|Data on the structure|
|Height of the barrier structure :||9.4 m|
|Data on the reservoir|
|Water surface||95 ha|
|Reservoir length||3 km|
|Reservoir width||530 m|
|Storage space||2.36 million m³|
The lake, about three kilometers long and 530 m wide, is located in the south of the Edinburgh Council Area on the western flank of the Pentland Hills . The next town is Balerno, three kilometers to the northwest . To the southeast rises the 449 m high Hare Hill . The brook Bavelaw Burn , which rises a few kilometers south on the slopes of East Cairn Hill , feeds the lake on the east side. It leaves the reservoir via a weir on the north bank to fill the adjacent Harlaw Reservoir . Leaving this, the Bavelaw Burn flows into the Water of Leith , which eventually drains into the Firth of Forth .
The Scottish engineer James Jardine is responsible for the planning of the reservoir . Construction, which served to supply Edinburgh's water supply, began in 1843 and was completed in 1848. Although the state water supplier Scottish Water operates the dams today, the water is no longer fed into the drinking water supply. Together with the Harlaw Reservoir, however, the Threipmuir Reservoir makes a significant contribution to flood prevention along the Water of Leith.
On the north-eastern bank, an earth wall 400 m long and 9.4 m high dams the lake. The Threipmuir Reservoir, which is a maximum of 5.2 m deep, can hold 2.36 million m 3 of water. At the capacity limit, the lake has an area of 94.8 ha .