$3.4m stormwater plan mulled
A PLAN to improve stormwater flows during extreme rain events in Warwick would cost ratepayers at least $3.4 million if adopted by the Southern Downs Regional Council, a study has revealed.
Councillors at a special meeting yesterday were told that parts of the stormwater network in town could fail to prevent overland flooding in "once in a century" rainfall, resulting in inundation of buildings.
While councillors agreed the chances of rainfall of that magnitude were slim, they also agreed to further consider a report produced by water consultants Engeny, based on hydrological modelling.
The modelling is separate to that compiled for flooding of the Condamine River and takes into account stormwater channelled through the pipe network and above ground along local roads and drainage channels and in detention basins.
Councillors yesterday heard the view of the experts was that Warwick's stormwater network was "generally undersized" and lacks "formalised overland flow paths".
A range of locations where improvements could be needed to manage extreme downpours were identified by the consultants, including parts of Easey and Tooth Sts, part of Horsman Rd and a section of Wood St in the vicinity of Wattle Ave.
The works could include new piping and earthworks to raise roadside embankment heights, along with increasing the capacity of detention basins at locations such as Matthews St at Glennie Heights.
Councillors were also told that some of the works, if proceeded with, would require land resumptions, with compensation paid over and above the $3.4 million in capital works.
Also factored in were the State Government's official climate change predictions, which foresee a rise in rainfall across the state of 10% between now and 2050, spurred on by a temperature rise of two degrees over the same period.
Planning director Ken Harris said most developers based their stormwater designs on one-in-two-year rain events, given the unlikely nature of the amount of rain considered by the report.
His engineering services counterpart, Peter See, conceded such rain was an extreme scenario but said that now having been armed with the information it would be "remiss of us to do nothing".
The consultant's report will be further considered at next week's round of committee meetings.