Southshore levee plan hailed
A new design concept shows that Southshore can be protected against possible inundation from high water levels in the estuary by creating a simple berm from Caspian St to the end of the Spit.
The report, commissioned by the Southshore Residents’ Association led by chair Bill Simpson, was produced pro bono by Gary Teear, managing director of OCEL NZ Ltd.
‘‘The solution is quite simple and well-known internationally, particularly to the Dutch – create a levee to protect the established houses and infrastructure on Southshore,’’ Teear said.
He proposes a mixture of berm and plantings, and rock walls as flood protection along the estuary edge. A berm would also form an elevated walk/cycleway linking to other established and planned walkways and taking advantage of spectacular views across the estuary.
The original 640 houses in the area reduced to 480 after the 2011 earthquake, but with new builds under way that number had recovered to close to 500, all served by the established infrastructure, Teear said. ‘‘It makes economic and social sense to protect a community of this size against the start of sea level rise.’’
The berm height was set to allow for the currently forecast one-metre sea level rise in 100 years.
Construction cost would be considerably less than the cost of the seawall protecting Beachville Rd, Redcliffs.
‘‘What is required is a relatively simple berm structure, similar to what the council has already employed around the New Brighton area to keep the Avon River from overflowing into New Brighton,’’ Teear said.
The report, hailed by the community, has the full backing of the Coastal Burwood Community Board. Board chair Kim Money said a meeting would be called ‘‘as soon as possible’’ between the board, the residents’ association and Regenerate Christchurch.
‘‘With the ramifications of the Tonkin and Taylor (2015) report, this community suffered another devastating blow with notification on their LIMs. Despite it all, they’ve rallied and done outstanding consultation,’’ she said.
Tonkin and Taylor computermodelled the impact of a 40-centimetre sea rise over the next 50 years and a one-metre rise over the next 100 years. The data was used to map out erosion and inundation zones across the region.
Bill Simpson, left, and Tim Sintes have welcomed an OCEL engineering report on estuary inundation defence..