MODELING MEGECH WATERSHED AQUIFER VULNERABILITY TO POLLUTION USING  MODIFIED DRASTIC MODEL FOR SUSTAINABLE GROUNDWATER MANAGEMENT,  NORTHWESTERN ETHIOPIA

DANIEL, ASFAW

dc.contributor.author	DANIEL, ASFAW
dc.date.accessioned	2020-09-08T11:16:53Z
dc.date.available	2020-09-08T11:16:53Z
dc.date.issued	2020-09-07
dc.identifier.uri	http://hdl.handle.net/123456789/11193
dc.description.abstract	1 ABSTRACT Ensuring access to improved sources of water and safe drinking water for all has been the Nation’s concern which is one of the 17 th UN Sustainable Goals set to be achieved by 2030. Groundwater is one of the valuable sources of freshwater. However, groundwater resources, especially in shallow aquifers, are susceptible to contamination. With this respect, the quality of groundwater in the study watershed has deteriorated due to industrial effluents and domestic wastes of Gondar city and small towns, and extensive use of fertilizer for agriculture purpose. Once the groundwater gets polluted, treatment is very difficult and expensive. Therefore, the most effective and realistic solution is to protect groundwater from contamination. Assessing the level of groundwater vulnerability level is crucial for effective groundwater management. With this in mind, the aim of this study is to assess the aquifer vulnerability of Megech watershed to pollution using modified DRASTIC model. The modified DRASTIC model uses eight attributes including, depth to aquifer, net recharge, aquifer media, soil media, topography, impact of vadose zone, land use land cover, and hydraulic conductivity of the aquifer. These thematic layers were integrated using Raster calculator tool in a GIS environment in order to identify and map the spatial distribution of hotspot areas. Fifteen composite groundwater samples were also collected and analyzed for selected water quality parameters to validate the model. Single parameter and map removal sensitivity analysis methods are used to identity significant parameters. The result of vulnerability analysis reveals that more than 85% of the groundwater of the study watershed is under medium to high vulnerability to water pollution. Aquifers highly vulnerable to pollution (5.74%) are mainly found in urban areas while the majority of the aquifers (80.34%) which are moderately vulnerable are dominantly found in cultivated lands. Spatially the highly vulnerable or hotspot areas of the aquifer confined in the central (Gonder city) and northeastern (Wegera and Gonder Zuria woreda) and southwestern (Dembia woreda) parts of the watershed. In the highly vulnerable part of the aquifer, the concentration of (NO 3 ) (17 mg/l) and total coliform (Tcf) (21cfu/100ml) in groundwater exceeded WHO permissible limit. The vulnerability map of the watershed heavily influenced by net recharge (R), land use land cover (Lu), and aquifer media (A). GIS application of the DRASTIC model and integrating Lu in the model was found to be a suitable method for analyzing the groundwater vulnerability in a watershed like Megech. Effective management of groundwater resources has now become a critical issue. Thus, the study will be helpful in proper management and development of available groundwater resources in the study watershed. Keywords: Modified DRASTIC model, Groundwater, Sustainable management, Megech watershed	en_US
dc.language.iso	en_US	en_US
dc.subject	GEOGRAPHY AND ENVIRONMENTAL STUDIES	en_US
dc.title	MODELING MEGECH WATERSHED AQUIFER VULNERABILITY TO POLLUTION USING MODIFIED DRASTIC MODEL FOR SUSTAINABLE GROUNDWATER MANAGEMENT, NORTHWESTERN ETHIOPIA	en_US
dc.type	Thesis	en_US