scholarly journals Evaluation and Prediction of the Impacts of Land Cover Changes on Hydrological Processes in Data Constrained Southern Slopes of Kilimanjaro, Tanzania

Earth ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 225-247
Author(s):  
Mateso Said ◽  
Canute Hyandye ◽  
Ibrahimu Chikira Mjemah ◽  
Hans Charles Komakech ◽  
Linus Kasian Munishi

This study provides a detailed assessment of land cover (LC) changes on the water balance components on data constrained Kikafu-Weruweru-Karanga (KWK) watershed, using the integrated approaches of hydrologic modeling and partial least squares regression (PLSR). The soil and water assessment tool (SWAT) model was validated and used to simulate hydrologic responses of water balance components response to changes in LC in spatial and temporal scale. PLSR was further used to assess the influence of individual LC classes on hydrologic components. PLSR results revealed that expansion in cultivation land and built-up area are the main attributes in the changes in water yield, surface runoff, evapotranspiration (ET), and groundwater flow. The study findings suggest that improving the vegetation cover on the hillside and abandoned land area could help to reduce the direct surface runoff in the KWK watershed, thus, reducing flooding recurring in the area, and that with the ongoing expansion in agricultural land and built-up areas, there will be profound negative impacts in the water balance of the watershed in the near future (2030). This study provides a forecast of the future hydrological parameters in the study area based on changes in land cover if the current land cover changes go unattended. This study provides useful information for the advancement of our policies and practices essential for sustainable water management planning.

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.


2017 ◽  
Author(s):  
Sharad K. Jain ◽  
Sanjay K. Jain ◽  
Neha Jain ◽  
Chong-Yu Xu

Abstract. A large population depends on runoff from Himalayan rivers which have high hydropower potential; floods in these rivers are also frequent. Current understanding of hydrologic response mechanism of these rivers and impact of climate change is inadequate due to limited studies. This paper presents results of modeling to understand the hydrologic response and compute the water balance components of a Himalayan river basin in India viz. Ganga up to Devprayag. Soil and Water Assessment Tool (SWAT) model was applied for simulation of the snow/rainfed catchment. SWAT was calibrated with daily streamflow data for 1992–98 and validated with data for 1999–2005. Manual calibration was carried out to determine model parameters and quantify uncertainty. Results indicate good simulation of streamflow; main contribution to water yield is from lateral and ground water flow. Water yield and ET for the catchments varies between 43–46 % and 57–58 % of precipitation, respectively. The contribution of snowmelt to lateral runoff for Ganga River ranged between 13–20 %. More attention is needed to strengthen spatial and temporal hydrometeorological database for the study basins for improved modeling.


2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Abera Shigute Nannawo ◽  
Tarun Kumar Lohani ◽  
Abunu Atlabachew Eshete

The alteration of spatial patterns of landscape interrupts water balance components in Bilate basin of Ethiopia. The aim is to characterize the spatio-temporal variation of surface-subsurface hydrological water balance using the WetSpass model comprising of soil type, topography, groundwater depth, and slope. Environment for Visualizing Images (ENVI) and Arc-GIS software were assimilated for the classification of Landsat images from 1989 to 2019 replicating the forest, shrub, and grasslands which decrease by 4.0%, 9.41%, and 14.87%, respectively, and agricultural land increasing by 27.06% from 1989 to 2019. The goodness of fit in surface runoff and subsurface flow for the two model outputs with the square of regression (R2) of 0.79 and 0.81, while the root mean square errors (RMSEs) 8.26 mm and 8.39 mm for 1989 and 2019, respectively, were calculated. Average annual interception, groundwater recharge, surface runoff, and actual-evapotranspiration were 36.4 mm, 127.34 mm, 614.95 mm, and 517.59 mm, respectively, revealing that WetSpass works remarkably in simulating the components of the hydrological water balance.


