Salmon caught on the Munster Blackwater during electrofishing survey.

Adaptive Management of Barriers in European Rivers | AMBER

Barriers are physical obstructions to the natural flow in rivers. Although they can be natural, for example, a waterfall, they are usually man-made structures. Barriers include culverts, dams, fords, sluices and weirs.

Fragmentation and dysfunction

Man-made barriers in rivers have brought many benefits to society over hundreds of years. They have facilitated navigation, power generation and recreation. Unfortunately, this has led to heavy river fragmentation across Europe and a major loss of natural river functioning. Barriers have restricted or eliminated migration pathways for a range of fish species including the Atlantic salmon, sea lamprey and European eel.

Raising awareness

The AMBER project seeks to raise awareness of the problems caused by stream fragmentation, the associated pressures on freshwater ecosystems and the need for innovative solutions to mitigate their negative impacts.

Identifying Europe’s barriers

The National Barriers Programme already works to identify and map barriers on Ireland’s rivers, but a major aim of the AMBER Project is to add to this knowledge and to create an overall atlas of barriers on the European river network. To contribute towards this in Ireland, Inland Fisheries Ireland surveys barriers on eight rivers across Ireland, examines their distribution and links their occurrence to various river channel characteristics, such as gradient and land use.

Case study: the Munster Blackwater

Another aim of this project is to do a case study of a demonstration site on the Munster Blackwater. The Munster Blackwater is one of Ireland’s largest rivers and is famous for wild Atlantic salmon fishing. It is listed as a Special Area of Conservation under the EU Habitats Directive for a range of habitats and species, including the Atlantic salmon, river lamprey, sea lamprey and twaite shad. The main channel has two large weirs, with almost the entire length of channel impounded between them. Impounding occurs when the river backs up, usually upstream of a barrier and can be long or short depending on the slope of the channel.

For this case study, Inland Fisheries Ireland will electrofish the channel to determine the fish community present and to use netting and acoustic telemetry to investigate the European eel populations. We will also tag dace and brown trout to learn more about their behaviour within the impounded section. Combining aerial drone surveys and temperature logger deployment, we will use this test case to investigate the potential impact of climate change on impounded rivers.

AMBER combines citizen science and cutting-edge technology and collaborates with different groups, including hydroelectric companies, water providers, NGOs, anglers and local authorities.

Get involved through citizen science

You can interact with the data gathered through the "Barrier Tracker" app and participate in further citizen science exercises on the AMBER project.

The Let it flow citizen science programme includes a free downloadable smartphone application. The “Barrier tracker” app allows participants to record new barriers they encounter on rivers and streams. Data gathered includes a photo of the barrier, the location of the barrier and the height of the barrier.


AMBER project big flag logo.