Water Resource

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/71

Browse

Start date: 2020Subject: search.filters.subject.GIS

Search Results

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    GIS BASED GROUNDWATER POTENTIAL MAPPING AND RECHARGE 1 ESTIMATION: A CASE STUDY IN MELKAODA WATERSHED RIFT VALLEY LAKES 2 BASIN, OROMIA, ETHIOPIA
    (Hawassa University, 2021-10-24) ADEM BUTA DEKEBO
    The groundwater potential zones of the Melkaoda Watershed were demarcated with the help of remote sensing and Geographic Information System (GIS) techniques. The parameters that were considered for identifying the groundwater potential zone like geology, slope, drainage density, geomorphic units, and lineament density were generated from satellite data and they were then integrated with weighted overlay in ArcGIS. Suitable ranks were assigned for each category of these parameters and weight factors were decided for them based on their capability to store groundwater using AHP approach and then the groundwater potential zones were classified into four categories as very low, low, high & very high. In addition, the groundwater recharge was estimated with the help of the WetSpass model using water balance approach. The parameters considered for this case generally included three types: hydro-meteorological (rainfall, temperature, wind speed, PET, and GWD), bio-physical (soil, landuse, topography, and slope), and attribute lookup (soil lookup, landuse lookup, and rain day lookup) tables. All the hydro-meteorological parameters were interpolated in ArcGIS for grid map preparation of each parameter and the prepared grid map was converted to ASCII file format for the effective model run. The model performance was checked through calibration and the obtained groundwater recharge result ranges 0.45 to 65.5 mm/year with the mean value of 32.87 mm/years and 3.4% contributed to groundwater as recharge. finally, the changes in groundwater recharge between two simulation period was stated again with help of WetSpass model using the LULC images of 1989 and 2018 to quantify the impacts of the LULCC. The parameters used for this analysis were the same as those used for groundwater recharge estimation except for the satellite image of 1989 and the LULCC analysis depicted that there was the expansion of built-up land and agricultural land. Agricultural land and built-up land were increased by 0.046, 2.56 rate per a year from 1989 to 2018 respectively. This paper finalized that there was access to the groundwater potential in the Melkaoda Watershed and this could overcome the water scarcity challenging the community in and around the area. The recharge which has been the main source of groundwater is decreasing from time to time as the result of this paper is indicating. Thus, to get sustainable groundwater potential, the recharge has to be well treated by increasing groundwater recharge
  • No Thumbnail Available
    Item
    ASSESSING THE IMPACT OF LU/LC CHANGE ON HYDROLOGICAL RESPONSE BY USING SWAT MODEL: A CASE STUDY AT DEDABA WATERSHED, ETHIOPIA.
    (Hawassa University, 2021-04-26) IBSA DIBO DEKO
    Water is a precious and finite resource and must be managed in sustainable way to meet human as well as environmental needs. Land use/land cover change has an impact for alteration of watershed hydrology. The watershed is undergoing land use change due to intensive cultivation andurbanization as a result of population growth which has an impact on hydrologicresponse of the watershed. This study quantified watershed runoff volume using SWAT modeland assessed the effect of land use/land cover change on the stream flow. In this study, the impact of LU/LCchange was carried out by using the Soil Water Assessment Tool (SWAT2012) model, which was integrated with GIS10.3 software. GIS and ERDAS IMAGINE2014 were used to generate LU/LCmaps from Landsat TM, TM, and OLI acquired in the years 1990, 2001 and 2018 respectively. The land cover maps were generated using the maximum likelihood algorithm of supervised classification. The classified maps were assessed using confusion metrics. The results of the analysis showed that the Agricultural land has expanded during the study period of 1990-2018. During the study period, forest land, and shrub and grassland decreased by 19.5% and 15.61% respectively while Agricultural land and Built-up area increased by 33..63% and 1.48% respectively. Using three land cover maps, three SWAT model setup were run to evaluate the impacts of LU/LC changes on the streamflow of the study watershed. The performance of the SWAT model was evaluated through sensitivity analysis, calibrationand validation by using SWAT-CUP. The Coefficients of determination and Nash–Sutcliffe were used to evaluate the model and it resulted in 0.87 and 0.73 for calibration and 0.82 and 0.68 for validation respectively. During the study periods, the simulation result indicated that streamflow increased in the wet season and short rainy season streamflow by 9.64% and 3.05% respectively, while decreasing by 5.6% in the dry season. The Surface Flow (SURQ) increased by 12.58% while Groundwater Flow (GW_Q) decreased by 14.83% due to the increment of Agricultural land. The study resultsshowed change in flow with change in land use/landcover, so it needs landuse planning and sustainable water resource management
