Moving water at Sydney Uni

On the one hand there are continued calls to the government to immediately buy or release water to “save the lower lakes”, but on the other hand we are very worried about including petrol in the carbon tax emission scheme. Seems like a bit of a contradiction...

The news this week was full of the problems with the lower Murray and the Murray Darling system again. This was because there were a range of new studies and reports which basically told us the same old story: The Murray Darling system is over extracted and the health of the system is bad and getting worse. I believe, however, that the interesting debate is whether it can be fixed, and particularly how easily it can be fixed. Is it just a matter of adding water?

I have already covered this topic a bit but last Friday (13 June) I have just spent a whole day listening to talks about “facing climate change” and wanted to share some of what was discussed on this blog. If there was one clear message on the day it was: I cannot believe parliament is discussing 5 cent per litre in the petrol price if we have these issues to worry about! In fact, one of the panellists at the end of the day remarked: I am glad I will be dead in 2050! Not exactly encouraging and not exactly showing much confidence in scientists and society having or reaching any solutions. Is there anything we can do?

Last week we dealt with evaporation. This week I am adding plants and thus dealing with evapotranspiration. The general statement is that Australia’s climate is characterised by the low rainfall and very high evapotranspiration. Increasing water use efficiency in irrigation should focus on reducing evaporation and increasing the amount of production per unit water applied (more crop per drop), and maybe climate change is going to help us, or is it not?

Or between a small and shallow or a large and deep storage?

The main problem of large scale irrigation in Australia’s Murray Darling Basin is the uncertainty of the supply of water and thus the need to store water in large ring tanks (up to several 100 ha in surface area) to manage the water. Such large basins, if they are also shallow can evaporate extensively and this a key problem the irrigation community struggles with. Using engineering we could make them deeper, but as a result we would loose more water in deep drainage. So no luck there…