Borehole Drilling

The borehole process — step by step

1. Geophysical groundwater survey

The first step is to assess the property and identify areas that may have a higher likelihood of intersecting groundwater.

A geophysical survey can provide information about the underlying geological conditions and assist in selecting a suitable drilling location and estimated drilling depth.

The survey is an assessment tool and does not guarantee that water will be found, the depth at which water will be encountered or the final borehole yield.

2. Site establishment

Once the drilling location has been identified, we prepare the site for drilling. This may include:

• Confirming the drilling position
• Assessing access for the drilling equipment
• Checking for known underground services
• Preparing the working area
• Positioning the drilling equipment
• Establishing a safe working area

The Customer must advise us of any known underground pipes, electrical cables, fibre, irrigation, drainage or other services before drilling begins.

3. Borehole drilling

The borehole is drilled through the identified geological formations to the required depth, subject to actual ground conditions.

During drilling, conditions can differ from the information obtained during the survey. Rock formations, fractures, cavities, unstable ground and other geological conditions can affect the drilling process, depth and borehole construction.

Where required, casing is installed to help support the borehole and protect it from collapsing or contamination.

Drilling does not guarantee that groundwater will be found or that the borehole will produce a specific amount of water.

4. Borehole development

After drilling, the borehole may need to be developed to remove drilling debris and improve the movement of groundwater into the borehole.

Development can help reduce sediment and drilling residue and prepare the borehole for testing. The exact development method will depend on the borehole construction and ground conditions.

5. Sustainable yield testing

Once the borehole has been completed and developed, a yield test can be carried out to assess how much water the borehole can sustainably produce. The testing can provide information such as:

• Pumping rate
• Water level
• Drawdown
• Recovery
• Borehole performance
• Sustainable yield

The results can then assist with determining an appropriate pump size and operating rate.

A borehole’s sustainable yield is not necessarily the same as the amount of water available at any one moment. Groundwater levels and recharge can vary depending on seasonal conditions and surrounding groundwater use.

6. Laboratory water testing

Once water is available, we recommend having the borehole water tested by a laboratory accredited by the South African National Accreditation System (SANAS) under the ISO/IEC 17025 standard, particularly where the water will be used for drinking or other sensitive applications.

A laboratory analysis can help identify water-quality characteristics such as:

• pH
• TDS
• Electrical conductivity
• Hardness
• Alkalinity
• Turbidity
• Colour
• Ammonia
• Chloride
• Fluoride
• Nitrate and nitrite
• Sulphate
• Dissolved metals
• Other parameters depending on the selected test

Water can contain microorganisms that are not visible and may not affect the taste, colour or smell of the water. Some microorganisms can cause illness, making microbiological testing particularly important when water is intended for drinking.

What does the microbiological test check?

Depending on the laboratory test selected, microbiological testing can include:

• E. coli — an important indicator of possible faecal contamination.
• Total Coliforms — helps indicate possible contamination or problems within the water system.
• Faecal Coliforms — indicates possible contamination from human or animal waste.
• Heterotrophic Plate Count (HPC) — measures the number of living, culturable heterotrophic bacteria in the water.

The results help determine whether additional filtration, softening, purification or other water-treatment equipment may be required.

7. Pump selection & installation

The pump should be selected according to the borehole depth, water level, sustainable yield, required flow rate, pressure and intended water usage.

We can assist with supplying and installing suitable borehole pumps and associated equipment. Pump selection should take the sustainable yield of the borehole into consideration to help avoid excessive pumping.

8. Filtration & water treatment

If the laboratory results identify water-quality concerns, we can design a suitable treatment system around the results. Depending on the water quality, this may include:

• Sediment filtration
• Activated carbon
• Water softening
• Iron and manganese treatment
• Specialised filter media
• UV treatment
• Multi-stage filtration
• Other purification systems

There is no single filtration system that is suitable for every borehole. Treatment should be selected according to the water analysis and intended use.

Your complete borehole solution

At The H2O Hub, we can assist you through the complete process:

Survey → Site Establishment → Drilling → Borehole Construction → Development → Sustainable Yield Testing → Laboratory Water Analysis → Pump Selection → Filtration & Purification

This approach allows us to look at the borehole, water quantity and water quality as a complete system rather than treating each part separately.

Important groundwater notice

Groundwater conditions can vary from property to property and can change over time. Water quality and availability may be affected by neighbouring properties, agricultural activities, factories, industrial activity, pollution, groundwater abstraction and natural changes in groundwater conditions.

For this reason, a borehole should be tested and monitored periodically, and we recommend water-quality testing at least every 12 months, or sooner if there is a noticeable change in the water’s colour, taste, smell or appearance.

A geophysical survey, drilling service or yield test cannot guarantee the presence, quantity, quality or long-term availability of groundwater.

Ready to explore your groundwater options?

Whether you are considering a borehole for your home, farm, business, commercial property or industrial application, The H2O Hub can assist from the initial assessment through to the final water solution.