Thames Coast Project

The Thames coast is situated on the west side of the Coromandel Peninsula between the towns of Thames and Coromandel. Regular flooding in the area threatens people’s lives and damages property. The Thames Coast Project aims to reduce flooding in Thames coast communities.

The western side of the Coromandel Peninsula (the ‘Thames coast’) contains many short steep catchments with streams that carry high quantities of sediment during floods. These streams deposit sediment, soil or gravel in a wide ‘fan’ formation or delta near the stream mouth. Over many years, communities have developed on these deltas, making them vulnerable to floods generated by short bursts of high intensity rainfall. The streams within these deltas are also unstable and are easily clogged with sediment during floods because of the high sediment loads.

The 'Weather Bomb' event in June 2002 and the Easter flood event in April 2003 emphasised the urgent need to address flooding and catchment management issues for communities on the Thames coast. During these flood events, one person died and about $13 million dollars worth of damage was done to private homes, campgrounds and local infrastructure (such as roads and rail links).

The Thames Coast Project is just one part of the wider Peninsula Project. The Peninsula Project addresses river and erosion issues from the mountains to the sea by integrating three key areas of work - flood protection, river and catchment management, and animal pest control.

In 2004, Waikato Regional Council and Thames-Coromandel District Council submitted a business case to central government seeking financial support for managing flooding along the Thames coast. In September that year, the government announced it would contribute $10 million over four years to the cost of the work.

The business case identified an integrated package of measures to address flooding issues along the Thames coast including flood protection, state highway bridge improvements and animal pest management on Crown land.

Flood protection

The government contributed:

• $0.69 million (30 per cent) towards the costs of purchasing 25 properties located in high flood risk areas
• $0.89 million (25 per cent) towards the costs of engineering works.

State highway bridge improvements

Transit committed to reviewing the costs and technical feasibility of the proposed State Highway 25 bridge improvements in Tararu, Te Puru and Waiomu for reducing flood risks.

Animal pest management

The government approved funding for the Department of Conservation to carry out animal pest control on Crown land:

• $365,000 to commence pest control planning and operations on the Thames coast in 2004/05
• $1.467 million for 2005/06
• $955,000 for subsequent years, in recognition that the effectiveness of pest control for flood mitigation purposes is dependent on pest numbers being maintained at a low level.

Waikato Regional Council and the Thames-Coromandel District Council have jointly initiated a number of responses following the ‘Weather Bomb’ event in 2002. Waikato Regional Council has:

• undertaken a detailed assessment of the flood hazards for each of the five priority communities (Tararu, Te Puru, Waiomu/Pohue, Tapu and Coromandel township)
• commissioned a detailed flood risk assessment from URS Consultants for each of the five communities - this assessment determines the risks in terms of risk to life, and risk to property and infrastructure in dollar terms
• investigated a range of options for managing flood risks as part of our natural hazards and risk mitigation work
• worked with representatives from each of the affected communities to identify the options their communities prefer
• put in place a comprehensive stream maintenance programme - this programme ensures sand, gravel, built-up silt, plant pests and other obstructions are regularly removed from streams and rivers
• constructed a floodwall and completed channel protection works at Tararu - the final stage of these works is the replacement of the state highway bridge (this work is expected to begin in 2008)
• protected residents at a Coromandel town retirement village with a stopbank
• stabilised the banks of the Te Puru and Waiomu streams with rock rip rap and planting
• purchased a number of high risk properties in conjunction with Thames-Coromandel District Council.

In August 2003, five community meetings were held along the Thames coast at Tararu, Te Puru, Waiomu/Pohue, Tapu and Coromandel Town. A Summary Report titled 'River flooding: reducing the risk' was mailed to ratepayers in each community. This report provided the basis for consultation.

Following the community meetings, working parties were established in each community to work with Waikato Regional Council and Thames-Coromandel District Council on the issues and options for their community. These groups have provided an essential link with the communities and assisted the councils in their decision making over the past four years.

In April 2004, newsletters (see PDF documents below) were sent to all ratepayers in the five communities outlining the recommendations for stream maintenance and some capital flood protection works made by the working parties, the potential rating implications and seeking feedback on these proposals.

In March 2006 newsletters were sent to all ratepayers in Coromandel town, Waiomu/Pohue and Te Puru confirming recommendations for flood protection works and seeking feedback through the Long-Term Council Community Plan process. In August 2006 the proposals adopted by council were outlined in another series of newsletters.