USAID ETHIOPIA...Verification and Findings of Each Project area 2.1.Gult 2.1.1. Location Gult is located in Amhara National Regional State in south Gonder Andabet Woreda. Itcan be

Ethiopia Health Infrastructure Program (EHIP)

Health Centers Groundwater Investigation Supplementary Report October 2017

This publication was produced for review by the United States Agency for

International Development. It was prepared by Tetra Tech, Inc.

USAID ETHIOPIA FROM THE AMERICAN PEOPLE HEALTH INFRASTRUCTURE PROGRAM

Supplementary Final Groundwater Investigation Report at Four Health Centers

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Contents

I. Introduction ................................................................................................................................... 3

1.1. Objectives of revisiting of sites ............................................................................................... 4

1.2. Approach and Methodology of the study .............................................................................. 5

1.2.1. Field investigation ............................................................................................................ 5

1.2.2. Desk study........................................................................................................................ 8

Part II. Verification and Findings of Each Project area ...................................................................... 9

2.1. Gult ......................................................................................................................................... 9

2.1.1. Location .......................................................................................................................... 9

2.1.2. Physiographical set up of Gult ....................................................................................... 9

2.1.3. Existing Water Supply ................................................................................................. 10

2.1.4. Geology and Hydrogeology of Gult area...................................................................... 11

2.1.5. Geophysical Survey ...................................................................................................... 16

2.1.6. Environmental aspects for the off-site of Gult health center ...................................... 18

2.1.7. Conclusion and Recommendations .............................................................................. 19

2.2. Maksegnit ............................................................................................................................. 22

2.2.1. Location ........................................................................................................................ 22

2.2.2. Physiographical set up of Maksegnit area. .................................................................. 22

2.2.3. Existing Water Supply .................................................................................................... 23

2.2.4. Geology and Hydrogeology ............................................................................................ 23

2.2.5. Geophysical Investigation............................................................................................. 27


2.3. Gulem Dengin....................................................................................................................... 31

2.3.1. Location ........................................................................................................................ 31

2.3.2. Physiographical set up of Gulem Dengin area ............................................................. 31


2.3.4. Geology and Hydrogeology .......................................................................................... 32



2.4. Gerbicho ............................................................................................................................... 38

2.4.1. Location ........................................................................................................................ 38

2.4.2. Physiographical Set up of Gerbicho ............................................................................. 38


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2.4.4. Geology and Hydrogeolgy ............................................................................................ 39


2.4.6. Conclusion Recommendations ........................................................................................ 42

III. Schematic Design, Delivery system and Power Generating system ........................................ 44

3.1. Schematic Design of Gult extracted from Google Earth .......................................................... 44

3.2. Water Well Design ............................................................................................................... 47

3.3. Proposition of Estimated Bill of Quantity for Boreholes ......................................................... 52

3.4. Propostion of Bill of Quantity for Solar PV and Pipe lines ................................................. 57

List of Figures

Figure 1. Discussion on Field Visit .......................................................................................................... 7Figure 2. Geophysical Investigation ......................................................................................................... 8Figure 3. Get to Gult Health Center ......................................................................................................... 9Figure 4. Hand Dug well site of Gult ..................................................................................................... 11Figure 5. Massive Basalt along the perennial river east of Gult Health Center ....................................... 12Figure 6; Geological map of Gult area. .................................................................................................. 14Figure 7. Hydrogeological Map of Gult area .......................................................................................... 15Figure 8. Gate to Maksegnit Health Center ............................................................................................ 22Figure 9. Geological Map of Maksegnit ................................................................................................. 25Figure 10. Hydrogeological Map of Maksegnit ...................................................................................... 26Figure 11. Get to Gulem Dengin ............................................................................................................ 31Figure 12. Geological Map of Gulem Dengin area ................................................................................. 33Figure 13. Hydrogeological map of Gulem Dengin area......................................................................... 34Figure 14. Geological Map of Gerbicho area.......................................................................................... 39Figure 15. Hydrogeological map of Gerbicho area ................................................................................. 40

List of Tables

Table 1. Geophysical Interpretation Result of Gult area ......................................................................... 17Table 2. Interpretation Result of VES in Maksegnit Health Center ........................................................ 29Table 3. Interpretation result of Gulem Dengin ...................................................................................... 36Table 4. VES interpretation result of Gerbicho ....................................................................................... 42


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I. Introduction

This report is an ancillary study document prepared by Shumet Kebede water Works

Consultant to TETRATECH/USAID, concerned on the possibilities of relocating the sitting of

wells inside the four named health centers compound than the previous proposed sites. The

report deals on Physiographical set up of the area, Geological, Hydrogeological, Water supply

schematic design and recommendations about the revisited four sites.

It is to everybody’s knowledge that the preceding study document has proposed the water supply

options of the 17 health centers constructed by USAID in Amhara National Regional State and

SNNPRS regions. As has been portrayed in the technical details of the previous Technical

Report, the scheme type proposed for most of the health centers is drilling of shallow to medium

depth boreholes, in most cases, inside the premises of the health centers. However, in some of

the health center sites, the well sites are located outside the compound of the health centers when

the health center compounds are identified to be poorly responsive to hydro-geological

parameters.

Of these sites, Maksegnit, Gult, and Gulem Denjin health centers in Amhara region and another

site named as Gerbicho in SNNPRS are revisited and studied again to relocate the sites and for

possible drilling options inside the health center compounds with an anticipated minimum daily

water demand of 5M3 per day, which is even less than 0.5 lit/sec.

Except Gult site left unchanged, the rest three well sites are shifted to the health center

compounds with adjustments on the depth of the wells with an anticipated minimum daily

abstraction of 5m3/day, as has been suggested by Tetra Tech/USAID.

The relocation of sites was conducted jointly by staffs from Tetra Tech and the consultant,

shumet kebede water works. The team members for the revision of the sitting of wells are: Mr.

