River Shin

River Shin
A suspension bridge crosses the Shin below the Falls of Shin
Location of the mouth within Scottish Highlands
Location
Country	Scotland
Physical characteristics
Source
• location	Little Loch Shin weir
• coordinates	58.0128°N 4.4017°W / 58.0128; -4.4017
Mouth
• location	Kyle of Sutherland
• coordinates	57°56.14′N 4°24.8′W

River Shin system
source source Allt nan Albannach Loch Dubh a' Chuail Loch Merkland Abhainn a Choire Merkland River Loch Shin Loch a' Ghriama headwaters source River Cassley Loch a' Ghorm-Choire Cassley power station Loch Fiag Duchally weir  A838  Fiag Bridge & River Fiag River Tirry Lairg dam Lairg power station Little Loch Shin  A839  Lairg Bridge tunnel site of Gruids Mill Grudie Burn Intake to tunnel Falls of Shin  A837  Shin Bridge Shin power station Kyle of Sutherland

The River Shin (Scottish Gaelic: Abhainn Sin, pronounced [ˈa.ɪɲ ˈʃin]) is a river in the Scottish North West Highlands.

The river flows from the southern end of Loch Shin, next to the village of Lairg. It flows in a generally southward direction, passing by Shin Forest and over the Falls of Shin. It joins the Kyle of Sutherland at Invershin, which then flows into the Dornoch Firth at Bonar Bridge and then the North Sea. The river is just 7 miles (11 km) long.

Route

The River Shin is fed by a number of streams and rivers which rise to the north and north-west of Lairg. Loch Dudb a' Chuail is located on the southern slopes of Meallan a' Chuail, a small mountain of 2,460 feet (750 m). Water from it flows along the Abhain a Choire ("Corrie River") past the settlement of Corriekinloch to reach the north-west end of Loch Shin. Loch Merkland is fed by a number of streams rising in the mountains, including the Garbh Allt, which flows eastwards to reach the western bank of the loch. It covers 430 acres (174 ha) and its surface is 377 feet (115 m) above Ordnance datum (AOD). The short Merkland River joins it to Loch a' Ghriama, which covers 270 acres (109 ha) and is at 318 feet (97 m) AOD. A narrow channel crossed by a bridge carrying a minor road joins it to Loch Shin.

Loch Shin is around 17 miles (27 km) long with a maximum depth of 162 feet (49 m). It covers 8,138 acres (3,293 ha) and its surface level is 312 feet (95 m) AOD. The level was raised by 35 feet (11 m) when the dam at its southern end was built, and so its surface area is also larger than it was. A short way along the loch on its south-western shore is Cassley power station, which discharges water collected from the headwaters of the River Cassley into the loch. This supply passes under Moavally mountain through a tunnel. The River Fiag enters the loch at Fiag Bridge, which carries the A838 road over its mouth. The river flows southwards along the narrow Glen Fiag from Loch Fiag, which collects water from a number of streams. The loch covers 363 acres (147 ha) and its surface is 650 feet (198 m) AOD.

As Loch Shin continues to the south-east, there is a promontary known as The Airde which is attached to the north-east bank. At its tip, near the disused Shinness Quarry, there are a number of prehistoric remains, including several hut circles. The next tributary to enter Loch Shin is the River Tirry, which rises to the south-east of Loch Fiag, and flows down the wide Strath Tirry, to the west of the A836 road. It is joined by two of its own tributaries, which rise to the east of the road. The first is the Abhainn Sgeamhaidh, which is crossed by the A836 at Rhian Bridge, near the hamlet of Rhian. The bridge has a single arch and is made of rubble. The second is the Feith Osdail, which flows from the east. Its flow has been augmented by the construction of a weir at Dalnessie on the River Brora, which diverts the headwaters of that river into the Feith Osdail. The weir and interconnecting channal were constructed as part of the Shin hydro-electric scheme. Close to its junction with the River Tirry, the river is crossed by the A838 road at Feith Osdail bridge. This is a single span rubble bridge designed by Thomas Telford and constructed around 1815, as part of his project to build the Parliamentary road from Bonar Bridge to Tongue, completed in 1819. Just before the Tirry enters Loch Shin, it is crossed by a bridge carrying the A838 road, near the settlement of Tirryside.

At the southern end of Loch Shin lie the dam and power station which were constructed in the 1950s, and which raised the level of the loch. The architecture is of a high quality with a prominent copper roof, as the structures form a focal point for the village of Lairg. Below the dam is Little Loch Shin, which is immediately to the west of Lairg. It is crossed part way down by the A839 road, and ends at the dam, from which water enters a tunnel to feed the power station at Inveran, and compensation water is released to maintain the flow on the River Shin.

Achany Glen

The River Shin properly starts at the weir or dam at the lower end of Little Loch Shin. A short distance below the dam, a prehistoric stone circle stands on the right bank. The river continues to the south and is crossed by a pedestrian suspension bridge. Soon the river flows over a weir, which runs diagonally across the river. There is an island near the right bank, formed by the leat running to the west of it which formerly supplied Gruids Mill, parts of which are still in situ. Close to the point at which the leat rejoins the river, early maps show a corn mill and a saw mill.

