Fish passes need to cater for all species – not just salmonids

During August 2019 I objected to a planning application by Waterways Ireland for rehabilitation works and construction of a fish pass (rock ramp) at Tinnahinch Weir Lower on the River Barrow, in the River Barrow and River Nore candidate Special Area of Conservation in Co Carlow. The Planning Reference is 19289 and the file can be found here. But surely building a new fish pass is a positive thing? Yes it is but fish passes need to cater for all species – not just salmonids. The submission I made is set out below.

I prepared the original Natura Impact Statement (NIS) for this proposed development and I identified a number of deficiencies in the design of the included fish pass – and highlighted a number of uncertainties in relation to the ability of certain fish species to use it. However, rather than make minor changes to the design Waterways Ireland decided to engage different consultants to prepare a new assessment. The reason they did this was that the design was already completed (in 2016) before I was asked to assess it, and approval had already been obtained from the Department of Housing, Planning, Community and Local Government (the Dept.) (the approval is in the planning file, letter dated 10/5/17). I was told that if the design changes I was proposing were incorporated that this would require a new application to the Dept. which would delay the submission of the planning application. Instead it was offered that “lamprey tiles” and “eel brushes” be included as an addition to address my concerns.

Tinnahinch Weir Lower on the River Barrow, in the River Barrow and River Nore candidate Special Area of Conservation in Co Carlow.

However, I did not think that was a satisfactory approach and instead recommended that the design be altered to ensure that all species were catered for in the rock ramp design. The changes I was proposing were relatively minor and would not have added any additional significant construction costs. It would have delayed the panning application however.

The changes I proposed involved ensuring that there was no “jump” at the top of the pass (as Lampreys and Shad cannot jump), and that lateral low-flow areas were included to allow weaker swimming species (e.g. lampreys and eels) to easily use the pass. I also recommended design changes for Shad (no zig-zag pools) and had queried the turbulence calculations. Because of this I was replaced as the ecological advisor on this project – for failing to “sign off” on the NIS as was being demanded by my former client Waterways Ireland. There was an expectation that as they were paying my fees that I should do what they wanted – and this was stated to me in a meeting. It was put to me that Inland Fisheries Ireland were the authority and I was asked why I thought that I could question their design. However, that was my role as an independent ecologist assessing the proposal. I was then replaced by the current consultants whom assessed the exact same design. The ecological surveys and assessment did not influence the design of this project – as is required when necessary under the Habitats Directive. This also has broader implications in relation to the treatment of consultants – and the ability to assess projects independently and objectively. My original draft Natura Impact Statement is also provided with this submission.  

Lampreys cannot climb or jump so having an upper ledge renders this design impassable for lampreys

I note that I am senior Aquatic Ecologist with just under 30 years’ professional experience. My key area of expertise and interest is in riverine fish migration and I hold a PhD from the National University of Ireland, Galway on juvenile eel migration. I am Fellow of the Society of Biology, a full Chartered Member of both the Chartered Institute of Ecology and Environmental Management and the Institute of Fisheries Management. I am the Principal Ecologist of Ecofact Environmental Consultants Ltd. which is one of the longest established independent ecological consultancy firms in Ireland.

Eels, Lampreys and Shad cannot jump like salmonids can. If you have a ledge or step in a fish pass then these species will not be able to use it

Although the applicant was Waterways Ireland (WWI), the fish pass design was commissioned by Inland Fisheries Ireland (IFI). This is essentially a joint project by both of these agencies – so IFI should not have had a regulatory role here as they were no longer independent. It is not known why IFI would apparently use their own resources to assist WWI with this project. A fish pass was always required for this site and WWI would have had to include one with any planning application for weir rehabilitation.  

