Borehole drilling has become a popular means of accessing groundwater. Water demand is high due to our country's resilience in agriculture and the growing population. Most of us have embraced drilling boreholes. Why do we do this?
Boreholes offer a reliable and sustainable domestic, commercial, and agricultural water source. But what is the average borehole depth in Kenya?
How deep should a borehole be in Kenya?
The depth of a borehole varies depending on several factors, including the purpose of the borehole, the location and geology of the area and the availability of water, the hydrogeology of the site, and the water demand.
According to data from the Water Resources Authority(WRA), the average borehole depth in Kenya is between 50 meters- 300 meters
.
Let's look at how the factors mentioned affect the borehole depth.
Factors affecting the depth of a borehole
The factors that determine the depth of a borehole in Kenya include:
Purpose of the borehole
Boreholes are typically drilled to depths between 30 and 150 meters for small-scale domestic use. This depth is usually sufficient to provide enough water for household use, including cooking, cleaning, and irrigation of small gardens.
However, some areas may require deeper boreholes due to the area's geology or the water table's depth. If the water table is at a shallow depth, then the depth of the borehole will be shorter. But, if the water table is deeper, the borehole will be more profound.
Deeper boreholes are mostly for larger-scale commercial or agricultural use. Boreholes can sometimes be drilled several hundred meters into deeper groundwater resources
.
Geology of the area
The geology of an area dramatically affects the depth of the borehole. For instance, the site's geology determines the type of aquifer in that location.
Sedimentary rocks are usually unconsolidated and semi-consolidated, and their aquifers are primarily moderate to highly productive. The borehole depth will vary between 70m to 150 m in such areas.
An area such as Nairobi has igneous volcanic rock formations- this means that the aquifer is moderately productive. The borehole depth for such geology varies between 150- 300 meters.
Location
Where are we drilling the borehole? Is it in an arid, semi-arid, or wet area? These factors will affect the depth of your borehole. Dry regions will have a deeper borehole than damp areas due to the difference in the water table.
Availability of water
The availability of recharge water in an area drastically impacts the borehole depth. If a site has easy accessibility to water, then the borehole will be of average depth.
But the borehole will be deep if an area has a water scarcity issue. It will range from 150 meters to more as the water table is deep.
Water Demand
The amount of water required also affects the depth of a borehole. Boreholes drilled for high water demand uses, such as agriculture or industrial processes, may need to be deeper to provide sufficient water.
Hydrogeology
The hydrogeology of an area, including the aquifer's recharge rate, can impact the depth of a borehole. In areas with low recharge rates, technicians will drill much deeper boreholes to access groundwater
.
Drilling technology
The type of drilling technology used can also impact the depth of a borehole. Modern drilling techniques like rotary and diamond drilling can reach greater depths than traditional ones.
Regulatory requirements
Regulatory requirements may also influence the depth of a borehole. In some areas, regulations may be in place to protect the groundwater resource and limit the drilling depth.
Note: Considering these factors when planning and drilling a borehole is essential to ensure a reliable and sustainable water source.
Requirements for borehole drilling in Kenya
WRA Regulations
The depth of a borehole in Kenya is subject to regulations by the WRMA. Before drilling a borehole, it's crucial to obtain the necessary permits and follow the guidelines set by the WRMA to ensure the sustainability of the water resource.
Overusing or misusing groundwater resources can lead to the depletion of aquifers and negatively impact the environment and local communities.
Site assessment
Before drilling a borehole, it is vital to have the site assessed. Qualified hydrogeologists or geologists survey the site and determine the area's geology, hydrogeology, and water availability.
During the survey, they can also determine what the depth of the borehole will be.
Environmental Impact Assessment(EIA)
An EIA determines the potential impact of a borehole on the surrounding environment. The assessment is essential before drilling as it helps identify the potential environmental risks and gives a solution or measures to mitigate them.
Conclusion
The average borehole depth in Kenya is between 50 and 300 meters, although this can vary depending on several factors. Boreholes offer a reliable and sustainable domestic, commercial, and agricultural water source. Still, it's essential to ensure that they are drilled and managed responsibly to ensure the long-term sustainability of the water resource. Contact Quantum Geoconsultants Limited, and let us drill that borehole for you today!
