When Phase 1 of the Yorkson Neighbourhood Development was constructed in 2006, some unique stormwater management systems were incorporated to protect the local aquifer. One of the objectives for the development was to ensure the underlying aquifer was continuing to be recharged. Because the soils are poorly draining, on-site infiltration could not be relied on as the only method of groundwater recharge. The stormwater management infrastructure includes a separate conveyance system in the streets of the neighbourhood to convey the cleanest stormwater from the residential roofs. The water conveyed in that separate system, called the 3rd Pipe System, is then treated and directly injected into the aquifer.
Since 2007, KWL has been retained by the Township of Langley to conduct water quality monitoring of the stormwater generated from the development and determine appropriate treatment for the 3rd Pipe stormwater. The program includes continuous flow monitoring inside manholes of both the 3rd Pipe System and traditional storm sewer system. The water quality program has included collecting grab samples, and composite storm samples for storm events up to 24 hours long using automated sampling machines. KWL analyzed lab results from the water quality samples and provided annual reporting of stormwater quality to the Township of Langley.
KWL is assisting the Township of Langley with the next stage of monitoring, which began in 2012, and focuses on bringing the treatment system on-line for the 3rd Pipe System. Treatment for the stormwater may include a regional sand filter and UV treatment.