Binnie provided a corridor wide drainage assessment which included documenting the existing conditions of 51 culverts[1] along the Hemlock Valley Road for the Ministry of Transportation and Infrastructure (MoTI). A hydrological assessment of the watershed included assessing future climate change. A risk assessment was completed which identified deficiencies and provided recommendations for long term management of corridor’s drainage infrastructure. The project began in March of 2020 and was completed in October of 2020. The Hemlock Valley Road is the only road available to residents of the Hemlock Valley community and visitors of the Sasquatch Mountain Resort, making it a crucial step for the MoTI in completing a long-term mitigation plan for the drainage infrastructure in this area.
Culverts are integral to controlling water flows and preventing flooding or road washout due to excessive rain. To assess the risks, our staff completed field reconnaissance and recorded the material type, dimensions, locations, evidence of structural deficiency, and potential performance problems (such as debris and vegetation blockage at inlet or outlet, local inlet/outlet scour, poor channel alignment) at all 51 culverts. Backing these observations was a photo log our team prepared of each crossing showing the existing conditions of the crossings. Upon inspection, our team discovered that many culverts were under-sized or not structurally sound, while other culverts were blocked with debris and sediment.
Binnie undertook a hydraulic analysis of all existing culverts, including an assessment of inlet and outlet conditions, culvert capacity assessments. Drainage channels above the roadway were also assessed for the possibility of debris flow or debris flood events.
In order to establish measurable assessments, our team created a quantitative scoring system for vulnerability screenings of the culverts in which relative scorings were defined for five categories of hazard at each crossing. The five categories for hazards included:
- Watershed Geomorphic Hazards
- Capacity Deficiency Hazard
- Channel Instability Hazard
- Hazard Due to Structural Deficiencies
- Inlet/Outlet Scour Potential
Each individual culvert crossing was classified based on level of risk (i.e., High/Medium/Low) based on the above hazard assessment. A summary of applicable remedial options was then finalized for all culverts based on the urgency identified in risk level determination. Using this information, our team provided recommendations and high-level cost estimates.
As of 2022, Binnie is working on the Hemlock Valley Road Realignment.
To know more about Binnie’s engineering solutions that build and connect communities, please visit our projects section.
[1] A culvert is a structure that allows water to flow under a road, railroad, trail, or similar obstruction from one side to the other. Typically embedded to be surrounded by soil, a culvert may be made from a pipe, reinforced concrete, or other material.
