Loch Earn

Loch Earn (Scottish Gaelic, Loch Eire) is a freshwater loch in the central highlands of Scotland, in the districts of Perth and Kinross and Stirling.

It is a long narrow loch, 17 km west of Crieff and is approximately 10.5km long, 0.8km at its widest point and 87m deep at its western end. Lochearnhead village is situated at the western end of the loch and St. Fillans village at the eastern end. From here, the River Earn flows eastwards from the loch, through Strathearn, and eventually joins the Firth of Tay some 75km away. Lochearnhead is the centre for the water sports activities on the loch; water skiing, canoeing and sailing. The loch is also stocked regularly with brown and rainbow trout and fishing, by permit, is possible from the shore and by boat.

To the south of the loch lies Ben Vorlich, a steep sided pyramid shaped peak. At 985m, this is a popular climb and the views from the top are spectacular. Just east of Lochearnhead, on the south side of the loch, is Edinample Castle, built by 'Black' Duncan Campbell of Glenorchy in 1584. Further east is Ardvorlich House, home to the Stewarts of Ardvorlich from 1580 (rebuilt in 1790).

Loch Earn is unusual in that it has its own apparent 'tidal system', or seiche, caused by the action of the prevailing wind blowing along the loch. This wind pressure on the surface causes the water level to build up at one end of the loch. As with all damped mechanical systems, applied pressure can result in an oscillation, and the water will return to the opposite end of the loch over time. In the case of Loch Earn, this has a period of 16 hours and the effect can be measured, but is difficult to observe. The resulting currents can create complex turbulance patterns, as higher layers of warmer waters mix with the lower lying colder waters of the loch.

Other bodies of fresh water which experience this seiche effect include Lake Geneva, Lake Garda, Lake Erie and Lake Baikal.