Author(s):  
Moh Sholichin ◽  
Tri Budi Prayogo

Lake Tondano is the largest natural lake in North Sulawesi, Indonesia, which functions as a provider of clean water, hydroelectric power, rice field irrigation, inland fisheries, and tourism. This research aims to determine the effect of land cover types from the Tondano watershed on the lake water quality. The Soil and Water Assessment Tool (SWAT) model was used to evaluate the rate of soil erosion and the pollutant load of various land types in the watershed during the last ten years. Rainfall data is obtained from two rainfall stations, namely Paleloan Station and Noonan Station. The model is calibrated and validated before being used for analysis. We use climatological data from 2014 to 2019. The process of the SWAT model calibration and validation was carried out with the statistical formulas of the coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE). The results show that the potential for pollution load from the Tondao watershed is organic N of 0.039 kg/ha and organic P of 0.006 kg/ha coming from the agricultural land. The results of this study conclude that the fertility conditions of Lake Tondano are at the eutrophic level, where the pollutant inflow is collected in the lake waters, especially for the parameters of total N (1503697.44kg/year) and total P (144831.36kg/year). The SWAT simulation results show deviation between the modeling and field data collected with the value of R2 = 0.9303, and the significant level ≤ 10.


2020 ◽  

<p>Hydrological modeling of a watershed is necessary for water resources planning and management. The hydrology of upper Ribb watershed has been analyzed using spatially semi-distributed Soil and water assessment tool (SWAT) model. This study aimed to determine the water balance components and its relation with the rainfall which reaches to the surface of the earth. Different spatio-temporal (land use, soil, digital elevation model, climate data, river discharge) data were used for hydrological modelling of Upper Ribb watershed. The applicability of SWAT model in Upper Ribb watershed has been evaluated using coefficient of determination (R2) and Nash Sutcliff efficiency (NSE) parameters. The calibration results revealed the observed data showed a very good agreement with the simulated data with the R2 and NSE values of 0.90 and 0.84 respectively. Similarly, the validation results of streamflow were acceptable with the R2 and NSE values of 0.80 and 0.82 respectively. The monthly average streamflow from Upper Ribb watershed were found 13.39 m3/s. The major portion of the rainfall contributes to the surface runoff due to the major percentage of the watershed is covered with agricultural lands. The groundwater flow was high in forested areas, while evapotranspiration was found very high in water bodies (Ribb reservoir). In this study area the rainfall showed a direct relationship with the streamflow. The ratio of streamflow and evapotranspiration with rainfall was 0.61 and 0.36 respectively. Due to the presence of high amount of surface runoff and evapotranspiration the deep recharge which contributes to the ground water is not that much significant.</p>


2020 ◽  
Vol 5 (2) ◽  
pp. 194-206
Author(s):  
Carolyne Wanessa Lins de Andrade Farias ◽  
Suzana Maria Gico Lima Montenegro ◽  
Abelardo Antônio de Assunção Montenegro ◽  
José Romualdo de Sousa Lima ◽  
Raghavan Srinivasan ◽  
...  

Land-use change has a significant influence on runoff process of any watershed, and the deepening of this theme is essential to assist decision making, within the scope of water resources management. The study was conducted for Mundaú River Basin (MRB) using the Soil and Water Assessment Tool (SWAT) model. The study aims to assess the issue of land-use change and its effect on evapotranspiration, surface runoff, and sediment yield. Input data like land use, topography, weather, and soil data features are required to undertake watershed simulation. Two scenarios of land use were analyzed over 30 years, which were: a regeneration scenario (referring to use in the year 1987) and another scene of degradation (relating to use in the year 2017). Land use maps for 1987 and 2017 were acquired from satellite images. Overall, during the last three decades, 76.4% of forest was lost in the MRB. The grazing land increased in 2017 at a few more than double the area that existed in 1987. Changes in land use, over the years, resulted in an increase of about 37% in the water yield of MRB. Changes have led to increased processes such as surface runoff and sediment yield and in the decrease of evapotranspiration. The spatial and temporal distribution of land use controls the water balance and sediment production in the MRB.


