Answers_to_questions.pdf

Answers to questions regarding RFP SOL-663-15-000001

Q: What casting material is required for the proposed well of Task 5 (Mehal Jarso)?

A: Proposals should be based on galvanized steel (Class B) as the required casing material. Section C.3.5 (RFP page 13): "The contractor will provide all necessary materials and construct a well with a 150 mm galvanized steel casing (Class B)...".

Section C.5 (RFP page 16) should be revised to delete: “Unless specified in the bills of quantities, uPVC blind and screen casings are specified they shall confirm to ISO 12818:1992

Standard with threaded male and female ends.

Internal Diameter (ID) Wall thickness

150mm (6”) 7.5 – 8.5mm

200mm (8”) 10.0 – 11.2mm

250mm (10”) 12.5 – 14.0mm

Screens shall conform to the same standards specified above.”

Q: Is there a maximum drilling depth for Task 5 (Mehal Jarso)?

A: The maximum drilling depth required is 130 meters. Section C.3.5 (RFP page 13) should be revised to delete "The contractor will confirm that the necessary depth of the borehole is 130 meters." and add "The contractor will drill the borehole to a maximum depth of 130 meters."

Q: Can a group site visit be organized?

A: A group site visit will not be organized, but anyone may organize a site visit on their own. Contact information for each health center is provided in Section C.1 (RFP page 9).

Clarifications

1. Each proposal package must include the following:

1) Technical Proposal (see RFP Section L.6.A page 76)

2) Cost Proposal (see RFP Section L.6.B page 76)

3) Annex A: CVs for Key Personnel (Project Manager and Groundwater Well Expert)

4) Annex B: Past Performance Form (see RFP Attachment V, PDF page 107)

5) Annex C: Self Disclosure Form (see RFP Attachment IV, PDF page 104)

2. Section C.1 (RFP page 9) should be revised to delete the table in its entirety and replace with the below table.

3. USAID will provide the available study and design details regarding the borehole drilling of

Task 5 (Mehal Jarso).

See Attachment to this amendment

Latitude Longitude Region Zone Woreda Name Phone Number

TO2 1 Jaradado 6.99278 38.37083 SNNPR Sidama Awasa Zuriya 13km from Finote Selam 300 km Alemu (Woreda Administrator) +251.916.58.1971

TO3 15 Sibiyia 7.18056 37.88807 SNNPR Hadiya Mirab Badewacho 13 km from Shone 270 km Desta (Woreda Administrator) +251.911.03.6335

TO3 2 Wacho 8.32628 38.61783 SNNPR Gurage Sodo 13 km from Buee 100 km Endale (Woreda Adminstrator) +251.912.24.7027

TO3 14 Mehal Jarso 7.12639 37.89917 SNNPR Hadiya Misrak Badewacho 7 km from Shone 270 km Biruk (Woreda Health Chief) +251.913.47.5973

TO3 8 Udassa 7.91769 38.46769 SNNPR Silte Silte 13 km from Koshe 180 km Aschalew Abera +251.912.24.5545

Site No.Group Contact Person

Site Name Location

Approximate Distance between Site and

Nearest Town

Approximate Distance between Site and

Addis Ababa

US Embassy, Entoto Street

P. 0.Box: 1014

Addis Ababa, Ethiopia

Main Report - Final

Feasibility Study and Design of Water Supply Systems for five

Health Care Centers in SNNRPS

January /2015

Karamara Engineering Plc www.karamaraengineering.com

P.O.Box 19847, Tele 0911514021, 0116633681, Fax 0116638861, e-mail:kameco@ethionet.et; ynegussei@gmail.com

Attachment 1 to Amendment No.1of RFP-663-15-000001 http://www.karamaraengineering.com/

Annex 1 -

Feasibility Study of Alternative Water Supply Source for Udassa and Mehal Jarso Health Care Centers

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source for Udassa and Mehal Jarso HCCs

Karamara Engineering Plc, P.O.Box 19847, Tele 0911514021, 0116633681, Fax 0116638861, e-mail:kameco@ethionet.et; ynegussei@gmail.com

Page ii

TABLE OF CONTENTS

1. INTRODUCTION ........................................................................................................................................... III

1.2 SUMMARY OF FINDINGS .............................................................................................................................. III

1.3 SCOPE OF THE WORKS ................................................................................................................................ III

