Flood mitigation: Don’t mention the dam

p2162-floods-Boessem-3By KIERAN FINNANE

 

The ‘d’ word – a dam – isn’t mentioned in the recommendations of the Alice Springs flood mitigation draft report, though it may be hiding behind “structural mitigation” measures that include “detention basins in the upper catchments”. Is a dam excluded? On the basis of the draft report, it’s not possible to say.

 

The draft report has been prepared by an advisory committee, appointed in February by the Chief Minister and chaired by Mayor Damien Ryan. The main thrust is that work is yet to begin and there is plenty of it. The immediate priority is to undertake “preliminary investigations”.

 

Inexplicably, after almost a quarter of a century of angst about flooding – following the 1992 moratorium on construction of a dam at Junction Waterhole – topographical data in the upper catchment of the Todd has still not been collected. This should be done in year one, says the report, suggesting a $500,000 budget allocation for the work.

 

The other “preparatory” work is to assess the trunk drainage infrastructure that handles stormwater across the town, to reduce the impact and / or frequency of localised stormwater flooding. This should also happen in year one, with a $300,000 allocation.

 

p2162-floods-Boessem-1Structural mitigation assessment should include a cost-benefit analysis and an order of priority in terms of effectiveness. This should inform a program of capital works over five to 10 years. A notional amount of $30m is suggested for the construction of three retention basins in the upper catchment.

 

However, “structural solutions have their limitations and no amount of intervention can stop flooding altogether”, warns the committee. “There will always be properties within the existing Alice Springs town boundaries that will be impacted upon by flooding.”

 

Given this, the town needs to be prepared and the committee recommends examination of all the obvious protective measures like an improved early warning system, sound evacuation plans and critical supplies storage in the event of the town being isolated for a period of time.

 

The impact of causeways crossing the Todd should be examined and a maintenance regime developed to reduce the build-up of sedimentation around them to maximise the “‘hydraulic efficiency’” of the river. This too should be done in year one, with a $100,000 budget suggested.

 

Flow-on effects should be considered for work that is already underway within the Department of Transport. The committee recommends that anything done as a result of a flood immunity study for the Mt John’s and Desert Springs areas does not make the situation worse elsewhere (amazing that this needs to spelled out).

 

p2311-Junction-Waterhole-3Similarly, any duplication of the Stuart Highway south of the Tom Brown Roundabout – currently being investigated by the DoT – would have to ensure a positive impact on the existing flood profile of Alice Springs. In this part of the report, there is reference to a possible widening of the riverbed as it passes through Heavitree Gap.

 

After significant protest, construction of a dam at Junction Waterhole (at right) was prevented in 1992 by a 20 year moratorium under the Commonwealth’s Aboriginal and Torres Strait Islander Heritage Protection Act, with a view to protecting sacred sites in the area. The committee is obviously keen to head off the kind of confrontation seen at that time. Its report includes this statement:

 

“The committee is certain that a successful adoption and implementation of flood mitigation measures must accommodate the community’s needs which include the customs and beliefs of its traditional owners.

 

“The committee acknowledges the guidance of Lhere Artepe in developing its recommendations and strongly recommends continuous communication and participation from Lhere Artepe throughout any further progress of these recommendations.”

 

Lhere Artepe (wrongly identified as an association in the draft) is the Aboriginal Corporation of native title holders. It is represented on the committee by Ken Lechleitner.

 

Other committee members are Russell Lynch, a resident, Michael Sitzler, a business owner, Jimmy Cocking of the Arid lands Environment Centre, and Rod Cramer of the Rural Area Association. The absence of women from the committee is glaring.

 

The full draft report is available here. It is open for public comment until 2 July 2016.

 

 

PHOTOS of the 1988 flood (a ‘1 in 50’, where water depth at Anzac Oval measured 3.9m) by Hans Boessem.

 

 

 

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10 Comments (starting with the most recent)

NB: If you want to reply to a previous comment, start your comment with this notation: @n where n is the number of the comment you want to reply to.
  1. Beverley Ruth Emmott
    Posted September 14, 2017 at 12:30 pm

    Put in a comment and get told I have already said that – well I did years ago but if it is recently said it was not me so someone is claiming to be me.

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  2. Beverley Ruth Emmott
    Posted September 14, 2017 at 12:28 pm

    Maybe someone can mention to the Town Council that it is time they got up to date and started recycling – there are many in Alice Springs without access to cars so the recycling shop is out of access and also so are the charities which are in town and well out of reach of those without cars.
    This morning I cleaned out the cupboards and got rid of cooking things we never use – the problem: No car and no-one to help get rid of them.
    If the council does not like that sort of thing going in the rubbish then they had best start recycling: Have one bin for general rubbish, one for recycling and one for garden.
    Expensive initially but far less so as time goes on and better for the charities and for the environment.
    However I start to wonder if they even care about staying up to date.