Tom Keefe and Mr. Samson Kifle from Tetra Tech and Mr. Shumet Kebede and Mr. Nuru

Mohammed (Hydrogeologist and Geophysicist) from the consultant.


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The first round site visit was conducted from September 3, 2017 to September 7, 2017 in

Maksegnit, Gult, and Gulem Denjin health centers in Amhara National Regional State whilst the

second round was performed from September 13, 2017 to September 15, 2017 in Gerbicho site

in South Nation Nationality Peoples Regional State, after celebration of the New Year Ethiopian.

The field site was done separately from the consultant team to respect conveniences.

The Report consist of mainly three parts

Objectives of the present study, Approach and Methodology of the study for all sites

Verifications and Findings for each Investigated site

Schematic Design, Delivery system and Power Generating system

1.1. Objectives of revisiting of sites

The principal objective of the study was:-

The objective of this contract is to identify borehole sites and provide schematic design

for the most feasible and cost-effective means of supplying water to the four health

centers.

The specific objectives includes (but not limited to):

Verification of previously studied sites and Groundwater assessment

To identify and propose appropriate scheme types and sitting of wells

Proposition of schematic design for off-site sources

Preliminary Recommendation of Pumping system

Preliminary Engineering estimates of drilling cost and construction cost

• • • • •


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1.2. Approach and Methodology of the study The methodologies adopted and applied in the project areas are widely accepted standards and

definitely improves the success rates significantly. The work at this stage consists of: Field Visits

and Desk Study. The Field Visit was the first approch performed for these four Health Centers,

for the reason that most of the works has be done by the same consultant. However, the previous

report was revised thoroughly.

1.2.1. Field investigationThe field investigation works were conducted from September 3 to September 7, 2017, in three

Health Centers, namely, Gult, Maksgnit and Gulen Dendin in Amhara National Regional State.

And then the second field visits performed from September 13 to September 15, 2017 at

Gerbicho Health Center in South Nation Nationality Peoples Regional State. The field works was

interesting that have been supported by a detail all rounded professional discussion and have

attained mutual understanding of the groundwater conditions at all revisited sites.

The major activities covered by the field work include:

Reaching to the project areas and visit previously selected borehole and spring sites

Brief explanation on the previously selected sites in terms of Physiographical, Geological

and Hydrogeological viability.

Transect walk in conformity along the inferred geological structures and drilled

boreholes, considering the remote sensing data interpretations and other relevant

documents analyzed at the first task.

Detailed assessment of structural and Geological setup of target areas and their relation

with Geological structures and Hydro-geological importance.

Evaluation of recharge and discharge conditions /catchment area and hydrometeorology/,

Evaluation of available drilled boreholes.

Geophysical investigations in the compound of Health Centers for feasible

Hydrogeological condtions and outside for non-feasible hydrogeological areas in the

compound of Health Centers

Discussion with relevant professionals and project coordinators

Selection of Borehole site based on the overall investigation and detail discussion with

the team.


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Collection of water samples and conduct in situ measurements

The most important equipments used include.

Earth Resistivity Meter (PASI, Brand New digital resistivity meter made in Italy)

pH and TDS meter

EC meter

Lap top computer

High resolution GPS (The UTM coordinates, i.e. Easting and Northing, obtained with the

help of a GARMIN II GPS receiver in Adindan datum and then transferred to WGS Datum)

Thematic Mapper satellite images and DEM(Digital Elevation Model 30X30m

resolution)

Digital Topographic Maps(1:50000) and Hydro-geological map of Ethiopia (1:50000)


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Figure 1. Discussion on Field Visit


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Figure 2. Geophysical Investigation

1.2.2. Desk study

Water Resources investigation at this phase started through examining the previous Groundwater

Investigation report. And then after field visits detail interpretation made Usage of Shuttle Radar

Terrain Mission (SRTM) data generating for Digital Elevation Model (DEM) with 30 * 30

meters resolution and identify regional structures and drainage patterns. After detail discussion

with Tetra Tech higher Experts and His Excellencies Mr. Tim Michael, water delivery rout

suggested. Finally this Technical Draft Report produced.


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Part II. Verification and Findings of Each Project area

2.1. Gult

2.1.1. Location

Gult is located in Amhara National Regional State in south Gonder Andabet Woreda. It can be

reached to the site through Jara Gedo Town, Which is third grade asphalt road to Jara Gedo town

and then 10 km to west through all weathered gravel road and 6 Kilometres along only dry

weathered road. The health centre is under construction and close to the final stage.

Figure 3. Get to Gult Health Center

2.1.2. Physiographical set up of Gult

Physiography is the physical characteristics of an area, which includes Topography, Drainage,

Vegetation cover, Soil type etc. The study of Physiographic features and identification of

geological structures and drainage patterns is done by interpretation of Enhanced Thematic

Mapper satellite images at a resolution of 30*30 meters. In order to confirm the observed SRTM

observation has been confirmed by Geo traverse.

Gult, is part of the North-western Highlands of Ethiopia, aligned in Guna mountains catchment

GULT HEALTH CENTER ,.,.......,_,,_.,,.,._., .......... _., -... ....... USAIDo,_...._ ... .,_..,,ltt,yo,-

7-A-), /..'i "NI.,

.&u 111.'S' "IA.,r l.\14Sta .... I: :,f: '11-t,tt ,-,,- • • t: +1-t:A .2-CJ!+ lr""f fl'I_,. -..u .. c :,c 1•• 41C +lltit•


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which has a peak altitude of 4120masl. The Health Center is located at a local water divide,

where either side is drained by intermittent streams. The intermittent stream has base flow for not

more than a month after the offset of the rainy season. The streams emerge at the foot of water

dividing hills fed by small catchment areas and generally drain to the Blue Nile basin located a

few kilometers away from Gult Village.

