The decision was made by members of the Waitaki District Council on Tuesday, who were presented with five different options with differing shapes and materials.
The design decided upon, a 7.1m-wide glued laminated timber bridge, is the cheapest of the options and has a budget of $8.59 million.
Council major transport projects manager Mike Harrison said there had been criticism about it being one lane and wooden.
It was valid criticism, but the council had already looked at building it out of steel and concrete and the option decided upon had the least impact on the public.
"Everything we’re using meets the design life of 100 years plus."
A key advantage of a wooden bridge was the lighter weight, which reduced size requirements for the foundation and substructure, as well as increased lateral loading resistance from the river’s flow.
The council had applied for funding from NZ Transport Agency Waka Kotahi (NZTA) and expected it to fund 57% of the project, but only at the lowest cost.
That meant if the council decided to add a second lane — expected to cost up to $4.2m — NZTA would cover none of that extra cost.
While it was theoretically possible to add a second lane to the design decided upon in the future, "it sounds easier than what it is", he said.
Once the design was completed and the funding approved, the council would call for tenders on the project. Changes could also be made to the design at that step.
Those tenders would then be put to the council.
If all went according to plan, construction could begin by the middle of next year, he said.
The council would need to buy a small piece of land from a homeowner in Kakanui for the build.
That and other community engagement could begin, now the design decisions had been made.
The new bridge will be built just upstream of the old bridge, built in 1899, in Waianakarua Rd.
