More than 1500 hectares of land burned in the Port Hills fires, heightening the risk of ash and soil entering local water systems, especially with the high amount of rain recently.
Murray Sinclair, the Christchurch City Council-appointed fire recovery manager, said work needed to start immediately to reduce the risk of silt and ash entering drainage systems.
Mayor Lianne Dalziel said one of the solutions looked at was using straw bales as barriers to stop silt going into the water.
River engineer and Port Hills resident Rob Blakely said the city council should plant native trees to stop contaminants entering waterways.
"They need to asses which of the waterways are priority and begin the planting to trap as much of the sediment up in the hills as possible before it gets too far down stream," he said.
Blakely said this was a chance for Christchurch communities to work together and assure that the next time this happened, people were better prepared.
A medium to long term recovery plan will be presented to the city council in May.