The area receives precipitation from its uni-modal rainfall pattern annually from June to

September. Gult is classified as humid sub tropical / weina Dega / based on the Ethiopian Agro-

climatic zoning. The mean annual temperature is 14-18 0C and the mean annual rainfall is 1000-

1200mm annually

Development of soil is very poor in the area; the thickness varies very few centimeters close to

the hill and very few meters downstream of the village. The prominent soil type is reddish

brown. The vegetations covet also poor except along the river.

2.1.3. Existing Water Supply

For village water supply the peoples are getting water from Excavated hand dug well. There are

three hand dug wells excavated along the Perennial River close to each other, however one of

them is not functional. Location of the hand dug well has a walking distance of 10 to 15 minutes,

therefore most of the community are getting water from unprotected perennial river, during wet

seasons peoples are preferring to fetch water from small seepages emanating at the banks of river

and stream to minimize their walking distance.

In order to supply potable and clean water the Regional Water Well Drilling Enterprise, which is

a governmental owned enterprise drilled two shallow wells along the perennial and seasonal

stream, but the wells are dry and abounded. The study team has evaluated positions of drilled

wells and has got locations of pinpointed sites has been found wrongly sited. Details are

elaborated in Geological and Hydrogeological part of this report.


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Figure 4. Hand Dug well site of Gult

2.1.4. Geology and Hydrogeology of Gult area

The regional Geological and Hydrogeological set up of the area is explained in the previous

study document. Hence, this report deals mainly on the local Geology and Hydrogeology of the

study area. The study team made geo traverse to understand the local geology along rock

exposures, seasonal streams and perennial rivers, besides its map based studies.

The rock exposure along the seasonal stream exhibits colluvial deposits and aphyric compact

basalt that covers the whole river bed extending to the cliff. See Fig 5, below


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Figure 5. Massive Basalt along the perennial river east of Gult Health Center

As it can be observed in the above picture, the exposed rock along the seasonal river bank is

massive and doesn’t exhibit cracks and fractures that can facilitate groundwater percolation. The

geological feature along the stream is characterized by massive alkaline to transitional basalt and

comprising small catchment area close to the hill.

Gult village is located on a hilltop and a local water divide bounded by two opposite lying

hanging valleys to the north and the south of the health center.

The south lying valley starts at the foot of the nearby hill and covers small catchment area. The

area is highly degraded and the intermittent stream is flowing over the basaltic layers (as shown

in the above figure). The rock units exposed on this part of the valley are fresh and massive in

nature. The joint density of the basaltic rock is minimal that favors runoff than infiltration of

water. Besides to these the poor hydrogeological situation of the area has been proven by the

well drilled in the area at a position of37P + 373434E and 1257252N along this stream, which

was drilled by Amhara water well drilling Enterprise to a depth of 60 m was dry. The study team


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surveyed the abandoned well site and has understood the site is wrongly selected without detail

and scientific step by step methodological procedures.

Hence, this part of the catchment is concluded as not feasible for drilling of wells from

Hydrogeological point of view.

The other side of the village, the North West catchment, drained by a perennial river with little

base flow, is characterized by massive alkaline to transitional basalt as exposed along the stream

bed. The recharge area stretches Far East and north of the village to the regional water divide

stretching N-S. The relatively elongated catchment area, presence of fractures and cracks,

exposed phonolites, volcanic extrusive plug prevails damming effect of surface and groundwater,

Presence of weak zones, river water forming an ox bow type structures, and presence of

productive hand dug wells are indicative parameters to consider the area as promising

hydrogeological site for drilling.

The Regional Water Well Drilling Enterprise also drilled a well to a depth of 70m on the

extrusive plug type structure but dry and abandoned. Similarly, there was mis-location of the

drilling site. It could have been out of censure, if it was drilled up stream of the plug type

structure.

For better justification further Geophysical investigation performed to confirm the presence of

groundwater and depth of abstraction, Geophysical study analysis verified in section 2.1.5.

The newly selected site is pinpointed upstream of the northern bridge at a position of 37P

373042E and 1257964N at an Elevation of 2344 m.a.s.l.


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Figure 6; Geological map of Gult area.

L..egend

• Loc,ation of' study area

Faul

- Road

River

Town

C+~ Gult new BH location

,0 2-5 5

·- -Geology

Tertiary

15 20 Kilometers


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Figure 7. Hydrogeological Map of Gult area

Legend O 2 4 8 12 1,a

Kilometers

• Loe tlon of udy r -Fault - Rod Ttiwn

Geology Tertiiary

PNlb T m b ,ousse) Form t1 on alkalln to transit! nal basalts oft n form in~ sh, Id vol.c no s w,u, mmor trachyte and p onolites plugs

r2s A,hllngi torrn~llon: Alkaline end trans~ ion,0,1 basaltic flows with rare I nlerc.a1 ation s. o nu ff

Gult new BH location

Hydrog1eolog1ical classification

Fractun~d aquifers with moderate productivity

Fraclures aqui1fers witli law to moderate producUvity


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2.1.5. Geophysical Survey

The geophysical Survey was conducted along the perennial river at a relatively flat land. The

maximum electrode spacing was AB = 440m.

The VES survey result revealed seven contrasting resistivity layers, the first layer shows reddish

brown soil cover, underneath of the first layer weathered intermediate basalt, with a resistivity

value of 3.5 ohm-m with thin thickness is characterized by highly weathered basalt and

transported colluvial deposits. The low resistivity value at this depth is the influence of the river.

The third layer is attributed to weathered and fractured basalt with a resistivity value of 18 ohm-

m with a thickness of 7.3m is characterized by weathered and fractured basalt with water bearing

formation. The fourth layer is attributed to massive basalt with a value of 256 ohm-m with a thin

layer then follows relatively low resistivity value 15.6 and 9.08 ohm-m with a thickness of 7 and

161m, respectively are characterized by fractured and weathered basalt and/or trachy basalt. The

layers are prevailing semi-aquifer property. The last layer is characterized by massive basalt

and/or trachy basalt. Based on the geophysical data signature the site is feasible for drilling of

wells to a depth of 180m.

