scholarly journals HYDROLOGIC BEHAVIOUR OF HIGHLAND CATCHMENT IN HUMID TROPICAL REGION USING QSWAT MODEL

Water resources planning and management of a region requires an understanding of the water balance in the region. The Soil and Water Assessment Tool (SWAT) with QGIS interface (QSWAT) has been used here to arrive at the water balance components in the Palapuzha watershed of Valapattanam river basin in Kerala. Valapattanam river drains an area of 1867 sq.km. with 456 sq.km. area in Karnataka State. The river basin receives an average annual rainfall of 3600 mm. The Palapuzha watershed drains an area of 237.25 sq.km with an average annual rainfall of 4562 mm. The QSWAT model has been calibrated and validated using data for a period of eight years (2000-2007) for which both rainfall and streamflow data are available. The model was successful in simulating monthly streamflow during the calibration and validation periods with Nash Sutcliffe efficiency and correlation co-efficient greater than 0.75 and percent bias less than 10%, showing that the model is very good for predicting streamflow in Valapattanam river basin. This calibrated model was used to arrive at the different water balance components in the Palapuzha watershed. The results obtained will be useful for the sustainable development and planning of the water resources system in the highland humid tropical watersheds

2018 ◽  
Vol 10 (9) ◽  
pp. 3277 ◽  
Author(s):  
Javier Senent-Aparicio ◽  
Sitian Liu ◽  
Julio Pérez-Sánchez ◽  
Adrián López-Ballesteros ◽  
Patricia Jimeno-Sáez

Climate change and the land-use and land-cover changes (LULC) resulting from anthropic activity are important factors in the degradation of an ecosystem and in the availability of a basin’s water resources. To know how these activities affect the quantity of the water resources of basins, such as the Segura River Basin, is of vital importance. In this work, the Soil and Water Assessment Tool (SWAT) was used for the study of the abovementioned impacts. The model was validated by obtaining a Nash–Sutcliffe efficiency (NSE) of 0.88 and a percent bias (PBIAS) of 17.23%, indicating that SWAT accurately replicated monthly streamflow. Next, land-use maps for the years of 1956 and 2007 were used to establish a series of scenarios that allowed us to evaluate the effects of these activities on both joint and individual water resources. A reforestation plan applied in the basin during the 1970s caused that the forest area had almost doubled, whereas the agricultural areas and shrubland had been reduced by one-third. These modifications, together with the effect of climate change, have led to a decrease of 26.3% in the quantity of generated water resources, not only due to climate change but also due to the increase in forest area.


Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1334
Author(s):  
Aminjon Gulakhmadov ◽  
Xi Chen ◽  
Manuchekhr Gulakhmadov ◽  
Zainalobudin Kobuliev ◽  
Nekruz Gulahmadov ◽  
...  

