In a bid to fight prolonged and crippling drought, Los Angeles has acquired millions of plastic "shade balls" to help with water conservation efforts.

The balls can not only reduce evaporation by more than 1 billion litres, they also help to safeguard water quality by blocking sunlight.

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Mayor Eric Garcetti released 20,000 balls into the Los Angeles Reservoir. There are now a total of 96 million shade balls covering the water.

"By reducing evaporation, the shade balls will conserve 300 million gallons of water each year," Mr Garcetti said.

Los Angeles had to approach several suppliers to obtain the millions of shade balls it required.

One of those manufacturers, Sydney Chase, prefers to call them "conservation balls" because she says they bring a number of environmental benefits.

"The reason they were originally referred to as shade balls is it was an issue of mitigating bromide in algae bloom and we found that there were so many more applications such as evaporation and eliminating a tremendous amount, up to 90 per cent of that, as well as protecting wildlife," she said.

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"If something were to enter the reservoir such as a deer or animal, they are not challenged or drowned while trying to escape back out of the pond."

In fact, shade balls could prove the difference between life and death for some livestock.

"We do also have a lot of reservoirs on farms and I mean that's a huge issue here in northern California. It certainly would be perfect for that situation," Ms Chase said.

"They're easy to deploy, there's no maintenance and they rise and fall with the level of the water."

Worth considering for some Australian dams

As to whether shade balls could benefit Australia, Adam Lovell, executive director of the Water Services Association of Australia said there were a number of factors to consider.

"Our dams here are so large that the cost of actually putting those balls down would just be too big," he said.

But while shade balls may not be the solution for Australia's large dams, Mr Lovell said they could prove useful for all the small dams and holding ponds scattered throughout regional Australia.

"There is that potential to use it if in sort of desperate measures," he said.

"It could save evaporation and it could of course also stop algae blooms, which also can be quite detrimental to stock watering."