The subject fish pass design was prepared around the same time as similar ones which have now been constructed at Hanover Weir, Carlow, and on the River Nore at Castletown, Co Laois. I had previously raised concerns directly with IFI regarding these “rock ramp” designs. Both of these fishways are also located in the River Barrow and River Nore Special Area of Conservation (cSAC). Both are salmonid passes and do not have features which can be used by lampreys and eels. Both passes have ledges and jumps at the top. Lampreys cannot climb or jump so having an upper ledge renders this design impassable for lampreys – especially Lampetra spp. These passes also provide no significant benefit for eels – eels cannot jump. Eels still need to climb around these weirs (as they always did) to pass with difficulty. The design used at Castletown and Carlow is again being repeated with the current proposed development at Tinnahinch Lower weir. Steps are shown in drawing for the proposed fish pass – requiring fish to jump. Therefore, species that cannot jump will not be able to use it. Provision of “lamprey tiles” and “eel brushes” as an addition will not mitigate for the design deficiencies.

“Rock ramp” fish way at Castletown weir on the River Nore; constructed during 2015. This is a similar design to the current subject application.
“Rock ramp” fish way at Castletown weir.Ledge and jump at top means that rock ramp cannot be used by lampreys. Lampreys cannot climb or jump so this upper ledge renders this impassable for lampreys (Lampetra sp.). This pass also provides no benefit for eels. Eels would still need to climb around the weir (as they always did) to pass this weir
“Rock ramp” fish way at Castletown weir. Close-up of the ledge at the upper end of the rock ramp. This prevents both lampreys and eels from using this pass. There are no Shad at this site – but it would not be possible for Shad to use this type of a fish pass
“Rock ramp” fish way at Hanover weir, River Burren, constructed during 2017. Broadly the same design as Castletown weir was used. Claims were made in the planning application that this pass could be used by lampreys and eels – but there was again a “jump” at the top and lateral low-flow areas were not provided. Lampreys cannot climb or jump.
“Rock ramp” fish way at Hanover weir, River Burren, constructed during 2017. Ledge and jump at top means that rock ramp cannot be used by lampreys. Lampreys cannot climb or jump so this upper ledge renders this impassable for lampreys (Lampetra sp.). This pass also provides no benefit for eels. Eels would still need to climb around the weir (as they always did) to pass this weir.

I identified that Lamprey species and the critically endangered European eel would have problems using the proposed fish pass design for Tinnahinch Lower weir. The NIS now states that “lamprey tiles” and “eel brushes” will be installed – in an apparent effort to address the deficiency which I had originally identified. However, there is no scientific evidence that lamprey tiles will work – contrary to statements made in the NIS submitted. If the rock ramp fishway had been properly designed, it would also work for all fish species and the provision of additional passes for lampreys and eels would have been unnecessary. Well designed rock ramps allow for passage of all species – but the current design proposed does not conform to a standard rock ramp. Lamprey tiles do not work – and the example of these tiles referred to in the current planning application (Annacotty weir, River Mulkear) has been discredited. The “lamprey tiles” and “eel brushes” are also not shown in the drawing (as it has not been updated since 2016).

On Page 17 of the NIS reference is made to the lamprey tiles which were previously in place at Annacotty weir, on the River Mulkear, Co Limerick. It is stated that “The installation of a rock ramp and partial breach of a weir resulted in extensive sea lamprey spawning in the upper reaches of the Mulkear catchment in 2014 despite a summer of low flow conditions”. This is a factually incorrect statement that cannot be supported, and it is noted that no rock ramp was ever built on the River Mulkear. Instead a weir (Ballyclough weir) was partially removed (without Appropriate Assessment). But there is no evidence that this action resulted in extensive Sea Lamprey spawning in the upper reaches of the Mulkear as claimed in the NIS for the current planning application. Ballyclough weir on the River Mulkear was located upstream of Annacotty weir – and this fish migration barrier is still in place. Despite claims which were made on websites at the time that “lamprey tiles” placed on this weir were a success, no scientific information in relation to this was ever published. The claims were made on the website of Mulkear LIFE ( However, this website has now been removed and is no longer available. The actual scientific publication that came from this project did not provide any claims of the lamprey tiles facilitating lamprey passage (Rooney et al, 2015). It has now been accepted that the lamprey tiles placed on Annacotty weir were ineffective and these tiles are no longer present at this weir. In the plates section of this submission I have presented recent photos from Annacotty weir showing both River Lampreys and Sea Lampreys blocked below this weir. It is of serious concern that these “lamprey tiles” are being proposed for the subject application site – when IFI know that they won’t work. Moreover, a well-designed rock ramp would facilitate the passage of all lamprey species.