100: ' ' ' ' ' Pa ' ' ' ' ' ' ' ' ' ' ' ' ' 0 ' ' -- ----~ ------~ ---- ' ' ' -- ··r·-----

"" ---- ,-------,-----' ' ' t ' ' ' ' ' ' ' ' ' ' ' ' ___ --:· <-' ' v ____ ' ' ' ' ' ' ' ' ' ' -----~------~---- ,~ .. _______ , _____

' ' ' ' ~ - ' ' ' ' ' ' ' '

0 ' ' ' ' ' ' ' - ' ' ' - ' ' ' ' ' ' - ···r······ ----- ----- ------ ---- ~-------,-----

' ' ' - ' ' ' ' ' ' - ' ' ' ' ' ' ' ' ' ' ' -----~------J----- ••••• L •••••• ~ ••••• - - - - - J. - - - - - - _,_ - - - -

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' AB/2 1 ' ' ' ' ' ' ' ' ' ' ' ' 1 10 100 1000


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Layers

Resistivity

(Ohm m.)

Thickness (m) Depth (m)

Probable formations (interpretation)

Remarks

1 12 0.8 0.8 Reddish brown soil

2 3.51 0.6 1.4 Weathered intermediate basalt

3 17.9 7.3 8.7 Highly Weathered basalt with colluvial deposit

4 256 5.2 14 Massive basalt

5 15.6 7 21 Weathered and fractured Basalt and/or trachy basalt

6 9.08 161 182 Weathered and fractured Basalt and/or trachy basalt

Water Bearing formation

7 213 substratum infinity Massive basalt and/or trachy basalt

Table 1. Geophysical Interpretation Result of Gult area

N p h d Alt 1 12 I 0. 775 I 0. 775 -0. 77 ~ 2 3.51 0.587 1.36 -1.36: 3 17.9 7.33 8.69 -8.69: 4 256 5.23 13.9 -13.9: 5 15.6 7.05 21 -20.91

6 9.08 161 182 -182. 7 213


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2.1.6. Environmental aspects for the off-site of Gult health center

Literally, the environmental impacts that could arise in the course of implementing such projects

are of two types; pre-operation and post-operation impacts. It is very important to forward some

remarks regarding environmental aspects of the water well drilling and water pumping from the

safe guard of the environment and as well as for sustainable and environmental friendly use of

the well.

There are no hazardous industrial wastes and practice of mechanized farming in the area that are

potential sources of risky contaminants. The excepted groundwater pollution is from bacterial

contamination from human and animal wastes as a result of poor hygienic and sanitary practice

from the upper catchments driven by the stream water. However, these are the most common

type of contamination to be managed by grouting the upper portion of the well section and

continuous chlorination of the well and storage tanks as well.

Drilling by its nature is less destructive, and has less disturbance of physical environments,

displacement of households etc. In the pre-operational/drilling/ phase, the project has less and/no

adverse effect on the environment, since the project needs a few square meters of area, and

displaces few volume of sub-surface soil and rock to the surface. Moreover, the drilling method

uses clay, foam and air that have negligible negative impacts on the surrounding areas.

Moreover, water to be pumped out from volcanic terrains has suitable chemistry for domestic,

agricultural, and industrial uses. No salt or toxic substance pumping is expected from such wells.

The daily water abstraction anticipated from this well is less that has negligible effect on ground

water table depletion and associated land subsidence.

In order to control to pollutants, preventive measures has to be taken during water well drilling.

The following and other appropriate measures should be taken to avoid any contamination of the

aquifer.

Appropriate cleaning and disinfection of the well has to be done after borehole

construction with recommended chemicals.

Pumping of the well should be as per the recommended safe yield and over pumping

should be avoided.


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The well has to be protected with sanitary/surface casing grouting, well head to seal

runoff and waste water percolating into the well.

Water quality has to be checked before use checking the compatibility

Periodic Water quality Monitoring has to be done for safety issues.

2.1.7. Conclusion and Recommendations

The main goal of the study is to verify the sites proposed in the preceding phase of the study

located in and out of the center, and propose best suited sitting of the well so that safe and

adequate water is abstracted for the Health Center. So as to achieve the goal, maximum effort

and different disciplines were incorporated one after the other. After a thorough investigation and

discussion with the team, the only possibility for Gult Health Center is drilling of a deep well

off-the compound about 780m North West of the Health Center along the perennial river.

As has been depicted in the geological part of the document, Gult Health Center is located on a

steep local water divide drained outward to the south and north, small catchment area, exposures

of fresh and massive basaltic units associated with very poor fractures and cracks network

favoring runoff rather than infiltration, moreover the dry and abounded well at the vicinity of the

Health Center obliged the team to look after outsides of the compound.

The North West catchment which is taken as promising hydrogeological area is comprising

elongated catchment area, presence of fractures and cracks, exposed phonolites, volcanic

extrusive plug prevails damming effect of surface and groundwater, Presence of weak zones,

river water forming an ox bow type structures, presence of productive hand dug wells and

geophysical signature are indicative parameters to consider the area is promising

hydrogeological site for drilling.

Land ownership in the Ethiopian context is public owned. There is only lease right for small

holder farmers. Thus, when a physical project for community use lies or passes on a land where

its lease right has been occupied, the local administration will arrange modalities for the project

owner for compensation of live crops, houses or plantation and loss of advantages for few years

time. Land is to be made available for project implementers after settling the above few issues.


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In the case of Gult well site, the identified well site lies on communal grazing land owned by the

local administration and the pipe line route follows an existing foot track for about 500m length

of the route. The rest route passes on barren land. Hence, compensation of crops and structures is

avoided to the minimum and/or negligible.