1.4 THE STUDY AREA ....................................................................................................................................... III

2. METHODOLOGY .......................................................................................................................................... IV

2.1 DOCUMENT REVIEW .................................................................................................................................... V

2.2 WATER POINT INVENTORY........................................................................................................................... V

2.3 SATELLITE IMAGERY .................................................................................................................................... V

2.4 TOPOGRAPHIC AND GEOLOGICAL MAPS ...................................................................................................... V

2.5 GEOLOGICAL AND HYDROGEOLOGICAL SURVEYING ................................................................................... V

3. FEASIBILITY OF BOREHOLE DRILLING ............................................................................................ VII

3.1 UDASSA HEALTH CENTRE .......................................................................................................................... VII

3.1.1 Location ................................................................................................................................................. vii

3.1.2 Existing Water Supply ............................................................................................................................ vii

3.1.3 Physical Setup ........................................................................................................................................ vii

3.1.4 Hydrogeophysical Study .......................................................................................................................... x

3.1.5 Summary and Conclusion ..................................................................................................................... xiii

3.1.6 Recommendation ................................................................................................................................... xiii

3.2 MEHAL JARSO ........................................................................................................................................... XIV

3.2.1 Location ................................................................................................................................................ xiv

3.2.2 Exiting Water Supply ............................................................................................................................ xiv

3.2.3 Physical Setup ....................................................................................................................................... xiv

3.2.4 Hydro-geophysical Study ...................................................................................................................... xiv

3.2.5 Summary and Conclusion ...................................................................................................................... xv

3.2.6 Recommendation .................................................................................................................................... xv ahable Cross-Out

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

Page iii

1. INTRODUCTION

This groundwater feasibility study is made as alternative water supply source for Udassa and Mehal Jarso HCCs.

Udassa town has an existing water supply from borehole supply. However, the borehole supply is often short of water due to low yield of the borehole. It was learnt that the Udassa municipality has no sufficient yield.

On the other hand Mehal Jarso town has no central water supply system and the communities make use of shallow wells equipped with hand pump.

1.2 Summary of Findings

This report outlines the hydrogeological studies carried out on the site so as to arrive at the right conclusions and recommendations. The report was based on the site visits, the findings and analysis of available hydrogeological, geological and review of geophysical data from the project area.

The report concludes that the area is of low to medium groundwater potential. Available data of boreholes near the surveyed area indicate low-moderate but varying borehole yields.

1.3 Scope of the Works

The scope of works includes:

• Site visits to familiarize with the project areas.

• To obtain, study and synthesize background information including the geology, hydrogeology and existing borehole data, for the purpose of improving the quality of assessment and preparing comprehensive hydrogeological reports,

• To carry out hydrogeological evaluation of the area in order to determine potential for groundwater and appropriateness of drilling boreholes at the sites.

• To prepare hydrogeological survey reports

1.4 The Study Area

The study HCCs Udassa and Mehal Jarso are found in Silte and Hadya zones of Southern Nations Nationalities and Peoples Region (SNNPR), as shown in fig 1 and 2.

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

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Fig 1 - Location Map of Udassa HCC

Lake

To Addis Ababa

To Awassa

Awassa

Fig 2 - Location Map of Mehal Jarso HCCs

To Addis Ababa

To Dilla

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

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2. METHODOLOGY

2.1 Document Review

Documents related to the study area have been reviewed to comprehend the local and regional geology, geomorphology, drainage and establish initial hydrogeological model of the study area. In addition to, review of well completion reports and lithologic logs of existing boreholes has been made.

2.2 Water Point inventory

The consultant has carried out inventory of water points (source type, current condition, depth, discharge, water level) that exist around the study area. Location of the water points has been taken by using GPS.

During the inventory work, information of the local community has greatly helped to locate water points.

2.3 Satellite imagery

Satellite imagery (Landsat ETM+ images) covering the respective areas has been used. In the event, GIS software, Global Mapper 11 has been used to acquire knowledge about the topography, geomorphology, geology/ geological structure and hydrogeological set up of the study areas. More so, the Global Mapper has helped to pinpoint GPS locations of important features, including water points.

2.4 Topographic and Geological Maps

Topographic maps (1:50,000 and 1:25,000 scales) covering the study area has been purchased from Ethiopian Mapping Agency, to locate the HCCs, study the topography and drainage of the project sites.

