Stormwater Chambers provide a low-impact development solution.

Mountain Equipment Co-op (MEC) has been “greening” their buildings for over a decade. In Spring of 2012 they completed what they consider to be their signature green building, designed to a LEED Gold standard. One component of achieving this standard was to develop an on-site storm and rainwater management system, eliminating the need to connect to the municipal storm sewer.

Challenge

The store is located on the banks of Lynn Creek and is in close proximity to the North Shore’s Spirit Trail. It was important for MEC to maintain the integrity of the natural environment surrounding the new building. The site designers needed to consider which natural opportunities the site presented to manage stormwater and capitalize on those opportunities.

Solution

The consultant designed a solution that included replacing a traditional storm sewer conveyance system with a complete infiltration mechanism for the minor system, using rain gardens, a gravel infiltration gallery under the parking lot, permeable pavers and the use of pre-fabricated underground storage chambers. The major system flow, was provided by on-site vegetated swales designed to convey water through a municipal park to discharge into Lynn Creek. The consultant recommended installing the stormwater chambers to maximize land use and allow for controlled infiltration into the ground. Storage below the west rain garden consisted of two rows of stormwater chambers wrapped in geosynthetic for separation and filtration.

LOCATION:North Vancouver, British Columbia

PRODUCT: Stormwater Chambers

PROJECT PARTNERS:

OwnerMountain Equipment Co-op

ConsultantKerr Wood Leidal Associates Ltd. GeoPacific Consultants Ltd.

ContractorPeak Excavating

Completion Date2012

Mountain Equipment Co-op

PROJECT PROFILEWATER MANAGEMENT

Storage for the major system under the east rain garden consisted of two rows of the Storm Chamber, which was also wrapped in a geosynthetic fabric. The overall strategy for the site was to infiltrate run-off up to the 10-year storm in the rain gardens with the help of the underground storage chambers.

Installation

The stormwater chambers are lightweight and easy to install. Due to the site constraints on either side of the building, Nilex was able to utilize different chamber sizes and capacities to suit the site and stormwater management needs. Once the chambers were covered with fill, the contractor was able to operate a small excavator over them in order to complete construction of a boulder wall in the rain garden without any damage to the chambers.

Results

The building site qualified for both stormwater credits 6.1 and 6.2 - Stormwater Treatment and Stormwater Quality Control. Stormwater is retained and infiltrated on-site, returned to the

water table through bioswales, rain gardens, permeable pavers, and the underground stormwater chambers. MEC was able to install a system that was able to take full advantage of the large amount of rain that falls on the West Coast while maintaining the integrity of the natural environment.

The Nilex Advantage

Nilex is committed to unearthing better results. Whether it’s for a civil, resource or environmental project, we offer the latest engineered and technically superior materials and techniques to save our customers time and money, and minimize the need to move or remove earth, and reduce the need for granular materials.

With over 35 years experience, a long-standing commitment to the environment and highly qualified staff, Nilex delivers the products and technologies that give clients an economic advantage with environmental benefit.

Mountain Equipment Co-op

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