  • No Thumbnail Available
    Item
    PHYSICAL IRRIGATION POTENTIAL ASSESSMENT FOR SURFACE IRRICATION: A CASE STUDY IN CHEMOGA WATERSHED, UPPER BLUE NILE BASIN, ETHIOPIA
    (Hawassa University, 2020-10-11) KASSANESH MELKAM MENGISTE
    Assessment of available land and water resources for irrigation is essential for planning their use, to utilize limited resources efficiently and for the sustainable production of crops and food security of the ever increasing people in developing countries like Ethiopia. The study was mainly focused on assessing the available land and water resources potential for surface irrigation of Chemoga Watershed. This was done by using Geographic Information System (GIS)-based Multi Criteria Evaluation (MCE) tools, a hydrological Soil and Water Assessment Tool (SWAT) model, and a Crop Water and Irrigation Requirements Program of FAO (CROPWAT) model. GIS was used to map the land suitable for surface irrigation based on slope, soil, land use /land cover, and river proximity. SWAT model was used to estimate the water availability, and CROPWAT model calculate the reference crop evapotranspiration, effective rainfall, net and gross irrigation water requirement of crops. Potentially suitable land for surface irrigation development was evaluated by selecting six crops (barley, wheat, bean, maize, onion, and potato). The result of the overall weighted analysis for these factors gave about 25462.08 ha (71.4 %) of the Watershed land considered as high to moderately suitable whereas 10427.53 ha (28.6 %) were not suitable for surface irrigation. The SWAT model was calibrated and validated from the available hydro metrological and spatial data. Model performance result showed in between the observed and simulated stream flow with coefficient of determination (R2) and Nash-Sutcliffe efficiency (ENS) values 0.86 and 0.7 for calibration, and 0.74 and 0.63 for validation, respectively and indicated a good performance of the model in simulating the hydrology. The annual average simulated stream flow was evaluated and 36.2 m 3 /s. The water demand required by the selected crops was 228.18m3 /s/ha. From the total available suitable land, only 12376.03 ha can be irrigating with the available water
  • No Thumbnail Available
    Item
    INSTITUTE OF TECHNOLOGY, FACULTY OF BIO-SYSTEMS AND WATER RESOURCES ENGINEERING, DEPARTMENT OF WATER RESOURCES AND HYDRAULIC ENGINEERING
    (Hawassa University, 2023-10-24) YONAS HAILU WASE
    The goal of this study was to assess the groundwater potential zone in a Deme watershed area of the Omo-Gibe basin, Ethiopia, where data availability was poor. In this study, a number of data from a variety of sources have been used, including climate, stream flow, and spatial thematic layers including land use maps, soil maps, drainage density maps, geology maps, slope maps, lineament density maps, and geomorphology maps. In order to estimate the recharge amount and its spatio temporal fluctuation in the watershed, Soil and Water Assessment Tool model was utilized. At the Orata Alem location within the Deme watershed, several modeling techniques, sensitivity analysis, calibration beginning from 1991 to 2001, and validation 2002 to 2006 periods, were applied. As a result, the results of the calibration and validation phases showed that the model can accurately and reasonably reproduce the stream flow pattern and the various hydrograph responses, as indicated by the Nash-Sutcliffe efficiency(ENS) values of 0.78 and 0.74 and the coefficient of determination(R 2) values of 0.81 and 0.76, respectively. The watershed's mean annual recharge rate is estimated to be 214.5 mm/y, with the northern top section of the watershed experiencing a recharge rate of 233.77 mm/y, the middle of the watershed experiencing a recharge rate of 214.72 mm/y, and the lower part of the watershed experiencing a recharge rate of 194.51 mm/y. Analytical Hierarchical Process was used to rank the various layers based on a pair-wise comparison matrix in order to estimate the final normalized weights of thematic map layers. Groundwater flow direction was determined by the Surfer model. GIS-based Multi-Criteria Decision Analysis was applied for mapping of groundwater potential zones and its results were used to identify three Groundwater Potential Zone: low, moderate and high, with area coverage of 26.3664 Km2 ,744.1776 Km2 and 271.9179 Km2 correspondingly. Around 71.4% of the region has a moderate groundwater potential, and 26.084% has a high potential. Lastly, groundwater well inventory data for 35 wells dispersed around the region were used to validate the Groundwater Potential Zone map in order to evaluate the model's efficacy. The validation results confirmed that 84.44% the study Ground water potential zone match with ground water well points in the Deme watershed, so that the applied approach provides well reasonable results that can help in planning, management and sustainable utilization of the groundwater resources in this water-stressed area.
