Project: Walnut Gate Shopping Centre, Langley, BC
Engineer: McElhanney Consulting
Client: Grosvenor Developments
Contractor: BS Blacktop
Volume: 770 m3 Detention Tank
System: Installed under Car Park
Design: 1:100 year storm
McElhanney Consulting Services Ltd, specified this innovative SWM System for a commercial development in Langley. The system was installed in July 2005.
The Raintank installation consisted of a 770 m3 detention tank installed under a car park. The underground detention system receives surface run-off through a network of catch basins connected to the tank by underground pipes. The depth of cover above the tank is 600 mm to substantiate H 20 Vehicle loading requirements.
Some of the collected storm water will ex-filtrate into the ground through the surrounding slightly permeable native soil. The remaining water will drain into the existing municipal storm sewers through a controlled outlet. By managing the storm water locally and delaying its release, this tank will prevent local flooding and stream erosion during heavy storms.
See Newsletter August 2005 for more details (found in Section #9)
Benefits of this system are:
- LEED Accreditation - Up to 12 LEED points can be earned using this system
- Easy to transport - Product is shipped flat-packed on pallets to the job-site.
- Cost Effective – Up to 60% cost savings over a concrete chamber system.
- Lightweight and Quick to install - No heavy machinery is required to off-load and/or install
- High Strength - Product is rated for H20 loading (i.e. can be used under car parks)
- Modular Design - There is typically 50% less excavation versus other systems
- High Infiltration/ Detention Capacity - Unlike chamber systems, this system does not require rock back-fill
Included are some photographs from our visits. These can be used to verify the satisfactory installation and that the product will meet the desired function of your design.