2021 ◽  
Author(s):  
Dinagarapandi Pandi ◽  
Saravanan Kothandaraman ◽  
K S Kasiviswanathan ◽  
Mohan Kuppusamy

Abstract Analyzing the Water Balance Components (WBCs) of catchment help in assessing the water resources for their sustainable management and development. This paper used Soil and Water Assessment Tool (SWAT) model mainly to analyze the variation in the WBCs through the change in the Land Use and Land Cover (LULC) and meteorological variables. For this purpose, the model used the inputs of LULC and meteorological variables between the year 2001-2020 at five year and daily time interval respectively from the Chittar river catchment. The developed models were evaluated using SWAT-CUP split-up procedure (pre-calibration and post-calibration). The model was found to be good in calibration and validation, yielding the coefficient of determination (R2) of 0.94 and 0.81 respectively. Furthermore, WBCs of the catchment were estimated for the near future (2021 - 2030) at monthly and annual scale. For this endeavour, LULC was forecasted for the year 2021 and 2026 using Celluar Automata (CA)-ANN and for the same period meteorological variables were also forecasted using the smoothing moving average method from the historical data.


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.


2020 ◽  
Author(s):  
Youngjin Ko ◽  
Hyun-Woo Jo ◽  
Sujong Lee ◽  
Halim Lee ◽  
Chul-Hee Lim ◽  
...  

&lt;p&gt;Water security depends on forests. Forest return less water to soil compared with grasslands or cultivation land because of their higher contribution to atmospheric moisture content via evapotranspiration. Water infiltration and retention are encouraged in forest soil by root systems. They are vital for reducing soil erosion and reducing drought by capturing fog water, reducing surface water run-off and promoting groundwater recharge. Deforestation and Afforestation in Korea Peninsula may cause change of water yield on precipitation storage and erosion control. This study is focus on how much water is contented in the changing land cover, especially forests. SWAT (Soil and Water Assessment Tool) model needs some data for simulation of water yield for example DEM, climatic data, land cover, soil data, etc. In this study, evaluation of water yield was performed at two time, 2005 and 2018 using SWAT model. Land cover was classified by using GEE (Google Earth Engine) which is useful tool for classification about enormous data. Through GEE, we got the two land cover maps, 2005 and 2018, these data were used for input data in SWAT model. Soil data is used by FAO Soil. To calibrate result data, we controlled some parameters like soil depth, porous volume which have stronger correlation between forests and soil properties. We can find that forest can store more water than other classes such as city, agriculture, and so on. In this study, we quantitatively estimated the water content by changing land cover. This study present functional positive effects of forests to store water. This study can be used in preparing various forest strategy in South Korea. Above all, this result maybe useful background data for supporting North Korea in afforestation.&lt;/p&gt;


2020 ◽  
Vol 79 (19) ◽  
Author(s):  
Naeem Saddique ◽  
Talha Mahmood ◽  
Christian Bernhofer

Abstract Land use and land cover (LULC) change is one of the key driving elements responsible for altering the hydrology of a watershed. In this study, we investigated the spatio-temporal LULC changes between 2001 and 2018 and their impacts on the water balance of the Jhelum River Basin. The Soil and Water Assessment Tool (SWAT) was used to analyze the impacts on water yield (WY) and evapotranspiration (ET). The model was calibrated and validated with discharge data between 1995 and 2005 and then simulated with different land use. The increase was observed in forest, settlement and water areas during the study period. At the catchment scale, we found that afforestation has reduced the WY and surface runoff, while enhanced the ET. Moreover, this change was more pronounced at the sub-basin scale. Some sub-basins, especially in the northern part of the study area, exhibited an increase in WY due to an increase in the snow cover area. Similarly, extremes land use scenarios also showed significant impact on water balance components. The basin WY has decreased by 38 mm/year and ET has increased about 36 mm/year. The findings of this study could guide the watershed manager in the development of sustainable LULC planning and water resources management.


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