Analysis of geological, Hydrogeological and Geophysical investigation should be completed by

pinpointing abstraction point. Before going directly pin point sitting physical parameters that

help for sitting was assessed. Accordingly Position of the well is pinpointed at 37P 373042E and

1257964N at an Elevation of 2344 m.a.s.l. upstream of extrusive plug type structure (near the

northern bridge) which prevails a damming effect. The site is selected at a common graze land of

the localities. Hence, there will be no any conflict with the intended project.

Water samples from nearby areas in this area are classified dominantly as Na-HCO3 and Ca-Mg-

HCO3 type; whereas few springs show mixed type water with SO4 and Cl. Sodium and Calcium

are the dominant cations followed by magnesium. The water type is classified as suitable for

human consumption, industrial and agricultural uses.

The following points was considered for sitting

Topography of the area with in the area of interest.

The geological/structural set up of the area.

The closeness of the site to the compound.

Pipe lay out path that couldn’t create conflict with private land owners.

Project cost through avoiding anchorage construction and other civil works.

Reducing collapse problems during drilling

Considered Hydro power Electrical Transmission Line, which is under construction (for

future use)

Risks to Groundwater pollution.

The study has been concluded on the following conclusions and recommendations.

A hydrogeological setting of the project area is site specific and comprises relatively

favorable area for ground water storage and utilization.

The annual amount of rainfall is enough to replenish the exploited ground water or the

out flow from the basin.


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The Water Chemistry is under the range of WHO and Ethiopian standared as taken

before.

Ground water utilization is promising from borehole with an average yield of 2-4 l/s

and anticipated drilling depth is 180m of depth.

Type of drilling method is predominantly DTH ROTARY with bit diameter of 9 7/8”

(Bit dia = 9 7/8”) and surface casing diameter should 12 inch and thus drilling for surface

casings should be carried out by 14 inch drilling bit.

Steel Blind and Perforated or Screen Casing should have an outer diameter of 6 5/6’.

The well site has to be fenced and guarded by metal poles and wire mesh of 25m2 for

security purposes.


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2.2. Maksegnit

2.2.1. Location

Maksegnit is located in Amhara National Regional State in south Gonder Merab Este Woreda. It

can be reached to the site through Jara Gedo Town, which is third grade asphalt road to Jara

Gedo Town and then 17 km to North through the only dry weathered road. The health centre is

under construction and close to the final stage.

Figure 8. Gate to Maksegnit Health Center

2.2.2. Physiographical set up of Maksegnit area.

The study of Physiographic features and identification of geological structures and drainage

patterns is done by interpretation of Enhanced Thematic Mapper satellite images at a resolution

of 30*30 meters. In order to confirm the observed SRTM detail investigation has been made by

Geo traverse.

Maksegnit, like its neighboring Gult site is physiographically located in the North-western

Highlands of Ethiopia, inside the main sub basin of Guna mountains catchment that rolls from


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Guna mountain peak down the Blue Nile Gorge. The area is drained by two major streams

surrounding the village on both sides before they merge as one to form the water fall south of the

village.

The village is located on hilltop overlooking the Blue Nile gorge southward. Two major streams

form the confluence on aphanaitic basaltic flows NE of the village where the previous borehole

site was located. These streams are draining extensive valleys from Jara gedo area to the main

Blue Nile River. The Health Center is located at a local water divide on a relatively elevated

ground aggravating run off than percolation.

Development of soil is very poor in the area; the thickness varies from very few centimeters to

very few meters downstream of the village. The prominent soil type is reddish brown clay soil.

The vegetation cover is also poor except along the stream embankments.

The area receives precipitation from its uni-modal rainfall pattern annually from June to

September. Maksegnit is classified as humid sub tropical / weina Dega / based on the Ethiopian

Agro-climatic zoning. The mean annual temperature is 14-18 0C and the mean annual rainfall is

1000-1200mm annually

Development of soil is very poor in the area; the thickness varies very few centimeters at the

Health center, and its thickness increases towards the perennial elongated river catchments. The

prominent soil type is reddish brown. The vegetations covet also poor very poor.


The villagers usually fetch water from unprotected intermittent springs at the foot of hills and

mostly from Zeray stream located NE of the village, about 1km away, accessed through a

moderately steep slope and winding foot tracks. The sources are usually contaminated with

bacteria and worms where water borne diseases are prevalent in the area

2.2.4. Geology and Hydrogeology

The terrain is an igneous volcanic terrain composed of the trap series. The village area and its

vicinity are composed of thin layer of residual soil underlain by tertiary volcanic rocks. It is

dissected, rugged topography over the Blue Nile River catchment.


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Transect walk made with team members to evaluate significance hydrogeological importance of

the outcrop rock characteristics across and along the slop towards elongated river catchments.

The exposures are characterized by massive alkaline to transitional basalt with minor cracks and

fractures. The seepages emanating at the foot of water divide and direct precipitation doesn’t

have significant role for groundwater percolation. Hence, an intermediate and deep aquifer

groundwater storage and movement expected at a distance rather than direct precipitation.

The local aquifer systems can support low yielding boreholes if drilled around. The area is

characterized by Moderate to low volcanic aquifer systems. Based on the desk and field survey

results, Maksegnit area is classified as Low groundwater potential area because of its geologic

makeup and geomorphology. Considering small amount of water demand of the Health center it

is possible to abstract groundwater at a depth. To determine the depth and confirm presence of

water geophysical survey made inside the compound.


