Waterwise on the Farm (Version 2)

3.  Water efficiency actions

Listed below are some actions that you can take to use water more efficiently.

All farms

These water efficiency measures could be applied on most farms and many of them are low or no cost options.

Leaks

There are two main ways to check for leaks.

Visual checks

Using your water networkmap (see Chapter 2), check the ground above your pipes to look for visible signs of a leak. Such signs can include:

  • unusually damp ground;
  • lusher than expected vegetation (for a recent leak);
  • reduced vegetation (for a long-term leak, because of reduced soil quality).

Flow monitoring

There are two main techniques that you can use to detect leaks that you cannot see:

  • record your meter readings. See ‘night flow’ top tip.
  • specialist leak detection. If you suspect that the leak is deeply buried or under concrete, then there is various equipment that you can use to detect this. This includes listening sticks, remote listening devices, pressure fluctuation sensors and ‘intelligent’ meters that ‘know’ your expected water-use patterns and then alert you to any unexpected flows. To find such services, either consult your local Yellow Pages or contact your local water company to see whether they run a leak detection programme.

Top tip: leak location

If you have shut-off valves on your water network, shut off different sections in turn and then reperform the night flow test. When the reading stops increasing, the section that you have isolated will be the one with the leak in it.

Taps and hosepipes

Fix dripping taps promptly and, where taps are used regularly, consider fitting automatic shut-off valves to make sure that they are not left running when unattended.

Fitting self-closing trigger nozzles to hosepipes will help you to:

  • control the flow of water;
  • direct the water more accurately to where it is needed;
  • eliminate wastage when the hose is unattended.

Check the nozzles regularly to make sure that they are free from blockages and damage.

Washing and cleaning

You can use dry-cleaning techniques, such as scrapers, squeegees and brushes, to remove solid waste from yards and pens before you clean them with water. This will reduce the amount of water you use, as well as the volume of dirty water that needs treating, storing and disposing of. It will also reduce the risk of creating diffuse pollution.

Top tip: pre-soak

If it takes a lot of water and effort to clean your parlour after milking, you could use a small amount of water (a bucket or so) to lightly wet the parlour first. This will make the muck stick less, reducing the amount of water that you will need to use to clean after milking.

Alternative sources of water: rainwater

You can re-use rain collected from the roofs of farm buildings for a variety of activities, including washing down yards and washing equipment. How much rainwater you can use depends on:

  • how much rain you receive. If you do not know your annual rainfall, your local Environment Agency office may be able to tell you the figure for your nearest rain gauge. See Chapter 5 for contact details. Please have your grid reference handy as this will speed up your enquiry
  • how much you can collect. This will vary depending on the size, slope and material that your roof is made from. Do not collect the water if your roof is made from, or coated with, bitumen, metals other than stainless steel, or concrete containing asbestos.

Calculating collectable rainwater

Collectable rainwater (litres) = roof area (m2) x drainage factor x filter efficiency x annual rainfall (mm) Drainage factor. This allows for evaporation that occurs when water is retained in irregularities in the roofing material. The factor can be viewed as the percentage of the rainwater that will flow off the roof. Examples of factors for different roof types are given in the following table.

Roof Type Drainage Factor
Pitched roof - tiles 0.75 - 0.9
Flat roof - smooth tiles 0.5
Flat roof - with gravel layer 0.4 - 0.5

Filter efficiency. Filters designed specifically for collecting rainwater will reject the first flush of rainwater, which carries any contaminants (such as leaves or bird droppings) off the roof. High quality filters typically have an efficiency of 90 per cent and so a factor of 0.9. The manufacturer will be able to supply the model-specific efficiency rating.

Example

A farm building with a pitched roof area of 300 m², using a downpipe filter unit with an efficiency of 90 per cent, in an area with 1,200 mm annual rainfall would yield:

300 x 0.9 x 0.9 x 1,200 = 291,600 litres of rainwater annually.

  • How much you can store. This depends on the space you have for storage and your demand for water. For regular demand such as stock watering, you will only need to store a few days’ requirement. Irregular uses that need a lot of water, such as irrigation, will probably need a larger tank.

Harvesting rainwater is particularly suited to dairy farms, as they tend to be located in the wetter areas of the country and have a regular demand for water. A study by the Environment Agency has found that a typical dairy farm could meet 20 per cent of its wateruse with rainwater.

Before using rainwater, you should check that this does not breach any hygiene or farm assurance scheme requirements that you are part of.

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