River Conon

The River Conon (Conann) is a river in the Highlands of Scotland. It begins at Loch Luichart, and flows in a south-easterly direction to be joined by the River Meig at Scatwell before passing through Loch Achonachie. It is joined by the Black Water at Moy Bridge, and the River Orrin at Urray, before flowing past Conon Bridge and into the Cromarty Firth (and thence the Moray Firth and North Sea).

The river is part of the Conon hydro-electric power scheme, with dams at Loch Luichart, Loch Meig and Loch Achonachie, and power stations at Luichart and Torr Achilty. This major scheme was developed by the North of Scotland Hydro-Electric Board between 1946 and 1961. Prior to that, a small power station had been built at the Falls of Conon in the 1920s, and a private scheme for the Brahan Estate was commissioned in 2015 at Dunglass Island.

The river system is fished for trout and salmon, but populations of these fish have not always been as healthy as they now are. The use of traps and fixed nets in the river and in the Cromarty Firth has been the subject of legal action since 1828. The construction of hydro-electric schemes has resulted in some of the salmon spawning grounds being lost, but fish lifts at the dams and a fish pass at the Falls of Conon have enabled fish to reach the River Bran, which was previously inaccessible to them, and some 100 mi of habitat suitable for young salmon has been developed. Although nets in the Firth have now gone, fish are predated by seals which live in the Firth, and hunt up river as far as Torr Achilty dam.

There are several islands in the river, including Moy Island, Dunglass Island and Garrie Island. The river is said to have once been the home of a water horse.

Route
The waters that form the River Conon rise on Mòine Mhòr ("Great Moss"), an upland peat bog to the west of Achnasheen and to the south east of Kinlochewe. A series of springs on the slopes of Càrn Loisgte and Carn Breac fall into Loch na Mòine Mhòr and Loch an Fhiarlaid, from which the Abhain Dubh ("Black River") flows eastwards to the diminutive Loch Crann, and the much larger Loch a' Chroisg, which is over 160 ft deep in places. The A832 Kinlochewe to Achnasheen road runs along the northern shore of the loch. From the eastern end of the loch, the waterway becomes the River Bran, and is crossed by a Parliamentary bridge at Achnasheen. This is a single span bridge built of rubble as part of a ten-year project to construct a road from Achnasheen to Strome Ferry between 1808 and 1819.

That road became the A890, but the bridge has been superseded by a wider one slightly further downstream. The river is joined by the Abhainn a' Chomair, which rises in the Glencarron and Glenuig Forest on the northern slopes of Cnoc na Mòine and Carn Gorm, where it is called the Allt Gharagain. This flows to the north, and turns to the north-east near the hamlet of Ledgowan, where it is joined by the A890 road and the Kyle of Lochalsh railway line. It enters a small loch, is joined by the Allt Mhartuin, and enters Loch Gowan. It joins the River Bran just before the railway bridge at Achnasheen railway station. The railway and the A832 road share the valley of the Bran as is continues eastwards. The valley widens to become Strath Bran, and after passing Achanalt railway station, the river enters Loch Achanalt.

The railway crosses to the south side of the waterway at a tiny river section called A Phait, between Loch Achanalt and Loch a' Chuilinn. There is a dam at the eastern end of the loch, and a little further downstream is Achanalt power station. This is housed in a tall single-storey building designed by James Shearer in 1952, built into a cliff at one end and constructed of random rubble. A fish pass consisting of natural pools and some artificial concrete pools enables migrating fish to bypass the power station. The River Grudie joins the River Bran on its left bank, and the Bran is crossed by the railway line close to Lochluichart railway station before the river enters Loch Luichart. The river from Loch a' Chuilinn to Loch Luichart is called the River Bran on modern maps, but was formerly called the River Conon and prior to that was called the River Conan

The River Grudie rises from a series of springs on the foothills of Meallan Chuaich, and is known as Abhainn a' Chadha Bhuidhe prior to entering Loch Fannich. Much of the outflow from the loch is via a tunnel to Grudie Bridge power station, but compensation water maintains the flow in the river, which follows a south-easterly course to reach the A832 road at Bridge of Grudie, with the power station immediately upstream of the bridge. Several of the tributaries of the Grudie are dammed, and a long surface pipeline feeds some of their flow into Loch Fannich.

