Call for expressions of interest: Hydrogeological and Geophysical Survey

Oxfam is a global movement of people who are fighting inequality to end poverty and injustice. Across regions, from the local to the global, we work with people to bring change that lasts.

OVERVIEW

Title and brief description of the assignment

Call for expressions of interest: Hydrogeological and Geophysical Survey

Assignment location

Sabawanaag, Bali Kaliil and Ali-Aadan- Hargeisa District, Marodijeh Region, Somaliland

Contract start date

1 March 2026(tentatively)

How to apply

Interested candidates are invited to submit with the following documents:

1)    A technical proposal with a detailed response to the TOR, with a specific focus on the scope of work, methodology, and timelines.

2)    Initial work plan and an indication of availability.

3)    A financial proposal detailing the daily rate expected including accommodation, transportation, stationery, taxes arising from the consultancy service (6% tax for National consultant and all other costs related to this assignment. (Operational and consultancy fees).

4)    Curriculum Vitae(s) (CV) of the proposed consultant(s), proving relevant experience and/or qualifications. If multiple people are involved, an outline of roles/ responsibilities also needs to be included.

5)    Evidence of conducting previous similar work by providing minimum two signed contracts / purchase orders (preferably from UN agencies and INGOs).

6)    Two relevant references (minimum) for previous comparable assignments.

7)    Proof of registration: The bidders also must include a copy of their registration at the relevant authority.

See section ‘7. Application Process’ for further details

Application deadline

21 Feb2026

Specific considerations

1.            PURPOSE OF THIS CONSULTANCY

This Terms of Reference (ToR) outlines the technical and operational requirements for conducting a Hydrogeological and Geophysical Survey to assess the technical feasibility of groundwater development in Hargeisa District, Marodijeh Region, Somaliland. The purpose of this ToR is to invite qualified consultants to submit a detailed technical and financial proposal for the execution of this assignment.  OXFAM plans to assess groundwater potential in selected locations within Hargeisa District to inform technical Go/No Go decisions on the feasibility and sustainability of developing a drinking water source for approximately 5,000 residents.

The groundwater assessment will determine whether enough and acceptable quality groundwater resources are available in the target areas. The objective of this assignment is to generate sufficient hydrogeological and geophysical evidence to support informed decision-making on groundwater development

• Assess groundwater availability and potential yield in the identified locations.
• Identify suitable aquifers (if present), including indicative depth, thickness, and expected drilling depth ranges.
• Recommend the most technically viable site(s) based on hydrogeological and geophysical findings.
• Assess potential groundwater quality risks.
• Provide sufficient technical information to support a Go / No-Go decision.

A target indicative yield of 12 m³/hour shall be used as a benchmark when evaluating groundwater potential and feasibility.

2.            SCOPE OF WORK

The consultant shall undertake a comprehensive hydrogeological and geophysical assessment including, but not limited to, the following components:

Desk Study

• Review of existing geological and hydrogeological maps.
• Review of previous groundwater studies and reports.
• Assessment of regional hydrogeological characteristics.
• Compilation of available groundwater data from nearby boreholes.
• Review of available groundwater quality information.
• Review of available hydro-climatic and rainfall information relevant to groundwater recharge and sustainability.

Field Hydrogeological Assessment

• Field reconnaissance of the proposed locations to assess geomorphology, drainage features, recharge pathways, land use, and existing water sources.
• Mapping of geological features.
• Identification of potential recharge areas.
• Survey of existing nearby boreholes (where accessible), including:
• Estimated depth
• Reported yield
• Water quality (if available)

 Geophysical Survey

The Contractor shall apply appropriate geophysical techniques to assess subsurface conditions.

Minimum requirements:

• Use of ERT (Electrical Resistivity Tomography) and/or VES (Vertical Electrical Sounding) methods.
• Clear justification of selected technique(s).
• Detailed description of:
• Array configuration(s)
• Electrode spacing
• Transect locations
• Number of profiles per site

·         The Consultant shall peg and geo-reference the final recommended borehole location(s) and document coordinates, site conditions, and access constraints.

The Consultant shall submit a detailed geophysical survey plan to OXFAM for written approval prior to field deployment. Field activities shall commence only after approval is granted.

3.             EXPECTED OUTPUTS Overall objective

The objective of this assignment is to generate sufficient hydrogeological and geophysical evidence to support informed decision-making on groundwater development

• Assess groundwater availability and potential yield in the identified locations.
• Identify suitable aquifers (if present), including indicative depth, thickness, and expected drilling depth ranges.
• Recommend the most technically viable site(s) based on hydrogeological and geophysical findings.
• Assess potential groundwater quality risks.
• Provide sufficient technical information to support a Go / No-Go decision.