Map Date

Published Project Features Number Name Scale

0638 A2 Leku 1:50,000 1979 Jeredado HCC 0738 A2 Tora 1:50,000 1975 Udassa 0838 D1 Bue 1:50,000 1975 Wacho 0737 D4 Shone 1:50,000 1976 Mehal Jarso and Sibeya

Geological Map - Geological Map of Ethiopia (2nd Edition) 1996, Ethiopian institute of Geological Surveys has been referred.

2.5 Geological and Hydrogeological Surveying

Traverses has been made in different direction of the study area to identify the type of rock types, stratigraphic set up and geological structures to identify the possible aquifer systems and estimate their aquifer parameter which are key issues to define the occurrence & movement of groundwater.

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

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The geology, geomorphology, topography and hydrology of the study area have been reasonably studied in the field to understand the local and regional groundwater flow and occurrence.

Furthermore considerable observation in the field was made such as.

• Information about existing boreholes were gathered and mapped.

• Springs and rivers etc. were assessed and inventoried.

• Yield of natural springs and streams assessed and information about their state of duration were acquired from the community.

Geophysical Data Review of electrical resistivity report that was made by the Ministry of Water and Energy has been studied. This document contains considerable data geophysical information about the area, which gave valuable data for the analysis.

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

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3.2 Mehal Jarso

3.2.1 Location

Mehal jarso HC is found in Hadya Zone, SNNPR about 7km SSW of Shone town. It lies approximately at grid references UTM 0378373 East and 0787878 North.

3.2.2 Exiting Water Supply

Mehal Jarso Kebele has no motorised or central water supply system. The people thereof are using water from multiple shallow drilled boreholes that are equipped with hand pumps.

One of the hand pumps is found in the immediate west of the HCC.

3.2.3 Physical Setup

a) Physiography, drainage and climate

The area is characterised by a gently undulating landscape, consisting of gentle valley slopes. In the investigated area, the altitude is ranging from 1900-1920m asl. Mehal jarso is found between two catchments namely Gere and Bone. It is situated almost at the headwater of Bone stream.

The investigated site lies within an area that experiences small to medium amount of annual rainfall. Overall, the climate is semi-arid. The annual precipitation in the investigated area varies from 750-800mm.

b) Geology

Similar to Udassa, the local geology around Mehal Jarso consists of the Dino formation, which includes peralkaline silicics of Pleistocene. The formation represents ignimbrites, tuffs waterlain pyroclastics, occasional lacustrine beds which are overlain by coarse un-welded pumiceous pyroclastic.

Around the study area, there are numerous faults that trend northeast-southwest direction.

3.2.4 Hydro-geophysical Study

a) Water Point

According to information obtained from the communities, depth of the shallow wells range between 15-30meters.

Pic 6 – Hand Pump Scheme in front of Mehal Jarso

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

Page xv

During the field visit we have observed that one of the well which is located in front of the Health Centre has been working almost all the day without depletion of water.

b) Groundwater Geology

Groundwater in the area occurs in the weathered and fractured section of the ignimbrite. The shallow groundwater is contained in the upper weathered part of the ignimbrites/pyroclastic and deep water is expected to occur in the faulted zone at deeper depth.

3.2.5 Summary and Conclusion

The suitability of the formations in the investigated area, which are basically volcanic and volcano sedimentary in origin, as aquifers depend largely on the development of secondary structures mainly faults and their subsurface extent and interconnection to other similar structure on regional scale. Another major factor is the degree of weathering of these volcanic rocks and their porosity. The study area is endowed with shallow groundwater. Shallow and deep aquifers in the area are attributed to weathering and tectonic processes respectively, which form unconfined and confined aquifers. The aquifers range in depth from 15 to 100 m.b.g.l.

3.2.6 Recommendation

The consultant recommends two alternative options.

a) The first option would be to share the shallow borehole that exists very close to the HCC by installing motorised pump. Prior to making the decision, it is highly recommended to conduct pumping test to evaluate the capacity of the well.

