scholarly journals Impacts of Climate Change Scenarios on Non-Point Source Pollution in the Saemangeum Watershed, South Korea

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1982 ◽  
Author(s):  
Ting Li ◽  
Gwangseob Kim
Keyword(s):  
Climate Change ◽  
South Korea ◽  
Point Source ◽  
Assessment Tool ◽  
Asia Pacific ◽  
Coefficient Of Determination ◽  
Climate Change Scenarios ◽  
Pollutant Loads ◽  
Monthly Streamflow ◽  
Rcp 8.5

Non-point source (NPS) pollution is a primary cause of water pollution in the Saemangeum watershed in South Korea. The changes in NPS pollutant loads in the Saemangeum watershed for an 81-year period (2019–2099) were simulated and analyzed by applying the soil and water assessment tool. Six climate model (BCC-CSM1–1, CanESM2, GFDL-ESM2G, HadGEM2-CC, INM-CM4, and MIROC-ESM) outputs using representative concentration pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) were obtained from the South Korean Asia-Pacific Economic Cooperation (APEC) Climate Center. Simulated streamflow and water quality were evaluated using the Nash–Sutcliffe efficiency (NSE) index and coefficient of determination (R2). The model satisfactorily simulated streamflow with positive NSE values and R2 > 0.5. Based on two climate change scenarios (RCP 4.5 and RCP 8.5), gradual increases of 70.9 to 233.8 mm and 1.7 to 5.7 °C in annual precipitation and temperature, respectively, are likely for two time periods (2019–2059 and 2060–2099). Additionally, the expected future average annual and monthly streamflow, sediment, and total phosphorus showed changes of 5% to 43%, 3% to 40%, and −55% to 15%, respectively, whereas the expected future average annual and monthly total nitrogen showed decreases of −5% to −27%. Future NPS pollutant loads in the Saemangeum watershed should be managed according to different climate change scenarios.

scholarly journals Spatiotemporal Features of Pollutant Loads in the Yan River Basin, a Typical Loess hilly and Gully Watershed in the Chinese Loess Plateau

2021 ◽  
Author(s):  
Yanni Song ◽  
Yiping Wu ◽  
Changshun Sun ◽  
Fubo Zhao ◽  
Jingyi Hu ◽  
...  
Keyword(s):  
Water Quality ◽  
Point Source ◽  
River Basin ◽  
Loess Plateau ◽  
Assessment Tool ◽  
Chinese Loess Plateau ◽  
Chinese Loess ◽  
Pollutant Loads ◽  
Monthly Streamflow ◽  
The Chinese Loess Plateau

Abstract Water quality is the restrictive factor for both ecosystem health and social development in the Chinese Loess Plateau, a unique area with most severe soil erosion, fragile ecology, and water shortage. Understanding the characteristics of the pollutant loads is of vital importance for the sustainability of eco-environment in the Loess Plateau. This study investigated the spatiotemporal changes of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) loads by combining the Soil and Water Assessment Tool (SWAT) and regression model Load Estimator (LOADEST) in a typical loess hilly and gully watershed—the Yan River Basin (YanRB). Results showed that the model simulations of monthly streamflow and pollutant loads were in good agreement with those derived from the in-situ observations. The temporal variation analysis suggested that the pollutant loads were generally rising in the study period (2001–2018) at four of the five stations and reached the maximum in 2014, and the multi-year (i.e., 2001–2018 with 2013 being excluded due to extreme rainfall) average loads of COD, TN, and TP at the Tanjiahe station, which is close to the outlet of the basin, were 15,021 kg/d, 3,835 kg/d, and 168 kg/d, respectively. The spatial distribution of the TN and TP loads along the river seemed to be quite unique because the TP level were obviously higher at the midstream (e.g., Zhujiagou and Ganguyi) than the downstream (e.g., Tanjiahe), and the TN level decreased when the river flowed from Zhujiagou to Ganguyi. Further, the seasonal analysis indicated that the nutrient loads were the highest in summer, followed by autumn, and the loads in these two wet seasons contributed the most of the annual pollution loads—about 76% and 84% for TN and TP, respectively, indicating the higher flow, the higher pollution load, a similar point based on the inter-annual analysis. In addition, the contribution analysis of point source and non-point source pollutions demonstrated that NPS led to most of the pollutant loads at the whole watershed—87%, 85%, and 84% of the COD, TN, and TP loads, respectively. Overall, this study provided spatiotemporal distributions of the key pollutant loads in the YanRB and can be valuable for water quality protection and pollution control in this area.

