Stormwater management facilities are designed and built to collect rainfall and surface water runoff. To ensure the Thornhill area has proper access to stormwater relief, improvements are coming to the stormwater management facility within Gallanough Park. 


Project timeline


2023: A new contractor with the expertise to complete a construction project of this scale has been hired by the City and work is now resuming. 


2022: A newsletter was sent to residents notifying them of construction delays caused by unforeseen circumstances with the hired contractor. 


2021: In October, a newsletter was shared with residents in the surrounding area, advising them that work was starting. 


2020: A contractor was hired to undertake the project, and public consultation was conducted. The community was invited, through online and print mediums, to review project material online and provide feedback. 


2015/2016: The preliminary reassessment of the stormwater modelling, to confirming and/or refining the design of the Thornhill area flood mitigation plan, began in 2015 and was complete in June 2016.


2014: An Open House was held to present the proposed park plans and stormwater management improvements to the community. 


2010: A Municipal Class Environmental Assessment process for a stormwater management facility in Gallanough Park was initiated based on the recommendations from both the Thornhill Storm Drainage Improvements Study and Thornhill Area Road Reconstruction/Stormwater Management Report. The objective was to develop a plan to address flood risk within the Thornhill area, north of Gallanough Park. Through this process, a dry pond stormwater management facility was determined to be the preferred solution.


2010: The City completed road reconstruction and watermain replacement for Thornridge Drive, Charles Street, Raymond Drive, Clarkhaven Street, Calvin Chambers Road, Brooke Street, Elizabeth Street and Old Jane Street. The drainage improvements on these streets included replacing undersized ditch inlets/catchbasins, deficient driveway culverts and improving roadside ditch conveyance capacity.


2009: An engineering design was completed for the reconstruction of the local roads identified in the Thornhill community. Drainage system improvements were incorporated into the scope of the work to address the recurring flooding problems in the area. The Thornhill Area Road Reconstruction/Stormwater Management Report, completed by contractor W.G. Clarke, provided the hydrologic and hydraulic stormwater model analyses of the drainage systems and informed the the drainage improvements incorporated into the road works. This work built on the original plan and recommendations within the Thornhill Storm Drainage Improvements Study completed by the consulting team at Genivar Ltd. Recommended drainage improvements included:

  • replacing the undersized ditch inlets and catchbasins, and deficient culverts.
  • improving the roadside ditch conveyance capacity.
  • constructing a new stormwater management facility in Gallanough Park.
  • constructing new diversion/relief storm sewers along sections of Thornridge Drive. 


2007/2008: The City identified the need to reconstruct selected roads in the Thornhill community. Prior to initiating the detailed design, a study was undertaken to assess the effectiveness and/or performance of the existing storm drainage system in the area. The Thornhill Storm Drainage Improvements Study, undertaken by the consulting team at Genivar Ltd., summarizes the findings of the investigation and identifies deficiencies in the existing drainage system that posed a flooding risk in the area.


Questions? Contact the project team directly at gallanough@vaughan.ca.


Infrastructure Delivery