Tender Description

Terms of Reference 

HYDROGEOLOGICAL AND GEOPHYSICAL INVESTIGATION FOR BOREHOLE SITTING

Reference:         GREDO – Ground Water Consultancy

Area of Interest:  Hydrogeological, geophysical investigation for borehole sitting 

Location: Bulow Village, Morogaabey Village and Sheikh Uways Village in Hudur District-Bakol Region 

Position Type:     Consultant/Firm

Duration:           14 days 

Start date:          23th July 2025

Introduction

GREDO is an indigenous local NGO. Non-profit non-partial, a non-political and voluntary organization based in Baidoa. To reach the most affected grass-root communities in the Bay, Bakool, and Lower Shebelle regions effectively and efficiently, the necessity of local partnership in relief programs appeared. Responding to the partnership need, a group of Somali intellectuals and well-wishers initiated in December 1992 a local non-governmental organization called Gargaar Relief and Development Organization GREDO).

To ensure delivery of this mission, GREDO’s WASH department focuses on improving access to clean water services in vulnerable communities across Somalia. It implements projects that include drilling boreholes, rehabilitating and construction of water sources, constructing sanitation facilities, and promoting hygiene awareness.

Background

The recurrent drought together with nutrition crises and other natural emergencies combined with poor WASH coverage and influx of internally displaced people (IDP) in target regions of Bakol highlights the needs for GREDO in partnership with IOM to continue reducing of vulnerabilities of displaced people through durable solutions. 

GREDO is implementing FCDO HARBS (Danwadaag) 5 years WASH project targeting drought and conflict affected communities in Bay and Bakol regions targeting Baidoa, Berdale, and Hudur districts providing immediate life-saving WASH services to the most vulnerable members of the community.  The project aims to provide durable solutions and sustainable WASH service through drilling of ONE new strategic Borehole with distribution network systems, storage tanks and new water kiosks.

Before drilling, GREDO intends to do a comprehensive assessment to establish the best possible location. If we don't use proper borehole siting techniques including hydrogeological surveys and groundwater prospecting, there's a good probability we'll end up with a dry borehole. Considering this challenge, GREDO will hire the best available consultant to conduct a hydrogeological study and groundwater prospecting by conducting geophysical survey in the selected areas for the new boreholes. The borehole siting will be completed in the year three third quarter of the project, along with a comprehensive report. Based on the results of the hydro-geological survey report., the borehole will be drilled in the best suited location among the investigated sites, which include Bulow Village, Morogaabey Village and Sheikh Uways village in Hudur District-Bakol Region. A complete report shall be developed for each sites for internal and donor records. Therefore, the objective of this survey is to ascertain the drilled borehole will meet or exceed the water demand for the next 20 years.

Overall Objectives Of The Hydro-Geological Survey

• Conduct hydrogeological and geophysical investigation for the optimal siting of a drinking water Borehole in Hudur district-Bakol region 

• To conduct geophysical survey of underground water in the aforementioned settlments in Hudur district and identify the most suitable location for drilling of the new borehole in terms of getting sufficient amount of water with acceptable quality, quantity and affordable depths

• Review of knowledge people have with regard to the hydro-geological conditions in the area,

• Identify the positive and negative environmental impacts of the proposed Borehole and recommend appropriate mitigation measures considering potential impacts on natural and secondary environments and assessed potential on shortand long-term impacts.

• Investigate Social and ecological effects of groundwater development including loss of agricultural and grazing land, population resettlement.

• Examine effects on the existing water supply such as Boreholes and Shallow wells, including fluctuation of water levels and interference of the cone of depression in the Boreholes.

• Potential environmental and social impacts by planned and unplanned (spontaneous) immigration into the area. 

• Effects of existing and predicted land use on the functioning and longevity of the water supplies.

Scope Of The Work

The Consultant is expected to use both secondary and primary data in the exercise.Secondary data will involve desk study of available information/data on existing Boreholes, drill logs, reports and maps while primary data will be obtained by carrying out field reconnaissance and measurements of existing Boreholes and  geophysical prospecting within the studied area using a combination of geophysical methods as below described. The outcome of the consultancy will be a detailed hydrogeological survey report giving details of the findings and recommendations. Also the consultant is expected to coduct Socio-economic and environmental impact assessment to identify the positive and negative impacts of the proposed interventions and recommend appropriate mitigation measures considering potential impacts on natural and secondary environments and assessed potential on short and long-term impacts.

Survey Approaches Required

The hydrogeological/geophysical investigations will be carried out in a multistep approach:

1. Desk study: Review of existing data, topographical maps, satellite images, existing studies and Borehole site investigations in the area, geological reports and maps (if available), borehole and surface water records, etc. 

2. Hydrogeological fieldwork: Detailed reconnaissance survey of project area. (GPS coordinates/P codes, water level measurements, condition of these boreholes, usage and performance, estimation of the hydraulic characteristics from existing well test and aquifer test, ), vertical geophysical prospecting at known boreholes  for calibration purpose : measurement of the real resisitivities of geological formations based on the existing borehole logs.

