Excavators could be used more in the future to chip away at Lake Dunstan's weed.
The Guardians of Lake Dunstan organised a trial last week using a digger equipped with a rake head to haul lagarosiphon out of a section of the lake by Richards Beach Rd in Cromwell.
It was undertaken under the control of Land Information New Zealand (Linz) and its contractor Boffa Miskell.
Guardians chairman Andrew Burton said using the method at that location was tough but the excavator operator, Ralph de Clifford, of Alexandra, did a great job.
"The trial area was in quite a difficult place, as there was about half a metre of sludge and silt, which has never been taken out since the Clyde Dam was built, so heaps of mud was brought out with the lagarosiphon.''
The Guardians hoped to use the method again before summer, he said.
"We are keen to see another trial in another area where pulling the weed out should be even more effective than this time.
"Overall, it was a successful trial and we hope this will lead to further use of the rake in the future,'' he said.
Linz had indicated it would use the method again in the lake, he said.
The excavator can grab lake weed about 18m from the shore, and pull out the whole plant.
The Guardians hoped a three-pronged attack could be used: this method, a weed cutter attached to a jet boat, and spraying.
While the raking method could only be used in a limited area, it relied less on the weather than spraying did.
"The Guardians are hopeful of getting the use of chemicals reduced by using mechanical methods instead, which of course is far more environmentally acceptable,'' Mr Burton said.
The problem in Lake Dunstan could not be controlled properly unless it was first tackled in Lake Wanaka, he said.
Linz could not be reached for comment yesterday.
