scholarly journals Multi-model ensemble projection of mean and extreme streamflow of Brahmaputra River Basin under the impact of climate change

Author(s):  
Sarfaraz Alam ◽  
Md. Mostafa Ali ◽  
Ahmmed Zulfiqar Rahaman ◽  
Zahidul Islam

Abstract The streamflow of Brahmaputra River Basin is vital for sustainable socioeconomic development of the Ganges delta. Frequent floods and droughts in the past decades indicate the susceptibility of the region to climate variability. Although there are multiple studies investigating the basin's future water availability, most of those are based on limited climate change scenarios despite the wide range of uncertainties in different climate model projections. This study aims to provide a better estimation of projected future streamflow for a combination of 18 climate change scenarios. We develop a hydrologic model of the basin and simulate the future water availability based on these climate change scenarios. Our results show that the simulated mean annual, mean seasonal and annual maximum streamflow of the basin is expected to increase in future. By the end of the 21st century, the projected increase in mean annual, mean dry season, mean wet season, and annual maximum streamflow is about 25, 178, 11, and 22%, respectively. We also demonstrate that this projected streamflow can be expressed as a multivariate linear regression of projected changes in temperature and precipitation in the basin and would be very useful for policy makers to make informed decision regarding climate change adaptation.

2021 ◽  
Vol 29 ◽  
pp. 107-121
Author(s):  
Priscila Esposte Coutinho ◽  
Marcio Cataldi

In the last century, changes in climate trends have been observed around the planet, which have resulted in alterations in the hydrological cycle. Studies that take into account the impact of climate change on water availability are of great importance, especially in Brazil’s case, where water from rivers, beyond being destined for human consumption, animal watering and economic activities, has a great participation in electricity generation. This fact makes its energy matrix vulnerable to variations in the climate system. In this study, a flow analysis for the head of the São Francisco river basin was performed between 2010 and 2100, considering the precipitation data of the CCSM4 climate model presented in the Fifth Assessment Report (AR5) from the Intergovernmental Panel on Climate Change (IPCC). Projections of future flow were performed for the scenarios RCP4.5 and RCP8.5, based on the SMAP rain-flow model, followed by a comparative analysis with the present climate. In general, we can observe that the decades of 2010 to 2100 will be marked by the high levels of precipitation, interspersed by long droughts, in which the recorded flow will be lower than the Long Term Average (LTA) calculated for the basin. Therefore, new management strategies must be considered to maintain the multiple uses of the basin.


Author(s):  
Fatemeh Saedi ◽  
Azadeh Ahmadi ◽  
Karim C. Abbaspour

Abstract The climate change impact on water availability has become a significant cause for concern in the Zayandeh-Roud Reservoir in Iran and similar reservoirs in arid regions. This study investigates the climate change impact on supplying water and water availability in the Zayandeh-Roud River Basin. For better management, the Soil & Water Assessment Tool (SWAT) was used to develop a hydrologic model of the Basin. The model then was calibrated and validated for two upstream stations using the SUFI-2 algorithm in the SWAT-CUP software. The impact of climate change was modeled by using data derived from five Inter-Sectoral Impact Model Intercomparison Project general circulation models under four Representative Concentration Pathways (RCPs). For calibration (1991–2008), the Nash–Sutcliffe efficiency (NSE) values of 0.75 and 0.61 at the Ghaleshahrokh and Eskandari stations were obtained, respectively. For validation (2009–2015), the NSE values were 0.80 and 0.82, respectively. The reservoir inflow would probably reduce by 40–50% during the period of 2020–2045 relative to the base period of 1981–2006. To evaluate the reservoir's future performance, a nonlinear optimization model was used to minimize water deficits. The highest annual water deficit would likely be around 847 MCM. The lowest reservoir reliability and the highest vulnerability occurred under the extreme RCP8.5 pathway.


2007 ◽  
Vol 56 (4) ◽  
pp. 27-33 ◽  
Author(s):  
B. van den Hurk ◽  
A.K. Tank ◽  
G. Lenderink ◽  
A. van Ulden ◽  
G.J. van Oldenborgh ◽  
...  

A new set of climate change scenarios for 2050 for the Netherlands was produced recently. The scenarios span a wide range of possible future climate conditions, and include climate variables that are of interest to a broad user community. The scenario values are constructed by combining output from an ensemble of recent General Climate Model (GCM) simulations, Regional Climate Model (RCM) output, meteorological observations and a touch of expert judgment. For temperature, precipitation, potential evaporation and wind four scenarios are constructed, encompassing ranges of both global mean temperature rise in 2050 and the strength of the response of the dominant atmospheric circulation in the area of interest to global warming. For this particular area, wintertime precipitation is seen to increase between 3.5 and 7% per degree global warming, but mean summertime precipitation shows opposite signs depending on the assumed response of the circulation regime. Annual maximum daily mean wind speed shows small changes compared to the observed (natural) variability of this variable. Sea level rise in the North Sea in 2100 ranges between 35 and 85 cm. Preliminary assessment of the impact of the new scenarios on water management and coastal defence policies indicate that particularly dry summer scenarios and increased intensity of extreme daily precipitation deserves additional attention in the near future.


Nativa ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 718
Author(s):  
Rafael Alexandre Sá ◽  
Marcos Koiti Kondo ◽  
Edson De Oliveira Vieira ◽  
Silvânio Rodrigues Dos Santos ◽  
Nayara Paula Andrade Vieira ◽  
...  

A simulação hidrológica de bacias hidrográficas tem se tornado uma ferramenta importante de planejamento e gestão de recursos hídricos, projetando-se inclusive a disponibilidade hídrica a partir das mudanças climáticas. Dessa forma, objetivou-se avaliar a eficiência do modelo hidrológico SWAT na simulação da vazão da bacia hidrográfica do rio Riachão, no Norte de Minas Gerais, sob impacto de cenários alternativos de elevação da temperatura média do ar. O modelo SWAT foi ajustado para o período de 01/01/2008 a 31/12/2014 e calibrado com os dados das vazões hidrometradas obtendo valores do coeficiente de eficiência Nash-Sutcliffe (NSE) de 0,74 e 0,79 e tendência percentual (PBIAS) 15,45% e 16,72%, nas fases de calibração e validação, respectivamente. A disponibilidade de água superficial da bacia hidrográfica para comparação dos cenários foi calculada por meio da curva de permanência da vazão de referência Q90, obtendo-se o valor de 0,081 m3 s-1 para o modelo calibrado. Os cenários de aumento da temperatura média da bacia em 1,5; 2,0; 3,0; 4,0 e 5,0 °C levaram ao decréscimo da Q90 em 7,66; 8,98; 10,49; 14,06 e 17,76%, respectivamente.Palavras-chave: escoamento superficial; modelo SWAT; cenários climáticos; gerenciamento de recursos hídricos. HYDROLOGICAL SIMULATION TOOL FOR MANAGEMENT OF WATER RESOURCES IN THE FUNCTION OF CLIMATE CHANGE IN THE RIACHÃO RIVER BASIN, MG, BRAZIL ABSTRACT: The hydrological simulation of watersheds becomes a major tool for planning and management of water resources, including water availability prediction from global climate change. Thus, the objective was to evaluate the efficiency of the SWAT hydrologic model to simulate the stream flow of Riachão river basin, North of Minas Gerais State, Brazil, under the impact of alternative scenarios with the increase in mean surface air temperature. The SWAT model was adjusted for 1/1/2008 to 12/31/2014 period and calibrated with data measurement obtaining values the Nash-Sutcliffe efficiency (NSE) of 0.74 and 0.79 and percent bias (PBIAS) of 15.45 and 16.72% was found to calibration and validation period, respectively. The surface water availability in the hydrographic basin was calculated by Q90 streamflow, with calibrated value of 0.081 m³s-1. The scenarios of increase in mean air temperature (1.5, 2.0, 3.0, 4.0 and 5.0 ºC) reduced Q90 by 7.66, 8.98, 10.49, 14.06 and 17.76%, respectively.Keywords: runoff; SWAT model; climate scenarios; water resource management.


Water Policy ◽  
2021 ◽  
Author(s):  
Mateus Gonçalves Michelan ◽  
Mateus Nardini Menegaz ◽  
Flávio Aparecido Gonçalves ◽  
Paulo Henrique Bretanha Junker Menezes ◽  
Rafael de Oliveira Tiezzi

Abstract In basins with multiple water uses, it is possible a conflict over water use may occur. This probability increases under a water scarcity scenario. Therefore, it is important to estimate the possible impact of climate change on water availability in this type of basin, to support the decision-making of its users. The Ribeirão do Cipó is an example of a Brazilian watershed susceptible to this situation. Besides having poor hydrological data, it is used for public water supply, electricity generation and recreation. The present work developed a methodology for estimating water availability impacted by climate change, which was particularly applied to this watershed. The methodology consisted of feeding the rainfall–runoff hydrological model called soil moisture accounting procedure with precipitation and evapotranspiration data projected by the Eta-CPTEC regional climate model and nested to three global climate models. The outputs methods were obtained in terms of average monthly flow, for 2010–2039, 2040–2069 and 2070–2099 for the representative concentration pathway (RCP) 4.5 and RCP 8.5 scenarios. Despite the small amount of hydrological data available on the basin, the results were similar to those of the methods used as reference, thus demonstrating that the methodology used can be an alternative in estimating flow for climate change scenarios.


