Traveston Crossing Dam catchment rainfall trends
January 8th, 2009 by Warwick HughesReading recently that the Queensland Premier Anna Bligh had pushed back for five years any action on building the Traveston Crossing Dam I thought the years end was a good time to post some catchment rainfall history.
Claims by the usual suspects about “worst drought ever”, and variations on this theme are shown to be rubbish. Just a normal, usual drought by the look of it.
A five year postponement sounds like the death knell to me.
Posted in News and Views, Water | 3 Comments »
January 8th, 2009 at 5:56 pm
Warwick, I remember the 1974 floods that show up so well on the graph.
January 9th, 2009 at 6:08 am
Warwick, on the subject of rainfall, did you see that the cash-strapped NSW Government paid Tandou $34 million for some water allocation in the lower Murrumbidgee. This is a sure sign that the current La Nina is going to cause some big flooding on the Murrumbidgee.
Did you also see that the Anglican church in the UK has invested 250 million pounds in Al Gore’s Generation Investment Management. This is a sign that AGW has peaked. It also means that Generation Investment Management will go bankrupt so that the church will lose all of that 250 million pounds.
January 11th, 2009 at 6:01 am
Warwick
A few observations:
Geographically, Maleny rainfall is probably more indicative of the catchment of Somerset Dam (Stanley River) than the catchment of the proposed dam at Traveston Crossing.
Surface water run-off from the Maleny region is already captured by Baroon Pocket Dam and diverted out of the Mary catchment to the Sunshine Coast (and Brisbane via the Northern Pipeline Interconnector when it is commissioned)
If you think the rainfall figures are variable – the streamflow figures are an order of magnitude more variable. The proposed damsite at Traveston crossing is simply nowhere near big enough to buffer the huge variability in streamflow at that site. Stated another way, the dam at Traveston crossing would not be able to harvest much of the high flows (they would simply flow right over the top of it as if it wasn’t there), and it couldn’t store water well enough to get from one high-flow period to the next without being pumped down to catastrophically low levels during the intervening dry spells.
Your figures nicely illustrate how the Mary catchment gets progressively drier as you move downstream (northwards). Annual surface run-off drops even more dramatically, from more than 200mm in the headwaters to less than 20mm in the lower reaches of the catchment.
Put this information together and you can see why the proposed dam at Traveston crossing would be such an environmental disaster. The lower reaches of the Mary are absolutely dependant on receiving stream flow from the upper catchment. That is why a dam at Traveston Crossing which captured and diverted that stream-flow would be so damaging in dry seasons. (Don’t forget that the Fraser Coast is also experiencing rapid growth in water demand which needs to be supplied from the Mary, as well as the Mary being the last river left in any sort of fit state to supply any significant fresh water to Hervey Bay and the Great Sandy Strait).
The political line that “most of the catchment is downstream of the damsite, therefore downstream impacts will be mitigated by inflows from downstream tributaries” simply does not apply to the Mary, particular in dry seasons.
Here is a link to some work recent work I have done on this issue – www.mrccc.org.au/downloads/LowFlows.pdf