Report of Research, Field Investigation and Survey of Robert D ...

6.5.2 Draft Memorandum to Council of Corporation of Tiny Township by David W. Lambden
O.L.S. dated June 6, 2002
This document is a preliminary report on investigations into the One Chain Road Allowances
created by the several Patents to John Goesmann in payment for his survey of the township.
O.L.S. Lambden goes to extreme detail in his investigation, most of which is not relevant to the
present situation, but at Section A, he reports on several aspects related to the original survey of
Tiny Township. Of specific note are his comments at A.4 where he confirms my finding that
Goesmann did not survey any proof lines, and only surveyed the concession lines.
This is a copyrighted document which O.L.S. Lambden provided to me on condition that I not
release copies without his approval. As such, copies are not included.
6.5.3 Field Book 38142 CLSR by T.A. Bunker, O.L.S. C.L.S., dated Mar. 5, 2010 (Tab 44)
This document is entitled ‘Report of Research of the Islands and Water Levels in Georgian Bay,
adjacent to Henvey Inlet Indian Reserve No. 2', prepared for Surveyor General Branch of
Natural Resources Canada. It is of interest because, among other things, O.L.S. Bunker
investigated the relationship between ‘IGLD1985 datum and CGVD28 datum. I wanted to
prepare a cross-section of the centre-line of both Road Allowances being surveyed to show
where the water’s edge would likely have been at different important dates, and having an
understanding of the difference between these two datums is imperative if we are to get reliable
results.
Quoting O.L.S. Bunker from Pages 7 and 8 of his Report, “Measured elevations must be referred
to a datum, a level surface from which the measurements are based. Elevations of the Great
Lakes are referred to the International Great Lakes Datum (IGLD). Due to Glacial Isostatic
Adjustment (GIA, often referred to a “post-glacial rebound”), the land around the northern side
of the Great Lakes is slowly rising, while the land to the south of the Great Lakes is slowly
sinking. Because of this, the elevations of benchmarks located around the lakes are changing
over time, and so the IGLD and benchmarks referred to it must be revised approximately avery
25-35 years in order to ensure that the elevations assigned to the benchmarks remain fairly
accurate.
The first IGLD was named IGLD 1955, and has since been replaced with a newer version, IGLD
1985. The date, 1985, is the central year of the period 1982-1988 during which water
information was collected for preparing the datum revision.”
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