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  3. Jenny McFarland
    Posted June 20, 2016 at 6:35 pm

    The previous dam site is a women’s sacred site. I was at some of the meetings about the proposed dam, and saw how much distress and anxiety the Arrernte women responsible for that site experienced.
    Any ground disturbing activities at sacred sites would need sacred sites clearances – and are unlikely to be authorised by the right people for those sites.
    There was also advice provided by engineers that a flood mitigation dam at that site would not work, and that scouring of the river was a risk.

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  4. Posted June 17, 2016 at 8:08 pm

    I’ve taken another look at the flood mitigation draft report, and I can’t escape the feeling this is an exercise in buying time.
    Only problem is, it’s becoming increasingly evident that there isn’t the time available envisaged within that document to proceed with flood planning and mitigation over the next five to 10 years.
    The pace at which extreme and/or record-breaking weather events have occurred locally, nationally and world-wide has risen markedly in recent years, and is well ahead of earlier expert predictions of the length of time it was thought climate change forecasts would take to eventuate.
    Given the general failure across much of the NT for the past quarter century to proceed with necessary civil infrastructure requirements, or even to maintain existing infrastructure (such as regional roads) to acceptable standards, we are probably no better prepared to cope with extreme weather exigencies now than we were 30 years ago. This document (along with other planning processes currently underway) is likely to become quickly irrelevant as I think we will find ourselves overtaken by events in the near future.

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  5. Outback Academic
    Posted June 17, 2016 at 8:24 am

    And as a Territory election looms, not so much as a mention from the different parties on the risk this poses to so many people and facilities in Alice Springs. Tragic!

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  6. Fred the Philistine
    Posted June 15, 2016 at 8:07 pm

    Don’t get excited. Some thing as simple as cleaning the river out and maintaining it would be a good start. The state the river is in is disgrace. At the moment it’s only a drain, and a poor tourism attraction.

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  7. Ian Sharp
    Posted June 13, 2016 at 11:11 pm

    Do I read that right? No fluvial geomorphologists or the like on the committee? Were any experts consulted? All due respect to Damien and co, but I hope some real expertise is taken on board on this.
    And now for my inexpert two bob’s worth: On the strength of my year of geomorphology studies at uni back in the 60s, and my observations back in the 1980s of the huge variations in the bed of the Ormiston creek as it passes through the pound, I wouldn’t worry too much about the “hydraulic efficiency” of the river. In any major flood event the river will sort that out itself. The floodout sand plumes on the Todd delta near the airport indicate that the floods we are are familiar with since the 1870s are merely minor events. A major flood would be devastating.
    In the short to medium term we should be considering retarding basins, levees, dams etc, but in the long run we should consider building new major facilities like hospitals, hotels, schools, shopping malls etc on higher ground, turning the flood plain areas along the river to parks and ovals that can be inundated with little long term damage.

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  8. Richard Bentley
    Posted June 13, 2016 at 6:00 pm

    The highway could be raised onto bridge structure in the gap and the water could then flow under the highway. A raised road widened would also provide space for cyclsists who are currently poorly served by the road.

    A retention basin is surely a dam that does not hold water for long. There could be additioanl inflow of fresh water into the underground acquifer’s however if water was held even for a short period.

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  9. Posted June 13, 2016 at 5:28 pm

    I’ve read the Alice Springs flood mitigation committee draft report (courtesy of this article) and it appears to be proposing a lot of reassessment and reworking over a long period of time, of earlier studies and proposals – in effect, a lot of activity without actually producing any useful results. Very bureaucratic!
    I liked the photo on page 13 depicting the 1988 inundation of the Leichhardt Building on the corner of Gregory and Leichhardt Terraces. At the time it was the regional headquarters of the NT “super” Department of Industries and Development, of which the former Department of Primary Production (where I was employed) was a part. I recall going into that building after the water had receded, the sodden carpet throughout the complex covered in slime and mud. Most memorable was the stench, I don’t think I’ve ever smelled anything worse!
    Interesting to note the reference on page 9 of the flood of March 1910, the largest on record for Alice Springs (the Telegraph Station, as it then was). The recent heavy flooding over much of Europe, especially the Seine River in Paris, was reported as being the worst recorded since 1910. One hopes this is only a coincidence.

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  10. Hal Duell
    Posted June 13, 2016 at 11:33 am

    To widen the riverbed where it passes thru Heavitree Gap would involve moving the highway and the railroad or carving into the eastern side of Heavitree Gap. The first option would be horrendously expensive while the second would have Buckley’s chance of getting up.
    On the other hand, to improve the “hydraulic efficiency” of the Todd, has anyone thought about removing the causeway just south of the Gap? It’s already one-way, and there is a good bridge just south of there.

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