Gibsons Mayor and Council:
I recorded the sea water level in Gibsons Harbour at 10:09 a.m. on Saturday, Jan. 16 when the high tide predicted by Fisheries and Oceans Canada was 16.1 feet (4.91 metres) for normal barometric pressure of 1,000 millibars.
At that time the barometer reading of 985 millibars plus an outflow wind estimated at 15 knots (28 km/h-) produced a sea water level of 17.4 feet (5.30 metres) as indicated on the tide gauge at Gibsons Marina. The sea water level was within a centimetre or so of the seawalk level at the proposed George development site.
“The historical recorded high water level at Point Atkinson occurred on Dec. 16, 1982 when the water gauge measured a total water level of 5.61 m (4.71 m tide + 0.90 m anomaly). The factors that led to the historical high water level were a combination of high seasonal tide, strong winds, low atmospheric pressure and a coastal sea-level height anomaly of approximately 0.2 m driven by one of the most intense El Niño events on record.”
This paragraph is contained in a Storm Surge Almanac for Southwestern British Columbia that was prepared for Fisheries and Oceans Canada and the B.C. Ministry of Environment by Scott W. Tinis, PhD, Oct. 7, 2011.
The simple arithmetic for Jan. 16 in Gibsons Harbour is that the 0.9 metre anomaly that occurred in 1982 would have produced a sea water level of 5.81 metres (19.1 feet). This level does not include any provision for an expected rise in sea levels estimated in the range of 0.3 to 0.9 metres.
I refer you to the Nov. 20 seminar Wading Through Sea-Level Rise: How Will Engineers and Planners Adapt to Changing Coastal Water Level and other educational events and articles by the Association of Professional Engineers of BC.
As you are currently evaluating development proposals in Gibsons Harbour I, and other taxpaying residents and business owners, would like to know what sea level has the Town established as a basis for designing developments and infrastructure? Also what measures are in place to limit financial liability of the Town and its taxpayers against potential losses from inadequate provision against sea water flooding over the anticipated lifetime of any waterfront construction?
John Roper, P. Eng., Gibsons
