Who will benefit from any proposed flood protection work on the Taieri is to be assessed so Otago Regional Council targeted rates can be adjusted accordingly.
A proposal to construct a diversion channel along the south side of School Rd to help mitigate flooding associated with the hill catchments between Mill Creek and Outram was considered by the council's engineering and hazards committee yesterday.
The proposal, which was instigated after community concerns arising from the April 2006 flood, would be incorporated as part of a suite of initiatives that would come before council to further help manage the Silver Stream flood hazard.
The diversion channel aimed to divert run-off from the hills north of Tirohanga Rd more directly into the upper ponding area, rather than it spreading over the flood plain.
It would provide some relief to properties at Wyllies Crossing and those bounded by Dukes Rd, State Highway 87 and School Rd, a committee report stated.
Cr Michael Deaker said there was an "element of stable doors and horses" in the proposal given the diversion channel was below the most populated part of the area.
He suggested it might be better placed further up where it would protect existing capital assets.
Engineering manager Ramon Strong said terrain, cost and practicality were the main reasons, combined with the old Mosgiel to Outram railway corridor alongside School Rd possibly making the proposal more easily implemented.
Cr David Shepherd said the significant costs associated with such a channel would not benefit many people and asked if such work would be rated to ensure the people receiving the benefit paid.
Engineering and natural hazards director Gavin Palmer said funding arrangements were being examined to see whether they were in line with the benefits from proposed work and reflected land-use change in recent times.
The work being done on the Silver Stream included establishing a good technical basis for understanding the benefits.
Corporate services director Wayne Scott said it had been decided it would be timely to review the rating-differential classifications on the Taieri when the information from the technical studies became available.
Dr Palmer said it was hoped the Silver Stream work would be available soon but as it was a big project with flow-on effects, it was important to get it right.
The long-term council community plan anticipated some work would go ahead, with inclusion of $4.3 million mostly for works to mitigate the flood hazard associated with the Silver Stream.
The committee also approved alterations to the East Taieri scheduled drains to address a drainage issue affecting an area northwest of Wyllies Crossing.