The migration of thousands of River Lampreys Lampetra fluviatilis is still blocked by Annacotty weir. Photo taken during April 2017 by Dr. Will O’Connor. River Lampreys could never use the “lamprey tiles” which were installed on this weir. These tiles never facilitated passage of 95% of lampreys as claimed in the subject planning application.
Dramatic photo showing River Lampreys trapped below Annacotty weir, Co Limerick (taken during April 2017 by Dr. Will O’Connor). This photo was taken in April 2017 when the “lamprey tiles” were still in place. Lampreys could never use the tiles placed at Annacotty weir yet this is used as an example in the current NIS with claims that 95% of lampreys could use the “lamprey” tiles installed by Mulkear LIFE.
Sea lampreys Petromyzon marinus clinging to Annacotty weir on the River Mulkear, Co Limerick. Photo taken during June 2018 by Dr. Will O’Connor). There is no scientific basis to support claims that 95% of lampreys could use “lamprey tiles” previously installed at this site.

It is now known that even the best placed “lamprey tiles” (studded tile passes) are “inadequate” for lamprey passage. Tummers et al (2018) found that the passage efficiency achieved was only 25.6% despite optimal placement of the tiles in their study (which would not be possible at Tinnahinch weir). It is stated in the Tummers et al (2018) paper the passage provided by optimally placed lamprey tiles is “inadequate in the context of the recommended 90–100% passage efficiency target per barrier to maintain viable diadromous populations“. This means that lamprey tiles are not a suitable solution for maintaining ‘Good Conservation Status’ of a SAC population. These tiles will certainly not work as a late addition inclusion to the design of a high turbulence rock ramp. These tiles are also not shown in the drawing. The fish pass being proposed for Tinnahinch weir is a salmonid fish pass – and has not been designed to cater for weaker swimming species and non-jumping species some of which are Qualifying Interests of the River Barrow and River Nore cSAC. 

In the NIS for the subject planning application it is claimed that “The lamprey tiles on part of the weir will further aid migration of sea lamprey during low flow (Q90), with similar structures on Annacotty Weir recording 95% (sic.) of all ascents being achieved on lamprey passes (Mulkear Life, 2014)”. The NIS misquotes and relies on this discredited study by Mulkear LIFE which has since been removed from its website. The lamprey tiles at Annacotty weir are also no longer present. There is no scientific evidence whatsoever for the claim that the lamprey tiles facilitated 93% passage as previously claimed by Mulkear LIFE on their website. The lamprey tiles placed on Annacotty weir have not worked for either migratory lamprey species. No River Lampreys could ever use them, and Sea Lampreys just clung to the base of the tiles. Mulkear LIFE published the results of a radio-tracking study at this weir (Rooney et al, 2015).  This peer-reviewed paper did not present any evidence that showed that lampreys could actually use the tiles. They did not repeat any of the unfounded claims of 93% passage previously made. Indeed, they specifically stated that “the expectation that increased lamprey passage should have resulted from the alterations [ ] was not observed“. This paper recommended barrier removal – an acknowledgement that the authors were indeed aware that the 93% claims could not be supported by science.

The “lamprey tiles” and “eel brushes” are not even shown in the drawings submitted with the current planning applications. It is not clear if they would be put on every step – or just at the top. The commitment to include them is an admission that the current proposed pass has not been designed for use by eels and lampreys.

The potential impact of the fish pass not working – or making fish passage worse for many species – was not assessed in the NIS. There have been many examples in Ireland of approved fish passes not working. This also happened at the original fish pass included at Lacken weir, Kilkenny during the Kilkenny Flood Scheme (see The lamprey tiles installed as part of the Mulkear LIFE project also did not work. Inland Fisheries Ireland have recently installed similar rock ramps at Hanover weir on the River Burren in Carlow, and at Castletown Weir on the River Nore. These fish passes are both salmonid passes only and do not cater for lampreys and eels. The NIS and EcIA state that Inland Fisheries Ireland (IFI) were consulted during the design of the current proposal. However, IFI are also are involved in the design of the project – and indeed the fish pass is their design.  

