Loch of Harray

Loch of Harray
Harray loch
Looking southwards along the shoreline
Location	Mainland Orkney, Scotland
Coordinates	59°1′24″N 3°13′40″W / 59.02333°N 3.22778°W / 59.02333; -3.22778Coordinates: 59°1′24″N 3°13′40″W / 59.02333°N 3.22778°W / 59.02333; -3.22778[1]
Type	freshwater loch
Primary inflows	Burn of Hourston and Burn of Netherbrough[1]
Primary outflows	Loch of Stenness[2]
Catchment area	45 sq mi (120 km2)[1]
Basin countries	Scotland
Max. length	4.66 mi (7.50 km)[1]
Max. width	1.75 mi (2.82 km)[1]
Surface area	3.75 sq mi (9.7 km2)[1]
Average depth	9 ft (2.7 m)[1]
Max. depth	14 ft (4.3 m)[1]
Water volume	951,000,000 cu ft (26,900,000 m3)[1]
Surface elevation	3.6 ft (1.1 m)[1]
Islands	several islets and stones[1]

The Loch of Harray is the largest loch of Mainland Orkney^[1] and is named for the nearby parish of Harray. It lies immediately to the north of the Loch of Stenness and is close to the World Heritage neolithic sites of the Stones of Stenness and Ring of Brodgar.^[3] In Old Norse its name was Heraðvatn.^[4]

Hydrology

The loch was surveyed^[1] on 21 August 1903 by Sir John Murray and later charted ^[5] as part of the Bathymetrical Survey of Fresh-Water Lochs of Scotland 1897-1909. Murray observed that Loch of Harray is a freshwater loch, the largest in all Orkney with an area of approximately 3.75 cubic miles (15.6 cubic kilometres) and volume of 951,000,000 cubic feet (0.0269 km³) and that it is somewhat influenced by the tides in the Hoy Sound although there is little variation in its level. The loch is connected to the Loch of Stenness at the Bridge of Brodgar.^[6] The two lochs together cover an area of 19.3 square kilometres (7.5 square miles) making the two combined the ninth largest loch in Scotland by area (as listed by Murray and Pullar (1910)). Murray recorded that despite there being an inlet allowing the free flow of water from the Loch of Stenness it has little impact on the marine biology of Harray and no seaweed was present, the water tasted fresh and normal freshwater plankton were seen. ^[7]

Natural history

The loch is a Site of Special Scientific Interest and has a large number of pondweed species three of which are scarce, a rare caddis fly (Ylodes reuteri) and is the only known site in Scotland for a nerite snail Theodoxus fluviatilis which is more commonly found in English rivers. A wide variety of wildfowl winter at the loch including pochard, tufted duck, scaup and goldeneye.^[8][9]

References