Monument record MHG55410 - Fundamental bench mark, Dalwhinnie

An underground concrete chamber containing two permanent height markers, and marked at ground level by a granite pillar about a foot high. The two primary reference points lie underground and consist of a gun metal bolt and polished flint both set into fine granolithic concrete and protected by iron covers. A gun metal bolt on the granite pillar provides a third reference point.
There are currently 194 fundamental bench marks across the UK mainland (22 in Highland) which were built between 1911 and the early 1950s. They are established along the Geodetic lines of levels at approximately 30 mile intervals. Dalwhinnie FBM records an altitude of 318.84m AOD. <1>

The Ordnance Survey Geodesy Team have asked to be notified of any development proposals which meet the following criteria:
1) If an FBM falls inside the boundary, or within 30m of the boundary of a proposed development upon completion.
2) If an FBM falls inside the boundary, or within 30m of the boundary of the "construction area" or any other temporary area of a proposed development.
They also wish to be notified in any other case where an FBM may be at risk of disturbance. Should an FBM be threatened they will create a new one nearby at their own expense before the threatened one is lost. This is to ensure the continuing integrity of this vital network. <2>

<1> Ordnance Survey, 2011, List of fundmental bench marks in Scotland (Dataset). SHG25583.

<2> Mann, B, 25/11/2011, Protecting Fundamental Benchmarks - information for adding sites (Text/Correspondence). SHG25584.