River Garnock

The smallest of Ayrshire’s six principal rivers, the Garnock’s source is in the Muirshiel Hills above Kilbirnie.

From here the Garnock flows for 39km before entering the sea, via a shared estuary with the River Irvine. Although it has a catchment area of 238km2, similar to the River Girvan, the Garnock itself is a relatively small river as its largest tributary, the Lugton Water, meets the Garnock below the tidal limit.

Principal land uses in the catchment area are agriculture, moorland and urban development. The most significant land use, forming 74% of the total, is improved or good rough grassland, much of which is intensively grazed. There is a relatively low level of forest cover (6.9%) in the Garnock catchment compared to rivers such as the Stinchar.

The Garnock flows through three large towns, Kilbirnie, Dalry and Kilwinning. Water management within the catchment is currently under review in the River Garnock catchment flood defence strategy.

The fishery on the River Garnock is managed by the angling clubs based in the three towns along the course of the river. The West Strathclyde Protection Order 1988 means that it is an offence to fish for freshwater fish within parts of the Garnock catchment without written permission.


River Garnock Catchment Map highlighting main tributaries.

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Key Features


  • With a catchment area of 238km2 The Garnock is the smallest of the six principal rivers in Ayrshire
  • Many water supply reservoirs constructed in the hills on the west side of the catchment. Caaf Water receives a compensation flow of 3.4Ml/day from the Camphill Reservoir
  • Several stillwaters within the catchment are operated as coarse fisheries, increasing the risk of establishment of alien species within river habitat

Catchment Characteristics

  • Rises in the Muirshiel Hills above Kilbirnie from where it flows for 39km before entering the sea via the shared estuary with the River Irvine
  • Major tributaries are the Rye Water, Caaf Water, Bombo Burn, Dusk Water and Lugton Water
  • River flows through the centres of the following major urban centres: Kilbirnie, Dalry and Kilwinning
  • Lugton water is the largest tributary with a catchment of 54km2


  • Common fish species present include salmon, trout, eels, stone loach, minnows, sticklebacks and lampreys. Roach were also recorded in the upper Lugton Water during 2006 electrofishing survey
  • Catchment suffers from many weirs and culverts which block or hinder passage of migratory fish
  • Water quality in the Lugton is degraded due to influence of sewage and agricultural run-off

River Garnock Gallery

Monitoring and Science on the River Garnock

Data is collected to allow evidence based management and restoration


We undertake electrofishing surveys for monitoring and consultancy purposes to investigate fish production in the main stem and tributaries.

We have a large database which may be available upon request for those requiring information.


A catchment wide Habitat survey was completed 2005, with funding from North Ayrshire Council, Scottish Natural Heritage and Garnock angling clubs. The Habitat Survey recorded many significant obstructions to fish migration ranging from fallen trees to impassable culverts and weirs. Pollution points and areas of habitat degradation were also recorded.


There is an ever increasing interest in lamprey species across the UK. Lamprey are an important species within the Garnock catchment and ART hold considerable data on their distribution. The Garnock supports all three native lamprey species and appear to be stable. River lamprey are protected as a schedule 3 fish species of the Conservation (Natural Habitats, &C) Regulations 1994. River and sea lamprey are a UK BAP species. Brook lamprey are listed on the International Union for Conservation of Nature (IUCN) Red List of threatened species.

Invertebrate Sampling


Invertebrates respond to long term changes in water quality therefore they can be used to determine pollution problems. ART provide various levels of assessment both commercially and for our own use.

Invertebrate sampling offers opportunities for citizen science.

Invasive Species Management


Over many years, ART have undertaken scientific habitat assessments to determine distribution and impacts of invasive species. Invasive weeds can have an impact on habitat and water quality. Through strategic management and control we continue to address issues created by these species.

ART have supplied training and chemicals to members of Kilwinning Angling Club who are now in control of hogweed and knotweed across the Garnock on an annual basis.

Atlantic Salmon Pressures Tool


ART contributed to the development of Fishery Management Scotland’s Atlantic Salmon Pressures Tool. This involved looking at all pressures affecting the species across Ayrshire. The FMS Pressures tool is an interactive mapping platform that will be  available to local river managers to inform and target management actions and to provide important evidence for policy development at national level. This tool will align very well with the forthcoming Fishery Management Plans that the Trust are currently developing for FMS.