Floating wetlands form part of new-look stream

A quake-damaged stormwater drain in Shirley which runs into Horseshoe Lake has been given a dramatic makeover.

New floating wetlands should help improve water quality.

The once unsightly concrete drain – known as Number 1 Drain - has been transformed into a naturalised stream complete with ponds and floating wetlands.

The floating wetlands are densely bedded with plants, which will send their roots into the water and take up nitrogen, phosphates and heavy metals, improving the water quality in Horseshoe Lake and the Avon River.

Christchurch City Council Land Drainage Manager Keith Davison says the extensive work done on Number 1 Drain – which was one of the concrete-lined waterways worst affected by the earthquakes - has reduced the flood risk for properties upstream in Shirley and improved the habitat for aquatic life.

“We did a fish survey prior to the works, and found four fish through the drain system. When we surveyed again recently, we counted 76 fish in just a small portion of the drain so naturalising the drain has clearly improved the aquatic habitat,’’ Mr Davison says.

“We’re thrilled to be able to help improve the health of our waterways, while reducing flood risk for people,'' Mr Davison says.