Thames protection and resilience project

The protection of Thames is a high priority for our district, after the Shoreline Management Pathways project showed that $1 billion in assets in the township are at risk over the long-term from hazards associated with sea-level rise.

Thames Protection and Resilience project aims to manage the risks to the Thames area from coastal hazards such as flooding and storms, which are expected to worsen as a result of climate change and sea-level rise. The initiative is part of the Shoreline Management Pathways (SMP) planning project, launched in 2019 to address risks along Coromandel’s 400 km coastline.

Through the Shoreline Management Pathways project, 138 unique adaptation pathways were developed, with Thames identified as a high-priority area due to $1 billion worth of assets at risk. The proposed design for Thames protection includes the construction of barriers, such as stopbanks, which will be adapted over time to accommodate a projected sea-level rise of 1 metre over the next century.

The project is a collaboration between Thames-Coromandel District Council, Ngāti Maru, and the Waikato Regional Council, alongside local communities and other iwi.

Flooding risks from streams

Work to understand flooding risks from Thames’ streams, or fluvial flooding, is close to completion. Final modelling reports on the river risk component of the project are expected in early 2025. The results will then be presented at a public meeting in February 2025, along with a wider project update.

The proposed protection design looks to integrate nature-based solutions, such as a chenier ridge, to boost resilience and create habitats. The project team has also undertaken preliminary catchment modelling to assess the flooding risks of Thames’ streams.

“We need robust, effective and long-lasting solutions," said project lead Amon Martin. "So, one of our challenges is to ensure we thoroughly understand all the intersecting risks. "These include fluvial flooding risks and the likely effectiveness of pumping stations and related mitigation proposals.” 

Coastal protection design

Progress has been made on getting a better understanding of the coastal protection design parameters, and eliciting community feedback on how protection might blend with existing amenities (such as the walkway and small gauge railway).

Public meetings in 2024 presented various concept designs for protection against a half metre of sea-level rise, and a one in one-hundred-year storm. This level of storm is becoming more frequent along our coastline, and puts Thames at significant risk of flooding.

After taking on board public feedback, the project’s governance team confirmed stopbanks will be constructed where space allows along the Thames foreshore. The stopbanks will generally follow the existing footpath, with an expected height increase of approximately 1.4 metres. In narrow areas with limited space, for example behind Pak’n’Save, a wall or sheet-pile solution will be required.

“Everyone involved in the project is also keen to explore additional nature-based solutions that will offer another layer of protection to our town,” said project lead, Amon Martin. “These solutions include things like shell banks, oyster islands and chenier ridges, which could bring a range of benefits, including as habitats for birds.”

Meanwhile, Richmond Villas Retirement Village has proposed partnering with our Council to deliver the section of stopbank protection associated with its property. The proposed partnership includes Richmond Villas leading the engineering, design and construction process, and covering all associated costs. It’s hoped construction on this section can begin in early 2025.

Fact-finding has been completed to guide roles and responsibility discussions with Waikato Regional Council, including a review of the Waihou Valley Scheme’s objectives and rating system.