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Figure 9. Geological Map of Maksegnit

0 2.5 5i --• loca ~on o s dy area Geology

- , aul Tertiary

- Roa

River

C•~ Maksegnit new BH location

0 15 20 Kilometers


26

Figure 10. Hydrogeological Map of Maksegnit

3700)0 l75000

Legend 0 2 4 8

4IIOOOCI

16 Kilometers

• Location of study area _ Fault _ Road Riv r .~ Town

Geology Tertiiary

IT]

. . -

PNlb T mab CGtJSS ) Fonnetl on, elkalln to transit! nel basalts oft n form inf.I sh1 Id vol<:ano s w1lh minor trachyte end phonoll tes plugs

r2a Ashongl form8Uon Alkalme end transitional bssalbc nows with rare interca1ation!i o f tuff

Maksegnit new BH location

Hydirog eolog ical c lassificatlon

Fractured aquif rs with moderate productivit y

Fraclures aqui.fers with km to moderate productivity


27

2.2.5. Geophysical Investigation

The Geophysical Survey was conducted in the compound of Maksegnit Health Center. The

maximum electrode spacing was AB = 1000m.

The VES survey result revealed ten contrasting resistivity layers, the first layer shows dry

reddish brown soil cover characterized by a resistivity value of 745m with a thickness of 0.5m,

and then follows a thin wet zone with a resistivity value of 22 ohm-m with a thickness of 0.5m is

attributed to wet soil. The third layer is massive basalt with a resistivity value of 210ohm-m

having a thickness of 2 meter. Following to this a thin weathered basalt with a resistivity value of

15.7 ohm-m is interpreted. Massive layer with resistivity value of 322 ohm-m interpreted over

the six and seventh layer, these layers are considered to be a shallow water bearing horizons with

a value of 40 and 67 Ohm-m, their thickness is about 10m. Hence, from a shallow aquifer at a

depth of 20 to 25m groundwater can be extracted. The Eighth and the Ninth resistivity layers are

characterized by high resistivity value comprising 237 and 162 ohm-m with a thickness of 266m,

which is thick and aquiclude horizon are attributed to massive basalt. The substratum is

characterized by moderately weathered and fractured basalt and/or trachy basalt interpreted as a

water bearing horizon with small amount of water.

Based on the geophysical data signature the well can be drilled in the compound of Maksegnit

Health Center to a depth of 300m.


28

P a I I I

I I I I I I -----~------, ---- - -----r------,- ---- - - - - - T - - - - - - -, - - - - -1 I I I

I

I I

I

.----.---~-'

I I ---- - .--- --- , --

I I I I -----L-- ___ .J __

I

---L I

I I I -r----- -,- ---- -----T -- - - - -,- - - - -

I

I I I I I I

- - - - - L - - - - - - J - - - - - - - - - - J. - - - - - _,_ - - - -I

10 AB/ 2 ~-~~~~~~~-~-~~~~~-~-~~~~

1 10 100 1000

N I e I h d Alt 1 754 0.45 0.45 -0.45(] 2 22.2 0.467 0.917 Lo.91 6

3 210 2.16 3.07 -3.07 4 15.7 4.06 7.14 -7 .1 3 1

5 322 5.84 13 -12.9 6 40 2.56 15.5 -15.5, 7 67.5 7.19 22.7 -22.7 8 237 60.8 83.5 -83.5 9 162 205 289 -289

10 I 16.5 C


29

Layers

Resistivity

(Ohm m.)



Remarks

1 754 0.45 0.45 Reddish brown soil

2 22.2 0.5 0.9 Wet Reddish brown soil

3 210 2.16 3.00 Massive basalt

4 15.7 4.06 7.14 Weathered basalt

5 322 5.84 13 Massive Basalt and/or Massive trachy basalt

6 40 3 16 Moderately Weathered and fractured Basalt and/or trachy basalt

Water Bearing layer

7 67.5 7.2 23 Moderately Weathered and fractured Basalt and/or trachy basalt

Water Bearing layer

8 237 60.8 83.5 Massive Basalt

9 162 205 289 Slightly weathered basalt

10 16.5 substratum infinity Moderatly weathered and fractured basalt and/or trachy basalt

Water Bearing layer

Table 2. Interpretation Result of VES in Maksegnit Health Center


The study in this specific site is conducted for the possibility of relocating the well sitting inside

the compound Health Center. Previously, the consultant has based its assessment on the best

possible and feasible hydrogeological site to supply water to the center without any defined daily

water requirement of the center. As a result, a well site relocated back to the compound with

possible depth adjustments after further geophysical data verification in the compound.

Based on the geological, hydrogeological and geophysical investigation inside the compound the

well can be drilled to a depth of 300m. The proposed well site inside the compound at a position

of UTM37P 378328E and 1250101N


30

Water samples from nearby area like jara gedo are classified dominantly as Na-HCO3 and Ca-

Mg-HCO3 type; whereas few springs show mixed type water with SO4 and Cl. Sodium and

Calcium are the dominant cations followed by magnesium. The water type is classified as

suitable for human consumption, industrial and agricultural uses.

Ground water utilization is poor from borehole with an average yield of 0.7 to 1.0 l/s

and anticipated depth of drilling is 300 mbgl.






31

2.3.Gulem Dengin

2.3.1. Location

Gulem Denjin is located in Amhara National Regional State, west Gojjam zone, Burie Woreda

about 15kms from Burie town of Gojjam on an all weather gravel road. The Geographic

coordinates of the health center location is UTM 37P 292400E, 1170838N, Elev. 1982m (WGS

projection)

Figure 11. Get to Gulem Dengin

2.3.2. Physiographical set up of Gulem Dengin area

Gulem Denjin village is Located in Burie Woreda of Amhara National Regional State. Gulem

Denjin site is physiographically located in the North-western Highlands of Ethiopia, as part of

the Blue Nile basin recharged mainly from Chokie mountain ranges. The village is surrounded

by a relatively deeper extensive valley aligned west to east situated north of the health center

than its rolling gentler plain in the south. There has been ample experience of drilling shallow


32

wells by the Regional Water Resources Development actors where about 5 shallow wells fitted

with manual pumps are operational for community use but all wells are located in the southern

plain area.