It is possible to have an acceptably located pass built to adequate basic design, only for it to fail because of excessive within-structure turbulence

The current proposed fish pass will have very high levels of power dissipation (turbulence). This is of significant concern and has not been addressed in a satisfactory way in the NIS to remove all reasonable scientific doubt as required for Appropriate Assessment. The turbulence levels predicted are well in excess of the levels recommended for lampreys, shad, eels, cyprinids, perch and pike. Indeed, they also exceed those recommended for salmonids (salmon and trout). The following is stated in the NIS on page 16. This is the only place where turbulence is mentioned, and no calculations are provided: –

The power dissipation of the fish pass is 279.99 W/m3 at AADF. This is higher than the 200 w/m3 maximum for migratory salmon (Armstrong et al. 2010). However, higher Pv figures may be accepted if the fish pass consists of a few pools only, or for very large fish facilities with discharge flows of more than several m3/s (Larnier, 2002). As the discharge rate through the proposed fish pass is up to 40 m3/s, this allows the higher energy dissipation figure to be accommodated. Lower Pv values (<150 W/m3) will occur during times of low flow (Q75-Q99) when species with weaker swimming capabilities can migrate. There will be no measurable impact on flow regime or water levels upstream and downstream of the proposed structure“.

However, the current proposed pass has a large number of pools (9+) and the quotation given from Larinier (2002) includes the following statement that “lower levels [of power dissipation] are advisable (less the 150 watts/m3) for [ ] fishways designed for shad and riverine species”. Of course, Shad and other “riverine species” occur in the Barrow and this fish pass will have to cater for Shad and Lampreys as they are Qualifying Interests of the SAC. DVWK (2002) point out that the turbulence of the flow through a fishway “should be as low as possible so that all aquatic organisms can migrate through the pass independently of their swimming ability”.

The ability of each species to use the proposed fish pass is not assessed in the same way in the NIS. It is done in a selective way with not all of the characteristics of the pass discussed. Turbulence is not mentioned for Shad and Lampreys as the turbulence levels modelled are clearly far too high for these species and it would not be possible to explain how this will be overcome. The turbulence levels are also well outside the recommended levels for salmonids and there is uncertainty that even salmon – which are strong swimmers and jumpers – will be able to use this pass at all times when they will be migrating. The target fish species need to be identified and it has to be explained in scientific detail how each of these species will be able to use the pass with reference to flows velocity, turbulence and the target fish species swimming abilities. This information is required for Appropriate Assessment and is not in the NIS.

Turbulence (power dissipation) is only mentioned once in the NIS and the turbulence calculations are not presented in the NIS or as part of the planning application. I contend that the main reasons for this is that it has not been possible to reconcile the high predicted turbulence with the passage capabilities of Shad, eels, lampreys, cyprinids, pike, and perch. During my involvement with the project I raised the issue of turbulence several times and my questions could not be answered. The turbulence through a fishway needs be as low as possible. Larinier (1992) recommends that turbulence should not exceed 150 to 200 W/m3. Armstrong et al (2010) stated that “It is possible to have an acceptably located pass built to adequate basic design, only for it to fail because of excessive within-structure turbulence”. Turbulence is therefore a key parameter in fish pass design, yet it has been largely ignored in the NIS. The calculations for turbulence are not included so can’t be verified. The only figure mentioned in the NIS is the turbulence at Annual Average Daily Flow (AADF). However, due to my original involvement with the project I have previously reviewed the model – and can confirm that the predicted Power Dissipation [W/m3] ranges from 95.3 to 887.10 W/m3. For >90%ile flows (i.e. >90% of the time) the turbulence will be above the recommended 150 W/m3 level, and for 50% of the time the turbulence will be greater that the highest level (200 W/m3) recommended by Larinier (2002). I expect that under most conditions that strong Atlantic salmon will probably be able to push through – but there is no scientific information presented in the NIS that demonstrates beyond reasonable scientific doubt that this will actually be the case. It is certain that other fish including Annex II listed Shad and Lamprey species will have problems. But this was always designed to be a salmonid pass and the passage abilities of other fish species were never taken into account in the design. An Appropriate Assessment cannot be completed in the absence of the turbulence calculations and an explanation of how Shad and Lampreys can use a pass with such high predicated turbulence levels.

