A River's Tale - The River Isla
|Sun, 13 Jan 2008 16:57
|The River Isla is the main tributary of the River Tay and flows through the counties of Perth & Kinross and Angus in Scotland. It is 74km in length, from it's sources in Caenlochan National Nature Reserve in the south of the Cairngorms National Park, to its confluence with the Tay, just north of Perth.
Part 1 Source
Strictly the Isla is formed by the joining of the Canness Burn and the Caenlochan Burn, but the Canness Burn is longer and so counts as the source. The Canness Burn begins on the slopes of Cairn of Claise:
The burn then cuts a gorge through the lip of the plateau:
It is one of several small burns flowing into Canness Glen:
These join the main Canness Burn flowing through the glen:
The Caenlochan Burn joins from the west at the foot of Canness Burn, just south of this ruin, and from hereon the watercourse is known as the River Isla:
|Sun, 13 Jan 2008 17:21
|Part 2 Glen Isla
Above Tulchan Lodge, Glen Isla is very much an upland glen, surrounded by high hills, and the River Isla is an fast-flowing stony upland river.
The Glenbrightly Burn joins at Tulchan Lodge:
Below Tulchan Lodge the glen begins to widen out is no longer so hemmed in by the hills:
The Glencally Burn joins at Dalhally:
The Isla is beginning to look like a river, rather than just another upland burn.
The glen itself is wide and flat-bottomed: typically U-shaped following glaciation.
Lower down, the Glenisla of road maps and road signs is a wide and gentle glen, with the road rarely revealing that a river flows through the valley.
There is only one major tributary in Glenisla, although it the Burn of Kilry is still a rather small burn.
|Sun, 13 Jan 2008 18:01
|Part 3 Gorges
At Craigisla, the Isla passes over the Higland boundary fault. moving from hard metamorphic rocks to softer sedimentary rocks. The result is the waterfall of Reekie Linn.
Below Reekie Linn the Isla flows in a gorge, up to 50 m below the level of the surrounding land, and with several smaller waterfalls. Much of this is on private land, however, and inaccessible.
The tributary of Melgam Water, dammed at Backwater Reservoir and Loch of Lintrathen, joins at Airlie.
Below this is the very narrow Den o' Airlie, which is also a National Nature Reserve.
A little lower downstream the Burn of Alyth joins and the Isla continues through steep-sided banks through Ruthven, where motorists can cross the river without even realising it is there.
|Sun, 13 Jan 2008 18:44
|Part 4 Strathmore
Finally, below Ruthven, the Isla breaks into Strathmore, a valley much larger than any of the water courses that flow through it and so, clearly, of some other origin.
The Dean Water, which rises in Forfar Loch, joins soon afterwards.
At last, the Isla can begin to gently meander towards its final destination.
Near Coupar Grange is the most significant tributary, the River Ericht, which was formed by the meeting of Black Water and the River Ardle at Bridge of Cally, above Blairgowrie.
Just downstream, the Isla passes Coupar Angus, the nearest thing to a significant settlement on its banks.
A little further on and the Lunan Burn becomes the last significant tributary.
Then, finally, just south of Meikleour, the Isla joins up with the Tay.