Pattison Creek – Emergency Debris Removal Works

Summit Earthworks was selected by Associated Engineering (AE) on behalf of the BC Ministry of Environment and Climate Change Strategy (MoECCS) to perform the sediment removal from Pattison Creek deposited by the November 2021 Atmospheric River Event (ARE).

An environmental management plan from MOTI was provided, and together with our Qualified Environmental Professional, Summit developed a Construction Environmental Management Plan (CEMP) for the project. Available equipment not previously equipped with vegetable-based oils were serviced accordingly for the execution of the project. Summit with Associated Engineering identified areas of concern outside the initial project footprint. In consultation with the Leq’a:mel First Nations hydrologist and cultural monitors, Associated Engineering, MoECCS representatives and design engineers applied in the section 11 amendment to extend the project footprint. The extension included 30 meters of creek-side sediment excavation, bank realignment, and restoration. A creek diversion plan was developed to limit sediment release into the active stream, and creek isolation with fish salvage was determined to be required and executed on two occasions.

The general scope, outline, and project activities include:

• Site isolation using strategically placed mega sandbags to create a temporary diversion channel and facilitate discharge pumping.
• Removal of watercourse substrate (including sediment and debris) using mechanical methods, involving multiple excavators, rock trucks, and dump trucks.
• Clearing and grubbing of woody debris from the access road and watercourses, with off-site disposal at an approved facility.
• Bank repairs and the installation of riprap for erosion protection.
• Maintaining fish passage around isolated work zones through the use of a diversion channel, under the supervision of a Qualified Environmental Professional (QEP).
• Rehabilitating disturbed areas of the streambank, restoring them to a stable condition.