Middle section
The railway and road follow the northern edge of Loch Luichart. Construction of the dam at the eastern end of the loch required some 2 mi of the railway to be relocated, because the level of the loch was raised, and a new station was built, which opened on 3 May 1954. Mossford hydro-electric station is sandwiched between the road and railway a little further to the east, and water from Loch Fannich passes through the station and discharges into Loch Luichart. There is a scattering of houses in the area, which form the hamlet of Lochluichart. The Allt Coire Mhuilidh flows southwards and into the loch near the hamlet of Corriemoillie, after which the road and railway are separated from the loch by a range of hills, the highest of which is Cnoc na h-lolaire at 1161 ft. The loch turns to the south, and the dam is to the north of Little Scatwell.

Below the dam, Allt a' Ghlinne joins the river on its right bank. A bridge carries the minor road from Little Scatwell, and immediately afterwards is Luichart power station, fed with water from Loch Luichart by a tunnel. The next tributary is the River Meig, which joins on the right bank. It rises as a series of springs and streams in Glencarron and Glenuig Forest, close to the source of the River Bran, but on the southern slopes of the hills. It passes through Gleann Fiodhaig and heads in a north-easterly direction to reach Loch Beannacharain. A minor road runs along the northern shore of the loch, which contains an artificial island at its eastern end, on which a prehistoric crannog settlement was built. Below the loch the river is joined by Allt Gleann Chorainn on its right bank, and then by Allt Gleann Meinich on its left bank. It turns to the east near the hamlet of Dalnacroich, where the wide valley is known as Strathconon. At Bridgend it is crossed by a bridge with three arches, approached by a causeway with six more arches. The structure dates from the early to mid-19th century. It carries the minor road that runs along Strathconon across the river to its southern bank. The river then enters the artificial Loch Meig, created by the dam at its eastern end, and passes through a natural arch before it joins the Conon.

Eastern section
The river continues eastwards to reach Loch Achonachie. On its southern bank is Orrin power station, which receives its water supply from Orrin Reservoir, an artificial loch on the River Orrin. Loch Achonachie was created by constructing a concrete mass gravity dam at its eastern end. It includes a Borland fish pass, to enable migrating fish to reach the upper reaches of the river, with a single-storey turbine hall and two-storey office block built into the dam structure. The architect was James Shearer, and the building is dated 1955. To the south of the dam is the Fairburn estate, 1100 acre of designed landscape, created in the late 18th and early 19th century, before it was remodelled by John Stirling in the late 19th century. As well as remodelling the park, he built a Baronial mansion house in 1877–78. Known as Fairburn House, it was designed by Wardrop and Reid, and most of it has three storeys, although it includes a five-storey tower.

The Black Water joins on the left bank, after which the A832 road crosses at Moy Bridge, running from a junction with the A835 road on the north bank of the river to the village of Marybank, to the south. Moy island is formed where the channel splits, and then the north bank is the southern edge of the Braham estate, 1295 acre of designed landscape. It was created in the 17th century, improved during the following two centuries, and hosts an extensive collection of specimen trees and rare species. The river is joined by the River Orrin on its left bank before it turns to the north, and the large Dunglass Island is now the site of a hydroelectric station for the Brahan estate. Conon Bridge railway station is close to the northern end of the island, and the Far North Line crosses the river on Cononbridge railway bridge. It was designed by Joseph Mitchell and constructed in 1860–62. With five arches and a span of 77 ft, it is sharply skewed, and this was achieved by building each span as five narrow spans, which are staggered to achieve the skew.

The railway bridge is the normal limit of tides. Next to the northern end of the bridge is an octagonal tollhouse, built by Joseph W Mitchell in 1828, which was used to collect tolls from people using Thomas Telford's Conon Bridge, which has since been demolished. The A862 road now crosses the river on a newer bridge. Garrie Island sits in the river before another road bridge that carries the A835 trunk road. The river channel widens to the south of Dingwall, as it becomes part of the Cromarty Firth. There is a rifle range to the east of Dingwall, and much of the firth is marked as a danger area. Beyond the danger area, the A9 road crosses the firth on Cromarty Bridge. This was opened on 12 April 1979, and is nearly 1 mi long. The deck is carried by 67 piers, designed to minimise changes to the tidal flows, in order to protect the feeding ground which are an important habitat for migrating birds. A maintenance programme costing £1.5 million drew to a close in June 2018. Beyond the bridge, the Cromarty Firth carries the waters of the Conon to the sea.

