Those Canterbury Plains - many centuries of change

All environments are local, and the Canterbury Plains have been through many centuries of vast change - affecting climate, sedimentation, rivers, surface water bodies and of course soils. A quick history:

1. Originally, forest from mountains to sea. Check the Forested Areas map in 'Tangata Whenua'...
2. Extensive 12-13 century burning of the forest cover, as the early Maori chased moas and other forest dwelling grocery items - inducing a much drier east coast climate over the ensuing centuries and leaving remnant bush only in foothills, valleys and isolated patches on the Plains proper.
3. Revegetation - low growth, tussock, spaniards, matagouri
4. Burning round #2 as the early Europeans cleared tussock and began to farm
5. Extensive sheep farms and some minor cropping, but limited by access to water until the race schemes of the 1870's onwards
6. Water races, fed from the Waimak, Kowai, Selwyn, and the foothill streams behind Windwhistle, for reliable stock water. This recharged aquifers as well as providing household water: the races eventually spanned fairly much the entire Plains excepting the dry stony Te Pirita corner. Farming extended to cropping on the deep silt loams where feasible.
7. The irrigation era - wells to 2-300m deep, and then the river-fed canal schemes of recent date. Uses expanded as well - seeds, more and different animals

To think that it is even possible to adjudge climate, river flows, optimal uses, and livelihoods, against such a background of continual change, is quite simply hubris.....some such changes (vegetation cover being a classic example) affect climate very slowly - on a scale of centuries.

The Rush to Judge is not assisted in terms of likely acceptance by the High and Mighty pronouncements from the We Know Best pulpits. There's more than a hint of Millenarian Fever about most of these, and like any other monomaniacal fixations, there's always the awful but (of course unacknowledged) possibility that despite the Perfection of their Vision, they are Quite Wrong.....