2014 ◽  
Vol 15 (4) ◽  
pp. 1517-1531 ◽  
Author(s):  
Gerhard Smiatek ◽  
Harald Kunstmann ◽  
Andreas Heckl

Abstract The impact of climate change on the future water availability of the upper Jordan River (UJR) and its tributaries Dan, Snir, and Hermon located in the eastern Mediterranean is evaluated by a highly resolved distributed approach with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) run at 18.6- and 6.2-km resolution offline coupled with the Water Flow and Balance Simulation Model (WaSiM). The MM5 was driven with NCEP reanalysis for 1971–2000 and with Hadley Centre Coupled Model, version 3 (HadCM3), GCM forcings for 1971–2099. Because only one regional–global climate model combination was applied, the results may not give the full range of possible future projections. To describe the Dan spring behavior, the hydrological model was extended by a bypass approach to allow the fast discharge components of the Snir to enter the Dan catchment. Simulation results for the period 1976–2000 reveal that the coupled system was able to reproduce the observed discharge rates in the partially karstic complex terrain to a reasonable extent with the high-resolution 6.2-km meteorological input only. The performed future climate simulations show steadily rising temperatures with 2.2 K above the 1976–2000 mean for the period 2031–60 and 3.5 K for the period 2070–99. Precipitation trends are insignificant until the middle of the century, although a decrease of approximately 12% is simulated. For the end of the century, a reduction in rainfall ranging between 10% and 35% can be expected. Discharge in the UJR is simulated to decrease by 12% until 2060 and by 26% until 2099, both related to the 1976–2000 mean. The discharge decrease is associated with a lower number of high river flow years.


2018 ◽  
pp. 70-79 ◽  
Author(s):  
Le Viet Thang ◽  
Dao Nguyen Khoi ◽  
Ho Long Phi

In this study, we investigated the impact of climate change on streamflow and water quality (TSS, T-N, and T-P loads) in the upper Dong Nai River Basin using the Soil and Water Assessment Tool (SWAT) hydrological model. The calibration and validation results indicated that the SWAT model is a reasonable tool for simulating streamflow and water quality for this basin. Based on the well-calibrated SWAT model, the responses of streamflow, sediment load, and nutrient load to climate change were simulated. Climate change scenarios (RCP 4.5 and RCP 8.5) were developed from five GCM simulations (CanESM2, CNRM-CM5, HadGEM2-AO, IPSL-CM5A-LR, and MPI-ESM-MR) using the delta change method. The results indicated that climate in the study area would become warmer and wetter in the future. Climate change leads to increases in streamflow, sediment load, T-N load, and T-P load. Besides that, the impacts of climate change would exacerbate serious problems related to water shortage in the dry season and soil erosion and degradation in the wet season. In addition, it is indicated that changes in sediment yield and nutrient load due to climate change are larger than the corresponding changes in streamflow.


2018 ◽  
Vol 38 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Gloria C. Okafor ◽  
Kingsley N. Ogbu

AbstractChanges in runoff trends have caused severe water shortages and ecological problems in agriculture and human well-being in Nigeria. Understanding the long-term (inter-annual to decadal) variations of water availability in river basins is paramount for water resources management and climate change adaptation. Climate change in Northern Nigeria could lead to change of the hydrological cycle and water availability. Moreover, the linkage between climatic changes and streamflow fluctuations is poorly documented in this area. Therefore, this study examined temporal trends in rainfall, temperature and runoff records of Kaduna River basin. Using appropriate statistical tools and participatory survey, trends in streamflow and their linkages with the climate indices were explored to determine their amplifying impacts on water availability and impacts on livelihoods downstream the basin. Analysis indicate variable rainfall trend with significant wet and dry periods. Unlike rainfall, temperature showed annual and seasonal scale statistically increasing trend. Runoff exhibit increasing tendency but only statistically significant on annual scale as investigated with Mann–Kendall trend test. Sen’s estimator values stood in agreement with Mann–Kendall test for all variables. Kendall tau and partial correlation results revealed the influence of climatic variables on runoff. Based on the survey, some of the hydrological implications and current water stress conditions of these fluctuations for the downstream inhabitants were itemized. With increasing risk of climate change and demand for water, we therefore recommend developing adaptive measures in seasonal regime of water availability and future work on modelling of the diverse hydrological characteristics of the entire basin.


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