Rain ensures critical water supply to Murray River

 

Altogether, over the three-year period 2006-2009 only 5040GL has flowed into the river, one fifth the long-term three-year average of 26,700GL.

The outlook for irrigation water for 2009-10 is grim.

Mr Freeman said after nine dry years, the soil was now so dry that the long-standing relationship between rainfall and inflow into the rivers had broken down.

“Even if you do get average rain, you get nothing like average run-off. In fact in most of the basin we have got no run-off from the rain.”

He said although there had been some rain in the northern basin, “we haven’t got the run-off. We will get a small inflow into Menindee Lakes.”

But Mr Freeman said the soil was now wet in the northern basin “and this most recent rain in the last few days is wetting up the southern basin to a point where it may respond and we might get run-off.”

Mr Freeman was also optimistic about the Bureau of Meteorology’s forecast for average rain over winter, the wettest time of year for the Murray system. “The outlook for the next three months is better than we have had for the last few winters, without doubt.”

Basin storages are now at 980GL, or 11 per cent of capacity, above the lowest year of 2007, but well below the average of 4670GL.

“It is a pretty gloomy story,” Mr Freeman said.

But he pointed out that there were some positives.

The series of algal blooms that extended down the Murray River from Albury to Wentworth before Easter have dissipated, thanks to the lower temperature.

“We have gotten through a terrible summer with minimal water, high temperatures and significant blue-green blooms without a major environmental disaster. I think that is good,” hesaid.

Mr Freeman added that salinity was at an all-time low.

“If you don’t irrigate, you don’t mobilise salt. People are talking about the water quality at Swan Hill — it is some of the best we have ever seen.”

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