scholarly journals Distribution Change of Invasive American Bullfrogs (Lithobates catesbeianus) by Future Climate Threaten Endangered Suweon Treefrog (Hyla suweonensis) in South Korea

Animals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2865
Author(s):  
Kyo Soung Koo ◽  
Minjee Choe
Keyword(s):  
Climate Change ◽  
South Korea ◽  
Native Species ◽  
Potential Distribution ◽  
Current Level ◽  
Climate Change Scenarios ◽  
Direct Impact ◽  
Lithobates Catesbeianus ◽  
American Bullfrog ◽  
Rcp 8.5

The American Bullfrog (Lithobates catesbeianus) has been imported into South Korea in earnest for food since the 1970s and introduced into nature due to release and escape. Accordingly, the influx and spread of American Bullfrogs are expected to have a direct impact on native species, but few related studies have been conducted on this. We predicted changes in the potential distribution and future distribution based on climate change scenarios to analyze how those changes affect critically endangered Suwon treefrogs. Suwon treefrog sites (63.9%, 78/122) overlapped with the distribution of Bullfrogs. According to the prediction of the future distribution of Bullfrogs, the overlapping of American Bullfrogs and Suwon treefrog will remain similar to the current level in the Representative Concentration Pathway (RCP) 4.5 scenario. On the other hand, in the RCP 8.5 scenario, the number of overlapping sites will increase to 72.1% (88/122) due to the spreading of the American Bullfrogs. The results show that climate change directly affects the distribution expansion of the American Bullfrogs but also indirectly can lead to an increased threat to Suwon treefrogs. In conclusion, our results strongly suggest why climate change should be actively addressed in terms of the spread of invasive species and the protection of endangered species.

scholarly journals Assessment of Streamflow from EURO-CORDEX Regional Climate Simulations in Semi-Arid Catchments Using the SWAT Model

2021 ◽  
Vol 13 (13) ◽  
pp. 7120
Author(s):  
Alberto Martínez-Salvador ◽  
Agustín Millares ◽  
Joris P. C. Eekhout ◽  
Carmelo Conesa-García
Keyword(s):  
Climate Change ◽  
Assessment Tool ◽  
Swat Model ◽  
Regional Climate ◽  
Future Climate Change ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Rcp 8.5 ◽  
The Impact ◽  
Semi Arid

This research studies the effect of climate change on the hydrological behavior of two semi-arid basins. For this purpose, the Soil and Water Assessment Tool (SWAT) model was used with the simulation of two future climate change scenarios, one Representative Concentration Pathway moderate (RCP 4.5) and the other extreme (RCP 8.5). Three future periods were considered: close (2019–2040), medium (2041–2070), and distant (2071–2100). In addition, several climatic projections of the EURO-CORDEX model were selected, to which different bias correction methods were applied before incorporation into the SWAT model. The statistical indices for the monthly flow simulations showed a very good fit in the calibration and validation phases in the Upper Mula stream (NS = 0.79–0.87; PBIAS = −4.00–0.70%; RSR = 0.44–0.46) and the ephemeral Algeciras stream (NS = 0.78–0.82; PBIAS = −8.10–−8.20%; RSR = 0.4–0.42). Subsequently, the impact of climate change in both basins was evaluated by comparing future flows with those of the historical period. In the RCP 4.5 and RCP 8.5 scenarios, by the end of the 2071–2100 period, the flows of the Upper Mula stream and the ephemeral Algeciras stream will have decreased by between 46.3% and 52.4% and between 46.6% and 55.8%, respectively.

scholarly journals Impact of climate change on the hydrology of a semi-arid river basin of India under hypothetical and projected climate change scenarios

2020 ◽  
Author(s):  
Sujeet Desai ◽  
D. K. Singh ◽  
Adlul Islam ◽  
A. Sarangi
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Assessment Tool ◽  
Circulation Model ◽  
Central India ◽  
Coefficient Of Determination ◽  
Climate Change Scenarios ◽  
Global Circulation Model ◽  
Calibration And Validation ◽  
Semi Arid

