Dormer Construction

EAST RANGIORA STORMWATER

EAST RANGIORA STORMWATER LOCATION Northbrook Road, Rangiora, Canterbury
CLIENT Waimakariri District Council
VALUE $1.9 million
PROJECT START Sept 2010
COMPLETION Sept 2011

SCOPE

A two-stage project for the construction and commissioning of a storm water attenuation and treatment system. The project involved the formation of a 340m long by 40m wide retention pond that was lined with a geo synthetic liner (GCL). This was constructed within an area where the water table was at or near ground level, positive water pressure existing. Works included bulk earthworks and shaping, tapping into existing natural springs, box culvert road crossings, construction of a new creek for fresh water crayfish, planting for future reserve. Stage 1 was the detention of the basin to separate the storm water flow from the natural ground water. This was in order to provide both retention and treatment of the storm water flows to project the spring feed receiving water bodies. Stage 2 was a broad open grassed water course to direct storm water from the end of the council pipes systems to the stage 1 detention basin.

PERFORMANCE

Environment

All works were carried out with very strict sediment control requirements (to protect adjacent native crayfish environments) and extensive global dewatering of the site.

Health and Safety

No significant incidents or any near misses were recorded across 5,400 man hours.

Programme

Dormer Construction Ltd’s work was interrupted (with consent from Council) when it involved itself in emergency works directly relating to the Canterbury Earthquakes. Delays experienced due to design failure were collaboratively resolved between all project participants.

Cost/Budget

Value and measure. Approved variations.