Never mind such things as costs, trees and other arguments I believe we should be including consideration of deciding between detain it or flush when making the final decision on Brownhill Creek.
The original engineering before the politics of “damming” the Brownhill Creek National Park was always centred around detaining the 100 year flow so that it would be manageable. In the more recent days the focus has been to move the water trough the creek system as fast as we can and get it out to the sea.
Why the change?
The more I think on this the more I get disturbed at the likelihood of someone falling into the upper reaches of the creek in a storm and being swept all the way down stream in an uncontrollable torrent. Uncontrollable because we have designed it that way. Worse still I would hate to think that someone is a child. I have images in my head of the recent Queensland floods and people being swept in the current downstream.
I have a real issue with being responsible for allowing this to be possible.
I am also troubled as a builder (once again) with us not trying to detain the flow. Providing a retention/detention tank on site is a must now in order to obtain development approval in many councils for any building work in excess of as little as 40 m2 of roof area. The reason for this is to delay the flow of stormwater/roof rainwater for a period of 2 or 3 days after a severe storm. The reason for this in turn is to avoid choking up the street stormwater system that can no longer cope with storms and the flooding that will inevitably eventuate.
And here as I read it we are creating a greater flow than probably all the houses that are being redeveloped together could create and saying that is a preferred option.
I will be looking for assurances on this.