BOREHOLE DRILLING AND STEPS INVOLVED
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. Engineers and environmental consultants use the term ”BOREHOLE” to collectively describe all of the various types of holes drilled as part of a Geo-technical investigation or environmental site assessment. Typically, a borehole used as a water well is completed by installing a vertical pipe (casing) and well screen to keep the borehole from caving. This also helps to prevent surface contaminants from entering the borehole and protects any installed pump from drawing in sand and sediment.
Drilling has over the years developed to a highly specialized and technical activity. Borehole drilling is the creation of a narrow, deep hole in the ground known as Borehole to access water. Drillers may sink a borehole using a drilling rig or a hand-operated rig.
FOUR STEPS IN BOREHOLE DRILLING
STEP 1 – GEOPHYSICAL SURVEY
The first thing that need to be determined is where the water is and how you will get to it. That is where the services of hydro-geologists are employed. They make use of a variety of borehole drilling methods to assess the geophysical properties of the underlying area.
These hydro-geologists ensures that you are not drilling into natural hazards or man-made infrastructure (pipelines, cables, phone lines etc).
STEP 2 – DRILLING AND CONSTRUCTION
Once the hydro-geologist has helped to prepare a path for the borehole drilling, the construction of the borehole starts. Once the borehole has been drilled, the necessary unstable lengths of the borehole are steel cased in an effort to reinforce the tube.
STEP 3 – DETERMINATION OF THE YIELD OF THE BOREHOLE
In order to most accurately gauge the yield of a domestic water borehole, an aquifer test is performed. This involve installing a test pump and pumping borehole water for a fixed set of variables; a given time at a given rate and then assessing the test’s impact on the water level in the borehole. Maximum yield is achieved by increasing the abstraction rate, ensuring optimum draw down of water in the borehole.
STEP 4 – PUMPING AND PIPING THE BOREHOLE
The kind of pumping system and piping installed in your new domestic water borehole depends solely on the intended use of the borehole water.