Engineering Hydrology
http://ir.haramaya.edu.et//hru/handle/123456789/77
2024-03-29T15:07:44ZIMPACT OF LAND USE LAND COVER AND CLIMATE CHANGE ON WATER BALANCE COMPONENTS HARGEISA WATERSHED IN SOMALILAND
http://ir.haramaya.edu.et//hru/handle/123456789/7670
IMPACT OF LAND USE LAND COVER AND CLIMATE CHANGE ON WATER BALANCE COMPONENTS HARGEISA WATERSHED IN SOMALILAND
Mohamed Abdisamed khalif; Meseret Dawit (PhD); Asfaw Kebede (PhD)
Understanding the hydrological environment and groundwater resource availability leads to
effectively planning, developing, and managing the available water resources. There are dif ferent physical and empirical models to understand the water balance components of a given
watershed. One of the spatially distributed physical models is the Wetspass model that’s re spond the impact of lulc on water balance components and climate Hargeisa watershed. The
Wetspass-M model has simulated the annual, monthly water balance components of the Har geisa watershed successfully, based on the model, the monthly water balance components in
the Hargeisa watershed is summed up by seasonality; the highest season recharge occurs in
summer were 0 to 74.9mm, sprin were 0 to 68mm, and Autumn moderate, while winter is dry.
The recharge rates performed by Wetspass model were consequently compared with those
achieved by empirical relations namely; Chaturvedi Formula (CF), Sehgal Formula (SF),
Krishna Rao Formula (KRF), and Bhattacharya Formula (BF). It was exhibited that average
rate of yearly groundwater recharge for calibration periods during 2014–2017 was
193.02mm/yr with RMSE and R², of 46.76mm, 0.7, respectively. The model also resulted in
monthly annual runoff in the watershed, which were seasonal 69.37mm, 59.38mm, and
40.4mm in the spring, summer, and autumn, respectively. Likewise, the AET seasonal water shed is 138mm, 159mm, 207mm, and autumn 158mm in the winter, spring, summer, and au tumn, respectively. The sensitivity analysis of the different input variables was conducted and
most of the variables are highly sensitive in the Hargeisa watershed. The analysis results
show that rainfall, soil, and slope are the most important hydrologic processes in the study
area in terms of affecting the amount and rate of the different water balance components. The
parametric coefficient of alfa coefficients, interception coefficients, and Lp coefficient are
also relatively sensitive. The calibration was made between the simulated and observed em pirical recharge through the coefficient determination R^2 0.87, which indicates a good cor relation between both. the future climate projected using Regional climate model based
CMIP5 namely single model ROC-ESM-CHEM under RCP4.5, and 8.5 scenarios, in the pro jected temperatures to rise incessantly, although the monthly annual rainfall increased, the
seasonal rainfall increased in winter, and autumn for both scenarios, but summer decreased
RCP4.5 13.47 and 9% 2020s, 2050s, and RCP8.5 2.47% 2050s. Spring decreased for both
scenarios in all periods. The Wetspass-M model has successfully simulated the annual
monthly water balance components.
The high variable distribution of the climatic inputs (parameters) with the variation in lulc,
soil texture, topography, and slope are responsible for variations of water balance elements
within the watershed. Likewise, the future climate projected result shows the increase in tem perature max/min annually and season, while the rainfall increases annually, but decreases
seasonally specifically rain season in the study
99p.
