Thursday, October 22, 2009

Isn't Aisling's death a stormwater wake-up call for Auckland?

There's been a little bit of news coverage of what Waitakere City Council - councillors and staff - must be going through after Aisling was found drowned in one of Waitakere's stormwater pipes.

There but for the grace of God go many of Auckland's Councils I think.

Stormwater has always been the "poor relation" of Auckland's waters.

This gives a good idea of what happens when a stomrwater pipe surcharges in heavy rain (shower gone past in this picture, but overland flow continues as land drains). The bulge of water will be surging from a stormwater pipe below ground. Here, there is an overland flow path above the pipe.

So far, in Auckland's restructuring, stormwater is running through the cracks...

Stormwater manhole lids are locked into place by lugs. The lids turn to lock. But in my experience stormwater lids routinely "pop off" or "pop open" under the pressure of stormwater when pipes are surcharged (full).

Who will control this infrastructure in Auckland's SuperCity?



This diagram gives a good idea of what a stormwater pipe looks like, and its connections to manholes and manhole covers above. (This image is actually a sewer pipe, but the principle is the same...). The diagram also shows some of the problems that arise, like cracks in the pipes, like tree roots getting in. All of these problems need to be managed. The pipes go where water goes.



Under present arrangements, stormwater pipes are controlled by Auckland's councils. Some Councils have integrated the management of stormwater infrastructure with that of water and wastewater. Three water strategies are what the modern world does. It is working reasonably well. But obviously not perfect as the Waitakere experience clearly demonstrates.
But under present proposals, Watercare will ONLY pick up water and wastewater. Nobody has said anything about what will happen to stormwater infrastructure.
So who will?




No comments:

Thursday, October 22, 2009

Isn't Aisling's death a stormwater wake-up call for Auckland?

There's been a little bit of news coverage of what Waitakere City Council - councillors and staff - must be going through after Aisling was found drowned in one of Waitakere's stormwater pipes.

There but for the grace of God go many of Auckland's Councils I think.

Stormwater has always been the "poor relation" of Auckland's waters.

This gives a good idea of what happens when a stomrwater pipe surcharges in heavy rain (shower gone past in this picture, but overland flow continues as land drains). The bulge of water will be surging from a stormwater pipe below ground. Here, there is an overland flow path above the pipe.

So far, in Auckland's restructuring, stormwater is running through the cracks...

Stormwater manhole lids are locked into place by lugs. The lids turn to lock. But in my experience stormwater lids routinely "pop off" or "pop open" under the pressure of stormwater when pipes are surcharged (full).

Who will control this infrastructure in Auckland's SuperCity?



This diagram gives a good idea of what a stormwater pipe looks like, and its connections to manholes and manhole covers above. (This image is actually a sewer pipe, but the principle is the same...). The diagram also shows some of the problems that arise, like cracks in the pipes, like tree roots getting in. All of these problems need to be managed. The pipes go where water goes.



Under present arrangements, stormwater pipes are controlled by Auckland's councils. Some Councils have integrated the management of stormwater infrastructure with that of water and wastewater. Three water strategies are what the modern world does. It is working reasonably well. But obviously not perfect as the Waitakere experience clearly demonstrates.
But under present proposals, Watercare will ONLY pick up water and wastewater. Nobody has said anything about what will happen to stormwater infrastructure.
So who will?




No comments: