scholarly journals Modeling Climate Change Impacts on Water Balance of a Mediterranean Watershed Using SWAT+

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 157
Author(s):  
Giuseppe Pulighe ◽  
Flavio Lupia ◽  
Huajin Chen ◽  
Hailong Yin

The consequences of climate change on food security in arid and semi-arid regions can be serious. Understanding climate change impacts on water balance is critical to assess future crop performance and develop sustainable adaptation strategies. This paper presents a climate change impact study on the water balance components of an agricultural watershed in the Mediterranean region. The restructured version of the Soil and Water Assessment Tool (SWAT+) model was used to simulate the hydrological components in the Sulcis watershed (Sardinia, Italy) for the baseline period and compared to future climate projections at the end of the 21st century. The model was forced using data from two Regional Climate Models under the representative concentration pathways RCP4.5 and RCP8.5 scenarios developed at a high resolution over the European domain. River discharge data were used to calibrate and validate the SWAT+ model for the baseline period, while the future hydrological response was evaluated for the mid-century (2006–2050) and late-century (2051–2098). The model simulations indicated a future increase in temperature, decrease in precipitation, and consequently increase in potential evapotranspiration in both RCP scenarios. Results show that these changes will significantly decrease water yield, surface runoff, groundwater recharge, and baseflow. These results highlight how hydrological components alteration by climate change can benefit from modelling high-resolution future scenarios that are useful for planning mitigation measures in agricultural semi-arid Mediterranean regions.

2020 ◽  
Author(s):  
Swatantra Kumar Dubey ◽  
Dr. Pankaj Kumar ◽  
Dr. Devesh Sharma ◽  
Aditya Kumar Dubey ◽  
Md. Saquib Saharwardi

<p>The Soil and Water Assessment Tool (SWAT) model is a watershed-based hydrologic model for simulating water balance at the basin scale. The SWAT model delineates the watersheds and create the Hydrological Response Units (HRUs) in the different watersheds of the basin using Digital Elevation Model (DEM), Land use, Soil and slope, and gives the water balance of the River basin. In this study, the ensemble CORDEX-SA driving GCM experiment are used to predict the water balance of the basin in the historical and future periods under the RCP4.5 and RCP8.5 scenarios. The Banas River Basin is located into the semi-arid region of Rajasthan, covered 13 districts and 5 Agro-climate zones. The basin is divided into the four zones on the basis of Agro-climatic to predict the water yield and understand water security using per capita water availability and metrological variables. It is projected that the per capita water availability will decrease, and drought frequency will increase in the future period under different scenarios. Considering the par capita water availability and meteorological variation, all the four zones are ranked, and it is found that zone 3 is more water-secure compared to other zones in the present and future periods. This study may help to understand the water scarcity status in the basin under different climate change scenarios and need more focus to improve the water management issues at the basin level.</p>


Author(s):  
Jennifer A. Curtis ◽  
Lorraine E. Flint ◽  
Michelle A. Stern ◽  
Jack Lewis ◽  
Randy D. Klein

AbstractIn Humboldt Bay, tectonic subsidence exacerbates sea-level rise (SLR). To build surface elevations and to keep pace with SLR, the sediment demand created by subsidence and SLR must be balanced by an adequate sediment supply. This study used an ensemble of plausible future scenarios to predict potential climate change impacts on suspended-sediment discharge (Qss) from fluvial sources. Streamflow was simulated using a deterministic water-balance model, and Qss was computed using statistical sediment-transport models. Changes relative to a baseline period (1981–2010) were used to assess climate impacts. For local basins that discharge directly to the bay, the ensemble means projected increases in Qss of 27% for the mid-century (2040–2069) and 58% for the end-of-century (2070–2099). For the Eel River, a regional sediment source that discharges sediment-laden plumes to the coastal margin, the ensemble means projected increases in Qss of 53% for the mid-century and 99% for the end-of-century. Climate projections of increased precipitation and streamflow produced amplified increases in the regional sediment supply that may partially or wholly mitigate sediment demand caused by the combined effects of subsidence and SLR. This finding has important implications for coastal resiliency. Coastal regions with an increasing sediment supply may be more resilient to SLR. In a broader context, an increasing sediment supply from fluvial sources has global relevance for communities threatened by SLR that are increasingly building resiliency to SLR using sediment-based solutions that include regional sediment management, beneficial reuse strategies, and marsh restoration.