Hydroelectric development
Dingwall and Strathpeffer, both slightly to the north of the Conon near its mouth, had been supplied with hydro-electric power since 1903, when an 80 kW station was financed by Colonel E W Blunt-MacKenzie, the husband of the Countess of Cromarty. It was located at Ravens on Ben Wyvis. In 1926, the Ross-shire Electricity Supply Company took over the scheme and attempted to expand its operation. They borrowed £20,000 under the Trade Facilities Act, which financed the construction of a dam at the eastern end of Loch Luichart, and a power station near the Conon Falls. The power station was 120 ft below the level of the loch, and contained two 500 kW generating sets. However, the company experienced difficulties in maintaining the system, and asked Scottish Power for help to manage and finance their operation in 1928. Scottish Power took over the company in 1931 when they bought all the share capital, repaid the startup loan, and increased the capacity of the Loch Luichart power station. By 1933, they had constructed a transmission line from the station along the shore of the Cromarty Firth and up the coast as far as Dornoch. and they were supplying electricity to an area of some 340 sqmi by 1938.

The dam for this scheme is thought to have been at the same location as the later dam. Two pipes ran from the dam to the turbine house, one of 3.3 ft diameter, which split into two near the turbine house, and a second of 5.6 ft diameter. Concrete cradles that carried the smaller pipe remain visible in the landscape, but most of those for the larger pipe have been destroyed by the construction of a road. The turbine house was being restored by the Hydro Board in 2008.

An even earlier scheme was located at the Orrin Falls on the River Orrin tributary. John Stirling of the Fairburn Estate used his workmen to build a turbine house by the Orrin Falls, and another further upstream. The project was overseen by a Mr Bagot from Glasgow, and Fairburn House had electric lighting by 1898. The river drops by around 50 ft through a series of waterfalls at the Orrin Falls, and a dam some 160 ft long was constructed at an angle to the flow of the river. Its maximum height was 11 ft and there was a fish ladder at its northern end. This appears to have replaced an earlier dam, the remains of which are just downstream of the current structure. A generator house was built by Gilbert Gilkes & Co Ltd of Kendal in 1926, and probably replaced an earlier building at the same location. The installation was abandoned, probably in 1961, when much of the flow of the Orrin was diverted through a tunnel to the Orrin power station on the banks of Loch Achonachie. However, the scheme was refurbished in the 1980s, and once again supplies power to Fairburn House.

North of Scotland Hydro-Electric Board schemes
The Conon Valley was one of the early hydroelectric schemes implemented by the North of Scotland Hydro-Electric Board, although it was constructed in three phases between 1946 and 1961. After the board was created in 1943, Edward MacColl the chief executive produced a list of 102 projects which he thought could be built, from small ones to huge ones involving several neighbouring glens. The initial scheme for the Conon Valley involved using water from Loch Fannich, which would flow through a tunnel to Grudie Bridge power station on the banks of the River Bran just before it entered the western end of Loch Luichart. When the board promoted their second scheme, that at Tummel-Garry, members in the House of Commons attempted to get the findings of the tribunal which had considered objections to it overturned, but this was defeated. In the House of Lords, Lord Kinnaird wanted to introduce a similar motion, but was persuaded not to. However, he introduced a debate to consider the future of the board, at which various members of the house suggested that hydroelectric power was not needed in Scotland, as it would soon be replaced by nuclear power. Lord Kinnaird did not succeed, and during the debate Lord Westwood, the leader of the house, announced that all objections to the Fannich scheme had been withdrawn following discussions between the board and the objectors. It thus became the board's third project when it was authorised in late 1945.

The project involved the construction of several aqueducts and tunnels, to divert additional flow into Loch Fannich. The surface of the loch was around 820 ft above ordnance datum (AOD), while the surface of Loch Luichart is 289 ft AOD. A sloping tunnel was constructed from a point above the site of the power station to a point around 90 ft below Loch Fannich. From there it was driven beneath the loch until there was only 25 ft of rock between the excavation and the water. Rock was carefully removed above the tunnel to reduce the thickness to 15 ft, and a large sump was excavated, into which the final plug of rock would settle when it was blasted away. Two temporary concrete bulkheads and one steel bulkhead were constructed in the tunnel, to protect the tunnel and to ensure that debris from the rock plug would not be washed downstream. The final blast was successful, and was the second time that such a technique had been used in Britain. Balfour Beatty carried out the work, and had also been responsible for the first use of this technique, at Loch Treig for the Lochaber hydroelectric scheme.

