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Druim Bhlar Flood Sinks

Durness, Sutherland.

Sinks near the road-end at Smoo.

A wide peaty depression contains a significant sink at NC 41414 66736 (Druim Bhlar Flood Sink), and what appears to be a choked sink at what may once have been an overflow channel at NC 41445 66730 (Druim Bhlar Overflow Sink).

Druim Bhlar Flood Sink is typically a dry depression clogged with peaty sediment. During periods of flooding, a pool sourced from an un-named marshy lochan to the south (NC 412 664) accumulates upon the peat and eventually causes its collapse under weight. During such times, the water has been observed to flow into a cave-like hole exposing fractured limestone and cherty bedrock, which has yet to be entered due to the unstable nature of the overhanging peat bank that reaches several metres in thickness.

The DB Overflow Sink has been partly excavated to a depth of 2m through beige-coloured weathered dolostone that belongs the upper Sangomore Formation, suggesting that de-facto limestone beds may be present in the subcrop nearby.

An enormous shakhole (Cubic Meterorite Crater) is located adjacent to these sites, centred on a square-shaped landscaped pool at NC 41447 66694.

Approx. 20m SW of the Overflow Sink, an opening amongst heather drops into a 4m-long winding body-sized tube through peat with possible bedrock exposed in places. The accessible section trends towards the Overflow Sink. This tube is referred to as 'Hammerschlag' and is probably related to overflow when Flood Sink is filled.

Alternative Names: None recorded.

Notes: A small quarried outcrop at the road end exposes a highly-fractured fault zone with thick cataclasite bands. This probably tends NE-SW (parallel with other faults in the area) and would underlie the flood sinks area. This exposes the Sailmhor Fm (inconsistent with the geological map that was surveyed prior to the 2025 'quarry')

Hydrographic Feeds: Un-named marsh