Sechelt Landfill Expansion Feasibility Assessment

The Challenge

The Sunshine Coast’s only landfill was running out of room

The Sechelt Landfill has served the Sunshine Coast since about 1971, taking waste from the District of Sechelt, the Town of Gibsons, the shíshálh Nation Government District and every SCRD electoral area. It was built as a natural attenuation site, without a liner or leachate collection, and was approaching capacity.

The Sunshine Coast Regional District asked SHA to determine whether a 15.4 ha site directly west of the existing landfill could be approved for development under the BC Landfill Criteria, and whether it could provide at least 50 years of disposal capacity.

Our Approach

A conceptual landfill designed to the Landfill Criteria from day one

• Regulatory pathway: identified every permit, technical study and approval needed to develop the site, including the steps for First Nation engagement and community consultation.
• Final contour design: compared several layouts and selected one that piggy-backs the expansion against the existing landfill, buttressed by a 10 m high toe berm and perimeter access road to maximize airspace.
• Borrow plan: designed the base excavation to supply about 208,800 m³ of on-site cover and construction material, while staying at least 1.5 m above the high groundwater level.
• Environmental controls: a lined base with gravity leachate collection to on-site pre-treatment ponds for discharge to sewer, stormwater benches every 15 vertical metres with a retention pond, and a landfill gas management plan.
• Operations and costs: a conceptual operating plan tied to the Pender Harbour Transfer Station, capital, closure and post-closure cost estimates, a cash-flow analysis and a project schedule.

Every element was designed to the BC Landfill Criteria, Second Edition: 50 m property buffers, 3H:1V maximum final slopes and minimum 4% crest grades.

The Outcome

A suitable site with capacity to 2080

SHA concluded that the site is suitable for landfill expansion. It generally meets the Landfill Criteria siting requirements, sits in a favourable hydrogeological setting, is isolated from residential areas, can supply its own cover material, and is economically favourable.

The design provides about 2.16 million m³ of airspace, enough for an estimated 56 years of landfilling, from 2025 to 2080. SHA recommended a site-specific hydrogeological investigation and early discussions with the District of Sechelt on accepting treated leachate. The SCRD has since retained SHA to assess vertical expansion and waste export options for its long-term disposal plan.