Cost to fix Rotorua road jumps $400k

Damage from a previous storm was still being fixed when last year's April 29 flooding caused a large slip on Paradise Valley Rd. The road is a key part of the 20-minute drive from Rotorua to the valley's farms, lifestyle blocks, and tourist attractions including Paradise Valley Springs wildlife park. The road repairs were initially due for completion in February, then March, and have since been put back again. The price tag has jumped by 40 per cent, but the Rotorua Lakes Council says that's not the norm in its capital works programme.

The cost of the unfinished Paradise Valley Rd repairs has ballooned to $1.4m.

The Rotorua Lakes Council has revealed heavy summer rain caused stability problems at the site, and the project design had to be adjusted.

These drove the cost of the works up from the $1m figure provided in early February.

It's covering 25 per cent of the costs, $350,000, and the New Zealand Transport Agency is paying the remainder.

The council's general infrastructure manager Stavros Michael told the Rotorua Daily Post "only final sealing of the road remains to be undertaken" this month.

"This involves final trimming and preparation of the surface for sealing."

The completion date depended on weather and the availability of equipment, materials, and contractors.

In February the Rotorua Daily Post reported that the finish date had been put back a month to March, but that had since become four months to June.

Michael said this was due to "soil saturation, a groundwater spring under the road formation that required special management and controls to avoid a major road collapse and further slope erosion which occurred during construction and required the road to be closed for a period due to safety concerns".

"Unscheduled road-widening which had to be undertaken was finished prior to Christmas, along with ground stabilisation works above and below the road. Most recently, work was delayed to facilitate the adjacent landowner with options to reinstate property access."

The road was currently open, but it was down to one lane with traffic signals in the area of the works.

It was closed off for two-and-a-half weeks in December, resulting in detours up to 30 minutes long.

It was initially hoped the closure would only last a weekend.

The Rotorua Lakes Council carried out an average of 160 infrastructure projects each year.

Money was allocated for these in each Annual Plan.

Michael said projects varied both below and above initial estimates.

"So savings made by some works being completed under the estimated cost, compensate for those that go over."

He said major construction projects such as bridges, road repairs, water mains, treatment plants, and pump stations, required "contingency funding" of about 10 to 15 per cent to allow for unforeseen circumstances.

"Emergency restoration works such as the Paradise Valley project have various construction risks by nature. Full and accurate knowledge of ground conditions is not always available or possible before work starts."

Paradise Valley Rd was included in an emergency works budget after the April floods, alongside repairs on Tarawera, Mountain, Mangatete, Parsons and Waiotapu Loop Rds as well as two bridges and a culvert in Rerewhakaaitu.

Michael said all up, these were originally expected to cost $6m, "but the final cost, including the Paradise Valley Rd job, will be about $4.5m... about 25 per cent under the total estimate".