Pjb

Butajira

Alaba Kulito

Shone Mehal Jarso

Qd Nt

Q

Legend

- Alluvial and Lacustrine Sediments; Clays, silts

- Dino Formation ignimbrites, tuffs water lain pyroclastic, occasional lacustrine beds

- Teltele and Surma basalts:Flood basalts

- Jima Basalts

- Faults

Qd

Q

Nt

Pjb

Fig. 7 - General Geological Map of Mehal Jarso area (Map taken from Geological Map of Ethiopia, 1:2,000,000 scale, EIGS 1990)

U.S. Agency for International Development Annex 1 - Feasibility Study of alternative Water Supply Source

Page xvi

b) The second option is to drill a borehole in the proximity and south of the health center at UTM 787715 East and 378422 North. This site is selected to avoid contamination of water by the wastes from the HCC.

The recommended depth of drilling at this site is 120m.

Annex 2 –

Pumping Test of Jarardado HCC Borehole - Final

U.S. Agency for International Development Annex 2 - Pumping test report of Jara Dado HCC Borehole

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TABLE OF CONTENTS

1. GENERAL INFORMATION ......................................................................................................................... III

1.1 BACKGROUND............................................................................................................................................. III

1.2 LOCATION ................................................................................................................................................... III

1.3 PURPOSE OF THE PUMP TEST ....................................................................................................................... III

2. PHYSICAL SETUP ......................................................................................................................................... IV

2.1 DRAINAGE AND CATCHMENT ...................................................................................................................... IV

2.2 GEOLOGY .................................................................................................................................................... IV

2.3 HYDROGEOLOGY ........................................................................................................................................ IV

...................................................................................................................................................................................... V

3 PUMPING TEST ............................................................................................................................................. VI

3.1 DESCRIPTION OF THE WELL SITE AND WATER SYSTEM .............................................................................. VI

3.2 BOREHOLE CONSTRUCTION DATA .............................................................................................................. VI

3.3 EQUIPMENT AND MANPOWER DEPLOYED ................................................................................................... VI

3.4 PUMPING TEST DATA .................................................................................................................................. VI

3.4.1 Preliminary Test ..................................................................................................................................... vi

3.4.2 Step Drawdown test ................................................................................................................................ vi

3.4.3 Constant Rate Test ................................................................................................................................. vii

3.4.4 Recovery test ......................................................................................................................................... viii

3.4.5 Pumping test data analysis .................................................................................................................... viii

3.4.6 Water Quality ........................................................................................................................................... x

4. CONCLUSION ................................................................................................................................................ XI

Page iii

1. General Information

1.1 Background

This report presents the procedures and analysis of pumping test that was performed by the team of Karamara Engineering Plc from November 04- 09/ 2014 in support of meeting Jeredado HCC’s water supply.

Jara Dado HC is the only amongst the five HCCs that has its own drilled borehole in its premise.

This borehole has been drilled by the U.S.G. in September 2012. Details information about this well is not available, except its depth reportedly is 75m deep. Hence the pumping test has been found to be mandatory to determine its yield capacity, water quality and other well parameters.

1.2 Location

Jara Dado is found in Sidama zone, about 18 km southwest of Awassa town. It is located at UTM 0430435 East and 0773019 North.

1.3 Purpose of the pump test

The main purpose of the pumping test is to estimate well performance, well yield and the aquifer’s ability to store and transmit water, aquifer extent, presence of boundary conditions and possible hydraulic connection to surface water.

Fig 1 – Location Map

Jeredado HCC

Lake Awassa

Lake Shala

Shashemene

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2. PHYSICAL SETUP

2.1 Drainage and Catchment

Lake Awassa is a Closed-catchment Lake with no surface water outflow. The lake is fed both by few ephemeral streams on the north-west and western side of the catchment and by the TikurWuha River, which is the only perennial river, enters Lake Awassa draining the Cheleleka swamp on the north-east side. Cheleleka swamp receives surface runoff from the head waters of the eastern rift escarpment and from groundwater upstream.

Lake Awassa is the smallest and the highest of the major MER lakes (1680 m.a.s.ll between the Ziway-Shala lakes to the north and Lakes Chamo and Abaya to the south. The lake lies within a nested caldera complex and is predominantly underlain by highly faulted ignimbrites and other silicic pyroclastic deposits (V.Kazmin 1979).

