The potential economic impact to Abbotsford and B.C. of a breach of the Matsqui dike could be between $1.8 and $2.6 billion, according to information presented at a committee of the whole meeting on Monday.
As erosion near the dike continues to be an issue on Fraser River banks, staff provided an update to council as part of an ongoing study launched last year with consultant Northwest Hydraulics Consultants.
The intent of the study, for which council approved $180,000 in funding last year, is to assess the causes and risks of the erosion, and to prioritize locations where erosion work may be required. The draft report of the study is almost complete, according to staff.
Last year, the city spent more than $1 million to fix erosion arcs on the banks of the Fraser River after one came within 30 metres of the Matsqui dike, which protects nearly 5,000 hectares of agricultural land, and major infrastructure such as Highway 11, railways, BC Hydro towers and the JAMES wastewater treatment plant.
A city report with the early findings states that much of the south bank of the river between Sumas Mountain and the tip of Matsqui Prairie is unstable.
The report puts forward the various options to address the problem, including upgrading the existing bank protection with continuous rock armoring, with costs between $6 million to $20 million (the report notes costs are estimates and rounded to the nearest $2 million); or upgrading the existing protection with rock spurs, set at a cost of $4 million. Also proposed is dredging the north side of the river, at $6 to $10 million every two years; or relocating the dike, which would cost about $21 million.
As the study is not yet complete, staff will consult with stakeholders, such as local First Nations, before officially recommending an option for council to consider later this year.