Lake Concept Floated For Thames Shoreline Protection

By John Freer

A novel idea to overcome the potential flooding threat to Thames while providing the town with what could be considered a very acceptable recreational resource.

Two locals, one being a retired consulting civil and structural engineer, the other having a background in mechanical and hydraulic engineering, have put forward the idea of developing a lake off the town’s coast from the Brown Street reclamation to the Karaka Stream outlet.

Max Bosselmann and Warren Sly were motivated to develop the concept after attending a recent public meeting relating to foreshore and flood protection.

The lake concept, while potentially being a prime recreational facility, would also provide a solution to mitigate flooding. And the pair believe the proposal is far more cost effective than other options.

“In our view the area from the Pak ‘n Save Supermarket up to a point just north of the Croquet green, is extremely vulnerable to flooding from a minor tsunami or storm surge and should be the main focus at this time,” Max and Warren state in their report.

“We suspect that a close study might reveal that the remainder of Thames is sufficiently well protected already, that no further works would be required for 20 or more years.

“We believe the initial scheme could probably be confined to the six or seven hundred metres north of the supermarket reclamation, with the remainder of Thames being tackled when sea level rise reaches the extent that it triggers action.”

The report continues that if the required new sea wall was to be constructed approximately 300 metres out to sea from the existing Brown Street shore line, it would link on to the existing Moanataiari area reclamation adjacent to the dog park.

“At the southern end it would link in to the existing Supermarket reclamation. This would enable the creation of a lake of area around 18 hectares which should be a sufficient size to enable its use as a detention facility to attenuate the Karaka Stream flow sufficiently, that no pumping is required and that the necessary floodgate facility is very modest in comparison to that which otherwise would be required.

“We visualise the area being developed as an attractive fresh water urban recreational lake. Ideally it would have a minimum water depth of about 1.2 metres and that something in excess of 1.5 metres would be available for temporary flood storage before any adjacent land is flooded.”

The pair firmly believe the lake concept would come at a significantly reduced cost bringing massive project savings overall.

While the seawall would be longer than currently estimated, the pair say the wall is only a small part of the overall project.

“The initial establishment of and the ongoing costs of pumping would be totally eliminated. The capacity requirement and cost of the required outlet floodgate structure would be greatly diminished.

“There would be negligible disturbance to the existing adjacent land uses and, instead, the new lake would enhance the property values and amenities of the area.

“The new lake would be sufficiently large for its use for small boat sailing, kayaking and other water sports and would likely attract many visitors to Thames.”

You can read the full report prepared by Max and Warren – open the link below.

Thames Foreshore PR Proposal