2023-11-01T00:00:00ZIMPACT OF LAND USE LAND COVER AND CLIMATE CHANGE ON WATER BALANCE COMPONENTS HARGEISA WATERSHED IN SOMALILAND
http://ir.haramaya.edu.et//hru/handle/123456789/7604
IMPACT OF LAND USE LAND COVER AND CLIMATE CHANGE ON WATER BALANCE COMPONENTS HARGEISA WATERSHED IN SOMALILAND
MOHAMED ABDISAMED KHALIF; Meseret Dawit (PhD); Asfaw Kebede (PhD)
Understanding the hydrological environment and groundwater resource availability leads to effectively planning, developing, and managing the available water resources. There are dif-ferent physical and empirical models to understand the water balance components of a given watershed. One of the spatially distributed physical models is the Wetspass model that’s re-spond the impact of lulc on water balance components and climate Hargeisa watershed. The Wetspass-M model has simulated the annual, monthly water balance components of the Har-geisa watershed successfully, based on the model, the monthly water balance components in the Hargeisa watershed is summed up by seasonality; the highest season recharge occurs in summer were 0 to 74.9mm, sprin were 0 to 68mm, and Autumn moderate, while winter is dry. The recharge rates performed by Wetspass model were consequently compared with those achieved by empirical relations namely; Chaturvedi Formula (CF), Sehgal Formula (SF), Krishna Rao Formula (KRF), and Bhattacharya Formula (BF). It was exhibited that average rate of yearly groundwater recharge for calibration periods during 2014–2017 was 193.02mm/yr with RMSE and R², of 46.76mm, 0.7, respectively. The model also resulted in monthly annual runoff in the watershed, which were seasonal 69.37mm, 59.38mm, and 40.4mm in the spring, summer, and autumn, respectively. Likewise, the AET seasonal water-shed is 138mm, 159mm, 207mm, and autumn 158mm in the winter, spring, summer, and au-tumn, respectively. The sensitivity analysis of the different input variables was conducted and most of the variables are highly sensitive in the Hargeisa watershed. The analysis results show that rainfall, soil, and slope are the most important hydrologic processes in the study area in terms of affecting the amount and rate of the different water balance components. The parametric coefficient of alfa coefficients, interception coefficients, and Lp coefficient are also relatively sensitive. The calibration was made between the simulated and observed em-pirical recharge through the coefficient determination R^2 0.87, which indicates a good cor-relation between both. the future climate projected using Regional climate model based CMIP5 namely single model ROC-ESM-CHEM under RCP4.5, and 8.5 scenarios, in the pro-jected temperatures to rise incessantly, although the monthly annual rainfall increased, the seasonal rainfall increased in winter, and autumn for both scenarios, but summer decreased RCP4.5 13.47 and 9% 2020s, 2050s, and RCP8.5 2.47% 2050s. Spring decreased for both scenarios in all periods. The Wetspass-M model has successfully simulated the annual monthly water balance components.
The high variable distribution of the climatic inputs (parameters) with the variation in lulc, soil texture, topography, and slope are responsible for variations of water balance elements within the watershed. Likewise, the future climate projected result shows the increase in tem-perature max/min annually and season, while the rainfall increases annually, but decreases seasonally specifically rain season in the study.
99
2023-11-01T00:00:00ZSTREAMFLOW PREDICTION FOR UNGAUGED WATERSHED USING HYDROLOGICAL MODEL: THE CASE OF ZAMRA WATERSHED, TEKEZE RIVER BASIN, ETHIOPIA
http://ir.haramaya.edu.et//hru/handle/123456789/7470
STREAMFLOW PREDICTION FOR UNGAUGED WATERSHED USING HYDROLOGICAL MODEL: THE CASE OF ZAMRA WATERSHED, TEKEZE RIVER BASIN, ETHIOPIA
Freweyni Kahsay; Dr. Asfaw Kebede
Prediction stream flow of ungauged catchment is important for water resources design,
planning and management system. Stream flow estimation in catchment is probably one of the
most basic and oldest tasks of hydrologists. In developing countries like Ethiopia most of the
rivers are ungauged. Therefore, applying regionalization techniques on an ungauged or poorly
gauged river basin is crucial. The study area of Zamra catchment have the scarcity of record
data, but the Zamra River have the capability of feeding the society nearby as source of small scale irrigation. Therefore, this thesis deals with stream flow prediction in an ungauged Zamra
catchment using GR4J hydrological model. Physical similarity regionalization techniques were
applied to identify physically similar catchments which would be the best donors for streamflow
prediction in ungauged catchments. For this study, seven gauged catchments located in gheba
sub basin of Tekeze river basin were used. The physical similarity among catchments was
determined by a weighted Euclidean distance based on catchment descriptors including
catchment topography, land cover, and soil type. The results of physical similarity index
indicate that all of the Watersheds are similar to each other. Gheba Nr Adikumsi Watershed
with S value of 0.99 are used as donor Watershed to calibrate GR4J model. The Time period of
2004-2013 is used for model Calibration, and the 2014-2018 period for validation. The result
shows that the calibrated gauging river have good agreement since Nash Sutcliff efficiency and
R
2
greater than 0.75. Discharge for the ungauged watershed simulates on a daily basis in the
period of 2004-2018 and with input data such as precipitation and potential evapotranspiration.
