Annacotty

The ultimate goal of this pilot project is to improve fish passage at Annacotty Weir on the River Mulkear for species such as Atlantic salmon, sea lamprey, river lamprey, eels and trout, helping them migrate both up and downstream. 

Annacotty Weir has been identified as a significant barrier to the free movement of fish and it is located within the Lower River Shannon ‘Special Area of Conservation’.

To progress the project, an Interagency Group for the Annacotty Fish Passage Project has been set-up, which includes representatives from Inland Fisheries Ireland, the Department of the Environment, Climate and Communications, the Department of Housing, Local Government and Heritage, Limerick City and County Council, the Office of Public Works (OPW), the National Parks and Wildlife Service (NPWS), the Local Authority Waters Programme (LAWPRO) and the ESB.

The pilot project will provide an opportunity to test a collaborative and ecology-focussed design approach. It will involve a multi-disciplinary panel of experts from the early stages of the decision-making process. The approach will inform similar future mitigation projects undertaken as part of the national restoration programme. 

Barrier mitigation is the modification or removal of instream manmade structures to help migrating fish, insects and animals and return the river to a more natural condition.

Across the European Union (EU), fragmentation of river habitats by barriers is one of five main causes of biodiversity loss. A recently published pan-European barrier inventory estimates that more than 1.5 million barriers of varying type and size are located across the European continent. Barriers modify the river habitat or hydromorphology which considers the physical character and water content of water bodies. Good hydromorphological conditions support aquatic ecosystems, with natural water flows and substrates providing physical habitat for biota such as fish, invertebrates and aquatic macrophytes.  Hydromorphological modification is one of the primary reasons (40%) why European rivers fail to achieve ‘good ecological status’ based on standards of the EU Water Framework Directive (WFD). 

River continuity is a key aspect of good ecological status. Removal or adaptation of barriers is part of the measures necessary to fulfil the legal obligations under the WFD. River continuity is necessary also to achieve the objectives of other EU legislation. For example, the Habitats Directive protects the Atlantic salmon and river and sea lamprey, which need to migrate between the sea and freshwater. The European eel, protected by the Eel Regulation, also needs river continuity to survive. It should further be noted that the WFD, under Article 4 (1)(c), also includes the obligation to achieve the objectives for ‘protected areas’, which include those set under the Habitats Directive.

The removal of weirs and dams is considered best practice as it restores the natural flows and conditions of rivers, as well as the benefits they provide. Removal opens fish migration routes and releases trapped sediment and nutrients that maintain habitat health. Therefore, it is important to prioritise removal over fish pass provision where possible. Fish passes should be a last resort as they do not adequately address the problems of habitat connectivity/ degradation and may not adequately provide passage for all fish species.  

To find out more about barrier mitigation, have a look at Brian Coughlan’s presentation.

The Annacotty Fish Passage Project was successful in securing funding through the Salmon and Sea Trout Rehabilitation, Conservation and Protection Fund, for the current phase of the project (phase one).

The aim of this fund is to rehabilitate, protect and conserve salmon and sea trout and their habitats. This fund is collected from a portion of the sales of salmon licences purchased by rod anglers and commercial fishers throughout the country.  

EUR 99,481 was secured through this fund in May 2022, which will be used to support the necessary environmental, engineering, and archeological studies during the current phase of the project.  

The cost of any proposed works will be estimated on conclusion of the current phase of the project and will be tendered for following a successful application for planning permission. 

Funding for the construction phase will be sought from appropriate funding bodies, such as the Department of Housing, Local Government and Heritage. This department has responsibility for the Water Framework Directive and the Habitats Directive.

The department expects to publish a River Basin Plan before the end of 2022. Within this, there will be the announcement of a major national restoration programme. This is likely to include works associated with weirs, such as the one at Annacotty along with other weirs and legacy structures. EU and Irish exchequer funds may also be available at the time of going to tender.

In 2022 the Mulkear river was a catch and release river for salmon because it did not meet its conservation limit. The conservation limit is the number of returning salmon that a river needs to produce future generations of salmon.  On the Mulkear the Technical Expert Group for Salmon (TEGOS) use a range of scientific indices such as fish counter data and rod catch data to determine if there will be a harvestable surplus available in the river the following year.  TEGOS determined that this was not likely in 2022 resulting in a catch and release river. 

Dace are a cyprinid fish with a European-wide distribution but are not native to Ireland. It was first introduced to the Munster Blackwater in 1889 and were first reported below Annacotty Weir in the 1990s. An ESB survey recorded dace upstream of Annacotty Weir in 2001 and again at Barrington’s Bridge in 2010 and in 2013. Dace are already able to traverse Annacotty Weir. Any impact of weir alterations on the dace population will be assessed as part of the options report.

Annacotty Weir is a high impact barrier to the migration of adult salmon and sea trout and a complete barrier to the migration of sea and river lamprey.  To these anadromous species, human-made barriers are considered one of the most pressing threats to existing populations.

Freshwater barriers to migration can block or delay migrating fish populations and may lead to increased mortality through diseases and predation. Delays in smolt migration may also affect their survival when they enter the sea. 

Almost all the Mulkear catchment, including the Mulkear River at Annacotty, is contained within the Lower River Shannon SAC (Special Area of Conservation).  

