TORONTO CSO EA
February 2009
Second stage of trunk sewer evaluation for Toronto’s Don and Waterfront CSO Project set to start.
Andrews Infrastructure is a member of a consortium being led by the MMM Group undertaking the Don and Waterfront CSO control project for Toronto Water. This multi-facetted project is intended to yield a long term strategy for controlling CSO’s and hence improving water quality in the Don River and the Inner Harbour. The project is proceeding through the Municipal Environmental Assessment process. Andrews Infrastructure is working closely with our colleagues from the Worksop, U.K. office of OnSite. OnSite are specialist contractors responsible for the trunk sewer inspection component of the project.

Andrews Infrastructure Role Includes:

• Preparation of an inventory and inspection of some 250 flow control structures, weirs and gate chambers. Detailed hydraulic characteristics of each structure were catalogued in a project database for subsequent use by the hydraulic modeling team.
  
• Inspection of 100,000 m of trunk sewers (ranging in size up to 3050 mm in diameter) and over 500 manhole structures. These sewers include all of the major trunks draining to the Asbridges Bay Wastewater Treatment Plant.
  
• Engineering assessment of the condition of the inspected infrastructure in accordance with WRc standards and guidelines.
  
• Development of an asset database in order to effectively disseminate inspection findings to other members of the consulting team. AI developed the comprehensive data management system (MSAccessTM ) with project specific functionality built in.
  
  The central Toronto trunk sewers, including the High Level and Low Level Interceptors and the Coxwell Trunk Sewer, were inspected in summer of 2008. The Interceptors are historically interesting having been constructed in the early 1900’s. The sewers include a mix of brick, concrete and composite brick/concrete and range in size from smaller egg-shaped sewers up to 3000 mm circular ones. Our inspection of the Coxwell Trunk Sewer resulted in the discovery of its well publicised structural distress. The balance of the trunk sewer system, which includes newer pre-cast concrete pipe, is situated throughout the Don River watershed and will be inspected starting in the spring of 2009.