Future Climate Change Impacts on River Discharge Seasonality for Selected West African River Basins

The changing climate is a concern to sustainable water resources. This study examined climate change impacts on river discharge seasonality in two West African river basins; the Niger river basin and the Hadejia-Jama’are Komadugu-Yobe Basin (HJKYB). The basins have their gauges located within Nigeria and cover the major climatic settings. Here, we set up and validated the hyper resolution global hydrological model PCR-GLOBWB for these rivers. Time series plots as well five performance evaluation metrics such as Kling–Gupta efficiency (KGE),); the ratio of RMSE-observations standard deviation (RSR); per cent bias (PBIAS); the Nash–Sutcliffe Efficiency criteria (NSE); and, the coefficient of determination (r2), were employed to verify the PCR-GLOBWB simulation capability. The validation results showed from satisfactory to very good on individual rivers as specified by PBIAS (−25 to 0.8), NSE (from 0.6 to 0.8), RSR (from 0.62 to 0.4), r2 (from 0.62 to 0.88), and KGE (from 0.69 to 0.88) respectively. The impact assessment was performed by driving the model with climate projections from five global climate models for the representative concentration pathways (RCPs) 4.5 and 8.5. We examined the median and range of expected changes in seasonal discharge in the far future (2070–2099). Our results show that the impacts of climate change cause a reduction in discharge volume at the beginning of the high flow period and an increase in discharge towards the ending of the high flow period relative to the historical period across the selected rivers. In the Niger river basin, at the Lokoja gauge, projected decreases added up to 512 m3/s under RCP 4.5 (June to July) and 3652 m3/s under RCP 8.5 (June to August). The three chosen gauges at the HJKYB also showed similar impacts. At the Gashua gauge, discharge volume increased by 371 m3/s (RCP8.5) and 191 m3/s (RCP4.5) from August to November. At the Bunga gauge, a reduction/increase of -91 m3/s/+84 m3/s (RCP 8.5) and -40 m3/s/+31 m3/s/(RCP 4.5) from June to July/August to October was simulated. While at the Wudil gauge, a reduction/increase in discharge volumes of −39/+133 m3/s (RCP8.5) and −40/133 m3/s (RCP 4.5) from June to August/September to December is projected. This decrease is explained by a delayed start of the rainy season. In all four rivers, projected river discharge seasonality is amplified under the high-end emission scenario (RCP8.5). This finding supports the potential advantages of reduced greenhouse gas emissions for the seasonal river discharge regime. Our study is anticipated to provide useful information to policymakers and river basin development authorities, leading to improved water management schemes within the context of changing climate and increasing need for agricultural expansion.

Download Full-text

Climate change and its impacts on river discharge in two climate regions in China

Hydrology and Earth System Sciences ◽

10.5194/hess-19-4609-2015 ◽

2015 ◽

Vol 19 (11) ◽

pp. 4609-4618 ◽

Cited By ~ 10

Author(s):

H. Xu ◽

Y. Luo

Keyword(s):

Climate Change ◽

River Discharge ◽

Climate Change Impacts ◽

High Flow ◽

Global Climate Models ◽

Assessment Tools ◽

Low Flow ◽

Climate Projections ◽

Seasonal Temperature ◽

Pronounced Increase

Abstract. Understanding the heterogeneity of climate change and its impacts on annual and seasonal discharge and the difference between median flow and extreme flow in different climate regions is of utmost importance to successful water management. To quantify the spatial and temporal heterogeneity of climate change impacts on hydrological processes, this study simulated river discharge in the River Huangfuchuan in semi-arid northern China and in the River Xiangxi in humid southern China. The study assessed the uncertainty in projected discharge for three time periods (2020s, 2050s and 2080s) using seven equally weighted GCMs (global climate models) for the SRES (Special Reports on Emissions Scenarios) A1B scenario. Climate projections that were applied to semi-distributed hydrological models (Soil Water Assessment Tools, SWAT) in both catchments showed trends toward warmer and wetter conditions, particularly for the River Huangfuchuan. Results based on seven GCMs' projections indicated changes from −1.1 to 8.6 °C and 0.3 to 7.0 °C in seasonal temperature and changes from −29 to 139 % and −32 to 85 % in seasonal precipitation in the rivers Huangfuchuan and Xiangxi, respectively. The largest increases in temperature and precipitation in both catchments were projected in the spring and winter seasons. The main projected hydrologic impact was a more pronounced increase in annual discharge in the River Huangfuchuan than in the River Xiangxi. Most of the GCMs projected increased discharge in all seasons, especially in spring, although the magnitude of these increases varied between GCMs. The peak flows were projected to appear earlier than usual in the River Huangfuchuan and later than usual in the River Xiangxi, while the GCMs were fairly consistent in projecting increased extreme flows in both catchments with varying magnitude compared to median flows. For the River Huangfuchuan in the 2080s, median flow changed from −2 to 304 %, compared to a −1 to 145 % change in high flow (Q05 exceedance threshold). For the River Xiangxi, low flow (Q95 exceedance threshold) changed from −1 to 77 % and high flow changed from −1 to 62 %, while median flow changed from −4 to 23 %. The uncertainty analysis provided an improved understanding of future hydrologic behavior in the watershed. Furthermore, this study indicated that the uncertainty constrained by GCMs was critical and should always be considered in analysis of climate change impacts and adaptation.