2.2 Geology

According to some study the main formations in the area were subdivided in to four lithologic units as follows:

• Volcano lacustrine deposits, which cover most part of the floor of the depression, composed mostly of volcanic origin (tuff, pumice, ash with small amount of diatomite:

• Recent acidic volcanic, which covers large part of the north and north-western part of the catchment where glassy rhyolitic rocks superimposed and form massive domes and thick obsidian flows:

• Basaltic lava flows, scoria and hyaloclastites, which are observed sprinkled on the flat catchment floor forming conical shapes.

• Ignimbrite of the rift floor and the rift scarp, which is common rock type for the region and covers the east, southwest and the southern part of the catchment where the top few meters of the rock is weathered and fractured in places with columnar joints.

Geological structures There is a number of rift system faults with north and northeast trend along which the longest axis of Lake Awassa is oriented. These faults are expansions (normal faults forming step faults.

They are mainly dominant to the south and south west of the lake. The volcanic collapse structure (caldera) forms nearly circular structure around Lake Awassa basin.

2.3 Hydrogeology

Hydrogeological study conducted by Tesfaye Cherne (hydrogeology of Lakes Region, EIGS, 1982) pointed out that Awassa Lake Catchment is covered by highly permeable lacustrine sediments, moderately permeable acidic volcanic (rhyolites. tuffs, pumice and obsidians) and low permeability ignimbrites and tuffs. Acidic volcanics are highly permeable when sorted and ignimbrites are highly permeable when they are jointed.

Quaternary sediments are dominantly distributed with large stretches at the eastern and western side of the lake and they overlay the ignimbrites. They consist of alternating fine and coarse sand beds, but they are predominantly fine to medium grained. The transmissivity of the lake

Page v sediments become higher when there is a higher proportion of coarser material like pumice sand beds. Based on borehole data and field observation the lacustrine sediments have medium to high transmissivity values ranging from 100 to over 1000 m2/day. The groundwater is generally unconfined. Average thickness of the lake sediments is estimated to be about 40 to 50 meters.

The temperature of the groundwater varies from 21 to 32 °C and conductivity from 230 to 1900 pS/cm.(W.W.D.S.E 20011).

Groundwater depth increases as a function of distance away from the lake in the south and southwest of the lake. The groundwater depth between Lake Awassa and Cheleleka swamp varies according to surface elevation, i.e. on the surface water divide the groundwater depth reaches up to 67 meters and decrease to 6.3 meters close to Lake Awassa and 10.3 meters near to Cheleleka (W.W.D.S.E 2001).

Geology

- Alluvial and Lacustrine Sediments;

Clays, silts

- Dino Formation ignimbrites, tuffs water lain pyroclastic, occasional lacustrine beds

Nazret Series:

Ignimbrite, Unwelded tuff, Ash flows, Rhyolites

- Faults

Fig 2 – Preliminary Hydrogeological Map Map

Jeredado

Lake Awassa

No

Qd

No

Qd

Qd

Qd

Nb

Permeability Groups (Km/d)

High, <81 mean 31

Moderate, <40 mean 8.5

Low, <1 mean 0.1

Nb

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3 PUMPING TEST

3.1 Description of the Well Site and Water System

The borehole is located in Lake Awassa catchment. The geology around the borehole is largely composed of the Quaternary sediments and they overlay the ignimbrites. Though lithologic log of the borehole is not available, it is anticipated that the sediments consist of alternating fine and coarse sand beds.

3.2 Borehole Construction Data

Jara Dado borehole has been drilled by the U.S.G in September 2012 to a depth of 75meters. The well is cased with 6inch pvc casing to its bottom. Prior to the test little information was available. However, after the test, some information about the well was retrieved. Accordingly its static water level was measured to be 47.8m below surface.

3.3 Equipment and Manpower Deployed

The contractor has used the following equipment for testing of the well.

• Chain block, 10ton, mounted on a Tripode

• Groundfose submersible pump, 30KW,

• Diesel driven generator, 80KVA,

• 220l capacity barrel for discharge measurement,

• Battery powered deep meter to monitor water level

• Stopwatch.

• Standard formats to record the data

Manpower deployed

• Supervising Hydrogeologist - 1

• Electrician - 1

• Plumber - 2

• Driver – 1

3.4 Pumping Test Data

3.4.1 Preliminary Test

Preliminary test has been made with the objective of testing the installed equipment whether are working properly or not and to design the appropriate discharge rate for the constant rate test. On this basis the pre-test was carried out for about 20 minutes at full discharge capacity of the pump which is 6.45l/sec.

