Borewell production and availability forecasting

What a production forecast is for

Farms, housing projects, factories and water schemes plan around water. A farmer needs to know whether the borewell can irrigate the planned crop area through the dry months. A housing society needs to know whether tanker supply will be required in summer. An industry needs to know whether the borewell can meet process demand or whether another source must be arranged.

A forecast answers those questions with a number and the assumptions behind it. It separates four things that are easily confused:

• what the well can sustain under the approved operating rate;
• what the pump and power supply can actually deliver in the hours available;
• what reaches the tank or the field after losses;
• what the user needs.

A tank can smooth out an hourly mismatch between supply and demand, but it cannot create water when the well falls short over weeks. An availability allowance can account for expected downtime, but it cannot prove the groundwater will support the remaining hours.

Define the forecast question first

Different decisions need different forecasts.

Combining all of these into one “monthly capacity” figure hides the period in which supply may fail. Record the start and end dates of the forecast, working days, shifts or power-supply hours, planned shutdowns and expected changes in demand. In a multi-well system, simply adding standalone well rates can overstate supply if the wells have not been tested running together.

Choose where the water is measured

Specify the measurement boundary: water discharged at the wellhead, water entering the storage tank, or water delivered to the user. Between those points there can be losses from leaks, overflow, treatment rejects or filter backwash. Measure those losses where possible; if they are assumed, label them as assumptions.

Compare forecast and actual at the same boundary. A wellhead forecast compared with a downstream meter will show an apparent shortfall even when the well is performing as planned. Our page on forecast variance and production control explains how to investigate differences.

The basic calculation

For a constant approved rate, the forecast volume is:

V = Q × H × A

• Q is the approved operating rate in m³/h (see operating rate decisions);
• H is the scheduled pumping hours in the period;
• A is the availability factor, the fraction of scheduled hours in which the system is actually able to run.

V is then in cubic metres. Where the rate or schedule changes during the period, for example a reduced rate in the dry season or different hours on different days, calculate each interval separately and add them: V = Σ (Q × H × A) for each interval. Keep the interval details visible in the worksheet rather than replacing them with a single blended rate.

One rule prevents a common error: count each outage only once. If planned maintenance hours have already been removed from H, do not deduct them again through A.

Worked example

Consider an illustrative well with an approved rate of 10 m³/h, scheduled to pump eight hours a day on 25 days in a month.

1. Scheduled hours: 8 × 25 = 200 hours.
2. Assume an availability factor of 0.95 to cover unplanned stops such as power failures and minor faults.
3. Forecast wellhead volume: 10 × 200 × 0.95 = 1,900 m³.
4. Suppose four hours of planned maintenance are removed from the schedule. Scheduled hours become 196, and the forecast is 10 × 196 × 0.95 = 1,862 m³. The 0.95 factor must now cover unplanned stops only.
5. If measured transfer losses between wellhead and tank are about 3%, water entering the tank is about 1,862 × 0.97 ≈ 1,806 m³.

Every figure here is illustrative. The result is arithmetic based on assumptions; it is not evidence that the well can sustain 10 m³/h for 196 hours in that month. That evidence comes from testing and monitoring.

Availability is not the same as utilisation

Availability is the share of time in which the well, pump and controls are able to perform. Utilisation is how much of that time they are actually asked to run. A healthy pump held off because the tank is full is available but not utilised. A pump that cannot start because of a fault is unavailable.

Decide and record what counts as unavailability. Typical items include:

• power supply outages and low-voltage periods, which can be significant in rural areas;
• pump, motor and panel faults, and the time to repair them;
• protective trips such as dry-run cut-outs;
• planned maintenance, if it is not already removed from the schedule;
• downstream restrictions, such as a full tank or a closed delivery line, which are usually counted as utilisation, not availability.

Different definitions give different percentages from the same log. State your definition rather than assuming the word explains itself.

Seasonal and uncertainty adjustments

In much of Telangana and Andhra Pradesh, borewells are drilled into hard rock, where water is held in fractures and weathered zones. Water levels often fall through the dry months and recover after the monsoon. A forecast for April and May should not use the same assumptions as one for September.

Present the forecast as a range rather than a single figure. A practical approach is to give a central case and a low case: the low case might use a reduced operating rate for the dry season, lower availability or longer power cuts. If the low case does not meet demand, plan the contingency now: extra storage, a tanker arrangement, a second borewell, or redevelopment of the existing well.

