It reveals sea-level rise in some parts of the Canterbury coastline could happen twice as fast as previously thought, as a result of increased land subsidence.
Christchurch City Council Coastal Adaptation Planning manager Jane Morgan says in some locations, where the land has sunk since the quakes, the amount of sea-level rise previously projected to happen by 2050 has already happened.
The greatest subsidence is happening around the edges of Avon Heathcote Estuary at Bexley, South New Brighton and Southshore, and at Sumner, Redcliffs, Lyttleton and Port Levy