Short version of the Dikes History: it’s a 1950s–60s dike, built cheap, patched ever since, never truly modernized.

1. When and why it was built

• Built after the 1948 Fraser flood to protect the waterfront, village core and resort from Fraser-/Harrison-driven lake rises. Get Into It Harrison!

• Folded into the 1968 Fraser River Flood Control Agreement, with “as-constructed” drawings for Harrison’s flood works prepared by Dayton & Knight. Government of British Columbia

2. Major upgrade milestones

• Provincial programs in the 1990s already talked about upgrades but they weren’t done. Harrison Hot Springs

• 2007 “Flood Works – Harrison Hot Springs Dike” project – localized repairs, not a full rebuild. Government of British Columbia

• 2016 Archimedes pump/floodbox upgrade so Miami River flows can still be pumped to the lake during high-lake events (designed for a 200-year Miami flow). Harrison Hot Springs

3. What the modern assessments say

• 2015 Lower Mainland Dike Assessment gave Harrison’s dike a crest rating of 2/4 and said it “does not meet minimum requirements.” Overall condition: 2.63/4, with “limited geotechnical data.” Harrison Hot Springs

• Region-wide work by Fraser Basin Council notes many Lower Mainland dikes (including Harrison’s) have insufficient crest height and geotechnical issues like seepage, meaning big “residual risk” remains even where dikes exist. fraserbasin.bc.ca

4. How standards changed under it

• The original Harrison dike was set to an historic level that no longer meets provincial design crest rules. Get Into It Harrison!

• New standards require: 200-year (or flood-of-record) water level plus settlement, climate-change allowance, wave run-up, and freeboard. When you apply that math, Harrison’s existing crest of 13.9 m falls short; the proposed minimum crest is 15.1 m – about 1.2 m higher than today. Harrison Hot Springs

5. Where that leaves things now

• Current project goal: raise and harden the waterfront dike and WWTP road using about $11 M in grants; if costs blow past that, they’ll phase work and rely on cheaper temporary barriers until more money shows up. Harrison Hot Springs

Blunt truth: Harrison is sitting behind a mid-century earth dike built to outdated standards, partially upgraded (pump, spot repairs) but never rebuilt to modern provincial criteria. The expert reports are basically a big red flag saying “you’re on borrowed time.”