Top 10 Considerations When Choosing a Borehole Pump

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The increasing cost of water, coupled with the shortage of groundwater, leaves both domestic and commercial customers with the need for alternative methods to supply clean, naturally filtered water for applications such as irrigation and drinking water for animals. For some however, the problem is reversed – a high water table can render land unusable. Whether you’re trying to lower the water table or find a cost effective solution to watering your plants, borehole pumps can provide the perfect solution.

However, choosing a borehole pump can be a difficult decision considering the large range available and number of variables to consider. So, how do you decide which one is right for the job? Our handy list of 10 considerations to choosing a borehole pump will help make this decision easier.

1)       What is the application of the borehole pump?

Once you know what you want to achieve with the borehole pump you can begin to plan your system. Are you hoping to irrigate a garden? Store water in a tank? Lower the local water table? All of these things, and more, are possible but they all have very different factors to consider.

2)       What is the diameter of the borehole?

You must know the size of the borehole to ensure it fits correctly. The smaller the borehole, the smaller the pump would need to be and this would mean the pump would have a tougher time pumping the water to the surface.

For this reason, a pump which is smaller in diameter would need to have more stages to achieve the same duty, which tends to increase the price of the pump. That said, it is cheaper to drill a smaller bore hole than a larger one, so you will have to find a balance you are comfortable with.

3)       What is the average depth of the water level?

It takes a lot of effort to move water against gravity and with every 10 vertical meters an extra bar of pressure is needed to overcome it. Therefore, it is important to know the average depth of the water to gain an understanding of the power required in your borehole pump.

4)       How far away is the water being pumped to?

Once you know the vertical distance you intend to pump the water, it is time to calculate the horizontal distance between the top of your borehole and the destination of the water. The further away it is being pumped, the more pressure is needed to overcome factors such as viscosity which restricts the flow of water. Although the effects of viscosity are relatively small they can mount up when pumping over a large distance.

5)       What is the size of the pipe (diameter)?

The diameter of the pipe is an important factor. Essentially, the rule is that a smaller pipe diameter will cause more friction than a larger pipe (all things being equal), therefore, more pressure would be needed to overcome the pressure loss caused by the friction.

6)       What is the above ground elevation of your pipework?

Make note of any elevation between the top of the borehole to the highest point the water will be pumped to. This figure combines with pipe diameter, pipe length, standing water level and drawdown level to arrive at a total system head.

7)       What sort of flow rate would you need to achieve?

It is important to know what flow rate you hope to achieve, for example, if you were sizing a borehole pump up to supply a sprinkler system you would need both pressure and flow to make it work effectively.

8)       Do you have a single or three phase power supply?

Some borehole pumps are only available in either single or three phase versions, therefore, you will need to know what power supply you have available as this will limit your options.

9)       How will the pump be controlled?

Will you require the pump to be controlled automatically or manually? This really depends on what you hope to achieve with your system. For example, if you are planning on reducing the local water table it may be worth using an automatic borehole pump. That way, when the water is brought to its desired level, the pump will turn off automatically and wait for the water level to refresh, at which point the pump would begin pumping again.

10)   What is the refresh rate of the borehole?

Refresh rate describes the time natural water level would recover if pumping was stopped. If, for example, your aim is to reduce the local water table, you would have to ensure the refresh rate was not higher than the flow rate your system could achieve. Imagine if you had a half filled barrel of water and every minute you took one bucket of water out of it but put two back in, the water level would rise rather than fall.

As one of the leading providers of water pumps, ATAC Solutions’ team of knowledgeable and experienced advisors are always on hand to help you select the best pump for your job.

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