the turbulence of the flow through a fishway should be as low as possible so that all aquatic organisms can migrate through the pass independently of their swimming ability

This fish pass was designed at the same time as the fish pass at Castletown weir and is a similar design. The design has not changed since the first published version in 2016. No changes were ever made to the design to reflect experiences at Castletown weir (and Hanover weir). To avoid making changes to the design the applicant even changed the project ecologist. Of course, the applicant is entitled to get a second opinion. However, by avoiding any discussion of turbulence in the NIS and adding in “lamprey tiles” and “eel brushes” the applicant has demonstrated that the issues I raised were in fact valid. However, these measures are inadequate to address the design deficiencies.

It is stated in the NIS that “although areas within and adjacent to the proposed rock ramp provide suitable habitat to support crayfish, there are no known historical records further downstream than immediately below Graiguenamanagh weir”. This is an untrue statement and in the surveys that I completed for the original NIS for this proposed development on behalf of Waterways Ireland (See Appendix 1) significant numbers of the White-clawed crayfish were found to be present. I also undertook a previous survey of the lower River Barrow on behalf of Waterways Ireland in 2013 for the proposed Barrow Canoe Trail (Ecofact, 2013). Significant numbers of White-clawed crayfish were also found during this survey, and crayfish were also found downstream as far as St. Mullins. Therefore, the applicant Waterways Ireland was well aware that crayfish were present in this area. However, it is claimed that this species is absent in the current proposal and the current proposed weir and fish pass has not been designed to be passable for this Annex II listed species. During my original involvement I advised that that the proposed minor design changes for lampreys and eels would also facilitate crayfish passage. However, these minor changes were resisted, and the crayfish are likely to have difficulty with the current proposed design. A case is made in the NIS that the current fish pass did not have to be designed for crayfish as the current site is outside of their historical range – however it was well know to the applicant that this area was an important site for this Annex II listed qualifying interest of the River Barrow and River Nore SAC based on my previous surveys of this site. Unfortunately crayfish populations in this area of the river have been impacted by crayfish plague – but this was a recent stronghold for the species, the applicant knew that they were present, and this pass has to be designed to facilitate crayfish and their future recovery in the River Barrow.

White-clawed Crayfish Austropotamobius pallipes at Tinnahinch weir (from Ecofact 2017).

Restoring runs of Shad in the River Barrow needs to be a priority. Shad are currently confined to the lower reaches of the River Barrow below the weir at St. Mullins. This leaves the SAC population very vulnerable due to its limited distribution – and also results in Twaite Shad and Allis Shad hybridising. The passage problems for Shad on the Lower River Barrow will have to be dealt with – and any fish pass proposed for Tinnahinch Lower weir will have to be future-proofed and fully take the requirements of Shad into account. A full assessment of the ability of Shad species to use this fish pass has not been provided. The implications of having jumps, zigzag steps and high turbulence in the fish pass is not discussed in relation to Shad. Allis Shad are not even mentioned in the fish passage assessment. The situation on the River Barrow is very similar to that on the River Severn (UK). On the River Severn there is now a major project to help restore Shad runs to this river – the project is called the “Unlocking the River Severn’ (see The key design problem with the proposed fish pass is that it was designed to be a salmonid pass – then retrospectively an attempt was made to try to explain how it would work for other species. This attempt started during my involvement with the current project – originally there was no attempt to explain how Shad could use the pass. However, this pass will not work for Shad and needs to be redesigned to cater for them.

Shad are a key target species and Qualifying Interest of the SAC and from the outset their swimming and passage abilities should have been fully considered when designing the fish pass. The turbulence in the current proposed pass is far too high for Shad. According to Larinier and Travade (2002), Shad become disorientated in turbulent water – “they prefer laminar, streaming flow, even if it has a significant velocity. They avoid very turbulent and/or aerated water zones wherever possible (eddies downstream of a plunge, hydraulic jump, boils and upwellings). When in these areas they move and orientate with far more difficulty than salmonids”. Larinier and Travade (2002) also note that “unlike most salmonids shad do not leap, but generally only pass obstructions by swimming. For this reason, they have great difficulty in passing “plunging flows” in which they tend to become disorientated, positioning themselves with their heads facing downstream in the counter-current at the surface”. There has been no attempt to cater for this behaviour in the design of the current fish pass. We have one chance to get the fish pass for Tinnahinch Lower weir right and it has to cater for a future “Unlocking the River Barrow” project. Otherwise the proposed fish pass is working against the Conservation Objectives of the River Barrow and River Nore SAC.