Download Full-text

Development of adaptive IWRM options for climate change mitigation and adaptation

Advances in Science and Research ◽

10.5194/asr-7-91-2011 ◽

2011 ◽

Vol 7 (1) ◽

pp. 91-100 ◽

Cited By ~ 4

Author(s):

W.-A. Flügel

Keyword(s):

Climate Change ◽

River Basin ◽

Climate Change Impacts ◽

Integrated Water Resources Management ◽

River Basins ◽

Danube River ◽

Central Component ◽

Mitigation And Adaptation ◽

Well Data ◽

Impacts Of Climate Change

Abstract. Adaptive Integrated Water Resources Management (IWRM) options related to the impacts of climate change in the twinning basins of the Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basin (UBRB) are developed based on the results obtained in the different work packages of the BRAHMATWINN project. They have been described and discussed in Chapter 2 till Chapter 9 and the paper is referring to and is integrating these findings with respect to their application and interpretation for the development of adaptive IWRM options addressing impacts of climate change in river basins. The data and information related to the results discussed in Chapter 2 till 8 have been input to the RBIS as a central component of the IWRMS (Chapter 9). Meanwhile the UDRB has been analysed with respect to IWRM and climate change impacts by various projects, i.e. the GLOWA-Danube BMBF funded project (GLOWA Danube, 2009; Mauser and Ludwig, 2002) the UBRB has not been studied so far in a similar way as it was done in the BRAHMATWINN project. Therefore the IWRM option development is focussing on the UBRB but the methodology presented can be applied for the UDRB and other river basins as well. Data presented and analysed in this chapter have been elaborated by the BRAHMATWINN project partners and are published in the project deliverable reports available from the project homepage http://www.brahmatwinn.uni-jena.de/index.php?id=5311&L=2.

Download Full-text

Climate change and its impacts on river discharge in two climate regions in China

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-12-7099-2015 ◽

2015 ◽

Vol 12 (7) ◽

pp. 7099-7126

Author(s):

H. Xu ◽

Y. Luo

Keyword(s):

Climate Change ◽

River Discharge ◽

Climate Change Impacts ◽

High Flow ◽

Assessment Tools ◽

Low Flow ◽

Climate Projections ◽

Seasonal Temperature ◽

Mean Flow ◽

Pronounced Increase

Abstract. Understanding the heterogeneity of climate change and its impacts on annual and seasonal discharge, and the difference between mean flow and extreme flow in different climate regions is of utmost importance to successful water management. To quantify the spatial and temporal heterogeneity of climate change impacts on hydrological processes, this study simulated river discharge in the River Huangfuchuan in semi-arid northern China and the River Xiangxi in humid southern China. We assessed the uncertainty in projected discharge for three time periods (2020s, 2050s and 2080s) using seven equally weighted GCMs for the SRES A1B scenario. Climate projections that were applied to semi-distributed hydrological models Soil Water Assessment Tools (SWAT) in both catchments showed trends toward warmer and wetter conditions, particularly for the River Huangfuchuan. Results based on seven GCMs' projections indicated −1.1 to 8.6 and 0.3 to 7.0 °C changes in seasonal temperature and −29 to 139 and −32 to 85 % changes in seasonal precipitation in River Huangfuchuan and River Xiangxi, respectively. The largest increases in temperature and precipitation in both catchments were projected in the spring and winter seasons. The main projected hydrologic impact was a more pronounced increase in annual discharge in the River Huangfuchuan than in the River Xiangxi. Most of the GCMs projected increased discharge in all seasons, especially in spring, although the magnitude of these increases varied between GCMs. Peak flows was projected to appear earlier than usual in River Huangfuchuan and later than usual in River Xiangxi. While the GCMs were fairly consistent in projecting increased extreme flows in both catchments, the increases were of varying magnitude compared to mean flows. For River Huangfuchuan in the 2080s, median flow changed from −2 to 304 %, compared to a −1 to 145 % change in high flow (Q05 exceedence threshold). For River Xiangxi, low flow (Q95 exceedence threshold) changed from −1 to 77 % and high flow changed from −1 to 62 %, while mean flow changed from −4 to 23 %. The uncertainty analysis provided an improved understanding of future hydrologic behavior in the watershed. Furthermore, this study indicated that the uncertainty constrained by GCMs was critical and should always be considered in analysis of climate change impacts and adaptation.

