to wetter conditions in the future.

Simulation-Optimization Model for Conjunctive Management of Surface Water and Groundwater for Agricultural Use

“…The region has a temperate climate with four distinct seasons and a temperature and precipitation of 12 • C and 1321 mm per annum, respectively. The majority of the annual precipitation occurs in the monsoon season (June to September), contributing to approximately 70% of the water availability [7,46,47]. The study area consists of a forest area (32.3%), an urban area (26.1%), paddy rice area (18.3%), barren land (8.1%), upland rice area (6.2%), and grassland and water area (3.5%) [4,46].…”

Predicting Climate Change Impacts on Water Balance Components of a Mountainous Watershed in the Northeastern USA

“…Global Climate Models (GCMs) are a useful tool to assess future climate change under differing greenhouse gas emission scenarios [11,24]. In recent years, future climate projections have been derived primarily from the fifth phase of Coupled Model Intercomparison Projects (CMIP5) [8,11] as CMIP5 consists of GCMs with higher spatial resolution, thereby generating more reliable outputs that address a wider variety of scientific issues of interest [25].…”

Ambient Air Quality Synergies with a 2050 Carbon Neutrality Pathway in South Korea

“…Therefore, the effects of low air quality in South Korea will worsen over time due to the steep increase in the aged population. Climate change is also predicted to have other, increasingly negative effects in South Korea [19][20][21][22]. For example, water quality in South Korea would be negatively affected by climate change [23].…”

“…The work aims to provide evidence for the potential of a 2050 carbon neutrality emissions pathway to synergistically improve atmospheric air quality, and thus support the case for more ambitious climate action in South Korea. The article first outlines the methodology used to calculate the greenhouse gases (GHGs) that would be avoided, as well as those of other air pollutants, as well as its methodology for calculating some of the health benefits of the climate Climate change is also predicted to have other, increasingly negative effects in South Korea [19][20][21][22]. For example, water quality in South Korea would be negatively affected by climate change [23].…”