3. Preparing hydro-geological maps which include location of existing boreholes and their water quality.

4. Geophysical measurements  vertical and horizontal electric sounding, vertical electric 3D tomography, EM method and possibly seismic refraction method are recommended for this assignment.

5. Analysis and interpretation of field data for selection of potential sites for drilling

6. Presentation of the results to hydrogeologist/geologist experts from GREDO and Southwest Ministry of Energny, Water, and Resources (MoEWR) for validation of the best possible site

7. Field validation of the site to ensure there is no obstacle for drilling (explaination and agreement with the community, no land tenure or future urban planning issues, access to drilling machine, risk of contamination, …)

Reporting

The final report will be submitted to GREDO after signed off and approval from the Ministry of Energny, Water, and Resources (MoEWR of southwest, Somalia. the report will be a comprehensive account of the whole of the Consultancy; it will review the existing literature and other relevant information, such as drilling logs, satellite images, etc. The report shall include all field data, interpretations and justifications, hydrogeological evaluations, conclusions and recommendations relating to the investigated areas. In addition, appropriate maps, diagrams and data plots shall be presented. Of considerable importance will be an objective assessment of the applicability and success of the methods applied

The outline table of contents of the final report will be as follows:

• Introduction, review of previous studies and environmental background hydrogeological information of the studied area, including history of groundwater depletion or known changes in quality : mineral content including unharmful –iron- and harmful -fluorides, nitrates…-; and toxic elements such as arsenic ;  bacteriological pathogens.

• Geology and hydrogeology (incl. Inventory of positive and negative boreholes, aquifer characteristics –storage and hydraulic- and well characteristics –sustainable discharge rate- based on on available data., and water quality)

• Methods of investigations, including Geophysical Techniques

• Calibration of the geophysical instrument at known boreholes (yield, log) for the geophysic characterization of the geological formations, including the aquifer(s).

• Methods of investigations, including combination of  geophysical methods.

• Geophysical prospecting on different sites.

• Detailed resistivity survey (Wenner & VES) and seismic refraction to delineate the productive aquifer

• Aquifer potential; sustainable yield & Water quality

• Interpretation and comparison of studied sites: aquifer and borehole potentials, Most suitable drilling site and justification , target aquifer(s) for drinking water production, mentioning assumptions, risks and risk management.

• proposed drilling method, with equipment characteristics (incl. estimation of the casing and screen positions)

• Simplified Environmental and societal impact of the drilling and required risks reduction measures

• Conclusion and recommendations

Expected Deliverables

The consultant/firm is expected to deliver: 

• An inception report  presenting 1/ the steps and methodology for the assignment against  the present Terms of Reference, and justifiying any difference or discard with the TOR ;  

• the implementation plan and requirements for the site investigation. A brief note with the recommended sites  selected for borehole reconnaissance and  geophysical survey, for GREDO’s validation before the field deployment, 

• The presentation of the field work, interpretations and conclusions to the GREDO and the water authorities.

• The final technical report

Work Plan

ACTIVITY DESCRIPTIONTime LineW1W2W3W4Secondary data collection, review of field documents on existing boreholes and studies, and analysis     Key informant interviews (face to face or remote)    Field work: Reconnaissance of existing boreholes, geophysical prospecting and final validation of the selected site     Presentation to GREDO and  authorities, Reporting    

Requirements

GREDO seeks to invite qualified consultants/firms who meet the following requirements to submit their detailed narrative and financial proposal on how to undertake the assignment.

1. Technical proposal on how the assignment will be conducted including methodologies, data analyses and interpretation, reports and schedules. ( List software to be used for analysis) ( 30%)

2. Proven field technical and field experience of Consultant  with Master’s degree in geology, hydrology, engineering geology, physical, or earth science, or in any related field and having good experience of working in this sector. (10%)

3. Consultancies performed in the last 10 years especially with reference letters for each hydrogeological surveys consultancy (15%)

4. Proof of availability of all the equipment’,      personnel and ability to mobilize them on short notice (Include list of equipment, Brand/Manufacturer, CVs of the personnel) to perform the survey. (15%)

5. Submit a detailed financial proposal including all professional fees, report costs and subsistence costs. Please note all costs must be broken down into details ( no lump sums, no contingencies etc) (30%)

The consultant/firm will be responsible for their own security; insurance while in the field and GREDO will not be responsible for any injuries or damages incurred during the assignment. The costs submitted must be inclusive of all anticipated expenses.

GREDO will select the geophysical surveyor based on their technical competence and experience. 

Mandatory Security Training

The consultant shall be expected to go through mandatory on-line security training and submit the certificate of completion to GREDO before the commencement of the task. Failure to deliver this will lead to an automatic disqualification. GREDO will advise on the security plan on appointment. 

APPLICATION PROCESS

Interested parties must submit their applications by email referenced under title 

HYDROGEOLOGICAL AND GEOPHYSICAL INVESTIGATION FOR BOREHOLE SITTING

at Consultant@gredosom.org

Deadline for submission: 06th August 2025

GREDO will consider applications from both individuals and firms. Applications shall clearly identify a team leader, who will be the sole responsible to deliver the outputs of the assignment. 

Consultants are requested to submit a proposal with a cover letter and must mention their expected total remuneration for this assignment.

Skills Required

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