Moving water at Sydney Uni

Finally some rain; It has been a dry couple of months, especially in Sydney. My garden looks like dust bowl and not because of the recent dust storms in Sydney. The amount of soil that was lost in those dust storms is scary and will take years to rebuild. It stresses even more the need to sequester carbon in our soils and many people have already pointed this out. The agricultural community would like to be paid for the amount of carbon they sequester and that is understandable, but, while there is great potential there are difficulties in monitoring the amount of carbon changed. But what about the water? The last month drier weather got me watching the “El Nino” monitor again to see if we are again in for a long drought, but it all seems pretty uncertain. It also got me thinking again about how the rainfall would change under changes in the global climate and how carbon and water would work together.

About two weeks ago there was an article in the newspaper which dealt with a story about salinity. Prof. Ian Acworth from UNSW discussed a study of groundwater levels that he completed with Aleksandra Rancic form DECC.The key point was that they believed to have found that the expression of dryland salinity was more related to climate variability then to landuse change.

"By studying historical records for thousands of water bores across NSW, researchers from the NSW Department of Environment and Climate Change and the University of NSW have shown that salinity is traceable to rising groundwater levels."

Well we knew that, but I assume that is the reporter not getting it right. it started off much more controversial:

"CLIMATE and rainfall, not land-clearing, have emerged as the main drivers of salinity in south-eastern Australia, in a study that could overturn years of research."

Ian knows how to kick up a controversial story and this one definitely got the airwaves buzzing. Several people have contacted me and checked whether I read the story and wanted to comment. I promised I was going to write something on my blog about this.

It has been a buzz in inland Australia: lake Eyre is filling! The ABC is making a big story about it with a story on 18 May and one today (25 May) although that one is more focussed on the organic beef producers in channel country. Overall it is recognised as a great event and a good thing for the area. I got really interested in the question how often Lake Eyre actual fills. So some real hydrology this time

An article in the Sydney Morning Herald on Saturday caught my eye because it was quite misleading in its content. It seemed to suggest that the water from the recent flooding in Tamworth was supposed to have reached the Darling river, if there was no pumping from agriculture. Anyway that is the tone that is set in the opening paragraph of the article. Only in the last 4 paragraphs does it get to the bottom of the issue, that most of the water would vanish naturally. I hate this type of reporting, although I can understand why the newspaper does it that way: it sells. But as my goal is to educate people about the Australian environment, this type of article makes me weep.

Well, it has been shown again that Australia really is the land of droughts and flooding rains. I have a short posting today. My PhD student, Dawit, sent me some pictures from his research site (a DWE monitoring site) in the Cockburn river near Tamworth. As you might have heard on the news, the area has had a lot of rain (150 mm+) in the last couple of days

Sorry, I am a bit late with posting this week. Oh, that might be assuming that somebody actually reads my ramblings (Preposterous!). Sustainable yield is used in all state and federal policies in relation to surface and groundwater and is currently the goal of a major CSIRO research project in the Murray Darling Basin. The CSIRO project seems to suggest that there is a measurable or quantifiable thing called “sustainable yield”. However, is there really something such as sustainable yield that we can scientifically or at least quantitatively define? Most definitions of sustainability in Australia echo the famous Bruntlandt report definition that reads: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Yes, I know, it is a very anthropocentric definition and it is also not very quantitative. It is in fact very qualitative and I think that is what makes the whole area of sustainability so problematic.. But back to water as that is what I wanted to discuss.

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?