Large Condominium Complex Development in the Heart of a Growing City Centre
A proposed hi-rise condominium development with 4 towers and 2 levels of underground parking in an urban area in the GTA with geological formation across the site comprised of silty sand aquifer to low permeability sediments, and an average grade elevation of approximately 200.00 masl. Excavation was planned in 2 phases, each having a 500m (1640 ft) parameter.
APPROACH AND OUTCOMES
E N G I N E E R E D D E W A T E R I N G S O L U T I O N
Aquatech worked closely with the General Contractor to design an engineered dewatering solution, factoring in the various water levels and geology across the site, and only targeting excavation areas where positive dewatering was necessary. The final design included a 360-meter and 360 m3/day (95,100 gal/day) Eductor System around the outside perimeter of the permeable shoring installed from grade that worked for both excavation phases.
Aquatech’s field installation crew provided a full installation of the Eductor wells and system including jetting and drilling the Eductor wells within the upper permeable sandy silt formation to control the seepage coming from the upper silty sand and sand layer - with the intention to draw down the water table below the invert of the excavation or to the interface of the low permeability till. In addition to the Eductor System, a localized WellPoint system was also installed around the perimeter of the elevator shafts to ensure no additional seepage occurred.
Aquatech Service and Monitoring teams provided regular system checks throughout the entire operation to provide preventative maintenance and required product service to ensure reliable and continuous operation, and avoid unnecessary breakdowns and delays.
F I L T R A T I O N & T R E A T M E N T
Due to on-site exceedances to the cities storm discharge criteria including TSS and Aluminum, an EnviroTank was utilized to settle out suspended solids from the discharge water, coupled with scheduled water quality tests throughout the life of the project.
Two months after dewatering commenced, Zinc contaminates were found in the water quality reports; Aquatech designed and installed a discharge treatment system to treat the zinc that met regulatory discharge water quality requirements.
M O N I T O R I N G
The dewatering and discharge filtration/treatment system was continuously and remotely monitored via Aquatech’s advanced remote monitoring, control and alert system with 24/7 dashboard access and live alerts. Measuring discharge flow, water level, water quality, vacuum and pressure, the monitoring system allowed us not only anticipate and manage preventative risk, but also real-time system tuning for maximum performance.
Throughout the colder months, Aquatech provided complete winterization of the dewatering system and continued to offer 24/7 on-call urgent support.
Aquatech completed the project on time and on schedule, and the wells were decommissioned and abandoned as per Ont. Reg. 903.
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