The importance of the study is in that the output data from the Model can be used in water
resource planning and management for its irrigation potential and any water harvesting
structures.
104p.
2023-11-01T00:00:00ZADEQUACY ASSESSMENT OF STORM WATER DRAINAGE SYSTEMS UNDER CLIMATE CHANGE: THE CASE OF CHIRO TOWN, WEST HARARGHE ZONE, ETHIOPIA
http://ir.haramaya.edu.et//hru/handle/123456789/6148
ADEQUACY ASSESSMENT OF STORM WATER DRAINAGE SYSTEMS UNDER CLIMATE CHANGE: THE CASE OF CHIRO TOWN, WEST HARARGHE ZONE, ETHIOPIA
Kelifa Abdella; Asfaw Kebede (Phd)
The failure of urban drainage systems due to extreme precipitation could cuase massive damage to infrastructures and great impact on socio-economic activity as a whole. The main goal of this research is to determine whether the existing roadside storm water drainage system in Chiro City is adequate or not for the incoming runoff from the within catchment, under both current and future climate change scenarios, using a hydrological model called the storm water management model (SWMM version 5.1.015). The study was focused on three specific objectives that aligned with this general objective. These include developing IDF curve for the study area, which was used to calculate rainfall intensity across various return periods. This rainfall intensity was utilized to generate design storms of various durations, which were then used as rainfall time series in the SWMM model. The second specific objective was to determine the capacity of existing drainage systems and evaluate their performance, while the third specific objective was to determine the adequacy of existing drainage systems under climate change. Basic data such as land use, DEM, drainage system, and precipitation data were collected and preprocessed to fulfill the requirements of the SWMM construction. For this particular study, the catchments discretized based on the natural topography taking into account the rivers and natural runoff channels as boundary lines. Sub-catchment was defined with the help of ArcGIS software. The intensity of rainfall derived from the IDF curve were converted to design hyetograph for 5,10, 25, 50, 100 year return periods.2hour duration at 10 minute time step was used to develop the design hyetograph. Rainfall pattern were gathered from the design storm hyetograph for all five return periods with a two-hour duration and used as an imput for SWMM. IDF curves for observed rainfall show an 88.60% increase in rainfall intensity from 5 year to 100 year return period, whereas IDF curves for projected rainfall show 95.09% increase in rainfall intensity. The rainfall- runoff modeling results for the conveyance system reveal that the majority of the rainfall in the study area were converted to surface runoff. The Maximum inflow is noticed at junction j101 were 4.25, 5.57, 6.12, 6.69 and 7.31m3/s under 5,10, 25,50,100 year return period respectively and flooding noticed under all storm events. Outfall 21 has the largest peak discharge under all five different return period. The results clearly reveal that in general more than 50% of existing storm drainage network are capable of withstanding rainfall for all return periods under both observed rainfall and climate change scenario. However, these doesn’t mean that the city have no flooding problems at all. Because, even though the percent of overloaded drainage line for all return periods are less than 50% of the total drainage line, there are overloaded ditches, and also others are filled with debris of solid wastes. Hence the area around those drainage line experiences high flooding problems.
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2022-12-01T00:00:00Z