That said, the situation has improved substantially since early February.

Local Land Service pastures officer Clare Edwards surveyed producers who attended the Oberon meeting held on 7th February (before it rained).

Of the 32 farmers who responded to the survey, 27 had dry dams on their property.

Overall 35per cent of dams were dry and 46pc were making decisions based on water availability.

Seems that many, while not entirely out of trouble, may have dodged a bullet in regards to water supplies.

I imagine many producers will take this into account as they plan for future dry seasons.

While running out of water is most difficult to handle, others have problems with water quality.

Some dams were and remain brown and turbid while others developed a growth of blue green algae (BGA).

I have submitted a couple of samples of suspect water to the laboratory, with Microcystis, a species of blue green algae, identified.

Of interest, these organisms are actually bacteria (named Cyanobacteria), not algae.

This means that the individual bugs are tiny and so a bloom of BGA looks like green paint on a water course.

The green growth that you can pick up as strands or tiny plants are not Cyanobacteria.

If in doubt please refer to the ever popular ‘What Scum is That,’ which could be mistaken for a social media site but is in fact a publication available on line to help you identify the growth on your dam.

Cyanobacteria can poison stock, either causing sudden death or liver failure.

About this time last year, then district veterinarian based at Condobolin, Kasia Hunter, reported that 40 of 3000 merino weaners died and another 120 showed signs of liver disease when their only source of water was heavily contaminated with blue green algae.

Previously a colleague reported that 28 Hereford cows died within 50 metres of a blue green algae infested dam some years ago.

People and pets are also at risk from BGA.

I read of a tragic case in Brazil, where 75 dialysis patients died from exposure to toxins in dialysis fluids.

While these reports are most concerning, in my experience deaths from blue green algae are rare.

In most cases stock are able to avoid the green scum which usually accumulates on one side of the dam, driven by the wind.

Blue green algae infestations are a threat on public water supplies.

I understand that these can be managed in some situations by creating water turbulence.

Barley straw in a dam is also reputed to suppress BGA while herbicides are an option.

However, blue green algae prefer still, warm water.

With rain and cooler weather, infested dams should now clear without intervention.

It would be remiss of me not to acknowledge that while we regard Cyanobacteria as the scum of the earth now, they are one of the Earth’s oldest life forms, essentially unchanged for three billion years.

Cyanobacteria can photosynthesise and have therefore been releasing oxygen into the atmosphere all this time.

We therefore owe our lives to Cyanobacteria. As if this wasn’t enough of a contribution, it is likely that the small green chloroplast in plants, responsible for photosynthesis, were Cyanobacteria that became incorporated into plants several hundred million years ago.

There must be a moral to this story somewhere.

Final Watts What

THIS will be my last contribution to this column.

Communicating with a wide readership for the last eight years has been a great privilege.

However, with the formation of Local Land Services I have a different job meaning that I cannot maintain this commitment.

I also believe that it is desirable both for our team and for you as readers that you hear from a range of authors to reflect the diverse skills and interests of our new organisation.

With the support of both you as readers and the editor of this publication, we aim to return in the future in a different format.

Until then all the best.