Abstract Climate change impact on the hydrology of the Betwa river basin, located in the semi-arid region of Central India, was assessed using the Soil and Water Assessment Tool (SWAT), driven by hypothetical scenarios and Model of Interdisciplinary Research on Climate version 5 (MIROC5) Global Circulation Model projections. SWAT-Calibration and Uncertainty Programs (SWAT-CUP) was used for calibration and validation of SWAT using multi-site streamflow data. The coefficient of determination, Nash–Sutcliffe efficiency, RMSE-observations standard deviation ratio and percent bias during calibration and validation period varied from 0.83–0.92, 0.6–0.91, 0.3–0.63 and −19.8–19.3, respectively. MIROC5 projections revealed an increase in annual mean temperature in the range of 0.7–0.9 °C, 1.2–2.0 °C and 1.1–3.1 °C during the 2020s, 2050s, and 2080s, respectively. Rainfall is likely to increase in the range of 0.4–9.1% and 5.7–15.3% during the 2050s and 2080s, respectively. Simulation results indicated 3.8–29% and 12–48% increase in mean annual surface runoff during the 2050s and 2080s, respectively. Similarly, an increase of 0.2–3.0%, 2.6–4.2% and 3.5–6.2% in mean annual evapotranspiration is likely during the 2020s, 2050s and 2080s, respectively. These results could be used for developing suitable climate change adaptation plans for the river basin.

scholarly journals Impact of climate change on hydrology of Manjalar sub basin of river Vaigai in Tamil Nadu, India

2016 ◽  
Vol 8 (3) ◽  
pp. 1670-1679 ◽  
Author(s):  
S. Janapriya ◽  
S. Santhana Bosu ◽  
Balaji Kannan
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Water Conservation ◽  
Tamil Nadu ◽  
Assessment Tool ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Rcp 8.5

This study evaluates the impacts of possible future climate change scenarios on the hydrology of the catchment area of the Manjalar sub basin of River Vaigai, Tamil Nadu, India carried out at the department of Soil and Water Conservation Engineering, Tamil Nadu Agricultural University during the period of 2011-2014 using Soiland Water Assessment Tool (SWAT). For the climate impact assessment the hydrological model was driven with output of bias corrected Earth System Models of the Coupled Model Intercomparison Project Phase 5 (CMIP5): HadGEM2. Climate scenarios were downscaled to a grid resolution of 0.22° x 0.22°. In this study RCP 4.5 and RCP 8.5 were included for future assessment with three future periods: 2012–2039, 2040–2069, and 2070–2098. The projected increase in maximum and minimum temperature for RCP 4.5 scenario is 0.8 to 2.3 ºC and 0.7 to 1.6 ºC and for RCP 8.5 scenario is 1.1 to 4.0 ºC and 1.0 to 3.1 ºC, respectively. Rainfall is projected to an increase between 9.2 to 15.2 per cent for RCP 4.5 scenario and an increase of 13.6 to 18.8 per cent for RCP 8.5 scenario during 21st century. The soil water storage and stream flow contribution to ground water are likely to increase in RCP 4.5 scenario and it would again decline for RCP 8.5 scenario during 21st century. The increase in annual rainfall evapotranspiration and surface runoff would be more in RCP 8.5 scenario compared to RCP 4.5 scenario. The possible changes projected by the study provide a useful input to effective planning of water resources of the study area.

scholarly journals Estimation of Hydrological Components under Current and Future Climate Scenarios in Guder Catchment, Upper Abbay Basin, Ethiopia, Using the SWAT

2021 ◽  
Vol 13 (17) ◽  
pp. 9689
Author(s):  
Tewekel Melese Gemechu ◽  
Hongling Zhao ◽  
Shanshan Bao ◽  
Cidan Yangzong ◽  
Yingying Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
Hydrological Modeling ◽  
Climate Model ◽  
Assessment Tool ◽  
Swat Model ◽  
Future Climate ◽  
Future Climate Change ◽  
Water Yield ◽  
Climate Change Scenarios ◽  
Rcp 8.5

Changes in hydrological cycles and water resources will certainly be a direct consequence of climate change, making the forecast of hydrological components essential for water resource assessment and management. This research was thus carried out to estimate water balance components and water yield under current and future climate change scenarios and trends in the Guder Catchment of the Upper Blue Nile, Ethiopia, using the soil and water assessment tool (SWAT). Hydrological modeling was efficaciously calibrated and validated using the SUFI-2 algorithm of the SWAT model. The results showed that water yield varied from 926 mm to 1340 mm per year (1986–2016). Regional climate model (RCM) data showed, under representative concentration pathways (RCP 8.5), that the precipitation will decrease by up to 14.4% relative to the baseline (1986–2016) precipitation of 1228 mm/year, while the air temperature will rise under RCP 8.5 by +4.4 °C in the period from 2057 to 2086, possibly reducing the future basin water yield output, suggesting that the RCP 8.5 prediction will be warmer than RCP 4.5. Under RCP 8.5, the total water yield from 2024 to 2086 may be reduced by 3.2 mm per year, and a significant trend was observed. Local government agencies can arrange projects to solve community water-related issues based on these findings.

