Overview Building Features Grade JK-6 Grade 7-12

Storm Water Management

Bio SwalesThe following principles were incorporated into the design of the storm water management (detention, retention, reuse, ground water recharging) system. All storm water must be managed to reduce offsite runoff, to reduce impacting the existing storm sewers both in quantity and quality to meet the requirements of the LEED principles.

This was accomplished by directing all stormwater runoff to bio-swales for hard surfaces. Bio-swales are meandering ditches set at a low grade of 0.2%. At the bottom of the bio-swale is a continuous pocket of granular material surrounded with geotextile fabric to create a storage void to permit the stormwater to percolate back into the ground. The top of the bio-swale is covered with a 12" thick layer of beach stone to create a landscaping feature and protect the underlaying earth.

Bio-Swale Sketch

Once the storage capacity has been exceeded, a 6" diameter perforated tile drain wrapped with a filter sock installed in the upper portion of the granular pocket will allow the stormwater to flow to the city storm sewer system.

As stormwater runoff flows through the bio-swale, pollutants are removed through filtering. Stone weirs have been installed to slow the flow of the stormwater runoff to permit pollutants to settle.

Based on a storm event of 1 in 5 years with a storm duration of 20 minutes, approximately 325 cubic feet of storm water will flow from the hard surfaces to the curb outlets. The bio-swales have a capacity to store 332 cubic feet below the tile drain.

The hard surfaced playground and grassed areas have all surface runoff directed to french drains which are similar to the bio-swale but the continuous granular pocket measures 48" wide by 36" deep with a tile drain in the upper portion. The french drain is covered with 4" of topsoil and grass seed to act as a filter for any pollutants and a shallow swale to collect the storm water runoff and allow the stormwater to percolate into the French drain and back into the ground. All excess runoff will be discharged into the municipal storm system.

Bio SwalesBased on a storm event of 1 in 5 years with a storm duration of 20 minutes, approximately 3,590 cubic feet of stormwater will flow toward the french drains. The french drains have a capacity to store 4,613 cubic feet below the tile drain.

Download architectural drawings of the Stormwater Management Plan.

Download architectural drawings of the Bio-Swale and Detailed Plant List.


Greater Essex County District School Board