Boreholes in Turkana County typically range from shallow to deep, depending on whether they target alluvial/lagga aquifers or deeper regional formations.
Typical depth range in Turkana
Studies and project reports show that borehole depths in Turkana vary roughly between 20 m and 200 m, with many community and household bores falling inside that band. Boreholes closer to seasonal rivers (lagga) and Lake Turkana are often shallower, sometimes under 50 m, while those further from known surface‑water features may need to be drilled to 100–200 m or more to reach stable, lower‑salinity aquifers.
Depth by location type
County‑level water‑resources assessments also note that some planned schemes target medium‑depth aquifers (35–80 m below ground level), especially where preliminary investigation data are available, and only deeper drilling (100+ m) is recommended where the shallow zone is saline or unreliable.
What “average” depth to plan for
If you are planning a borehole project in Turkana County, planners and drilling contractors often use an effective planning depth of about 100–150 m as a practical working average, assuming:
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You are not immediately on a known lagga or river‑alluvium belt.
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You want to tap reasonably stable groundwater with lower risk of drying in dry seasons.
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You accept higher cost and longer drilling time to secure a higher‑yield, longer‑life bore.
For a more precise figure, many water‑supply projects in Turkana design bores in the 120–180 m range when targeting deeper aquifers that can support schools, health centres, or small‑town reticulation.
Why depth varies so much
Several factors create this wide spread in required borehole depth:
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Distance from lagga or Lake Turkana: closer sites often produce shallow bores; inland sites need more depth.
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Groundwater quality: shallow aquifers near dry riverbeds can be saline or brackish, forcing deeper drilling for fresher water.
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Aquifer type: alluvial sands and gravels near lagga are shallow, whereas deeper sedimentary or fractured‑rock aquifers may need 100–200 m.
In practice, if you are developing land at some distance from rivers or lakes in Turkana County, it is reasonable to budget for a 100–150 m borehole as a working average, while still commissioning a pre‑drilling resistivity survey to confirm whether 80 m or 180 m is more appropriate for your specific site.