No.1 Drain – Christchurch Golf Course, Shirley – Water Polishing

This stormwater polishing project at Christchurch Golf Club was commissioned by Christchurch City Council to reduce flood risk, improve water quality, and enhance aquatic habitats. The original Number 1 Drain, damaged in the 2011 earthquake, divided the golf course with vertical concrete banks, which were replaced by natural slopes planted with native rushes. A section of the drain was rerouted underground before entering two new water detention lakes, reconnecting the course's north and south areas.

​

Five floating treatment wetland (FTW) islands were installed, covering 1,000 square meters (20% of the pond surface) and providing final filtration and reducing contaminants entering Horseshoe Lake Reserve and Avon River, the catchment destination. Completed in 2019 with a project budget of NZ$1.9 million, the installation has improved water clarity, increased dissolved oxygen, and attracted new fish, insect, and bird species.

​​

“We conducted a fish survey before the work and found just four fish. A recent survey counted 76 in a small portion of the drain, showing clear improvement in aquatic habitat. We’re thrilled to be able to help improve the health of our waterways, while reducing flood risk for people.”

– Keith Davison, Christchurch City Council Land Drainage Manager, 16 July 2019

​

Key Benefits:

• Improved water clarity

• Increased diversity of fish and insect species

• Introduction of new bird species to the golf course

• Elevated dissolved oxygen levels

• Enhanced visual appeal and creation of a landscape feature within the course