Welcome to part-1 of a 4-part series concerning the drilling and equipping of boreholes. We shall cover the entire process from having the site survey to commissioning of the borehole.
A borehole is a narrow shaft bored into the Earth’s crust in order to locate gas, water, oil or for other purposes. Here, we shall limit our scope to water.
Did you know that the deepest borehole on Earth is the Kola Superdeep Borehole in Russia?
Typical borehole depths in Kenya vary according to area and hydrogeology. E.g. in Nairobi, Karen, typical borehole depth is 400m and in Embakasi, 250m.
Before embarking on drilling a borehole, it’s important to note the items that you may require. In Kenya, you will require 3-documents
1. Hydrogeological Survey.
2. NEMA (National Environment Management Authority) permit.
3. WRMA (Water Resources Management Authority) drilling permit.
The contractor will be required to have been registered fully with National Construction Authority (NCA).
The Hydrological survey report is obtained from a registered hydrologist.
With this information, you can approach a Drilling Contractor to do the actual drilling for you.
Once the borehole has been drilled, the driller will issue a Borehole Completion Record (BCR) from WRMA that contains important information concerning that borehole. This information can then be shared with us so that we can do a proposal for the most suitable equipment.
The Borehole Completion Record has information such as
1. Borehole depth.
2. Tested yield.
3. Borehole profile.
4. Static Water Level, SWL.
5. Pumping Water Level, PWL.
Other information that the borehole owner will need to avail is:-
1. Distance to power house from wellhead, d1.
2. Distance from power house to water delivery point d2.
3. Horizontal distance to water delivery point, d3.
4. Elevation from well head to water delivery point.
5. Existing pipe material, and diameter.
The above information will help us get the appropriate cable length and pipe length. The pipe length and diameter are important for getting the frictional head loss which are an important component of the Total Dynamic Head, required for the specification of suitable equipment.
With this information, we’re ready to do a borehole equipping proposal for you.
Credits – Peter Munyoki, borehole