The loch is entirely man made, being created by the damming of the Errochty Water, the river which runs down the glen.

The diamond-headed buttresses provide extra strength to deal with possible tremors from the Highland Boundary Fault which runs just to the south of Pitlochry.

Other small streams flow directly off the 892-metre-high (2,927 ft) mountain of Beinn a' Chuallaich which stands just to the south.

The catchwater then goes through a tunnel in the hill which separates the Garry and Errochty valleys to join the loch.

[5][6] The north shore of the loch has a narrow surfaced road which is not open to general traffic, there being a locked gate at Trinafour to prevent access.

A track goes through the woodland from Trinafour and then continues in open country along the south shore until it reaches the ruin of Ruighe nan Saorach.