In this study, the applicability of three gridded datasets was evaluated (Climatic Research Unit (CRU) Time Series (TS) 3.1, “Asian Precipitation—Highly Resolved Observational Data Integration Toward the Evaluation of Water Resources” (APHRODITE)_V1101, and the climate forecast system reanalysis dataset (CFSR)) in different combinations against observational data for predicting the hydrology of the Upper Vakhsh River Basin (UVRB) in Central Asia. Water balance components were computed, the results calibrated with the SUFI-2 approach using the calibration of soil and water assessment tool models (SWAT–CUP) program, and the performance of the model was evaluated. Streamflow simulation using the SWAT model in the UVRB was more sensitive to five parameters (ALPHA_BF, SOL_BD, CN2, CH_K2, and RCHRG_DP). The simulation for calibration, validation, and overall scales showed an acceptable correlation between the observed and simulated monthly streamflow for all combination datasets. The coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) showed “excellent” and “good” values for all datasets. Based on the R2 and NSE from the “excellent” down to “good” datasets, the values were 0.91 and 0.92 using the observational datasets, CRU TS3.1 (0.90 and 0.90), APHRODITE_V1101+CRU TS3.1 (0.74 and 0.76), APHRODITE_V1101+CFSR (0.72 and 0.78), and CFSR (0.67 and 0.74) for the overall scale (1982–2006). The mean annual evapotranspiration values from the UVRB were about 9.93% (APHRODITE_V1101+CFSR), 25.52% (APHRODITE_V1101+CRU TS3.1), 2.9% (CFSR), 21.08% (CRU TS3.1), and 27.28% (observational datasets) of annual precipitation (186.3 mm, 315.7 mm, 72.1 mm, 256.4 mm, and 299.7 mm, out of 1875.9 mm, 1236.9 mm, 2479 mm, 1215.9 mm, and 1098.5 mm). The contributions of the snowmelt to annual runoff were about 81.06% (APHRODITE_V1101+CFSR), 63.12% (APHRODITE_V1101+CRU TS3.1), 82.79% (CFSR), 81.66% (CRU TS3.1), and 67.67% (observational datasets), and the contributions of rain to the annual flow were about 18.94%, 36.88%, 17.21%, 18.34%, and 32.33%, respectively, for the overall scale. We found that gridded climate datasets can be used as an alternative source for hydrological modeling in the Upper Vakhsh River Basin in Central Asia, especially in scarce-observation regions. Water balance components, simulated by the SWAT model, provided a baseline understanding of the hydrological processes through which water management issues can be dealt with in the basin.


Author(s):  
Osypov Valeriy ◽  
Speka Oleh ◽  
Chyhareva Anastasiia ◽  
Osadcha Nataliia ◽  
Krakovska Svitlana ◽  
...  

Abstract Climate change impact on water resources has been observing in Ukraine since the end of the 20th century. For now, only large-scale climate impact studies cover Ukraine territory, having low credibility for a specific catchment. This study aims to calculate future changes in river discharge, water flow components, and soil water within the Desna basin and evaluate vulnerability trends on this basis. The framework assembles the process-based SWAT (Soil and Water Assessment Tool) model and eight high-resolution regional climate models (RCMs) driven by RCP4.5 and RCP8.5 emission scenarios. The climate models are provided by the Euro-CORDEX initiative and based on three RCMs (RCA4, HIRHAM5, and RACMO22E) forced by five general circulation models (CNRM-CM5, EC-EARTH, IPSL-CM5A-MR, HadGEM2-ES, and MPI-ESM-LR). The results preferably show a moderate increase in the annual discharge till the end of the 21st century. The intra-annual changes of water balance components negatively affect the vegetation period because of higher dryness and temperature stress but reduce flood risk, diffuse pollution, and water erosion in the far future. In the river basin management plan, the highest attention should be paid to adaptive strategies in agriculture because of possible water deficit in the vegetation season under future climate scenarios.


Author(s):  
S. P. Aggarwal ◽  
P. K. Thakur ◽  
V. Garg ◽  
B. R. Nikam ◽  
A. Chouksey ◽  
...  

