Integrated Hydrogeological Investigation of Upper Bilate River Catchment: South Western Escarpment of Main Ethiopian Rift
| dc.contributor.advisor | Ayenew, Tenalem (PhD) | |
| dc.contributor.author | Legesse, Sintayehu | |
| dc.date.accessioned | 2018-07-10T13:25:37Z | |
| dc.date.accessioned | 2023-11-09T14:09:31Z | |
| dc.date.available | 2018-07-10T13:25:37Z | |
| dc.date.available | 2023-11-09T14:09:31Z | |
| dc.date.issued | 2009-06 | |
| dc.description.abstract | The study was conducted at Upper Bilate River Catchment 230km, South West of Addis Ababa and East of Hossana to characterize aquifer and assess hydrogeological system of Upper Bilate catchment by giving particular emphasis to groundwater potential investigation, mechanism of recharge and groundwater surface water interaction, in an integrated manner. Data has been collected from the respective institutes and organizations and processed using hydrogeological and GIS and remote sensing software. Integrated approaches of hydrogeological investigations are adopted by paying particular attention to geology, recharge estimation, hydrogeological system and hydrogeochemistry in the assessment of water resources potential of the catchment. Areal depth of precipitation of the area was estimated by categorizing the area in to unimodal and bimodal zones. Potential evapotranspiration (PET) of the area and the water body was estimated using Thornthwaite Mather and Penman Combination methods and Pan Evaporation method respectively. Actual Evapotranspiration (AET) was estimated using Turc and Soil moisture balance methods. Base flow separation and conventional water balance approaches were used to estimate recharge. To characterize the aquifer system of the area pumping test data, well completion reports, well logs and geology of the area were analyzed. Piper plots, Collins bar diagram and Hierarchical cluster Analysis (HCA) were used to classify the water chemistry. Maps, cross-sections and well-logs are used to show groundwater flow system and recharge discharge conditions. The estimated values of PET are 1222.93mm and 842.4mm using Penman and Thorhthwaite method respectively. The results indicate that, the highland which is unimodal rainfall pattern zone receives more precipitation (1284.65mm) than the lowland (1216.6mm). Pan Evaporation method resulted about 2.57mm for the open water evaporation which was insignificant as compared to the area. AET was estimated to be 800.92mm and 1019.8mm using Turc and Soil moisture balance methods respectively. The estimated recharges of the area are 129 and 96.18mm using base flow separation and water balance approaches respectively. The average of the two values is taken as the annual recharge of the area which is 9.2% of the total precipitation. The pumping test analysis results indicate that the hydraulic conductivity of the area ranges from 0.17 – 8.8 m/d and the mean and median were 2.17 m/d and 1.12 m/d respectively. There was variation in water type from Low TDS Na-Ca- HCO3 to high TDS and EC Na-HCO3 water types. Accordingly, the western and northern part of the area is recharging zone and the central and southern part is discharge zone while the area just southeast of Boyo plain is categorized under deep groundwater zone due to the damming effect of Ambericho fault. Thus, detailed hydrogeological especially remote sensing and geophysical investigation should be conducted to delineate major water bearing zones, aquifer thickness and aquifer depth in the volcanic and alluvial formation particularly in the northern part of the study area. Key words: Upper Bilate, western escarpment, recharge estimation, aquifer characterization, hydrochemistry, recharge/discharge zone. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/7727 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa Universty | en_US |
| dc.subject | Upper Bilate | en_US |
| dc.subject | Western escarpment | en_US |
| dc.subject | Recharge estimation | en_US |
| dc.subject | Aquifer characterization | en_US |
| dc.subject | Hydrochemistry | en_US |
| dc.subject | Recharge/discharge zone | en_US |
| dc.title | Integrated Hydrogeological Investigation of Upper Bilate River Catchment: South Western Escarpment of Main Ethiopian Rift | en_US |
| dc.type | Thesis | en_US |