2014 ◽  
Vol 128 (1-2) ◽  
pp. 99-112 ◽  
Author(s):  
Isabelle Tobin ◽  
Robert Vautard ◽  
Irena Balog ◽  
François-Marie Bréon ◽  
Sonia Jerez ◽  
...  

2020 ◽  
Vol 183 ◽  
pp. 03002
Author(s):  
Youssef Brouziyne ◽  
Abdelghani Chehbouni ◽  
Aziz Abouabdillah ◽  
Jamal Hallam ◽  
Fouad Moudden ◽  
...  

Rainfed agriculture is becoming increasingly vulnerable to climate change. This situation is expected to worsen under most future climate projections, which might increase the risks linked to food security and economies which depend on it. Providing insights about the potential responses of rainfed crops to climate change will helps on designing future adaptation strategies. In this study, large amount of data and the agro-hydrological model SWAT have been used to investigate future climate change impacts on rainfed wheat and sunflower crops in a semiarid watershed in Morocco (R’dom watershed). Downscaled CORDEX climate projections were used in generating future plants growth simulation for R’dom watershed in the 2031 to 2050 horizon under two Representative Concentration Pathways (RCPs): 4.5 and 8.5. The main results of climate change scenarios highlighted that R’dom watershed will undergo significant decrease in water resources availability with more impact under the scenario RCP 8.5. Water productivities of both studied crops could be lower by up to -21% in comparison with baseline situation. Different sustainable management strategies have been simulated using SWAT model under climate change context. The adopted approach succeeded in building up sustainable management strategies toward secured food security in the future.


Author(s):  
Youssef Brouziyne ◽  
Lahcen Benaabidate ◽  
Aziz Abouabdillah ◽  
Rachid Bouabid ◽  
Abdelghani Chehbouni

Abstract. Precipitation changes and water use patterns are two factors affecting the water quantity; obviously, hydrologic processes are always linked to many elements in the watershed scale, so to understand water management issues it is fundamental to analyze the different elements of hydrologic processes occurring in the watershed. In this study, the “SWAT” model (Soil and Water Assessment Tool) has been used to simulate the water balance for the present climate conditions on a semi arid watershed located in the central North of Morocco (R'dom). The study watershed covers an area of 1993 km2, and is hosting farming, pasture and forestry related activities. The water stress situation in the R'dom watershed can be summarized as limited resource facing increasing water demand. SWAT model was first run and calibrated under current climate; and was driven with downscaled climate simulations to generate future hydrological projections for R'dom watershed in the 2031 to 2050 horizon under two Representative Concentration Pathways (RCPs): 4.5 and 8.5. The results of the study showed that the water balance in R'dom watershed is dominated by evapotranspiration and the water resources distribution within the watershed is uneven and follows a decreasing gradient matching the flow direction. The main results of climate change scenarios showed that R'dom watershed will undergo significant decrease of water resources availability with more economic impact under the scenario RCP8.5 as all areas hosting the economical activities will be affected and the highest changes of water yield should be under this scenario.


Author(s):  
Lal Muthuwatta ◽  
Aditya Sood ◽  
Matthew McCartney ◽  
Nishchitha Sandeepana Silva ◽  
Alfred Opere

Abstract. In the Tana River Basin in Kenya, six Regional Circulation Models (RCMs) simulating two Representative Concentration Pathways (RCPs) (i.e., 4.5 and 8.5) were used as input to the Soil and Water Assessment Tool (SWAT) model to determine the possible implications for the hydrology and water resources of the basin. Four hydrological characteristics – water yield, groundwater recharge, base flow and flow regulation – were determined and mapped throughout the basin for three 30-year time periods: 2020–2049, 2040–2069 and 2070–2099. Results were compared with a baseline period, 1983–2011. All four hydrological characteristics show steady increases under both RCPs for the entire basin but with considerable spatial heterogeneity and greater increases under RCP 8.5 than RCP 4.5. The results have important implications for the way water resources in the basin are managed. It is imperative that water managers and policy makers take into account the additional challenges imposed by climate change in operating built infrastructure.