There is a poorly preserved prehistoric hut circle on the right bank of the river. The hut is around 36 feet (11 m) in diameter, but there is no obvious evidence of associated land use. Shortly afterwards, the Grudie Burn joins on the right bank, after it has passed through the single-arched Achany Bridge, which carries the B864 road. This section of the Shin valley is known as the Achany Glen. At Inveran, the river is crossed by two bridges, the oldest dating from around 1830. It has three arches, with the centre arch being taller than the outside arches. It was bypassed by a newer bridge when the A837 road was realigned. On the right bank is Inveran power station, supplied with water by a tunnel from Little Loch Shin. It has a copper roof, sculpted panels showing mythical Celtic beasts, and a panel showing "Shin Power Station". The outfall from the station is a little further downstream, where there is a dam which prevents migrating fish from entering the station. The Shin then joins the Kyle of Sutherland. Near the junction on the left bank is Invershin farm and salmon station. The buildings date from the early 19th century, and include a boiling house and two ice houses. Salmon were par-boiled and despatched to market initially by sea and later by railway.

Hydro-electric development

The Shin hydro-electric scheme was implemented by the North of Scotland Hydro-Electric Board. After the board was created in 1943, they produced a list of 102 projects which they thought could be built, from small ones to huge ones involving several neighbouring glens, including that for the Shin. The scheme has a catchment area of around 250 square miles (650 km²) in an area where the average yearly rainfall is 60 inches (1,500 mm) and the total head is around 265 feet (81 m). These figures are considerably smaller than for many of the Board's other schemes, but the local population was fairly small and scattered, and so the capacity of the system was consequently lower. Plans to implement the scheme were published in 1951, and it became the 32nd constructional scheme promoted by the Board. Parliamentary approval to proceed was received in the summer of 1953, after lengthy negotiations, and George Wimpey & Co began work on the contract in 1954.

The scheme was the most northerly on the Scottish mainland of those implemented by the Board. It involved constructing a concrete gravity and earthfill dam across the river at the southern end of Loch Shin, which raised the level of the loch by 35 feet (11 m). The dam is 1,740 feet (530 m) long and 66 feet (20 m) high. It required 40,000 cubic yards (31,000 m³) of concrete and 76,000 cubic yards (58,000 m³) of earth to complete it. The consulting engineers for the construction were Sir Murdoch MacDonald and Partners. The dam is used to release compensation water to maintain flows in the river below, and that water is fed through a 3.5MW vertical Kaplan turbine which is built into the dam. The water first passes into Little Loch Shin, a small reservoir immediately below the dam. Its level is controlled by a weir at the downstream end, but much of the water passes into a long tunnel, which carries it to the Inveran power station, located on the west bank of the River Shin close to its junction with the Kyle of Sutherland. Additional water enters the tunnel from the Grudie Burn, and the tunnel feeds water to two horizontal Francis turbines, each of which was connected to a 12MW generator. On exit from the power station, the water passes back into the Shin.

The Lairg dam has a fixed spillway in the centre, with higher parapet walls to either side. There is a lower spillway at the north-east end of the dam, with gates to control its operation. The power station building is a two-storey design, integrated into the dam wall, and faced with random rubble. The architect for the design was James Shearer, and architectural details include carved panels and armorials. In common with many of their projects, the engineers were responsible for the functional form of the buildings, but the architect decided on their appearance and style. This led to a style which was called vernacular modernism, and reflected the attempt to ensure that the buildings harmonised with the landscape.

To ensure that migrating salmon could still reach their spawning grounds on the upper river, a fish screen at Inveran stops them from entering the tail race of the power station. Borland fish lifts are installed at the Little Loch Shin weir and the Lairg dam. THe flow in the river is maintained by releasing compensation water from the weir, but even this is used to generate electricity, as the water passes through a small turbine built into the weir. It was one of the first uses of a "compensation set" in the country. This part of the scheme was completed in 1959, although the dam and weir were ready for impounding of water to begin in January 1956.

The scheme included another power station on the banks of Loch Shin. Cassley power station is fed by water collected from the headwaters of the River Cassley, which runs parallel to Loch Shin, but further to the west. 5 miles (8 km) of new road were required to access the site, because of its remoteness. A pipeline to the west of the river collects water from the Allt a' Chnaip Ghiubhais and the Allt Loch Carn nan Conbhairean, while one to the east collects water from the Allt Moavally. The pipes feed into a headpond, created by building Duchally weir. From there, the water passes through two small turbines to enter a tunnel which carries it beneath Moavally, a hill of 1,677 feet (511 m), to the western shore of Loch Shin. Cassley power station has two turbines, capable of generating a total of 10MW, and was used to feed the area around Durness in the far north west of Scotland. The power station was completed in July 1960.

The flow into Loch Shin is augmented by some of the headwaters of the River Brora, to the east of Loch Shin. A weir near the Dalnessie Estate diverts water into an aqueduct, which discharges into the upper reaches of the Feith Osdail, a tributary of the River Tirry, which flows into Loch Shin. Another aqueduct captures some of the flow in the upper tributaries of the River Vagastie to the west of Vagastie Bridge on the A836 road, and diverts the water into the Allt an Locha Ghaineamhaich, close to Loch Gaineamhach. This is also a tributary of the River Tirry.

Bibliography

• Miller, James (2002). The Dam Builders - Power from the Glens. Birlinn. ISBN 978-1-84158-225-2.
• Payne, Peter L (1988). The Hydro. Aberdeen University Press. ISBN 978-0-08-036584-8.

Media related to River Shin at Wikimedia Commons