Monitoring makes the range more reliable over time. Monthly meter readings, pumping water levels and run hours, recorded under consistent conditions, show how the well actually behaves through each season and allow next year’s forecast to rest on measured experience rather than assumption.

Keeping the forecast honest

1. Tie every forecast to a current, approved operating rate.
2. State the period, schedule, boundary and availability definition.
3. Show intervals separately where rates or hours change.
4. Label each input as measured, interpreted or assumed.
5. Compare with actual meter readings at the same boundary every month.
6. Revise the forecast when the operating rate, pump, demand or season changes.
7. Keep earlier versions so trends can be seen.

How Reddy Compressors helps

Yield testing, flushing and redevelopment all depend on the right air, so the compressor behind them matters as much as the forecast. We supply all types, all brands and all models of borewell compressors: new machines, used and refurbished units, rentals, service and spare parts. We are an independent multi-brand specialist working on ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic, Doosan and others, not an authorised dealer of any brand. We have tie-ups with all major and reputed brands.

When a forecast shows that a well will fall short, the answer is often more drilling, deepening or redevelopment, and that needs reliable high-pressure air. From our office at Tarnaka, Secunderabad, our team of more than 20 service engineers and technicians supports rig owners and drilling contractors across Telangana and Andhra Pradesh, and we supply across India. We help by:

• selling new and used borewell compressors and hiring from our own fleet;
• matching pressure and flow to the drilling job, typically 600–1,500 cfm at 200–400 psig (13.8–27.6 bar);
• keeping drilling compressors available through scheduled service and quick parts supply;
• supplying spares identified from the nameplate and the old part.

For drilling compressors on hire, our own fleet is serviced every 300 running hours. See borewell compressor rentals and hire and the borewell and DTH compressor library.

What to send us

• Type of work: new borewell, deepening, flushing or redevelopment.
• Hole diameter, depth and formation expected.
• Rig and hammer details.
• Site location and number of holes or project duration.
• Whether you want to buy new, buy used or hire.
• Nameplate photo of any existing compressor needing service or spares.

Frequently asked questions

How do I calculate how much water my borewell will give in a month?

Multiply the approved pumping rate in m³/h by the scheduled pumping hours in the month and by an availability factor for unplanned stops. For example, 10 m³/h for 200 hours at 0.95 availability gives 1,900 m³ at the wellhead. Then deduct transfer losses to the tank. Use a tested, approved rate, not the flow seen during drilling.

Why is my borewell giving less water in summer?

In hard-rock areas such as much of Telangana and Andhra Pradesh, water levels usually fall during the dry months because recharge stops while pumping continues, both from your well and neighbouring ones. The pump then works against a deeper water level and may trip on dry run. Plan a lower summer rate, more storage or an additional source.

What is availability in borewell water supply?

Availability is the share of scheduled time in which the well, pump, controls and power supply are able to run. Power cuts, faults and protective trips reduce it. It is different from utilisation, which is how much of the available time the pump is actually asked to run, for example when it stops because the tank is full.

Can I add the output of two borewells to get total supply?

Only with caution. Wells close together can interfere, so each may produce less when both run than when tested alone. Adding standalone rates can overstate the combined supply. A test with both wells running together, or careful monitoring of water levels during combined operation, gives a more reliable basis for the forecast.

What should I do if my forecast shows the borewell will not meet demand?

Consider more storage to use the well over longer hours, reducing losses, adjusting demand, arranging an alternative source, or flushing, redeveloping or deepening the well. Drilling work needs a suitable high-pressure compressor, which we can supply on sale or hire. No intervention can guarantee extra yield, so test again afterwards and update the forecast.

How often should a borewell production forecast be updated?

Compare the forecast with actual meter readings every month and update it when the operating rate, pump, demand, storage or season changes, or after any redevelopment or deepening. A seasonal review before summer is particularly useful in hard-rock areas, where dry-season water levels often set the real limit on supply.

Related pages

• Forecast variance and production control
• Operating rate decisions and revision triggers
• Borewell yield testing and production duty
• Groundwater, geology and drilling method selection
• New borewell compressor sales
• Borewell compressor service and repairs