The main tunnel was around 3 mi long. No dam was built at Loch Fannich, as the water level could be drawn down by up to 50 ft, but five years later a dam was constructed, raising the surface level to 840 ft AOD. At the lower end of the tunnel, water is conveyed to Grudie Bridge power station by a steel pipeline which is above ground. It is 8 ft in diameter, but as it progresses downhill, the internal diameter reduces, and the walls get thicker. Close to the power station, it splits into two feeds, each of which supplies a 12MW vertical shaft Francis turbine. This was one of the last projects to use a surface pipeline, as the board were keen to reduce the visual impact of their schemes subsequently.

The power station building is clad in red Tarradale sandstone and was designed by the architect James Shearer of Dunfermline. Shearer had previously worked on other schemes, including the first to be commissioned at Nostie Bridge and had approached MacColl with the suggestion that the power station should be built of stone, to blend in with the surrounding architecture. MacColl readily agreed, but when it came to designing the structure at Grudie Bridge, he felt that construction in stone would be too slow and cost too much, and so prepared sketches for a concrete, steel and glass building. MacColl asked if Shearer had seen concrete buildings after they had been exposed to the Scottish weather for 20 years, and when Shearer admitted that he had not, MacColl organised a weekend visiting buildings to see how concrete weathered. As a result, the use of local stone to face large concrete buildings became a policy within the Board, and Grudie Bridge power station was redesigned as a consequence.

Second phase
The second phase of the scheme involved damming the River Vaich to form Loch Vaich and the Glascarnoch River to form Loch Glascarnoch, above the point at which the two rivers became the Black Water. To reduce the amount of cement used, the Glascarnoch dam consisted of a concrete gravity dam with earth fill. It was constructed by Reed and Mallik and was 1753 ft long, with a maximum height of 141 ft. The Vaich dam was smaller, at 843 ft long and 123 ft high, and was built by the same contractor. The flow into both lochs was increased by building aqueducts and tunnels to capture water from other watercourses, and a tunnel fed water from Loch Vaich into Loch Glascarnoch. The surface level of Loch Vaich is 840 ft AOD, while that of Loch Glascarnoch is 827 ft AOD. A 4.5 mi tunnel from just above the Glascarnoch dam feeds water to Mossford power station, on the bank of Loch Luichart.

The waters of the River Bran, which flows into Loch Luichart, were exploited by building a small dam across the river below Loch Achanalt and Loch a' Chuilinn, to supply the Achanalt power station close to the Grudie Bridge station. This arrangement provides a head of 66 ft and the station has a capacity of 2.4MW. A mass gravity dam was built at the eastern end of Loch Luichart, with a tunnel to supply water to Luichart power station at the western end of Loch Achonachie, which can provide 34MW from a head of 184 ft. Additional water was obtained by building a concrete gravity and earthfill dam across the River Meig, to form Loch Meig. The dam was built by Duncan Logan (Contractors), and was 585 ft long with a height of 86 ft. A tunnel transfers water from Loch Meig to Loch Luichart. The final part of this stage was to construct a dam across the River Conon at Torr Achilty, to create Loch Achonachie. The mass gravity dam is 808 ft long and 76 ft high. The water level only varies by 2 ft, as the main function of the dam is to regulate compensation water in the river below, but discharges are fed through Torr Achilty power station, which can generate up to 15MW.

Third phase
The third stage of the project was to modify the River Orrin, which drops by some 700 ft in the 6 mi above its junction with the Conon. A mass gravity dam was constructed 8 mi from the junction, which was 1025 ft long and 167 ft high. The resulting reservoir is nearly 5 mi long. Because the water level is around 135 ft higher than it was when it was just a river, a second dam had to be built to prevent water flowing down a branch in the valley. This is an earth dam with a concrete core, of a similar length to the main dam. Over 3 mi of tunnel and a steel pipeline deliver the water to Orrin power station on the southern shore of Loch Achonachie. This phase cost £2.8 million, of which a substantial amount was needed to ensure that fishing could continue in the valley.

Because of the large changes in the surface level of the reservoir, the only type of fish pass that was acceptable to the fishing interests was a Borland fish pass. This is similar to a navigation lock, with an upper and lower pool, connected by a sloping shaft. Water flowing out of the lower pool attracts migrating fish such as salmon, and a sluice gate then closes so that the shaft fills, enabling the fish to reach the upper pool and to proceed upstream. Juvenile smolts can enter the upper pool and slither down the shaft when leaving the spawning grounds. A Borland fish pass can accommodate changes in the upper surface level of 20 ft, but because the level of the Orrin Reservoir varies by much more than this, four fish passes were built. Similar fish passes were also installed at Torr Achilty, Luichart, Meig and Achanalt dams, and whereas fish had previously been unable to access the Conon above Conon Falls, the fish passes opened up some 20 mi of river to them, as far upstream as Achnasheen. As part of the project, 200,000 salmon fry were released into the Upper River Bran.

