04 Aug 2016

Moves to improve water quality in the Heathcote River could see a new filtration system introduced to remove sediment and contaminants from stormwater entering the waterway.

Christchurch City Council staff have presented a report to the Infrastructure, Transport and Environment Committee which recommends the Council pilot a special stormwater filtration device.

It is planned to locate the filtration device at the planned new pump station in Richardson Tce, which is due to be built in 2017 to reduce flooding in Woolston.

The new pump station is being built as part of the Council’s Land Drainage Recovery Programme.

The filtration device will cost about $1.5 million but should significantly reduce the amount of contaminants entering the Heathcote from the 270 hectare stormwater catchment around highly trafficked roads such as Ferry Rd, Moorhouse Ave, Fizgerald Ave, Ensors/Aldwins Rd and Wilsons Rd.

Zinc from tyres and copper from brake pads that gets washed off the roads when it rains is one of the principal sources of contaminants, along with sediment, in our waterways.

Figures suggest a filtration device like the one proposed could reduce dissolved metals by up to 25 per cent and sediment by 40 to 50 per cent.

In a report prepared for the Committee, Three Waters Planning & Delivery Manager John Moore said community aspirations for improved water quality would not be met without the implementation of water quality devices, such as the proposed filtration device, within existing urban catchments.

“If water quality standards are to be met it will be necessary to eliminate most construction sediments, much of the vehicle sourced copper, most roof zinc and approximately half of vehicle sourced zinc,’’ Mr Moore said.

The Committee agreed to recommend to the Council that it approve construction of a pilot stormwater filtration device at the Richardson Tce pump station and instigate a monitoring regime to gauge its effectiveness.

Watch a video which shows how filtering devices work.