scholarly journals Water Temperature and Hydrological Modelling in the Context of Environmental Flows and Future Climate Change: Case Study of the Wilmot River (Canada)

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2101
Author(s):  
Christian Charron ◽  
André St-Hilaire ◽  
Taha B.M.J. Ouarda ◽  
Michael R. van den Heuvel
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Environmental Flows ◽  
Low Flow ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Water Abstraction ◽  
Surface Water Flow ◽  
Modelling Studies ◽  
Rcp 8.5

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

scholarly journals A hydrological modelling-based approach for vulnerable area identification under changing climate scenarios

2020 ◽  
Author(s):  
Sonam S. Dash ◽  
Dipaka R. Sena ◽  
Uday Mandal ◽  
Anil Kumar ◽  
Gopal Kumar ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Fold Increase ◽  
Maximum Temperature ◽  
Climate Scenarios ◽  
Vulnerable Area ◽  
Temperature And Precipitation ◽  
Monthly Streamflow ◽  
Rcp 8.5 ◽  
Streamflow Data ◽  
Critical Zones

Abstract The hydrologic behaviour of the Brahmani River basin (BRB) (39,633.90 km2), India was assessed for the base period (1970–1999) and future climate scenarios (2050) using the Soil and Water Assessment Tool (SWAT). Monthly streamflow data of 2000–2009 and 2010–2012 was used for calibration and validation, respectively, and performed satisfactorily with Nash-Sutcliffe Efficiency (ENS) of 0.52–0.55. The projected future climatic outcomes of the HadGEM2-ES model indicated that minimum temperature, maximum temperature, and precipitation may increase by 1.11–3.72 °C, 0.27–2.89 °C, and 16–263 mm, respectively, by 2050. The mean annual streamflow over the basin may increase by 20.86, 11.29, 4.45, and 37.94% under RCP 2.6, 4.5, 6.0, and 8.5, respectively, whereas the sediment yield is likely to increase by 23.34, 10.53, 2.45, and 27.62% under RCP 2.6, 4.5, 6.0, and 8.5, respectively, signifying RCP 8.5 to be the most adverse scenario for the BRB. Moreover, a ten-fold increase in environmental flow (defined as Q90) by the mid-century period is expected under the RCP 8.5 scenario. The vulnerable area assessment revealed that the increase in moderate and high erosion-prone regions will be more prevalent in the mid-century. The methodology developed herein could be successfully implemented for identification and prioritization of critical zones in worldwide river basins.

scholarly journals Climatic suitability predictions for the cultivation of macadamia in Malawi using climate change scenarios.

2021 ◽  
Author(s):  
Emmanuel Junior Zuza ◽  
Yoseph Negusse Araya ◽  
Kadmiel Maseyk ◽  
Shonil A Bhagwat ◽  
Kaue de Sousa ◽  
...  
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
General Circulation Models ◽  
Food Sources ◽  
Climate Change Scenarios ◽  
Crop Species ◽  
Cascading Effects ◽  
Northern Regions ◽  
Rcp 8.5 ◽  
Model Approach

Climate change is altering suitable areas of crop species worldwide, with cascading effects on people and animals reliant upon those crop species as food sources. Macadamia is one of Malawi's most important and profitable crop species. Here, we used an ensemble model approach to determine the current distribution of macadamia producing areas across Malawi in relation to climate. For future distribution of suitable areas, we used the climate outputs of 17 general circulation models (GCM's) based on two climate change scenarios (RCP 4.5 and RCP 8.5). We found that the precipitation of the driest month and isothermality were the climatic variables that strongly influenced macadamia's suitability in Malawi. These climatic requirements were fulfilled across many areas in Malawi under the current conditions. Future projections indicated that large parts of Malawi's macadamia growing regions will remain suitable for macadamia, amounting to 36,910 km2 (39.1%) and 33,511 km2 (35.5%) of land based on RCP 4.5 and RCP 8.5, respectively. Of concern, suitable areas for macadamia production are predicted to shrink by −18% (17,015 km2) and −22% (20,414 km2) based on RCP 4.5 and RCP 8.5, respectively, with much of the suitability shifting northwards. Although a net loss of area suitable for macadamia is predicted, some currently unsuitable areas will become suitable in the future. Notably, suitable areas will increase in Malawi's central and northern regions, while the southern region will lose most of its suitable areas. In conclusion, our study provides critical evidence that climate change will significantly affect the macadamia sub-sector in Malawi. Therefore area-specific adaptation strategies are required to build resilience.

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