Development of soil is moderate in the area; the thickness of soil in the low lying plains accounts

to some meters of depth overlying the basaltic flows. The prominent soil types are reddish brown

clay soil to black cotton soil. Eucalyptus is the common type of vegetation found everywhere

apart from cultivated farms.

Gulem Denjin area receives uni-modal rainfall that lasts from June to September. The mean

annual rainfall is characterized by high mean annual rainfall ranging from 1100-1200mm. The

mean monthly minimum and maximum temperature ranges from 10-14 0C and 16-20 0 c

respectively.


The villagers usually fetch water from shallow wells almost all of them drilled in the southern

gentle plain fitted with manual pumps. There are about 5 of them with depth ranges of 60m to

80m including the recently drilled well that is yet to be operational. A new shallow well drilled at

a location recommended by our previous report for the Health center, but information about well

characteristics couldn’t be found easily.

2.3.4. Geology and Hydrogeology


vicinity are composed of residual soil underlain by tertiary volcanic rocks. It is dissected, rugged

topography over the Blue Nile River catchment. The local aquifer systems can support boreholes

to be drilled around. The area is characterized by porous media and volcanic aquifer systems.

Based on the desk and field survey results, Gulem Denjin area is classified as low to moderate

groundwater potential area.


33

Figure 12. Geological Map of Gulem Dengin area

Legend

Gulem dengin new BH location


34

Figure 13. Hydrogeological map of Gulem Dengin area


The geophysical Survey was conducted in the compound of Gulem Dengin Health Center at a

relatively flat land. The maximum electrode spacing was AB = 660m.

The VES survey result revealed eight contrasting resistivity layers, the first layer shows black

cotton soil, beneath lays wet soil. These two layers extending to a depth of 1.2m, and then

follows massive basalt with a resistivity value of 156 ohm-m with thin thickness reaching to 3m..

The fourth layer is attributed to weathered and fractured basalt with a resistivity value of 18

ohm-m with a thickness of 7.3m is characterized by weathered and fractured basalt with water

-I ;

1-:: d

~ Gulem dengin new BH location

) • ' ,:


35

bearing formation. The fourth layer is attributed to weathered and fractured basalt with a

resistivity value of 18.3 having a thickness of 3m. A massive basaltic layer underlain with a

resistivity value of 1288 Ohm-m with a thickness of about 5m, and then follows moderately

weathered basalt with a thickness of 12m. The seventh thick layer is attributed to massive basalt

with a thickness of 52m. The last layer is characterized by moderately weathered and fractured e

basalt with a resistivity value of 50.5 Ohm-m with an infinity thickness. Based on the

geophysical data signature the well can be drilled to a depth of 150m.

1000~ ' ' ' ' ' ' Pa ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ~-----~------~ ' ' ' ' ---- -----r ---------- - - - - - - y - - - - - - -,- - - - -

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' - ' ' ' ' ' _____ ,_ ______ ,, ---- _____ .. _____ ., ___ o---·-----

' ' ' :~ ... ' ' ' ' ' ' ' ' '

100 ' ' .,

' ' £ 1 ' ' ' >- ' ' --. ' ' ' -----r------~---' ' -----r- ---- .. ----

>- ' ' ' ' ' ' ' ' ' ' ' ' >- ' ' ' ' ' ' ' ' ' ' ' ' ~- ---_._ - ____ J ---- -----L------~----- - - - - • J.. - - - - - _,_ - - - -

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' AB/2 10 ' ' ' ' ' ' ' ' ' ' ' '

1 10 100 1000


36

Layers

Resistivity

(Ohm m.)



Remarks

1 212 0.5 0.5 Black cotton soil soil

2 61.2 0.8 1.3 Wet soil


4 18.3 2.3 5.4 Moderately Weathered Basalt

5 1288 4.34 10 Massive basalt

6 52.7 12.6 22.3 Weathered Basalt Water Bearing formation


8 50.5 substratum infinity Weathered and fractured Basalt


Table 3. Interpretation result of Gulem Dengin

N p h d Alt -

1 212 I o.427 0.427 -0.426

2 61.2 0.78 1.21 -1.201

3 156 1.37 2.58 -2.58"

4 18.3 2.78 5.36 -5.36~

5 1288 4.34 9.7 -9.7

6 52.7 12.6 22.3 -22.21

7 738 52.1 74.4 -7 4.4: 8 50.5


37


The borehole site in this specific site is relocated to the health center compound after all the

necessary investigation is conducted in and outside the center. As usual, depth adjustments are

made here also after considering the topographic differences during shifting assisted by the

geophysical log data obtained during the second survey.

Water samples from nearby boreholes in this area are classified dominantly as Ca-HCO3 and Na-

Mg-HCO3 type; Sodium and Calcium are the dominant cations followed by magnesium. The

water type is classified as suitable for human consumption, industrial and agricultural uses.

Hence, the new well site location sited inside the compound is at UTM37P 292400E and

1170838N (WGS projection).

Ground water utilization is poor from borehole with an average yield of 2 to 3 l/s and

anticipated depth of drilling is 150m.




Steel Blind and Perforated or Screen Casing should have an outer diameter of 6 5/6’. In

this case the consultant recommending Steel castings for the reason that in some cases

drilling might extended beyond the target depth due to different unseen reasons. From our

experiences drilling companies don’t show willing to install PVC casings if the well is

below 150mbgl. Considering our experiences we are supposed to recommend steel

casings. However, in the bill of quantities the price of PVC stated as well, which has to

be considered during contract agreement.


38

2.4. Gerbicho

2.4.1. Location

Gerbicho is located in SNNPRS, Sidama zone, Aleta wondo wereda, 11kms from Aleta wondo

town on an all weather road partly covered with asphalt. The health center is located at

Geographic coordinates of UTM 37 + 438277E, 723717N, elevation 1989m (WGS projection).

