Purpose
The purpose of this assessment is to determine if repairs are needed to the berms and floodwalls. Repairs might be needed due to damage or degradation over the past 36 years, including the ice jam in February 2022. The study area is shown in Figure 1.
Figure 1. Study Area
Background
The Churchville neighbourhood is located on the Credit River between Steeles Avenue West and Highway 407. The low-lying neighbourhood has a long history of flooding, including at least 34 floods between 1922 and 2022 which were primarily caused by ice jams. The flood in 1987 led to the Churchville Flood Control Project which installed berms, flood walls and backflow prevention valves (Figure 1) to mitigate riverine flood risk. The total length of the berms and flood walls is approximately 875 m, of which 340 m are located on private property. The City has no easements across these private properties.
The drainage system has also been modified since the original Flood Control Project. In 2006, Paradise Homes Mahogany Inc. installed a new storm sewer on Victoria Street to drain a new subdivision down to the Credit River. Catchbasins on Victoria Street were connected to this new sewer and flapgates were installed to prevent the river from backing up the new sewer onto Victoria Street. In 2010, Peel Region replaced the storm sewer and flapgate northeast of the Churchville Road bridge during a sanitary sewer project.
An ice jam event occurred in the Churchville neighbourhood from February 17th to 23rd, 2022. Approximately 35 to 45 mm of rain fell overnight on February 16th over a snowpack of about 30 cm, resulting in 50 to 60 mm of runoff across the Credit River watershed. River ice quickly broke up and began to move downstream. An ice jam formed in the elbow of the Credit River downstream of the Churchville Road bridge. Rising water levels backed up through multiple storm sewer systems and may have also overtopped the berm. Approximately 15 to 20 homes were flooded and residents from about 100 homes were evacuated. The ice remained stuck until February 23rd, 2022.
Project Overview
The City’s consultant will:
- Review background information and confirm applicability of the Lakes and Rivers Improvement Act (LRIA).
- Verify that all the relevant permissions to undertake required work on private property have been acquired.
- Conduct investigations, including topographic survey, visual inspection, structural assessment, geotechnical investigation, and fluvial assessments.
- Prepare a condition assessment report that includes all assessment methods, observations, analyses, conclusions, and recommendations.
- Prepare an asset management strategy for the berms and flood walls, including estimated costs, prioritization of remedial measures, a roadmap for approvals or remedial measures, annual maintenance tasks, expected life cycle, and administrative requirements to carry out the repairs.
