Floodwater diversion option

A small depression through a pocket park at the end of Lanark St could be one way to divert surface water from Mosgiel's main shopping street in extreme rainstorms.

A depression would channel some water away from Gordon Rd into Lanark St, where it would enter the stormwater system, Dunedin City Council transportation operations manager Graeme Hamilton said.

Council and New Zealand Transport Agency staff met earlier this month to discuss ways of preventing the flooding of Gordon Rd shops that happened in an unusually heavy deluge in early November.

Excess water flowing on Gordon Rd used to be diverted down Lanark St before it was closed off at the Gordon Rd end about 10 years ago, Mr Hamilton said.

Creating a depression through the pocket park there now - the depression could still be crossed by mobility scooters - could see that water diversion happening again.

That would help, as the issue was around the volume of flowing water being such that the entry points to the underground stormwater system were unable to receive all of it in such a short space of time, he said.

Another idea being considered was widening the channels around pedestrian crossing protrusions so they could hold more water.

While no decisions had been made, they were two examples of minor improvements that could be made to reduce the amount of water flowing on Gordon Rd in exceptionally heavy deluges like that which caused the most recent flooding. Who would pay for the work would be decided later, he said.

Ideas would be formalised and presented to the Mosgiel-Taieri community board in the first quarter of next year.




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