Download Full-text

EVALUATION OF CLIMATE CHANGE IMPACTS ON WATER LEVEL, DISCHARGE, AND INUNDATION IN KINU AND KOKAI RIVER BASINS USING RRI MODEL

Journal of Japan Society of Civil Engineers Ser B1 (Hydraulic Engineering) ◽

10.2208/jscejhe.74.5_i_7 ◽

2018 ◽

Vol 74 (5) ◽

pp. I_7-I_12

Author(s):

Shiori ABE ◽

Yasutaka WAKAZUKI ◽

Yosuke NAKAMURA ◽

Takahiro SAYAMA

Keyword(s):

Climate Change ◽

Water Level ◽

Climate Change Impacts ◽

River Basins

Download Full-text

Assessment of climate change impacts on water balance and hydrological extremes in Bang Pakong-Prachin Buri river basin, Thailand

Environmental Research ◽

10.1016/j.envres.2020.109544 ◽

2020 ◽

Vol 186 ◽

pp. 109544 ◽

Cited By ~ 1

Author(s):

Thundorn Okwala ◽

Sangam Shrestha ◽

Suwas Ghimire ◽

S. Mohanasundaram ◽

Avishek Datta

Keyword(s):

Climate Change ◽

Water Balance ◽

River Basin ◽

Climate Change Impacts ◽

Hydrological Extremes

Download Full-text

Projection of Hydro-Climatic Extreme Events under Climate Change in Yom and Nan River Basins, Thailand

Water ◽

10.3390/w13050665 ◽

2021 ◽

Vol 13 (5) ◽

pp. 665

Author(s):

Chanchai Petpongpan ◽

Chaiwat Ekkawatpanit ◽

Supattra Visessri ◽

Duangrudee Kositgittiwong

Keyword(s):

Climate Change ◽

Air Temperature ◽

Extreme Events ◽

River Basins ◽

Annual Rainfall ◽

Extreme Floods ◽

Extreme Flood ◽

Rcp 8.5 ◽

Near Future ◽

Far Future

Due to a continuous increase in global temperature, the climate has been changing without sign of alleviation. An increase in the air temperature has caused changes in the hydrologic cycle, which have been followed by several emergencies of natural extreme events around the world. Thailand is one of the countries that has incurred a huge loss in assets and lives from the extreme flood and drought events, especially in the northern part. Therefore, the purpose of this study was to assess the hydrological regime in the Yom and Nan River basins, affected by climate change as well as the possibility of extreme floods and droughts. The hydrological processes of the study areas were generated via the physically-based hydrological model, namely the Soil and Water Assessment Tool (SWAT) model. The projected climate conditions were dependent on the outputs of the Global Climate Models (GCMs) as the Representative Concentration Pathways (RCPs) 2.6 and 8.5 between 2021 and 2095. Results show that the average air temperature, annual rainfall, and annual runoff will be significantly increased in the intermediate future (2046–2070) onwards, especially under RCP 8.5. According to the Flow Duration Curve and return period of peak discharge, there are fluctuating trends in the occurrence of extreme floods and drought events under RCP 2.6 from the future (2021–2045) to the far future (2071–2095). However, under RCP 8.5, the extreme flood and drought events seem to be more severe. The probability of extreme flood remains constant from the reference period to the near future, then rises dramatically in the intermediate and the far future. The intensity of extreme droughts will be increased in the near future and decreased in the intermediate future due to high annual rainfall, then tending to have an upward trend in the far future.

Download Full-text