CHAPTER ONE: INTRODUCTION1.1 Background Mogadishuis the capital city of Somalia, so it is based on all the institutions of theFederal Government of Somalia, foreign embassies, UN agencies, NGOs as well asthe main business in Somalia. That has resulted in the city’s crowd of otherresidents of the city who have been looking for a better life in Mogadishu. Ithas caused the city’s population to grow.
The rapid urbanization of the cityleads to increased use of water. It is therefore important that specialconsideration is given to the city’s drinking water, so that their quality andquantity will be improved.Since the centralgovernment collapsed there was a gab in knowledge of Groundwater quality and aswell as characteristics of the aquifer the bearing layer of groundwater.Therefore, this study will try to address the existing borehole water qualitiesin Mogadishu city, also it will reflect knowledge of hydraulic properties inthe area in order to be aware the magnitude of water that can be relied on thelong term in future. This study should be asset to the Somali people as awhole, especially those in Benadir region. Thewater used in Mogadishu is borehole water which is similar to all parts of thecountry where the boreholes are the most sources of water.
The disturbance thatthe water users of Mogadishu residents fear is the water quality. This isbecause most of the boreholes situated over a local area in the city, and thecity spread across borehole areas. That can lead the contaminants to transportinto the aquifer layers and get in touch with the bearing water layers underthe ground, thus the water contaminated. This study aims to find out about the quality of water used in terms ofphysical and parameters as well as the properties of aquifer. I thought that mystudy becomes one of the first studies on evaluation of water quality andaquifer characteristics since the collapse of the central government in Somaliain 1991, especially in the city of Mogadishu and it will add significantimprovement to the knowledge of borehole water qualities and the aquifercharacteristics.
Thisstudy will focus on ensuring the quality of water in the Yaqshid district ofBanadir region, Mogadishu. We will also explore the lower floors of the waterusing the VES method. Therefore, we will enable to do numerical analysis of thehydraulic properties of the aquifer. 1.3.
0 Objectives1.3.1 Overall objectivesThe overallobjective of this study is to evaluate the existing borehole water qualitiesand Aquifer characteristics of hydraulic properties using Vertical ElectricalSounding “VES” Instruments. 1.3.2 Specific objectivesThespecific objectives of my research will be To establish the aquifer parameters for Mogadishu area groundwater. To determine the nature and extent of contamination of water supply from the boreholes. Establish seasonal variation of the quality of water supplying from the boreholes.
Problem StatementIn 2015 Mogadishu hasexperienced the death of at least 50 people due contaminated water supplied bya borehole in Yaqshid district. Also it affects many families who have beenused this borehole as a supply and many of them had been deployed to thehospitals in Mogadishu.Therefore,Mogadishu has a concern about its water quality and it should be evaluated inorder to check the quality of borehole water. To be clear about this problem, Ihave a report to quote it from CNN Channel in December 11, 2014 and thefollowing is the quoted report: By Omar Nor and Greg Botelho, CNN in December 11, 2014.”At least 50 people have died in Somalia afterdrinking contaminated water from a well in northern Mogadishu, an official inthat East African Country said Thursday.
The deputy commissioner for Yaqshiid district, toldCNN about the deaths among those who drank from the newly constructed well.More than 150 people who had water from that well were recently hospitalized.” Therefore, fromhere it is clear that the borehole water contaminations exists in Mogadishu andneed to take action in order propose the level of quality we have andappropriate needs again to raise water quality in the city.This study intendsto evaluate the physical and chemical parameters in order to check the qualityof borehole water in Mogadishu, and to propose appropriate solution to solvethe identified problem. The population growth of thecity and rising water consumption makes it an important step in assessing thequality and quantity of borehole wells. Therefore, the study will concentrateon discovering the quality aspects in terms of physical and chemical parametersand hydraulic properties of the aquifer zone. CHAPTER TWO LITERATUREREVIEW 2.1 Water Distribution on Earth Groundwater Importance and distribution of water onthe EarthAs we know, most ofthe earth has been covered by water.
An over 75% of the earth’s surface iscovered by water. The oceans constitute the majority of that which is not fitfor human consumption. The fresh water mostly is protected up in the icecapsand glaciers. The freshwater onthe earth’s surface which is fit for the human consumption is less than 1% ofthe total water in the world. (1)The distribution ofthe world’s water is presented in Table 1-1: Salt water in oceans: 97.2% Ice caps & glaciers: 2.
14% Groundwater: 0.61% Soil moisture: 0.005% Atmosphere: 0.001% Fresh surface water: 0.
