Commercial development in Edmonton, AB, uses subsurface retention chambers to meet municipal requirements
One of the largest subsurface storm water management systems installed to date used more than 1,900 StormTech MC-4500 chambers to control runoff. Measuring 96 m by 119 m (315 ft by 390 ft), it has a storage volume of some 10,000 cu m at the 800-acre Aurum Energy Park in Edmonton, AB, and it was designed to meet the city’s storm water requirements.
The chambers from Advanced Drainage Systems Inc. (ADS) are designed in accordance with CSA, AASHTO, and ASTM design standards, which qualifies the StormTech units to be used in commercial and municipal projects.
The StormTech chambers are used as a retention system in order to hold the storm water long enough for it to dissipate through the outlet to prevent overloading the existing creek and reduce erosion and flooding.
The system was constructed of 1,963 StormTech MC-4500 chambers with 212 end caps in a 2.13-m- (12.7-ft-) deep excavation. Clean, crushed angular stone was used to backfill the system from 0.20 m (9 in.) below the chambers to 0.3 m (12 in.) above the chamber. A well-graded aggregate was used as sub-base up to the bottom of the pavement section for the parking lot. The cover over the entire system was 2.13 m (7 ft).
Water feeds into the system from six catch basins, each connected underground to an inlet manifold constructed from 600-mm- (24-in.-) diameter ADS N-12 corrugated HDPE pipe and a 121-m (400-ft) run of 150-mm (6-in.) perforated N-12 pipe as an underdrain leading to the outlet control structure. ADS 315ST woven geotextile was placed over bedding store for scour protection at all chamber inlet rows. This project utilized the patented StormTech Isolator Row, which is constructed with StormTech chambers and can remove a significant percentage of total suspended solids (TSS) and other common storm water pollutants.
The lightweight characteristics of the chambers not only made for efficient and economical transportation to site, but also allowed each chamber to be lifted and maneuvered by two people without heavy equipment.
The MC-4500 is rated to provide a 100-year-service life. Able to handle large storm water flow volumes, it measures 1.5 m (5 ft) from the bottom to the top of the corrugation and has a base spread of more than 2.4 m (8 ft). The MC-4500 provides more storage volume per square foot of land area than any other chamber on the market and is generally installed under parking lots such as the one at the Aurum development.
“The practicality of a subsurface unit is being embraced more and more by engineers, urban planners and architects,” said Ewout Leeuwenburg, ADS senior vice president of international operations. “A StormTech system saves valuable space, reduces land use, provides a means to meet environmental regulations and is a long-life, easy-to-install solution. The MC-4500 and our other StormTech products provide a highly cost-effective method for controlling storm water required for projects such as the Aurum Energy Park. And not only are the chambers easy to install, planning a system is now also very easy using our new StormTech Design Tool.”
The tool provides the ability for site-specific applications and can be accessed and used through multiple platforms, including smartphones, tablets and other mobile devices. System designs are produced in PDF and CAD formats with data that allows users to estimate the total installed cost.