The water resources status and availability of any river basin is of primary importance for overall and sustainable development of any river basin. This study has been done in Beas river basin which is located in North Western Himalaya for assessing the status of water resources in present and future climate change scenarios. In this study hydrological modelling approach has been used for quantifying the water balance components of Beas river basin upto Pandoh. The variable infiltration capacity (VIC) model has been used in energy balance mode for Beas river basin at 1km grid scale. The VIC model has been run with snow elevation zones files to simulate the snow module of VIC. The model was run with National Centre for Environmental Prediction (NCEP) forcing data (Tmax, Tmin, Rainfall and wind speed at 0.5degree resolution) from 1 Jan. 1999 to 31 Dec 2006 for calibration purpose. The additional component of glacier melt was added into overall river runoff using semi-empirical approach utilizing air temperature and glacier type and extent data. The ground water component is computed from overall recharge of ground water by water balance approach. The overall water balance approach is validated with river discharge data provided by Bhakra Beas Management Board (BBMB) from 1994-2014. VIC routing module was used to assess pixel wise flow availability at daily, monthly and annual time scales. The mean monthly flow at Pandoh during study period varied from 19 - 1581 m<sup>3</sup>/s from VIC and 50 to 1556 m<sup>3</sup>/sec from observation data, with minimum water flow occurring in month of January and maximum flow in month of August with annual R<sup>2</sup> of 0.68. The future climate change data is taken from CORDEX database. The climate model of NOAA-GFDL-ESM2M for IPCC RCP scenario 4.5 and 8.5 were used for South Asia at 0.44 deg. grid from year 2006 to 2100. The climate forcing data for VIC model was prepared using daily maximum and minimum near surface air temperature, daily precipitation and daily surface wind speed. The GFDL model also gives validation phase scenarios from 2006 to 2015, which are used to test the overall model performance with current data. The current assessment made by hydrological water balance based approach has given reasonable good results in Beas river basin. The main limitation of this study is lack of full representation of glacier melt flow using fully energy balance model. This component will be addressed in coming time and it will be integrated with tradition hydrological and snowmelt runoff models. The other limitation of current study is dependence on NCEP or other reanalysis of climate forcing data for hydrological modelling, this leads to mismatch between actual and simulated water balance components. This problem can be addressed if more ground based and fine resolution grid based hydro meteorological data are used as input forcing data for hydrological modelling.


The use of hydrologic models to predict the relevant processes occurring within a catchment will serve as a veritable tool for water managers and planners for a sustainable management of water resources especially in the absence of quality and reliable data. The Soil and Water Assessment Tool (SWAT), a physically based semi-distributed hydrological model interfaced with MapWindows GIS software was used to simulate the different components of water balance and estimation of water yield of the Lower Benue River Basin in Nigeria. Climate data of three weather stations; Lokoja, Makurdi and Ibi located close to the catchment were used to simulate the stream flow of the catchment. The model was calibrated and validated using measured streamflow at Makurdi gauging station and subsequently used to predict the water balance and water yield of the catchment. Model evaluation gave R2 value of 0.79 and RSR of 0.45 for the calibration period, while R2 of 0.74 and RSR of 0.51 were recorded for validation of the model indicating a reasonable agreement between the measured and simulated flows. The prediction of water balance showed that more than a third of the water loss from the catchment is due to evapotranspiration. Sub-surface flow accounted for over 50% of the water balance simulation, while stream flow yielded only 10% as a result of the shallow slopes of the study area. The maximum water yield recorded in the study area occurred in 2009 with a value of 162,862mm representing 8.74% for the 20 year period while the lowest water yield for the period occurred in 2015 with 45,458mm representing 2% of the total water yield for the period. Overall, results show a progressive reduction in streamflow and precipitation since 2012 in the catchment and 2015 recorded the least values for the period of study. These findings show that SWAT is a viable tool for predicting future scenarios for water resources management in the catchment.


This study mainly focus on hydrological behavior of watersheds in The Manjira River basin using soil and water assessment tool (SWAT) and Geographical information system (GIS). The water balance components for watersheds in the Manjira River were determined by using SWAT model and GIS. Determination of these water balance components helps to study direct and indirect factors affecting characteristics of selected watersheds. Manjira River contains total 28 watersheds among them 2 were selected having watershed code as MNJR008 and MNJR011 specified by the Central Ground Water Board. The SWAT input data such as Digital elevation model (DEM), land use and land cover (LU/LC), Soil classification, slope and weather data was collected. Using these inputs in SWAT the different water balancing components such as rainfall, baseflow, surface runoff, evapotranspiration (ET), potential evapotranspiration (PET) and water yield for each watershed were determined. The evaluated data is then validated by Regression analysis, in which two datasets were compared. Simulated rain data from SWAT simulation and observed rain data from Global Weather Data for SWAT was selected for comparison for each watershed.


2016 ◽  
Vol 20 (7) ◽  
pp. 2877-2898 ◽  
Author(s):  
Hannes Müller Schmied ◽  
Linda Adam ◽  
Stephanie Eisner ◽  
Gabriel Fink ◽  
Martina Flörke ◽  
...  

