Ayrshire’s largest river rises at Glenbuck Reservoir on the boundary of Ayrshire and Lanarkshire and flows westwards 63 kilometres to its estuary at Ayr on the Firth of Clyde.It has a catchment area of 574 sq. kilometres and its principal tributaries include the Greenock Water, Lugar Water, Water of Fail and Water of Coyle.Principal land uses in the catchment area are agriculture, forestry, mineral extraction, leisure and recreation and urban development, the largest settlements being Ayr, Cumnock, Catrine, Ochiltree, Muirkirk and Sorn.Notable features include Sites of Special Scientific Interest (SSSI’s) at Howford by Mauchline and the Failford Gorge, and an opencast coal mining industry.Fish species include salmon, sea trout, brown trout, grayling, eel, stickleback, minnow and stone loach.River management is undertaken by the River Ayr Salmon Fishery Board, riparian owners and numerous angling clubs either as riparian owners or tenants.

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Key Features

  • Largest river in Ayrshire.
  • Large human population in middle and upper reaches, e.g. Cumnock.
  • Intensive dairy farming in lower half of catchment.
  • Productive soils on Permian sandstones and Coal Measure rocks including limestone.
  • Very high conductivity levels, increasing with distance from sea, primarily due to inputs from historic and current mining activities.
  • Industrial heritage of mining and mills e.g. Catrine.
  • Several old mill structures hinder fish migration.
  • Modern industry e.g. chipboard plant, opencast mines.
  • Constant threat of pollution from operational and disused coal mines.
  • One of largest salmon rod catches in Ayrshire, similar to River Doon.
  • Juvenile salmonid production greatest east of Mauchline and Cumnock in cleaner upland tributaries such as the Greenock, Guelt and Glenmuir.
  • Salmon in tributaries with altitudes over 300m, highest reached by salmon in Ayrshire.
  • Grayling population unique in Ayrshire (River Irvine population extinct).
  • Sea lampreys recorded in 2004 (may still be present in other Ayrshire Rivers).
  • Low impact of conifer forestry and acidification compared to other Ayrshire rivers.
  • ‘Source to sea’ River Ayr Walkway opened by East Ayrshire Council in 2006.
  • High scenic value in areas such as Failford Gorge SSSI, Barskimming Estate.
  • No large stillwaters in catchment, although many small lochs stocked with rainbow trout.

Ayrshire Rivers Trust research and monitoring on the River Ayr includes:

  • Annual electrofishing survey on behalf of the River Ayr District Salmon Fishery Board (DSFB) to monitor salmon fry production in the main stem and larger tributaries as well as a comprehensive survey of smaller tributary sites.
  • Habitat survey published in 2005. This survey provided a detailed inventory of habitat type and quality, pollution sources, obstructions to migration as well as identifying priority areas for habitat restoration.
  • Lamprey survey as part of a national survey funded by SNH. Sea lampreys (juvenile stage) were found in the lower river. Other lampreys (which could be either river or brook lampreys) are widespread throughout the catchment.
  • Survey of the River Ayr grayling population completed in 2003. The survey found that grayling occurred throughout the main stem of the River Ayr and that growth rates were good in comparison with other rivers.
  • Invertebrate surveying introduced in 2005 to compliment other data collected at electrofishing sites.
  • Monitoring of water quality parameters in July 2006 found that oxygen levels in the Lugar Water downstream of Cumnock, were below the EU defined standards for salmonid waters. Further investigations into this issue are planned with SEPA.
  • Invasive plants surveys carried out in 2008 and 2012 to assess the distribution and density of Giant Hogweed and Japanese Knotweed.
  • Smolt trap operated in 2010 to assess the success of the DSFB’s sea trout stocking policy.
  • Salmon egg survival trials conducted in winter 2010/11 and 2012/13 to assess survivability across the catchment with regards to inputs from mining and agriculture.
River Ayr at Barskimming
River Ayr at BarskimmingRiver Ayr at Auchincruive
River Ayr at AuchincruiveUpper Ponesk
Upper Ponesk BurnGlenmuir Water
Glenmuir WaterWeirs at Catrine
Historic weirs at CatrineCoyle waterfall
Waterfall on Water of Coyle