3.4.2 Step Drawdown test

One of the tests planed was step drawdown test to determine a maximum sustainable pumping rate for the constant-rate pumping test. However, as the water pressure was very high, we couldn’t throttle the pump in order to maintain the different pumping rate as planned. Instead

Page vii water was flowing at the full capacity of the pump.

3.4.3 Constant Rate Test

The goal of a constant-rate pumping test is to estimate hydraulic properties of an aquifer system such as transmissivity, hydraulic conductivity and storativity (storage coefficient).

The most common form of pumping test is the constant-rate test in which a control well is pumped at a constant rate and water-level response (drawdown) is measured in one or more surrounding observation wells and optionally in the control well itself. Apparently in this case, the drawdown has been observed in the well itself since no observation well was available.

Following the preliminary test and after ensuring the full recovery of water level from the preliminary test to its original level, a constant rate test was performed with the maximum discharge rate, which was measured to be 6.45l/sec. The pumping phase of the test was planned for duration of 24 hours, considering the water demand. During the pumping test water levels were monitored using measuring deep meter and the water level dropped from 47.8m to 47.7 m at the end of the test. The total drawdown recorded at the end of the 24hour continuous test was 10cm only.

Pumping-phase water-level data for the well has been plotted on drawdown time graph (fig 3).

The raw data is lso presented in table 1.

It may be noted that groundwater level essentially stabilized and drawdown almost ceased to change after about the second minute of pumping.

Fig 2 – Pictures of the pumping test

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3.4.4 Recovery test

Recovery of water level with time has been recorded immediately after the pumping stopped both in the preliminary and constant rate tests. The recovery phase began at 8:10 a.m. on Nov 07/2014. Apparently, it was observed that the recovery test was so fast that 100 percent of the water column recovered in ten seconds.

3.4.5 Pumping test data analysis

In this case pumping test analysis has been made using the constant rate pumping. Apparently, analysis using the step drawdown was not successful because the consultant was not able to reduce the flow of water to observe the drawdown at the different discharge rate due to pressure of the water. Similarly the recovery data was so fast that we were not able to construct the recovery curve for the analysis. For this reason our analysis is limited to drawdown-time data observed from the constant rate pumping test.

In the event, the Cooper and Jacob (1946) solution (or Jacob's modified none-equilibrium method), which is useful for determining the hydraulic properties (transmissivity and storativity) of none-leaky confined aquifers has been deployed. The analysis involves matching a straight line to drawdown data plotted as a function of the logarithm time since the start of pumping.

Boundary Condition A plot of Time - drawdown graph on a semi logarithmic scale is shown in figure 4 below.

Jacob’s straight-line analysis (Cooper and Jacob 1946) was conducted on the section of the curve between 5minutes and 100minutes of the test.

47.75

47.8

47.85

47.9

47.95

48.05

48.1

48.15

0 200 400 600 800 1000 1200 1400 1600

Drawdown

R ec ov er y

Pumping Period

W ater L evel (m

Recovery Period

Fig 3 - Drawdown and Recovery graph constructed from previous data

Time (minutes))

Page ix

Furthermore, the shape of the drawdown curve suggests an apparent boundary condition represented by a constant drawdown happening, after 720minutes. In terms of the local hydrogeological setup of the area, this may happen when the cone of depression intercepts Lake Awassa, thereby causing a recharge effect on the drawdown data.

Aquifer parameters The curve matching to determine the transmissivity and storativity of the aquifer by using the Jacob's modified non-equilibrium has been made using a computer program known as AquiTest pro. The program provides visual and automatic methods for matching the Cooper and Jacob method to pumping test data.

The aquifer parameters/ characteristics which are evaluated by this test are:

• Hydraulic conductivity or transmissivity: the ability of an aquifer to transmit water (how permeable it is);

• Specific storage or storativity: a measure of the amount of water of a confined aquifer will give up for a certain change in head;

Henceforth, Transmissivity and storativity were calculated on the section of the curve selected between 25-420 minutes using the formula shown below. This section of the drawdown may represent the true aquifer characteristic because the cone of depression apparently had not been affected by any boundary.

