Page 1 of 15

Journal for Studies in Management and Planning

Available at http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 7

July 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 129

Characterization of Aquifers in Lower Gidabo

Catchment, Southern, Ethiopia

Genet Mathewos Messene1 and Mamuye Tebebal Ejigu2

1Addis Ababa Construction and Housing Development office; Design, Construction and Supervision

core process, Bole Sub-city, Addis Ababa, Ethiopia;

E-mail: genetmathewos7@gmail.com

2Federal Technical and Vocational Education and Training Institute, Department of Research,

Technology Transfer and Industry Linkage, Addis Ababa, Ethiopia;

E-mail: bic.ma12@gmail.com

Abstract

Aquifer characterization is indispensable

for active development and management of

ground and surface water resources. The

important characteristic of groundwater

rectification is the capability to determine

accurate estimation of aquifer hydraulic

characteristics. It is important to deliver a

common intelligences for exchange of

ideas. Yet, groundwater potential study

and aquifer characterization is rarely

conducted in Lower Gidabo catchment.

Topographically, the catchment is undulated

ranging from 1170 m of low flat lands

near Lake Abaya to 3200 m AMSL. In this

study, groundwater prospective of the

catchment was assessed in terms of aquifer

characteristics with hydraulic conductivity,

transmissivity and storativity. The study

targeted to contribute detailed aspect of

aquifer hydraulic properties and

hydrogeological features in the catchment.

Arc GIS 9.3 and Aquifer test programs

were used for the study. Hydraulic

conductivity of the aquifer ranges from

3.5*10-4

to 2.91*10-3m/day. Likewise, the

transmissivity and storativity are ranged

from 1*10-3

to 1.05*10-1 m

2

/min and

8.29*10-5 to 4.11*10-3

respectively. The

major aquifer units of the area are

weathered and fractured basalts. These

types of aquifer formation are recognized

to be good groundwater formations. As per

the result perceived, hydraulic properties

and lithologic formation of an aquifer are

variable throughout the catchment.

Key word: Groundwater potential, Aquifer

Test, Lower Gidabo catchment, Aquifer

characterization; Lithological formation.

1. Introduction

Groundwater is the largest source of fresh

water in the world. In many parts of the

world, especially where surface water

supplies are not available; for domestic,

agricultural and industrial water needs can

be met by using the water beneath the

ground (Kumar, 1997). Many major cities

and small towns in the world depend on

groundwater for water supplies, mainly

because of its abundance, stable quality.

Besides, it is inexpensive to exploit

particularly in scarce surface water supply

area (Morris et al., 2003).

One of the fundamental conditions for the

growth and development of a nation like

Ethiopia is certainly the progressive

fulfillment of its most urgent water needs

(Tamiru, 2006). Ethiopia is known with

good water potential, however quit a small

Page 2 of 15

Journal for Studies in Management and Planning

Available at http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 7

July 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 130

portion of this resource is presently

developed in the rural areas; the limitation

being too high initial development cost.

Previously developed groundwater sources

are used primarily for drinking water

supply, it offers access to safe water for

approximately 40-80 percent of the water

supply provided to the urban population,

and it is the largest fresh water source in

the country. Despite, the high initial cost,

groundwater is increasingly becoming an

important source of drinking water supply

(Getachew, 1998).

The important feature of groundwater

improvement is the capability to determine

exact estimations of aquifer hydraulic

characteristics (Paul, 1993). Aquifer

characterization is essential for effective

ground and surface water development and

management (Wittenberg and Sivapalan,

1999). Aquifer characterization is vital to

provide a common considerate for

discussions. It is developing sufficient

understanding of an aquifer or group of

aquifers to support decisions affecting the

groundwater resource. It is imperative for

understanding the major hydrologic

processes and hydrogeological properties

that govern the occurrence, flow and

replenishment of water through and out of

an aquifer. These parameters are estimated

through pumping tests carried out on water

wells. The hydraulic properties estimated

with the aid of aquifer test for the well

field design phase to clear the most

efficient design (Layen, 2014). Hydraulic

properties of an aquifer can be determined

by conducting aquifer tests and measuring

the specific capacities of wells (Lucy,

2013). In some illustrations, groundwater

monitoring wells may not be present onsite

to conduct pumping or slug tests. In these

situations, it is acceptable to obtain an

estimate of the aquifer properties based on

engineering and geological material

descriptions as well as from correlations

between these descriptions and some

commonly measured soil properties.

The area under the study comprises parts

of Lower Gidabo River catchment in

Sidama and Gedeo Zones. Water is basic

for socio-economic development of the

people whose income is primarily

dependent on agriculture. However, due to

drought, poor water supply and sanitation

services; several socio-economic activities

are reduced. Similarly, most of the

residents living in the area are rural people

whose livelihood is mainly dependent on

agriculture with poor water supply and

sanitation services. Large part of the

catchment is suitable for agricultural

activities and settlement. Nevertheless; it

is affected by flooding, erosion and

sedimentation problems. With rising

population growth in the catchment, the

consumption of water supply is advanced,

which rely on the sources of ground and

surface water to meet the demands of

water supply. Further, the fast growing of

industry and residential needs extra water

mainly in dry season. Accordingly, the

stockholders are concerned in the

development of groundwater supply

projects. Thus, a better understanding of

the hydraulic properties of an aquifer is

vital for groundwater development. The

gap of understanding aquifer characteristic

and hydro-lithological formations are the

factors in developing groundwater supply

projects. Therefore, assessment of aquifer

characteristics in the catchment is a main

approach for improving the use of

groundwater resource. The study was

Page 3 of 15

Journal for Studies in Management and Planning

Available at http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 7

July 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 131

conducted on aquifer characterization in

Lower Gidabo catchment. It was addressed

to understand the characteristics and types

of aquifer formation in the catchment. This

study provides vital information about the

aquifer, which is ready to lend a hand in

the possible development and management

of water resource in the catchment.

2. Materials and Methods

2.1 Description of the study area

The study was carried out in Lower

Gidabo catchment, Abaya Chamo Sub- basin, SNNPR, Ethiopia. It is located

between 6°39’N to 6°12’N and 38°14’E to

38°21’E covering an area about 1047.5

km2

. The altitude of the catchment ranges

from 1170 to 3200 m AMSL. Lower

Gidabo catchment contains 38 sub-basins

which includes some tributaries that

contribute to the Gidabo River. The study

area lies in six Woredas which are found

in Sidama and Gedeo zones viz. Aleta

Wendo, Aleta Cuko, Wenago, Dilla, Dara,

and Bule woredas. The climate ranges

from Woina Dega to Dega, it is generally

characterized by subtropical Woina Dega

on the rift floor and temperate to humid

Dega climatic zones on the escarpment

and adjacent highlands. The mean annual

rainfall and temperature is 1,100 mm and

20°C respectively. The slope of the

catchment rages from 0 to 91 percent. The

catchment area is covered by 73.3% of

intensively cultivated land, 9.5%

moderately cultivated land, 14% shrub

land, 1.7% marsh land and 0.16% forest.

Legend

$+ Town

Catchment

Figure: 1 Location map of Lower Gidabo catchment

Legend

$+ Town

Catchment