A target indicative yield of 12 m³/hour shall be used as a benchmark when evaluating groundwater potential and feasibility.

Specific outputs

The survey must:

• Identify potential aquifer type(s), depth(s), and thickness.
• Estimate potential groundwater yield.
• Identify hydrogeological risks.
• Assess likelihood of achieving the target yield (12 m³/hr.).
• Identify areas unsuitable for groundwater development.
• Clearly state survey limitations and uncertainties.

If multiple aquifers are identified, each must be evaluated and presented separately.

The Consultant shall consider inter-annual rainfall variability and recommend conservative abstraction assumptions where groundwater recharges are episodic.

 Decision framework
The Consultant shall provide a clear technical conclusion for each assessed site indicating whether groundwater development is recommended (Go) or not recommended (No-Go). The conclusion shall be based on an integrated assessment of:
• Estimated sustainable yield relative to the 12 m³/hour benchmark
• Aquifer depth, thickness, and continuity
• Technical feasibility of drilling and abstraction
• Identified hydrogeological risks
• Indicative groundwater quality risks

Assumptions, limitations, and confidence levels shall be clearly stated.”

This assignment does not include drilling, test pumping, or laboratory water quality analysis. Groundwater quality assessment shall be indicative only and based on interpretation, secondary data, and risk indicators. The Consultant shall advise whether laboratory testing is recommended during or after drilling.

Site Selection Considerations

The Contractor shall assess and recommend technically suitable locations based on:

• Hydrogeological findings
• Accessibility
• Flood risk (avoid flood-prone areas)
• Distance from contamination sources (minimum 50 meters from latrines, refuse pits, or pollution sources)
• Proximity to the target community
• Potential social and land-related risks, including land ownership, access constraints, and community acceptance.

Final recommended site(s) must be justified with technical evidence.

Any alternative site proposed outside the initially identified locations must be clearly justified and agreed upon with OXFAM and the Government line ministry.

4.            METHODOLOGY

Desk Study

• Review of existing geological and hydrogeological maps.
• Review of previous groundwater studies and reports.
• Assessment of regional hydrogeological characteristics.
• Compilation of available groundwater data from nearby boreholes.
• Review of available groundwater quality information.
• Review of available hydro-climatic and rainfall information relevant to groundwater recharge and sustainability.

Field Hydrogeological Assessment

• Field reconnaissance of the proposed locations to assess geomorphology, drainage features, recharge pathways, land use, and existing water sources.
• Mapping of geological features.
• Identification of potential recharge areas.
• Survey of existing nearby boreholes (where accessible), including:
• Estimated depth
• Reported yield
• Water quality (if available)

Geophysical Survey

The Contractor shall apply appropriate geophysical techniques to assess subsurface conditions.

Minimum requirements:

• Use of ERT (Electrical Resistivity Tomography) and/or VES (Vertical Electrical Sounding) methods.
• Clear justification of selected technique(s).
• Detailed description of:
• Array configuration(s)
• Electrode spacing
• Transect locations
• Number of profiles per site

·         The Consultant shall peg and geo-reference the final recommended borehole location(s) and document coordinates, site conditions, and access constraints.

The Consultant shall submit a detailed geophysical survey plan to OXFAM for written approval prior to field deployment. Field activities shall commence only after approval is granted.

1.            PROFILE REQUIREMENTS

The consultant should have the following competencies:

Essential

The Consultant must:

• Hold valid operational licenses.
• Demonstrate proven experience in hydrogeological and geophysical investigations.
• Provide qualified hydrogeologist and geophysicist personnel.
• Provide references from similar assignments.

Desired

·         Experience in using technology for survey.

1.            APPLICATION PROCESS Submission deadline

Quotations and applications must reach Oxfam no later than [Feb 21, 2025].

Submission instructions

·         Responses must be submitted electronically to: [email protected]

·         The subject of the mail should be Call for expressions of interest: Hydrogeological and Geophysical Survey in Hargaisa Maroodijeex Region

·         All attached documents should be clearly labelled so it is clear to understand what each file relates to.

Clarifications

Any questions, remarks or requests for clarification can be sent up to 10 days before the submission deadline in writing. The (anonymised) questions will be answered to all applicants.

Administrative compliance (list of documents to be submitted)

Responses must be submitted and prepared in [English] and received by the deadline.