Client Township of Langley Duration 2017 – Ongoing
The Township retained Binnie in 2017 to perform hydrologic and hydraulic assessments for various independent project sites within the Township and to develop designs for either the rehabilitation of existing culverts, the removal and replacement with the new structure(s), or a combination thereof. The projects, completed under three subsequent contracts include:
Latimer Creek Culvert Rehabilitation
Matheson Creek Culvert Replacement
West Creek Culvert Replacement
Howe’s Creek Culvert Replacement and Rehabilitation
Cave Creek Culvert Replacement
Pepin Creek Culvert Replacement
Anderson Creek Culvert Replacement
Salmon River Tributary Culvert Rehabilitation
Palmateer Creek Culvert Replacement
Upper Little Campbell River Tributary Culvert Replacement
Detailed hydrologic assessments including climate change were completed for each natural watercourse including establishing PCSWMM models. Sub-catchment areas and physical parameters (i.e. land use, runoff parameters, infiltration parameters, and watershed depression and storage features) were defined based on field observations, aerial photos, as-built records, the Township’s GIS map, and, where available, ISMPs for the catchment areas. Binnie’s team completed a detailed survey of all project sites including watercourses, roadways, utilities, and private properties near the works.
Binnie worked closely with ToL’s environmental consultants to obtain authorizations or approvals for the proposed instream works. Binnie’s water resource engineers incorporated fish passage considerations into the detailed design including outlet pools, rock weirs, baffles, culvert embedment and riparian planting to facilitate fish passage, and dissipate energy while preventing scour and erosion during peak flow events. In accordance with the Township’s preferences for a more natural headwall structure, Binnie also incorporated Sierra Slope retaining walls into the culvert replacement design at several locations.
The projects were successfully designed, tendered, and constructed to meet the tight In-stream Work Window schedules. To ensure that the culverts were constructed on schedule, Binnie proposed that the Township order the box culverts directly from the supplier. This recommendation reduced the construction budget and helped to deliver the projects on time. A key to the success of this project was the consistency of regular updates with the Township and quickly addressing any concerns raised by the Township or contractors.