RURAL INFRASTRUCTURE
‘Blanket’ keeps lid on open-stored water While many parts of New Zealand seem to be experiencing flooding and above-average rainfall, in only a few months this could change to long dry spells.
available to reduce the water loss. It
Available information about the effects
than the net loss through usage or
of climate change to our seasons
evaporation. Once a dry spell sets in
has made water management and
this can change very rapidly and the net
planning somewhat of a lottery. With
loss then becomes hugely significant.
good foresight there is still a lot that
You can now reduce the effects of
can be done to mitigate the effects
evaporation on a surface area of any size.
of available open-water storage
New product WaterGuard can be simply
for both stock and irrigation.
poured on to any water surface, usually
The effects of evaporation on open-
by just walking along a length of the dam
water storage reserves are immense
while pouring. A product that is safe on
and often underestimated. A single
crops and stock and reduces evaporation
square metre of water surface can
by up to 60 percent has the potential to
easily lose up to 8 litres to evaporation
be a game changer.
every day in summer, and a 1ha dam
It does not need to be applied around
can lose up to 80,000 litres of water
the full perimeter. For very small dams,
that is essential for animals and
it can be applied at a single point. For
growing crops.
large reservoirs or dams WaterGuard
These water loss figures have been
can be applied from several points
largely meaningless to the industry to
along the edge of the water storage
For further information, contact your Farmlands Technical Field Officer or the friendly team at your local Farmlands store.
date, with limited management options
or even by air or boat. As with smaller
Article supplied by Key Industries
has become accepted that a large percentage of open-stored water will be lost to evaporation. This is not too significant if the volume of fill is greater
water bodies, it should be applied from locations along the edge such that the prevailing wind will assist it to spread. WaterGuard is produced from polymers that strongly repel each other when they come in contact with water. This results in a strong spreading action across the surface, forming a liquid ‘blanket’ to reduce evaporation. Once the film is in place, it is very resistant to disturbances. It will move around slowly over the surface but will not build up at one end of the water body. In the event of rain, the blanket will not be affected as it will allow the rain to go through without disturbing the film. WaterGuard will be available from early November in 5L and 20L containers.
SAVINGS IN EVAPORATION This example shows the effect of WaterGuard on a 0.5ha body of water over the 3 months of summer. Area m²
Litres of WaterGuard applied at 21day intervals
Evaporation without WaterGuard (megalitres)*
Evaporation with WaterGuard (megalitres)**
Evaporation saving (megalitres)**
5000
7.5
4.5
1.8
2.7
* Assuming typical daily evaporation rate of 10mm ** Assuming 60 percent savings in evaporation
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THE FARMLANDER | 55