2014 ◽  
Vol 6 (1) ◽  
pp. 161-180 ◽  
Author(s):  
Hamid R. Solaymani ◽  
A. K. Gosain

This paper aims to summarize in detail the results of the climate models under various scenarios by temporal and spatial analysis in the semi-arid Karkheh Basin (KB) in Iran, which is likely to experience water shortages. The PRECIS and REMO models, under A2, B2 and A1B scenarios, have been chosen as regional climate models (RCMs). These regional climate models indicate an overall warming in future in KB under various scenarios. The increase in temperature in the dry months (June, July and August) is greater than the increase in the wet months (January, February, March and April). In order to perform climate change impact assessment on water resources, the Arc-SWAT 9.3 model was used in the study area. SWAT (Soil and Water Assessment Tool) model results have been obtained using present and future climate data. There is an overall reduction in the water yield (WYLD) over the whole of the KB. The deficit of WYLD is considerable over the months of April to September throughout KB due to the increase in average temperature and decrease in precipitation under various emission scenarios. Statistical properties in box-and-whisker plots have been used to gain further understanding relevant to uncertainty analysis in climate change impacts. Evaluation of uncertainty has shown the highest uncertain condition under B2.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 676 ◽  
Author(s):  
Natalja Čerkasova ◽  
Georg Umgiesser ◽  
Ali Ertürk

In this paper we focus on the model setup scheme for medium-size watershed with high resolution, multi-site calibration, and present results on the possible changes of the Minija River in flow, sediment load, total nitrogen (TN), and total phosphorus (TP) load in the near-term (up to 2050) and long-term (up to 2099) in the light of climate change (RCP 4.5 and RCP 8.5 scenarios) under business-as-usual conditions. The SWAT model for the Minija River basin was setup by using the developed Matlab (SWAT-LAB) scripts for a highly customized watershed configuration that addresses the specific needs of the project objective. We performed the watershed delineation by combining sub-basin and hillslope discretization schemes. We defined the HRUs by aggregating the topographic, land use, soil, and administrative unit features of the area. A multisite manual calibration approach was adopted to calibrate and validate the model, achieving good to satisfactory results across different sub-basins of the area for flow, sediments and nutrient loads (TP and TN). After completing the climate change scenario calculations, we found that a net decrease of flow (up to 35%), TN (up to 34%), and TP (up to 50%) loads are projected under both scenarios. Furthermore, we explored the changes in the streamflow composition and provide new insight on the reason of projected nutrient load decrease.


2016 ◽  
Author(s):  
Hongwei Ruan ◽  
Songbing Zou ◽  
Zhentao Cong ◽  
Yuhan Wang ◽  
Zhenliang Yin ◽  
...  

Abstract. Precipitation stations are usually scarce and unevenly distributed in inland river basins, which restrict the application of the distributed hydrological model and spatial analysis of water balance component characteristics. This study regards the upper Heihe River Basin as a case, and daily gridded precipitation data with 3 km resolutions based on the spatial interpolation of gauged stations and the regional climate model is used to construct the soil and water assessment tool (SWAT). This study aims to validate the superiority of high-resolution gridded precipitation for hydrological simulation in data scarce regions. A scale transformation method is proposed by building virtual stations and calculating the lapse rate to overcome the defects of the SWAT model using traditional precipitation station data. The gridded precipitation is upscale from the grid to the sub-basin scale and results in accurate representation of sub-basin precipitation input data. A satisfactory runoff simulation is achieved, and the spatial variability of the water balance components is analysed. Results show that the precipitation lapse rate ranges from 40 mm/km to 235 mm/km and decreases from the southeastern to the northwestern areas; its changes trend is consistent with precipitation. The SWAT model achieves monthly runoff simulation compared with gauged runoff from 2000 to 2014; the determination coefficients are higher than 0.71, the Nash–Sutcliffe efficiencies are higher than 0.76 and the percent bias are controlled within ±15 %. The meadow and sparse vegetation are the major water yield landscapes, and the elevation band at 3,500 m to 4,500 m is the major water yield area in this basin. Precipitation and evapotranspiration presented a slightly increasing trend, whereas water yield and soil water content presented a slightly decreasing trend. This finding indicates that the high-resolution gridded precipitation data well depicts its spatial heterogeneity, and scale transformation significantly promotes the application of the distributed hydrological model in inland river basins. The spatial variability of water balance components can be quantified to provide references for the integrated assessment and management of basin water resources in data scarce regions.


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