SACs protect important environments and species as listed in the EU Habitats Directive.

Annacotty Weir has been altered on several occasions in the past. In the earliest Cassini maps of Ireland, there are only ‘waterfalls’ marked at Annacotty. A weir in a different configuration is present in the maps charted in the early 1900s. The orientation of the weir was altered by the OPW in the mid-1990s to the present arrangement and a Denil fish pass was constructed.  

Mulkear LIFE (2009-2014), an EU Commission-funded project, focused on salmon, sea lamprey and otter in the Mulkear catchment. As part of this project, sea lamprey passage was improved at Annacotty weir through the addition of a plastic egg cup- like climbing substrate (lamprey tiles) attached to the weir face.  

The Denil fish pass was the standard fish pass constructed at the time and built with only adult salmon in mind.  

This does not meet modern criteria that requires consideration of all species and their differing swimming abilities.  The lamprey tiles installed during the Mulkear LIFE project have degraded over time and require continuous maintenance. They only offer improved passage over the barrier to sea lamprey and not to river lamprey.   

All options for fish passage improvement at the weir in Annacotty will be fully assessed in terms of environmental constraints and engineering designs. Subject to planning constraints, these will include, but are not limited to: 

• The complete removal of the weir 
• The partial removal of the weir 
• A bypass channel construction (which would leave the existing weir in place) 
• A rock-ramp fish pass construction (Infront of the existing weir)  
• A rock-ramp fish pass construction (through the existing weir) 
• Conventional engineered design fish pass (Denil fish pass, Pool pass, etc...) 
• Improvement to the existing fish pass (Denil pass)  
• Do-nothing/status quo scenario 

Depending on the results of the environmental and engineering surveys, a preferred option will be put forward by the consulting engineers. This will follow the outcome of a decision matrix that will identify the most advantageous proposal from an environmental, technical and economic perspective.  

Find out more by watching this presentation from Alan Cullagh: Annacotty Fish Passage Project - Alan Cullagh Presentation 

In the first instances, all the options will be assessed by the consultants in terms of the environmental and engineering design implications. This will involve the use of a standard decision-making matrix, which will score elements of each option. The option with the highest score will become the preferred option.  

For example, if the environmental reports show that a bypass channel cannot proceed because of a particular issue, then this option will score zero under the decision-making matrix. 

Find out more by watching this presentation from Alan Cullagh: Annacotty Fish Passage Project - Alan Cullagh Presentation 

Yes, short-term or temporary solutions could be considered to provide fish passage whilst a permanent modification for Annacotty is planned and constructed.  

Ideally, any temporary solution should be relatively long-lived, preferably 5-6 years minimum to cover the lengthy timescale that barrier mitigation processes can take. 

Temporary solutions should also be quick to install, robust, low maintenance and should represent good value for money. A temporary solution should facilitate the migration of all fish species of interest, and it should be able to operate continuously and effectively during the construction phase of the permanent structure.  

There are several potential temporary solutions available, including tiles, prefabricated passes, and other substrate fishways. 

The Annacotty Weir is in a Special Area for Conservation. Any proposed works at the weir (temporary or otherwise), will have to be screened for Appropriate Assessment before they can proceed. If the Screening for Appropriate Assessment determines that a Natura Impact Statement is required, this could trigger the planning process. 

The Annacotty Fish Passage Project is a complex project with multiple stages, some of which run in parallel. The project has been designated a pilot project to assist with the design and implementation of the national restoration programme  by the Department of Housing, Local Government and Heritage. 

During this period of assessment, Inland Fisheries Ireland will engage with stakeholders through workshops, webinars, the provision of information and other outreach initiatives to highlight the issues around the Annacotty Fish Passage Project.  

A range of studies will be undertaken to understand the effect of any change to the weir and its impact on river levels and flows downstream and upstream.  

All options for fish passage improvement at the weir will be fully assessed, including: complete removal, partial removal, bypass channel construction, rock-ramp fish pass construction and the ‘do-nothing/status quo’ scenario.   

These initial studies will also identify any ecological or engineering constraints that may influence the choice of final fish passage improvement option.   

When all the options for fish passage improvement have been fully assessed, Inland Fisheries Ireland will organise another public meeting for stakeholders to present consultants’ findings and recommendations and to hear the public’s views. This will be done prior to the start of any planning permission process. 

General project stages: 

• Preliminary project work 
• Formation of a interagency stakeholder group. This includes representatives from Inland Fisheries Ireland, Limerick City and County Council, LAWPRO, NPWS (National Parks and Wildlife Services), OPW (Office of Public Works), ESB, the Department of Environment, Climate and Communications and the Department of Housing, Local Government and Heritage 
• Stakeholder Engagement and Public Information Events (ongoing) 
• Tendering for the environmental consultants and consulting engineers 
• Undertaking all technical and environmental assessments 
• Review of reports and decision matrix  
• Presentation of the preferred options to stakeholders  
• Application for planning permission to Limerick City and County Council for the final agreed design. 
• Tendering for the construction stage of the final agreed design.  
• The construction stage of the project during the environmental window  
• Commissioning of the new fish pass improvement works. 

Given the complexity of this project and the associated legislative and planning requirements (especially around any proposed works), it is likely that this will be a multi-year project.