It is a serious omission in the NIS that downstream fish passage has not been assessed. Fish migration occurs in two directions, yet downstream migration has been completely ignored in the NIS.

There is no evidence that a proper species-specific Otter survey was completed. Details on the days the surveys were completed, the actual extent of the areas surveyed and the weather conditions and water levels at the time are not provided. No signs of Otter activity were recorded during the survey – but in the absence of full details of the survey completed it is impossible to be sure that this was an adequate assessment. It appears that all the surveys were undertaken during a quick one-day site visit It is mentioned several times that “multi-disciplinary” surveys – rather than “species-specific” surveys were completed; and it seems that Otters were just surveyed in general when other surveys were being completed. This is not a satisfactory approach for a sensitive Qualifying Interest.

The proposed development site is within a Kingfisher territory but no species-specific survey for this Annex I bird species was undertaken. Indeed, no bird survey was undertaken, and the current works are proposed to take place during the bird nesting season. The area around Tinnahinch Lower weir and the access areas to same are overgrown and significant disturbance of potential bird nesting areas will occur. The failure to undertake a formal bird survey is therefore a serious omission.

Riparian woodland occurs at the proposed development site and this habitat has links to alluvial forest (91E0). However, the required scientific data that this is not priority habitat is not provided in the NIS. The statement that no woodland will be cleared is not credible as the site and access areas to the site do contain woodland, and there will have to be clearance, disturbance and indirect impacts on riparian woodland and trees.

No bat survey was undertaken. The proposed works will affect bat habitats and potentially tree roosts for bats will be affected. Bats and the potential impact on bats are not considered in the current planning application.

The potential for Freshwater Pearl Mussels (FPM) to be present is dismissed – but no evidence for this is actually presented. No survey for FPMs was undertaken. It is possible that an undiscovered population is present, and a survey should have been completed.

Although it is claimed that standard lamprey ammocoete survey methods (using 1m2 quadrates) were followed, there are indications in the text that this was not actually done. There are references for example to a 5 x 2.5m patch of lamprey nursery habitat where juvenile lampreys were “observed escaping the sediment at depths of >1.2m, beyond the limit for the electro-fishing equipment used in such a large watercourse”. However, of more concern is that a key mitigation is that juvenile lampreys will be removed from the works footprint using electrofishing. The possibility of doing this is however contradicted by the statement that electrofishing cannot be completed at depths >1.2m. It is stated in the report that the most numerous lamprey species recorded was Lampetra spp. However, later it is stated that “no sea lamprey (Petromyzon marinus) ammocoetes were recorded”. It is known that Sea lamprey ammocoetes are more likely to be encountered in deeper water habitats (even >2m) than their Lampetra spp. counterparts (Taverny et al, 2011). However, these deeper areas were not surveyed and no mitigation for protecting lampreys in deeper habitats has been provided. It is quite possible that the large numbers of juvenile lampreys seen escaping at depth may have been Sea Lamprey ammocoetes which are at unfavourable conservation status in the SAC, and nationally. Loss of lamprey nursery habitat which has been identified as important on “a catchment level” in the JBA report has not been assessed. This has implications for the Appropriate Assessment.

No method statement for the electrofishing has been provided. No evidence has been provided to show that the significant numbers of lamprey ammocoetes at this site can in fact be removed in advance of the works. Indeed, the NIS specifically states that electrofishing cannot be undertaken in deeper water where the juvenile lampreys are present.

