Canterbury Water Strategy

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Ecan has just released the Canterbury Water Strategy ). You can get a free CD-ROM with a 145 page Acrobat file on it. There is nothing too threatening for canoeing, unless developers target the Hurunui above the Mandamus River confluence, and the Rangitata above Klondyke. Tha Clarence is another river to watch out for. The guts is that all the small Canterbury rivers are over allocated and future water for irrigation will have to come from "harvesting" the bigger rivers and storing water.

tim0's picture

2. It would be quite the intake structure to have any sort of effect on freshers going down our rivers. OPening an intake structure during a fresh would probably destory it or at least dump large amounts of sediment in the storage area which would be expensive to extract. At present the Waimak schemes close down during NW high flows. Point is the intakes will not have much effect on bed movement during high flow events.

The filling of storage will occur in periods when there is suitable flows all year rather intakes during only the irrigation season as present in many schemes. The RDR is different in that it occurs all year and operates the Highbank and the Drop? power stations when ever possible.

nathan1's picture

Hmmm, advocates of the water storage concepts are going to use this report as a weapon for their schemes. I think there are a few concerns.
1) There should be one type of abstraction system on a river. Either storage or "run-of-the-river". These schemes should not allow both from the same river, otherwise we lose too much. The big flows will be tailed off for storage AND there will still be abstractors (who aren't part of the above schemes) taking surface water even when the river is running at only modrate flows. Double whammy on natural values.
2) The loss of the big flows as water is stored will lead to a reduction in natural character of Canterbury's braided waterways. Moderate to large flows are needed to wipe out weedy woody vegetation that forms on islands in the braids, protecting habitat for indigenous plants and animals. Will removing these flows mean that only the sporadic big (and here I mean a classic 2000cumec Waimak flood) flows will do this?

Braided rivers are created by a constantly varying flow regime, at present the low and moderate flows are heavily modified. In the future medium to high flows may well also be significantly modified. We need to think about these issues. The abstractors of river water and developers of these schemes have a poor record of mitigating their effects on the environment. A common attitudew is that water flowing in a river is wasted if it is not being used.

This issue may not seem to be a biggie to paddlers, but in terms of natural values we need to think about the big picture. Water quality, natural-ness of flow regime, value to indigenous species, recreational values.

I'd be keen to read your thoughts, and to work with others on the issues concerning our waterways.

Nathan