Council to monitor erosion for now

While Timaru District councillors have expressed concern at the rapid rate of erosion at Patiti Point, they have backed away from major protection works for the area.

A report prepared for the Timaru District Council from policy analyst Fabia Fox outlined various options to tackle the problem of rapid, ongoing erosion at the popular cycling and walking spot.

The councillors were presented with three options at the council’s infrastructure committee meeting on Tuesday. The first option, which was to do minimum site monitoring, would cost between $8000 per year for surveying and $25,000 for road upgrade or fence installation.

The second option, which was to increase monitoring at the site, would cost between $15,000 to $25,000 per year. The third option was to increase monitoring and construct a wave protection system at the beach level along the site.

The wave protection system could take the form of rock riprap, geo-textile sandbags, concrete tetrapods, a retaining structure or a composite solution.

According to Fox’s report, the first two options would not ‘‘address the ongoing erosion issues at the site or guarantee ongoing vehicle or pedestrian access to Otipua Beach’’.

‘‘However, with a greater level of information available through increased monitoring, council will be better equipped to manage the risk of cliff instability and loss,’’ Fox’s report says.

A wave protection system was considered by Fox and councillors to be unsustainable, as the cost of such a system was estimated to be between $250,000 to $500,000, with an ongoing maintenance cost of $5000 per year over 50 years.

The councillors agreed to increase the monitoring at Patiti Point, but decided not to push ahead with full remediation measures due to the potential cost involved.

However, all of the councillors expressed concern about the state of Patiti Point.

Cr Dave Jack said the ongoing erosion at a popular spot for cyclists and walkers was concerning.

‘‘Gee whiz, we are in danger if there’s another weather event,’’ Jack said.

Cr Steve Wills agreed.

‘‘We are going to have significant problems going into the future. We need to start seriously looking at both the protective measures and also the costing of it. We can’t just park this and move on,’’ he said.

‘‘The ongoing costs for this are going to be astronomical. This is something we need to work with Environment Canterbury and central government on. Sooner or later, central government will have to get onboard.’’

Cr Paddy O’Reilly also believed that it would be an ongoing cost.

Mayor Damon Odey said the council was aware of the effects climate change had on coastal erosion, and it was searching for extra funding from central government to address the problem.

The problems with erosion at Patiti Point have been ongoing for several years.

Council officers were so concerned about the erosion that it commissioned engineering firm WSP-Opus to undertake a assessment of the extent of cliff erosion and loss, and recommend possible remedial options.

In November last year, a WSPOpus geotechnical engineer undertook a walkover of the site and noted that several metres had been lost at locations along the cliff, which prompted further investigation from the council.

‘‘Based on visual inspections completed by council officers last month, there are at least six points where the walkway is within three metres of the cliff edge and there are spots with considerable overhang,’’ Fox’s report says.