Private schemes
At Dunglass Island, a weir at the upstream end controls the flow of water along the western side of the island, and there is a second weir half way along the eastern channel. During 2015, two Achimedes screw turbines were installed at the upstream weir, to provide power for the Brahan estate. The turbines produce a maximum of 100 kW, and energy not used by the estate is sold to the National Grid. The turbines, which were commissioned in October 2015, are designed to work with a head of just 5 ft. Because the level of the river fluctuates by up to 2.3 ft as a result of discharges from the older hydro-electric schemes further up the river, the screws are set at different heights, to ensure the water is used efficiently whatever the river level.

Fishing
The River Conon and its tributaries are fished for trout and salmon, but the present healthy state of the fish populations does not reflect the history of the river. The catching of salmon in the river and in the Cromarty Firth, which is protected from the open sea, has been a lucrative occupation for several centuries, and by the early 19th century, there were a large number of fixed nets in the firth, as well as nets and fixed salmon traps called cruives in the river. The Cromarty Estate fought a long battle in the courts to prevent other riperian landowners from using stake nets. It lasted from 1828 to 1837, and the court agreed with their case in 1838, prohibiting the use of fixed engine nets in the Firth. This became a byelaw in 1865. As fishing for salmon became more popular, the river proprietors realised that very few salmon were reaching the upper reaches of the river system to spawn, as so many were being caught in traps at Brahan or netted elsewhere.

In 1890, a group of river proprietors leased the cruives and net fishing rights at Brahan. For a while, no trapping or netting took place at these locations, but this resulted in many more fish being caught in the Firth. The cruives were in use again by 1901, but the catch was dwindling, and rod fishing started to become unviable. In 1920 the Moray Firth Salmon Fishing Company was set up by Sir John Stirling, Lord Roberts and others. The company bought up the fishing rights in the Firth and the Conon estuary, and no netting took place for a while to allow stocks to recover, after which they reintroduced fishing. They did not get the balance right, as stocks dwindled in the 1980s. The average number of fish caught in the Firth between 1977 and 1986 were 502 salmon and 1478 grilse, adult salmon that had only spent one year at sea before returning to the river. The Atlantic Salmon Conservation Trust bought the fishing rights in the Firth in 1991 and mothballed them.

The Conon and the Black Water were spring fisheries, but both rivers became less wild and more predictable after the construction of the hydroelectric scheme at the Falls of Conon in the 1920s and the major schemes built between 1946 and 1961. Although there had been floods in 1892 and 1922, there were four major floods between 1962 and 1989, with water levels on the Marybank to Moy Bridge road reaching 16 ft in 1962. Subsequently, compensation flows from Loch Luichart were increased, to ensure that the loch had spare capacity at times of flood. The North of Scotland Hydro-electric Board bought all of the salmon fishing rights, apart from those owned by Sir John Stirling of the Fairburn estate, who refused to sell. The Board installed fish lifts at the dams, including a fish ladder at the Falls of Conon, enabling fish to reach the River Bran for the first time, and creating large new spawning grounds. They also created a large capacity hatchery, and guaranteed compensation flows on the Conon all year round, which prevented low water levels in the summer months from curtailing fishing.

The spawning grounds of the Black Water were largely destroyed by the damming of the river, and the dams do not have fish lifts. A fish trap on the upper Black Water is used to catch adult salmon, which are used to provide eggs for the hatchery. Although the fish lifts meant that adult salmon could more easily return to the spawning grounds above the dams, they were not well suited for smolts attempting to return to the sea, but modifications have been made to improve this situation. The Orrin and the Meig are no longer very accessible to adult salmon. The Orrin was particularly affected by dirt and silt being washed downstream while the works were being constructed, and an outbreak of ulcerative dermal necrosis in 1967 further affected fish stocks. In the ten years prior to 2006, the hatchery handled 2.6 million eggs each year, and during the same period, nearly 100 mi of habitat suitable for juvenile salmon were brought into use. Although fish stocks appear to be recovering well, they are regularly predated by seals, as there is a population of around 400 in the Firth, which hunt on the river as far upstream as Torr Achilty dam. There is a large population of pike in the lower Conon, and a significant population of perch in the Bran. Mink have also become established in the area, particularly on the Black Water.