Site

Coatesville-Riverhead Highway and Dairy Flat Highway Roundabout

Specifier

Blue Barn Consulting Ltd

Contractor

DempseyWood

Description

Coatesville - Riverhead Highway Roundabout - Auckland site requirements:

-Dangerous stretch of a busy road with high traffic flow. Coatesville-Riverhead Highway has ±5,000 VPD and Dairy Flat Highway has ±15,000 VPD.

-Expected to generate high levels of contaminants of Gross pollutants (trash and debris), increased sediment mass load from vehicle movements, hydrocarbons and heavy metals.

-Constrained site from steep slopes on a narrow road corridor so not enough room for rain gardens.

-Catchment area of 2,568m2 and 3,709m2.

Solution:
-Custom designed Filterra® with a footprint of 29.7m2.

-The device is practical to construct and maintain and had safety elements from all stages of construction and operation fully considered.

-Use of treatment train with pretreatment upstream of a Cascade Separator®. The pretreatment removes most of the coarser sediment and gross pollutants which ensures performance and maintenance frequencies are optimised.

-Cascade Separator® is an innovative hydrodynamic separator that captures sediment and gross pollutants while also removing hydrocarbons, litter and debris from stormwater runoff and provides the highest removal efficiency of any Stormwater360 Gross Pollutant Trap.

-Filterra® is the next generation of biofiltration devices. Filterra® removes contaminants, including nutrients and metals, reduces stormwater flows and blends into the urban environment.