0009% Table 1-1. The distribution of the world’s water GroundwaterImportance in the study areaGroundwater, whichis in aquifers below the surface of the earth, is one of the most importantnatural resources of all Somalia’s regions including Mogadishu as domesticwater supply, livestock and small scale irrigations. That means, apart from theareas along the Juba and Shabelle rivers, all other regions depend ongroundwater for their water uses.2.1.2 Groundwater Occurrence / Hydrologic cycle and Groundwater According to the Freeze and Cherry (1979),groundwater is defined as the subsurface water that occurs beneath the watertable and flows though geological formations of voids in the soils andpermeable layers that are fully saturated. It is valuable supporter of generalecosystem and does not exist in isolation but it is part of main factors in thehydrological cycle as shown in the figure 2.
1 below. (2)The water cycle isthe continuous dynamic cycle of water circulation from the earth’s surfacebecause of evopotranspiration and to the atmosphere and vice versa. Thiscirculation of water is known as the hydrologic cycle.As a definition ofhydrologic cycleThe hydrologiccycle is the process by which the water is circulated from the earth’s surfacesto the atmosphere through evaporation and transpiration and back again to thesurface through precipitation. (1)There are manyprocesses that involve the formation of hydrologic cycle, the most importantones include: evaporation, transpiration, condensation, precipitation andrunoff.Although theperimeter circulation cycle is consistently stable, the distribution ofdifferent systems is constantly changing.The sun is playing major role in hydrologicalcycle systems. The sun takes water from stored water in different storagesystems (in the oceans, lakes and rivers etc) and transferred it through theatmosphere.
The water back again to the earth’s surfaces such oceans throughdifferent routes. The rainfall component on the earth’s surfaces infiltratesinto the soil with remainder evaporating into the atmosphere or as runoff torivers. Soil moisture can both be taking up by plants and transpired or flowquickly as inter flow to a river channel. Some of that infiltrated water willgo down deeply into the ground through pores and voids in the permeable layerformations, then it will accumulate on an impermeable beds and make itsaturated and eventually forms what is known as groundwater.
The underground water-bearingformation that is capable of yielding considerable amount of water is referredto as an aquifer. Figure1-3. A generalized and simplified diagram of the hydrologic cycle 2.1.
3 Groundwater flow Large appreciableamounts of water are stored in the subsurface. The moving of groundwaternormally is very slow. As appreciating of water cycle, the water of the groundcomes from precipitations that infiltrates downward from the earth’s surface.
(3) The water that goes below the surface of the earthmay be determined to exist in two main zones or environments classified asVadosa Water and Phreatic water or Groundwater. In Vadosa waterconsists of the upper layers near the earth’s surface which is unsaturated zone,and it is exists in three different types of environment; soil water,intermediate vadose water and capillary water. ¾ The soilwater forms a thin layer confined to the near the surface depth of the earth. Itmay estimate to occur at depth between 1.0 to 9 m and is held up by the rootzone of vegetable cover and it is lost to the atmosphere due to transpirationand evaporation. ¾ The intermediatevadose zone, it occurs emediately after the soil water zone.¾ The capillarywater zone, also called as capillary fringe. This is the zone which in-touchwith the water table, therefore in the fine particles the groundwater is drawnupward by capillary action from the saturated zone lying underneath.
a) Theupper layers near the earth’s surface which is unsaturated zone, and water isavailable in varying amounts that change over time, but does not saturate thesoil.b) Belowthis layer is the saturated zone, where all of the pores and spaces betweenrock particles are saturated with water.(3) This area is used to describe term of groundwater.
The groundwatermovement/flow depends on the geological gradient of that particular area. Ingenerally the water flows to the downward, from higher energy elevation to thelower energy an elevation. As well as the groundwater flow and rate of movementdepends on the aquifer hydraulic properties and permeability. According to (Freeze and Cheery 1979)aquifer is defined as a saturated permeable geological formation unit thatallows passing water through it to yield significant amounts of water underordinary hydraulic gradients. (2) Accordingto (Freeze and Cheery 1979) aquiferis defined as an underground layer of water-bearing permeable geologicformation that can transmit significant amounts of water under ordinaryhydraulic gradients. (2)Types ofaquifers1. Confinedaquifer 2. Unconfinedaquifer 3.
Perchedaquifer Aquiferproperties 1. Porosity2. Transmissivity3. Hydraulicconductivity Hydraulic conductivity is a measure of the material’s ability to allow waterto pass through it. It is defined as the proportionality constant with respectto the specified discharge of a porous method under the hydraulic gradient ofthe unit in Darcy’s law:Where v is specificdischarge L/T, K is hydraulic conductivity L/T2 and iis hydraulic gradientdimensionless.