2.4.2. Physiographical Set up of Gerbicho

Gerbicho site is physiographically located on the west facing slopes of the South Eastern

highlands of Ethiopia, within the main Ethiopian Rift. The eastern escarpment of the Rift is

sharply defined and owes steep and sharp slopes while ascending from west to east. The area is

densely vegetated and hills around the foot of the escarpment are dwelling areas where Gerbicho

is one of its type.

As a result of its topographic break and occurence of steep slopes, ground water table has better

chance to cross ground surfaces expressed in the form of low yielding springs and water oozing

contacts around the foot of hills.

There has been no previous experience of drilling in this village rather tapping of natural springs

and reserving the flow is quite common practice.

The Development of soil is moderate in the area; the thickness of soil in the low lying plains

accounts to few meters of depth overlying the basaltic flows. The prominent soil types are

reddish brown clay soil to black cotton soil.

Project areas located in SNNPRS Region are dominantly classified as Humid Sub Tropical

(Weina dega) and cold humid sub- tropical, dominated by distinctly bi-modal (two peak) rainfall

pattern. Rainfall is well received from September to November and March to May. The mean

annual rainfall of the project area and its surrounding are characterized by high mean annual

rainfall ranging from 1000-1200mm. The mean monthly minimum and maximum temperature of

the study areas and its surrounding area ranges from 10-14 0C and 16-20 0 c respectively.


39


The villagers usually depend on protected springs with concrete storage reservoirs located at the

foot of hills after descending down on sharp and steep slopes. In most cases, the spring discharge

decreases with the offset of the wet season and gets replenished considerably in winter.

2.4.4. Geology and Hydrogeolgy


vicinity are composed of residual soil underlain by tertiary volcanic rocks and in few cases by

the Rift formation. The local aquifer systems can support shallow to medium boreholes to be

drilled around. The area is characterized by porous media and volcanic aquifer systems.

Gerbicho area is classified as low to medium groundwater potential area.

Figure 14. Geological Map of Gerbicho area

Geological Map of Garbicho Area -

P ng • S r alf.h Center

2 3

Legend

Geological Structure

Roads

II

+ [±] Garbicho new

BH location

I


40

Figure 15. Hydrogeological map of Gerbicho area


The geophysical Survey was conducted in the compound of Gerbicho Health Center at a

relatively flat land. The maximum electrode spacing was AB = 440m.

The VES survey result revealed seven contrasting resistivity layers, the first layer shows black

cotton soil, beneath of it lays weathered basalt. These two layers are extending to a depth of

1.5m, and then follow weathered basalt with a resistivity value of 22 ohm-m with thin thickness

Hydroeological Map of Garbicho Area


41

of 2m. The fourth layer is attributed to massive basalt with a thickness of 4m with a resistivity

value of 340 ohm-m. The fifth and six layers are relatively moderate resistivity value are

attributing to Slightly to moderately weathered basalt with a thickness reaching to 148m The last

layer is characterized by moderately weathered and fractured water bearing basalt with a

resistivity value of 50.5 Ohm-m with an infinity thickness. Based on the geophysical data

signature the well can be drilled to a depth of 180m.

N 1 2

3 4 5 6 7

1000 Pa I I I I I I

- - - - - , - - - - - - 1 - - - - - - - - - - r - - - - - - , - - - - - - - - - - T - - - - - - -,- - - - -I I I I I

I I

.--.... I I

.......... --~-- ---J-- - - - - - L - - - - - - _. - - - - - - - - - - .L - - - - - - -•- - - - -

I I ----- ______ J ____ _

I I I I

I I I

I

I I I I

-----r------,-----

I I _____ L ______ J ____ _ I I I I

I I I I I I

0 - T - - - - - - -,- - - - -

I I I I

I I

- - - - - .L - - - - - - _,_ - - - -I I I I

: : AB/2 I I

10 100 1000

__e h d Alt 34.6 I 0. 755 0.755 -0. 75~ 206 0.694 1.45 1-1.44~ 21.9 1.62 3.07 -3.06~ 340 3.71 6.78 -6. 771 104 9.07 15.8 -15.8~ 90.5 139 155 -154.~ 33.2


42

Layers

Resistivity

(Ohm m.)



Remarks

1 34.6 0.7 0.7 Black cotton soil soil

2 206 0.7 1.4 Moderately weathered basalt

3 21.9 1.6 3.0 Weathered basalt


5 104 9.07 15.8 Slightly to Moderately Weathered Basalt

6 90.5 139 155 Moderately Weathered Basalt

7 50.5 substratum infinity Weathered and fractured Basalt


Table 4. VES interpretation result of Gerbicho

2.4.6. Conclusion Recommendations

The previous scheme types proposed was developing and pumping a series of springs located NE

of the health center. Taking in to consideration of the low water demand of the health center,

i.e 5,250 lit/day, it is revised to leave the idea of developing springs outside but to drill a deep

well inside the health center compound.

Based on Geological, Hydrogeolgical and Geophysical investigation the new well site is located

inside the compound is at UTM position of37P 438277E and 723717N .

Ground water utilization is poor from borehole with an average yield of 1 to 2 l/s and anticipated

depth of drilling is 180m. In line with this we are recommending the following points for future

consideration during drilling


43




Water samples from nearby boreholes in this area are classified dominantly as Ca-HCO3

and Na-Mg-HCO3 type; Sodium and Calcium are the dominant cations followed by

magnesium. The water type is classified as suitable for human consumption, industrial

and agricultural uses.


USAID/Ethiopia U.S. Agency for International Development

US Embassy, Entoto Street PO Box 1014

Addis Ababa, Ethiopia

Documents

USAID ETHIOPIA...Verification and Findings of Each Project area 2.1.Gult 2.1.1. Location Gult is located in Amhara National Regional State in south Gonder Andabet Woreda. Itcan be