It has applied to Environment Canterbury for consent to begin small-scale trials over a threeyear period in Southshore, McCormacks Bay and Humphreys Drive.

Christchurch City Council project co-ordinator Ken Couling says the trials will focus on practical methods that minimise impacts on the Estuary eco-system.

“We’ll be looking at how we can best control the growth of the sea-lettuce beds and finding the most effective, practical means of removing the lettuce stranded on shore. Options to be considered for controlling growth include mowing and suction dredging operations by boat,” he says.

At present, the Council can only collect and remove sea lettuce from the beach at Southshore three times a year, as it only has consent from Environment Canterbury for this area. The last clean up took place just before Christmas when more than 193 tonnes of sea lettuce build-up was cleared from the Estuary foreshore at Southshore, between Godwit and Tern Streets.

Removals are restricted to the high tide areas on the eastern side of the Estuary, where the Council has consent to use tractor-mounted rakes and front-end loaders.

“We’ll be looking at whether other mechanical methods will work on the softer sediments in Humphreys Drive. Trials of alternative removal methods such as shorebased suction may also be undertaken,” says Mr Couling.

For more information contact the Christchurch City Council Customer Centre on 941 6840, or go to www.ccc.govt.nz/quickanswers/ and search under ‘lettuce’