  • No Thumbnail Available
    Item
    Effects of land use land cover changes on soil erosion risk in Beshilo sub basin and the influence on Tebi dam, north eastern highlands of Ethiopia
    (Hawassa University, 2022-03-15) Andarge Getachew
    Continuous increase of world’s population and demand for food and staple production poses a major challenge for agriculture in the short and medium period. In the current study area, soil loss information and evaluation of risk of potential of soil erosion was not assessed. So, the aim of these study is to assess and analyze the impact of land use land cover change on soil erosion risk using remote sensing and GIS techniques in the upper bushilo sub-basin northern-eastern highland of Ethiopia between 1990 and 2020. Primary materials and tools used are ArcGIS 10.8 software, ENVI 5.3 software, Landsat satellite image of 1990, 2000, 2010, and 2020, ASTER DEM /DEM 30X30 was downloaded from USGS earth explore, Google earth pro as use for base map that also were downloaded for the four study periods. GPS, Camera, Internet access, and computer software were used for data processing and GIS analysis. the watershed’s computed soil loss ranged from zero in plain areas and water courses to large over 68.7t ha-1 yr -1 . In very degraded sloping regions and at specific spots of steep slopes of the watershed, gross soil loss rate ranged to 79.65 t/ha. It shows a larger spatial variation of soil loss over the watershed. It is mainly caused by the difference in soil, rainfall, slope, land cover, and improper land management. The estimated mean annual gross soil loss from 1990-2020 under the entire watershed is about a 9.94 t/ha/yr. Within the study period (1990-2020), 41723.8 ton soil has transported to Tebi dam. The GIS-based RUSLE model can assist decision-makers in effective planning for erosion control studies on risky areas
  • No Thumbnail Available
    Item
    GIS-BASED SURFACE IRRIGATION POTENTIAL ASSESSMENT: A CASE STUDY IN BILATE RIVER WATERSHED, SOUTH-WESTERN, ETHIOPIA
    (Hawassa University, 2021-04-26) ALELU MANAMO MERASA
    The major problem associated with rainfall-dependent agriculture in Ethiopia is the high degree of rainfall variability and unreliability. As a consequence, food insecurity often turns into famine. Irrigation development is one of the key strategies to increase agricultural production and alleviate poverty. This study, therefore, aimed to assess the surface irrigation potential and land resources potential of the Bilate River Watershed for irrigation expansion. Watershed delineation, identification of potentially irrigable land, and estimation of irrigation water requirement and surface water resources availability of the study area were the steps followed to evaluate this irrigation potential. Irrigation potential was mapped by using GIS of the watershed; Arc SWAT model was used to estimate the water resources availability in the watershed; Analytical hierarchy process (AHP) comparison was used to conduct land suitability assessment and a CROPWAT 8.0 model was used to determine the crop water requirement for major crops of the study area. To identify potentially irrigable land, irrigation suitability factors such as soil physical properties, slope, land use/ land cover, and distances from the water supply (sources) are taken into account. The final results of the overall weighted overlay analysis of irrigation land suitability indicate that 317,841ha (64%) are highly suitable (S1), 153,459ha (30.91%) are moderately suitable (S2), whereas 25,039ha (5.044%) are not suitable (N) for surface irrigation development. The SWAT model was calibrated and validated. The observed monthly streamflow values have a coefficient of determination (R2 ) and Nash-Sutcliffe Coefficient (NSE) of 0.77 and 0.66 respectively for the calibration period and 0.81 and 0.64 for the validation period. The irrigation water demand required by five major selected crops which are grown in the study area throughout the growing season was found to be 663.04 m 3 /s. The annual dependably simulated streamflow was 225.14 m 3 /s. The estimated dependably available flow can potentially irrigate only an area of 53,645.77 ha for highly suitable areas. The result showed that the water demand of the crops was greater than the available dependably flow of the watershed. Therefore to increase the irrigation potential of the watershed sprinkler or drip irrigation methods can be used