Calculating Your Farm Water Usage Requirements

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Calculating Your Farm Water Usage Requirements

Careful water planning is essential before investing in your farm and costly constructions. This planning means performing a detailed water audit for your farm, calculating your farm water requirements and then working out appropriate water sources that you can tap into. This article is intended to help farmers calculate their water usage needs.

Areas of Farm Water Usage

While your farm will have unique water requirements depending upon your produce and/or stock, there are four general areas of water use to consider on your farm property:

  1. Household water use
  2. Gardens, lawns and shrubbery
  3. Irrigation for crops
  4. Stock water use

Household Water Use

Throughout developed areas, people generally use between 170 to 220 litres per day. In Melbourne, residents are encouraged to contain their daily water use to a maximum of 155 litres per day. While detailed water usage calculations can be performed, estimates would place annual household water requirements between 50,000–70,000 litres per person. If you’re water conscious and make use of water efficient devices, then you could easily fall within the lower water usage boundary.

Gardens, Lawns and Shrubbery

You should also factor in allowances for gardens, lawns and shrubbery and general vegetables you might grow. The following table, courtesy of Agriculture Victoria website, provides water allowance estimates during a summer period based upon general experience in Victoria and would benefit from local adjustment to meet your specific circumstance:

Type Watering allowance in litre per m2 (averaged over the year)
 Rainfall > 800 mm 500–800 mm < 500 mm
Native garden (no lawn) 50 100 150
Lawn with shrubs 150 300 450
Vegetable garden 300 600 900

While convenient to work with average water requirements, specific daily requirements may vary considerably over the year and from year to year and depending upon your location.

Irrigation for Crops

It would be an enormous task to provide water requirements for all of crops that can be grown in Australia, throughout their different stages from plantation through to harvest at the end of their season. Numerous crops can be grown throughout Australia and it is assumed you aren’t going to farm a particular crop with your eyes closed, but you’ve performed much research.

While you might get away with average gardening water requirements, it is important that you don’t do this with your crops since the quality of your produce and indeed whole farming business depends upon your yield.

With this, you need to know:

  • the precise water requirements specific during your crops seasons
  • how long you will need water from plantation to harvest
  • the amount of water necessary throughout different growing stages of your crop.

Some crops such as lettuce and cabbage need water right up to harvest whereas dry crops like maize or sunflowers may have minimal water requirement during their ripening up until harvest stage. It important to calculate when you will need the most water, and ensure you will have enough water during those periods.

Stock Water Use

If your farm will have stock, then the drinking requirements for grazing animals will differ based upon weather, water quality, nature and quality of feed and stock type, breed and maturity.

During summer months you can anticipate about 25% more water, and during winter 25% less. While we expect you’ll know more details water requirements for your stock, the following table provides a starting point for quickly estimating stock drinking requirements:

Stock Annual average drinking water requirement
(litres/animal/year)
Sheep:
nursing ewes on dry feed 3,650
mature sheep – dry pasture 2,555
mature sheep – irrigated pasture 1,280
prime lambs – dry pasture 1460
prime lambs – irrigated pasture 400
Cattle:
dairy cows, dry 29,200
dairy cows, milking 54,750
beef cattle 25,550
Weaners (250-300kg) 18,250

These figures are general estimates for the amount of water stock will consume, however water will also need to calculated for farm cleaning and other miscellaneous stock management activities.

The amount of water required for such activities depend upon your stock type, equipment used and practices in use. For example, if breeding sheep, then you will need to set aside water for sheep dips to rid them of parasites.

To assist with calculating your farm water usage, the Victorian government has put together an online farm water calculator. While you should perform careful estimates, we recommend you giving it a go with information you already know.

If interested in using rainwater tanks as part of water storage needs, we offer very competitive multiple water tank options. National Poly Industries loves to help Australian farmers and service the agricultural industry. We understand how important having a reliable water supply is and won’t let you down.