Choose a drilling point based on evidence
Surveying helps compare potential locations on a property using geological context and geophysical observations. This is more defensible than choosing a point based only on convenience or surface appearance.
Service Overview
Hydrogeological Survey: a practical guide for Kenyan projects
Groundwater does not occur uniformly beneath a property. Fractures, weathered zones, rock types, recharge conditions and nearby boreholes all affect the likelihood of finding a productive aquifer. A competent investigation considers the available evidence together rather than treating a single instrument reading as certainty. Survey results guide a decision; drilling and pumping tests are still needed to establish the actual borehole performance.
A useful survey report documents the site context, method, observations, recommended point and technical reasoning. It should also state limitations and explain the proposed drilling target. The report supports permit applications and planning, gives a contractor a starting design basis, and helps the client compare scope and cost. Keep the report with the borehole records so future maintenance or rehabilitation work has a reliable baseline.
Benefits
What a well-planned hydrogeological survey project can deliver
Plan for the likely drilling conditions
A technical recommendation gives the owner and drilling contractor a common starting point for access, estimated target depth, rig planning and the discussion of possible geological variation.
Support project approvals
A clear report can form part of the supporting documentation requested during water-resource and environmental approval processes. The exact forms and requirements must be confirmed with the relevant authorities.
Reduce avoidable uncertainty
A survey cannot remove geological risk, but it helps make that uncertainty visible before mobilization. Knowing the assumptions and limitations supports more realistic budgets, schedules and contingency planning.
Our Process
From first assessment to handover
Project briefing
We establish the proposed use, property location, access, existing water sources and any available borehole or geological records.
Site reconnaissance
The survey team reviews terrain, surface geology, drainage and relevant site constraints before undertaking the planned measurements.
Geophysical assessment
Appropriate geophysical methods are applied to investigate subsurface conditions and compare candidate drilling points. Method choice depends on the site.
Report and recommendation
Findings are interpreted and documented with a recommended location and planning guidance. The report is used to coordinate approvals and the next project stage.
Equipment & Technical Scope
Equipment selected for the site and the job
Survey tools may include geophysical equipment for electrical resistivity or other appropriate field measurements, GPS or mapping tools, and instruments for recording site observations. The method is selected by the technical team according to terrain, geology, access and the question the investigation needs to answer. No instrument alone can directly certify an aquifer’s future yield.
Good fieldwork also depends on calibration, repeatable measurement procedures, accurate location records and careful interpretation. The survey report should identify the method and provide enough context for a drilling contractor to understand the recommendation. Where existing borehole records or maps are available, they can help inform interpretation but should be checked for relevance to the specific property.
Planning Advice
How to evaluate a borehole survey report
Check that the report identifies the property and survey date, describes the methods used, and shows the recommended point clearly enough for the drilling crew to locate it. It should explain the reasoning behind the recommendation and identify the estimated target depth or expected geological sequence as an interpretation, not a certainty.
Look for limitations. Nearby boreholes, old maps and geophysical readings provide evidence but do not guarantee that groundwater at one point will behave like a borehole elsewhere. Ask the hydrogeologist which assumptions matter most and what conditions could change the recommendation during drilling.
Use the survey to plan the full project. Confirm permit responsibilities, site access, estimated drilling scope and how the contractor will record encountered formations. After drilling, use the completion details and test-pumping report to guide pump selection. Keep all records together for future water-quality checks and maintenance.
Technical Considerations
Important decisions for a successful project
Define the decision the survey must support
Before fieldwork, explain whether the immediate objective is to select one drilling point, compare several points, support a permit application or investigate an existing borehole problem. The objective affects the area assessed, field method and report detail. Share the planned water use and approximate demand because the technical recommendation should be interpreted in the context of the project, not as an isolated instrument result.
Provide useful site information
Accurate coordinates, property boundaries, access arrangements and known underground or surface constraints help the survey team work efficiently. If the land has existing boreholes, springs, wells or geological records, provide their locations and any known depth or performance history. Nearby data may help interpretation, but it should not be transferred uncritically to the proposed location because aquifers and fractures can change over short distances.
Distinguish measurement from interpretation
A geophysical instrument records a response that must be interpreted using geological understanding and the limitations of the method. A report should make clear which information was directly observed and which statements are interpreted or estimated. Ask the hydrogeologist to explain alternative readings, confidence and the reasons for ranking one location above another. This makes the recommendation more useful than a map pin without supporting analysis.
Plan approvals as a separate workstream
Survey delivery and statutory approvals are related but not identical. Confirm which applications are required for the property and who prepares, submits and follows them up. Authority requirements may vary and can change, so a survey report should not be treated as automatic authorization to drill. Build time for review and approval into the project schedule and keep submission receipts and correspondence with the technical file.
Use results to manage project risk
A recommended drilling point helps with planning but does not eliminate the possibility of low yield, variable formations or water-quality concerns. Agree what happens if the drilled result differs from the recommendation, including technical reporting and any decision about deepening or moving. Budget contingency realistically and avoid committing to a final pump until construction and test-pumping information are available.
Relevant Experience
Portfolio context: surveys supporting varied client types
Milimani’s published project portfolio includes educational clients such as East University Kitengela and Moi Girls Isinya, alongside commercial and infrastructure work involving Sigma Feeds and China Road and Bridges Company. Different sites call for different survey questions, demand estimates and access plans.
These portfolio references illustrate sector breadth, not a promise that a new survey will produce the same result. A new site needs its own field assessment, documented recommendation and approvals appropriate to its location.
Explore projects and client sectorsClient Feedback
A reliable process matters
“We needed a dependable water source for our students and community. Milimani Drilling delivered a strong, well-managed project and followed through with practical support.”
Frequently Asked Questions
Common questions about hydrogeological survey
What does a hydrogeological survey include?
A survey typically includes a project briefing, site observations, appropriate geophysical assessment, interpretation and a report recommending a drilling location. Exact methods vary with site conditions and the agreed scope. Ask the provider to specify methods, deliverables, limitations and whether permit-support documentation is included.
Does a survey guarantee water?
No. A survey estimates groundwater potential based on available evidence and helps select a technically recommended location. Actual depth, yield and water quality can only be established through drilling, borehole completion and testing. Responsible providers describe uncertainty rather than promising a result.
How long does a survey take?
Field time depends on property size, terrain, access, number of locations to assess and the selected method. Report preparation and review take additional time. Ask for a schedule that separates fieldwork from report delivery and any permit support.
Is the report used for permits?
Survey reports are commonly part of borehole planning and may be required in approval applications. Requirements change by authority and location, so confirm the current documents required with WRA, environmental authorities and county offices as applicable.
Can I use an old survey report?
An existing report may be useful if it covers the same property and conditions remain relevant, but age, site changes, intended demand and current approval requirements can affect whether it is acceptable. Have a qualified professional review it before relying on it.
What should I prepare before the survey?
Provide the exact location, property access arrangements, intended uses and expected demand. Share any existing borehole records, nearby well information, maps or prior reports. Mark boundaries and disclose site constraints such as buildings, power lines and restricted access.
Should the survey assess more than one drilling point?
Comparing candidate locations can be useful when a property is large, access is restricted or the preferred area has conflicting constraints. The number of points and survey coverage should be agreed before fieldwork because it affects method, time and reporting. A comparison should explain why one point is recommended over another, not just list readings. The final location must also be practical for rig access, future pump infrastructure and protection from contamination sources.
Plan Your Project
Discuss your water requirements with our team
Send us your project location, intended water use and any existing site records to discuss a survey scope.