Dunedin City encompasses a very large area and draws a significant portion of its water supply from catchments further inland.
About three-quarters of Dunedin’s main water supply could be out of action for up to a year after a massive blaze engulfed an area near Middlemarch at the weekend.
At a media briefing in Dunedin yesterday, Mayor Aaron Hawkins said the fire had eliminated the use of the main water catchment for Dunedin, the Deep Stream Reservoir.
Water from the catchment was contaminated by ash and a small amount of run-off containing fire suppressant chemicals.
Both the Deep Stream Reservoir and Deep Creek Reservoir were of strategic importance for the Dunedin City Council, he said, as they were the only reservoirs that could supply water to all suburbs in Dunedin.
Dunedin residents were asked to voluntarily conserve water while the severity of the impact to the Deep Stream Reservoir was assessed in the coming weeks by council staff.
The voluntary water restrictions would most likely remain in place over the summer and more formal restrictions could be considered based on the weather over the coming months.
One of the things we’re not that good at grappling with yet is the confluence of climate change and environmental conditions created by humans. I’ve written in the past about how drought can be driven by climate change but made much worse where humans are using land in unsustainable ways. Likewise flooding.
In this case, I think we need to start looking at land management as a way to mitigate climate change and the on-the-ground effects of climate change. If we’re heading into more frequent drought cycles, then it makes sense to adopt practices that make our landscapes as resilient as possible. A fire the size of Middlemarch once every three or four decades is very different from having such fires regularly.
The questions I have today are this,
That last one is going to upset a few people. We’re basically talking about NZ having substantial dry tussock country that used to be under slash and burn farming (burnoffs, aerial spraying, and overgrazing that kee vegetation to a minimum). I don’t know how much this applies to the land burnt at Middlemarch, but there are farmers and volunteer firefighters pointing to the problems of increasing conservation estate that is now highly flammable.
I don’t know what the solution is here, although I would like to see the work being done by regenerative agriculture people in such landscapes/climates. I suspect that it involves planting forests that prioritise non-flammability over forestry or natives except where that forestry or native restoration is low risk.
This ties in with general ecological sensibility and the value in placing ourselves back within nature. The ODT was light on detail about the issue with the water supply but there’s also this to consider. Those catchments require rainfall, and how that rainfall is captured matters. Tussock yields more water into the landscape than short grazed pasture. Trees are probably better yet. Hard to imagine anything worse for that landscape than being burntoff, for its own sake and for ours.