Institute of Technology

Permanent URI for this communityhttps://etd.hu.edu.et/handle/123456789/66

The Institute of Technology focuses on education, research, and innovation in engineering, technology, and applied sciences to support sustainable development.

Browse

Subject: search.filters.subject.SWAT Modeling

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    STREAM FLOW RESPONSES TO CHANGES IN LAND USE/LAND COVER: THE CASE OF UPPER GIDABO CATCHEMENT, RIFT VALLEY LAKES BASIN, ETHIOPIA
    (Hawassa University, 2017-10-11) TESFAHUN TADEWOS BATE
    The study analyses the land cover change between the 1996, and 2011, and the effect these changes have had on stream flow on Upper Gidabo catchment. Within Upper Gidabo catchment land use is undergoing major changes due to pressures of human activities. Changes in land use have potentially large impacts on water resources by causing more surface runoff, decreased water retention capacity, loss of wetland and drying of river. In this study, both the Soil and Water Assessment Tool (SWAT) model and Spearman`s rank correlation statistical time series analysis for measured stream flow were applied to understand the stream flow variability and land use dynamics effect on stream flow of Upper Gidabo catchment. Land use maps of 1996, and 2011 were derived from satellite images and analyzed using ERDAS Imagine 2014 software. From the land cover change analysis results it was found that there has been a substantial decline of forest lands, shrub lands, wet lands and drastic expansion of agricultural land. The SWAT modeling results showed that an increase of stream flow by 21% comparing the two land use maps (1996 versus 2011). The analysis also revealed that flow during the wet months has increased by 9.53 % while the flow during the dry season decreased by 2.36 %. Furthermore the Spearman`s rank correlation test has been applied to detect the monotonic trend existence on the mean annual, seasonal, 1- and 7- days annual minimum and maximum flows. The Spearman`s rank correlation - test demonstrates that in the case of 1-day maximum flow, no significant trend is noticeable; however, the extreme low flows indicators (e.g.1day minimum,7 day minimum) and dry seasonal flows exhibited statistically significant decreasing trends. Generally, the combined results of the SWAT model and the statistical tests revealed that land use change has caused a significant increase on mean annual stream flow and decrease dry season flows of the studied watershed during the period. The identified result is important to inform optimal water resource management and to plan and manage water resources development within the watershed in a sustainable manner
  • No Thumbnail Available
    Item
    IMPACT OF LAND USE/LAND COVER CHANGE ON CATCHEMENT HYDROLOGY: THE CASE OF GIDABO CATCHEMENT, RIFT VALLEY LAKES BASIN, ETHIOPIA
    (Hawassa University, 2021-03-18) TESHOME MEKONNEN KAYESSO
    The study analyzed the land use/land cover change between the 1996, and 2016, and the effect these changes had on Hydrology on Gidabo catchment. Within Gidabo catchment land use is undergoing major changes due to pressures of human activities. Changes in land use have potentially large impacts on water resources by causing more surface runoff, decreased water retention capacity, loss of wetland and drying of river. In this study, both the Soil and Water Assessment Tool (SWAT) model and Spearman`s rank correlation statistical time series analysis for measured stream flow were applied to understand the stream flow variability and land use dynamics effect on stream flow of Gidabo catchment. Land use maps of 1996, 2006 and 2016 were derived from satellite images and analyzed using ERDAS Imagine 2014 software. From the land cover change analysis results it was found that there has been a substantial decline of forest lands, shrub lands, wet lands and drastic expansion of agricultural land. The SWAT modeling results showed that an increase of stream flow by 21% comparing the three land use maps (1996, 2006 & 2016). The analysis also revealed that flow during the wet months has increased by 9.53 % while the flow during the dry season decreased by 2.36 %. Generally, the combined results of the SWAT model and the statistical tests revealed that land use change has caused a significant increase on mean annual stream flow and decrease dry season flows of the studied watershed during the period. The identified result is important to inform optimal water resource management and to plan and manage water resources development within the watershed in a sustainable manner
  • No Thumbnail Available
    Item
    HYDROLOGIC RESPONSE TO LAND USE/LAND COVER CHANGE IN THE GENALE DAWA RIVER BASIN, ETHIOPIA
    (Hawassa University, 2019-08-06) MARTA AYE YALEW
    Land use land cover change has been one of factors responsible for altering the streamflow of the watershed on the Genale Dawa river basin leading to impacting river flows. The study mainly focused on estimating land use land cover change on streamflow. Land use land cover maps of 1986 and 2013 were obtained from Ethiopian Mapping Agency. The maximum likelihood algorithm of supervised classification was used in ERDAS Imagine 2014 software tool. A physical based, semi-distributed hydrological model, SWAT was used to investigate the impact of land cover change on streamflow of Genale Dawa River Basin gauged at Halwen. Land cover change analysis has shown an increment of cultivated land from 9.5% to 17.6%, agriculture land 9.1% to 19%, and built up areas 5.2% to 14.4%, while a decrement in the forest area from 31.15% to 19%, and water body from 7.2% to 7%, shrub land from 15.9% to 8.2%, Wet land from 8.8% to 4.9% and Grass land from 13.2% to 9.6% between 1986 and 2013. The performance of the SWAT model was evaluated through sensitivity analysis, calibration and validation. The model was calibrated using flow data from 1990 to 2001 including 2 year warm-up period and validated using data 2002 to 2007. Both the calibration and validation result show good agreement between observed and simulated stream flow with NSE and R 2 values of 0.86 and 0.88 for calibration and NSE are 0.84 and 0.85 for validation. Sensitivity analysis has shown that the curve number is the most sensitive parameter that affects stream flow of the watershed. The result of this study indicated that the mean monthly stream flow were increased by 8.5% for wet season and decreased by 3% in the dry season over 30 year’s period. As a result it might be possible to conclude that for the catchments the impacts were significant. Therefore, it can be deduced that LULC impact for the study area might be the most sensitive than the propagated uncertainty on catchment flow.