Accordingly using Jacob’s method the Transmissivity, conductivity and storativity had been calculated to be 1.75-2 m2/sec (1512 m2/day), 6.44-4 m/sec (55.4m/day) and 3.54-1 respectively. Moreover, it may also be noted that the results of the same parameters obtained using the Thiess method are almost identical.

Generally the Transmissivity value is very high and exhibit that the aquifer in the area is highly productive.

Where T= Transmissivity Q = discharge during pumping m^/day s = drawdown difference for one log cycle of time in meters

Fig 4 - Cooper-Jacob Method of Analysis

Boundary Condition

Page x

Specific Capacity of the Well The productivity of a production well is generally expressed by the term specific capacity which is the yield of the well per unit of drawdown. Hence the specific capacity of the well has been estimated to be 64.5l/sec/m, which is a very high value.

3.4.6 Water Quality

Samples were collected from the borehole at the last hours of the 24 hours pumping test for physic-chemical water-quality analyses.

The sample has been sent to the laboratory of the Water Works Design and Supervision Enterprise. The result of physico-chemical analysis is presented in fig. 6. According to the analysis the following elements has been found to be in excess of the standard limit set by WHO and Ethiopian Institute of Standard Authority.

• The Sodium (Na) mg/l) content of the water is 305mg/l. According to WHO and Ethiopian

Institute of Standard Authority, the maximum allowable quantity is 200 mg/l. Excessive sodium in water causes undesirable taste.

• The Fluoride content of the water is 6.36mg/l. The maximum allowable for drinking, according the standard set by WHO and Ethiopian Institute of Standard is 1.5mg/l. Hence the content of the fluoride in Jara Dado borehole greatly exceed the standard limit. Excessive fluoride causes mottling of teeth and in severe cases can result in crippling skeletal fluorosis.

Fig 5 - Thiess Method of Analysis

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4. CONCLUSION

Pumping test analysis of the Jara dado borehole reveals that the aquifer in the area is highly productive. The specific capacity is generally very high. However, the fluoride content of the water is very high and for this reason the water is not potable for drinking.

Page xii

Fig 6 – Water Quality Analysis

Page xiii

Fig 7 – Cooper Jacob Analysis

Page xiv

Fig 8– Thiess Analysis

Page xv

Karamara Engineering Prvt. Ltd. Co P.O.Box 19847, Tel 0116 633681, Fax 0116 638861, e-mail: - kameco@ethionet.et

CONSTANT DISCHARGE TEST RECORD SHEET

Client: USAID Date test started: November 06/2014 Location: Sidama Duration: 24 hr Date test completed: November 08/2014 Well Designation: J-BH1 Static Water level :47.8m Well Depth(m): 75m Discharge rate: 6.45l/sec

Time since Water level Drawdown, s Remark

Date pumping Started (min) Below datum (m) (m)

November 07/2014, 8:30am 0 47.80 0.00

1 47.85 0.05 2 47.90 0.10 3 47.90 0.10 4 47.90 0.10 5 47.90 0.10 6 47.90 0.10 7 47.90 0.10 8 47.90 0.10 9 47.90 0.10 10 47.90 0.10 12 47.90 0.10 14 47.90 0.10 16 47.90 0.10 18 47.90 0.10 20 47.90 0.10 25 47.91 0.11 30 47.91 0.11 35 47.91 0.11 40 47.91 0.11 45 47.92 0.12 50 47.92 0.12 55 47.93 0.13 60 47.93 0.13 70 47.94 0.14 80 47.94 0.14 90 47.94 0.14 100 47.94 0.14 120 47.95 0.15

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140 47.96 0.16 140 47.97 0.17 160 47.98 0.18 180 47.98 0.18 200 47.98 0.18 220 47.98 0.18 240 47.98 0.18 270 47.99 0.19 300 47.99 0.19 360 48.00 0.20 420 48.00 0.20 480 48.02 0.22 540 48.04 0.24 600 48.06 0.26 660 48.08 0.28 720 48.10 0.30 780 48.10 0.30 840 48.10 0.30 900 48.10 0.30 960 48.10 0.30 1020 48.10 0.30 1080 48.10 0.30 1140 48.10 0.30 1200 48.11 0.31 1260 48.11 0.31 1320 48.12 0.32 1380 48.12 0.32 1440 48.12 0.32

1441 47.80 0.00 Recovery

4. Conclusion