The Importance Of Good Borehole Siting When Drilling A Borehole In Zimbabwe
Choosing a borehole site in Zimbabwe is a critical part of the process of providing a safe and reliable supply of groundwater.
The best sites are those in which catchment (natural water input) may be maximized. Such locations are not necessarily those that receive the highest rainfall (which may occur in upland watersheds). ‘Bottomlands’ – such as river valleys and lake basins – tend to be areas of the maximum catchment as both surface water and groundwater migrate towards them under gravity.
 |
| The Importance Of Good Borehole Siting When Drilling A Borehole In Zimbabwe |
 |
| The Importance Of Good Borehole Siting When Drilling A Borehole In Zimbabwe |
- Perched Aquifers: At site A, a shallow dug well may provide a little water from a ‘perched’ aquifer in the weathered zone above relatively impervious (low porosity) mudstones. If this well was extended into the mudstones it might produce very little additional water. A perched aquifer is normally limited in size and lies on an impervious layer higher than the area’s general water table.
- Shallow Unconfined Aquifers: The term ‘unconfined’ refers to an aquifer within which the water is open to atmospheric pressure: the so-called piezometric surface (pressure head level) is the same as the static water level (SWL) in the borehole. At site B, a borehole extracts water from an unconfined sandstone aquifer, the SWL of which is somewhat lower than the level of flow in the river. This sandstone aquifer is in a good catchment area because of the recharge from the river.
- Confined Aquifers: A ‘confined’ aquifer may hold groundwater under greater pressure so that when punctured by a borehole, the SWL rises to a higher piezometric level. If the piezometric surface happens to be above ground level (which is not uncommon), water will flow out of the borehole by itself: this is known as ‘artesian water’. Deep borehole C intersects the sandstone aquifer and a deeper confined aquifer in fissured limestone; because of overpressure in the limestone aquifer, the SWL in C may be at the same or higher elevation than in B. The limestone aquifer may have no source of replenishment; so the water in it is ancient, or ‘fossil,’ and could be exhausted if over-exploited.
- Fracture Zone Borehole D, which has been drilled into fractured granite (shaded area), finds water held in the fracture zone. Fracture zones develop during geological times as a result of the severe mechanical stress, caused by tectonic movements, that is exerted on non-plastic formations.
- Hydrogeological basement Site E, a borehole sunk into massive granite on top of a hill, is dry. In this situation, it would be a waste of time and money to extend a deep borehole (such as C) into the metamorphic basement, which is generally known as the ‘hydrogeological basement’ or ‘bedrock.’
The bedrock marks the level below which groundwater is not likely to be found.
We have a substantial presence and experience in Borehole Siting, Borehole Drilling, Borehole Installation, and Solar Systems.
Standard Prices For Borehole Drilling
Borehole Siting (Geo-Survey)
Drilling & Casing (40m)
Standard Class 6 Casing included.
Premium Casing Upgrade
Upgrade to Class 9 Casing for extra durability.
Borehole Deepening / Extra Metres
For drilling beyond 40 metres.
Double Casing
For unstable ground conditions.
Tank & Tank Stand
5000 Litre Tank with a 4-metre Stand.
Disclaimer & Contact Information
ProWater Solutions makes no representations or warranties express or implied in relation to this website or the information and materials provided on this website. ProWater Solutions shall not be responsible for, and disclaims all liability for loss, injury, expense or damage (whether direct or consequential) of any nature whatsoever which may be suffered as a result of or which may be attributable, directly or indirectly, to the use of or reliance upon any information, links or services provided through this website. ProWater Solutions reserves the right to in its absolute discretion to modify, upgrade, update, suspend or withdraw this website or any part thereof at any time.
Request ProWater Solutions Services
ProWater Solutions links you to the best borehole drilling service providers in Zimbabwe. Contact us for FREE advice on your project:
David (Sales)