Abstract. When assessing global water resources with hydrological models, it is essential to know about methodological uncertainties. The values of simulated water balance components may vary due to different spatial and temporal aggregations, reference periods, and applied climate forcings, as well as due to the consideration of human water use, or the lack thereof. We analyzed these variations over the period 1901–2010 by forcing the global hydrological model WaterGAP 2.2 (ISIMIP2a) with five state-of-the-art climate data sets, including a homogenized version of the concatenated WFD/WFDEI data set. Absolute values and temporal variations of global water balance components are strongly affected by the uncertainty in the climate forcing, and no temporal trends of the global water balance components are detected for the four homogeneous climate forcings considered (except for human water abstractions). The calibration of WaterGAP against observed long-term average river discharge Q significantly reduces the impact of climate forcing uncertainty on estimated Q and renewable water resources. For the homogeneous forcings, Q of the calibrated and non-calibrated regions of the globe varies by 1.6 and 18.5 %, respectively, for 1971–2000. On the continental scale, most differences for long-term average precipitation P and Q estimates occur in Africa and, due to snow undercatch of rain gauges, also in the data-rich continents Europe and North America. Variations of Q at the grid-cell scale are large, except in a few grid cells upstream and downstream of calibration stations, with an average variation of 37 and 74 % among the four homogeneous forcings in calibrated and non-calibrated regions, respectively. Considering only the forcings GSWP3 and WFDEI_hom, i.e., excluding the forcing without undercatch correction (PGFv2.1) and the one with a much lower shortwave downward radiation SWD than the others (WFD), Q variations are reduced to 16 and 31 % in calibrated and non-calibrated regions, respectively. These simulation results support the need for extended Q measurements and data sharing for better constraining global water balance assessments. Over the 20th century, the human footprint on natural water resources has become larger. For 11–18% of the global land area, the change of Q between 1941–1970 and 1971–2000 was driven more strongly by change of human water use including dam construction than by change in precipitation, while this was true for only 9–13 % of the land area from 1911–1940 to 1941–1970.


Author(s):  
O.I. Lukіanets ◽  
V.V Grebіn

In the article, in order to identify the generalized role of changes that occurred in the Psel River basin with such climatic indicators as air temperature, amount of precipitation, their form of precipitation, the structure of water bodies feeding, as well as water flow in the modern period, the average water balance for a long-term period was calculated the Psel river basin near the town of Gadyach. In general, the water balance equation shows the ratio of water input and consumption within a river basin, taking into account changes in its reserves over a selected time interval and allows one to assess the relationship of its individual components. In the article identifies changes in the ratio between the inflow (amount of precipitation) and consumption of water (total evaporation and runoff) for two periods – the climatic norm of 1961-1990 and modern 1990-2019. Analysis of the temporal dynamics of the water balance components of the Psel river basin showed that the values of the water balance components within the Psel river basin near the town of Gadyach in the modern period have decreased in comparison with the period of the climatic norm – the amount of precipitation by 6,2%, water flow by 17,5%, evapotranspiration by 1,8%. But, analyzing the relationship between the inflow and outflow of water in the basin for the two study periods 1961-1990 and 1990-2019, it can be stated that during the period of the climatic norm, the percentage of water flow from the total precipitation was greater (coefficient water flow 16.2%) than in the modern period (coefficient water flow 14.2%). With regard to total evaporation in water-balance ratios, its share in the water-balance ratio has increased over the modern period (1990-2019). If during the period of climatic normal (1961-1990) the aridity coefficient was 83.8%, then in the modern period, it is 85.8%. That is, the “redistribution” of the water volumes of atmospheric precipitation took place towards the total evaporation with a decrease in the volume of water used to form the water runoff. For the basin of the river Psel – the city of Gadyach in the modern period on the average ≈ 11 mm (or ≈ 130000000 m3) evaporate instead of replenishment of water resources. In the previous period of 1961-1990, on the contrary, ≈ 12 mm (or 136000000 m3) did not evaporate, but flowed into the water bodies of the basin.


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