It is stated on Page 17 of the NIS that “Sea lamprey tend to migrate into Irish rivers in May during periods when flow conditions are falling”. Sea Lampreys are known to enter rivers much earlier than this – at least March/April (Maitland 2003) with records as early as January/February (Hardisty 1986). Adult spawning Sea Lampreys could well be present in the study area during construction works and no mitigation has been provided for this. Indeed, no specific timing of the works is provided. A calendar of fish spawning times is given in Table 2.1 of the NIS – however Shad are left out of this table. On page 58 it is stated that “Works will only be undertaken outside of the spawning season (October- April)”. However, what spawning season this refers to is not given. Lampreys (all species) will spawn during this time and the impact of this is not assessed in the NIS. Elsewhere in the NIS it is stated that “Prior to the outset of works Inland Fisheries Ireland will be notified and no instream works shall be carried out during the closed season for instream works (October 1st to June 30th)”. There is therefore uncertainly with regarding when the instream works will actually be completed – and the timing of these works is only assessed in relation to statutory close seasons for salmonids and not the requirements for protecting the Qualifying Interests of the SAC. 

It is of serious concern that there is no provision for a site compound despite the scale of these works within the River Barrow and River Nore SAC and the relatively isolated and inaccessible location. No welfare or refuse facilities will be provided, and vehicle parking and refuelling is proposed to happen as required in an ad hoc manner. This is a totally unacceptable approach for works within a sensitive Natura 2000 site.

The hydrology model prepared has excluded the canal from the assessment. Therefore, the role of the canal during a flood event is unknown. Water will potentially flow down the canal and then onto the fish pass in a flood event. This has not been assessed. The extent of rock armouring to be used is also currently not known. It is stated in the NIS that that the “full extent will be agreed by the on-site Engineer”. This is again an unsatisfactory approach in a Natura 2000 river channel.

Information on the overall Barrow navigation has not been provided in the NIS and a full explanation of why weir removal is not an option is not provided. An assessment of the impact of other weirs on the Barrow navigation is also not included – and many of these weirs are also impacting on fish migration in the river. A full cumulative impact assessment of the Barrow navigation scheme is therefore required. The drawings submitted for the current application suggest that similar fish passes will be installed on other weirs on the river – however no assessment or consideration of this has been included. The “do nothing” scenario has also been assessed (i.e. the weir continues to deteriorate, eventually collapses and fish migration is restored).

No Environmental Impact Assessment (EIAR) Screening was completed. This project will have “significant effects on the environment” as it is located in the River Barrow and River Nore SAC. It is not explained anywhere in the application why an EIAR is not required and this a breach of EIA Directive (2014/52/EU).  

The current design will have to be changed to make this pass more suitable for fish species other than salmonids. For eel, this will involve making sure that there are no jumps and ledges and abrupt lateral changes in flow. The armouring will need to be set back – or more boulders could be placed in front of the armouring to slow down flow and create a lateral low-flow area. These changes will also benefit lampreys, crayfish and coarse fish. For Shad a recommended design change would be to ensure that the steps are not set out in a zig-zag layout and that the size of the gaps are increased to allow for shoals to pass though. Turbulence will need to be reduced perhaps by reducing the slope. These changes would not add any additional costs to construction and were recommended previously to both Waterways Ireland and Inland Fisheries Ireland – but were not taken into account.

The proposed pass in its current form is a salmonid pass only. Any fish pass installed at this site has to optimise passage for all migratory species present, including the Annex II listed Twaite Shad, Allis Shad, Sea Lamprey, River Lamprey and the critically endangered European eel. The requirements of these species were not taken into account during the design of this fish pass. Therefore, I recommend that the planning permission for the current planning application be refused on the basis that the fish pass has not been designed to ensure that passage for fish other than salmonids. The design for the proposed fish pass was prepared in advance of the ecological assessment in 2016 – and there was no opportunity for design changes to be taken into account following the ecological assessment and surveys completed. Late additions such as the “lamprey tiles” (which will not work) and “eel brushes” (not shown in drawings) will not compensate for the original design flaws identified.

PS: It is of serious concern that the fish passage improvements at Castletown weir were listed in Ireland’s Eel Management Plan; Action 3a: Castletown Weir 2015. The “rock ramp” provides a local improvement for salmon and trout – but this pass is no better for eels than what was there already. This is a salmonid pass – not an eel pass. The fact that this fish pass was presented as an eel project is of great concern and shows the poor attitude to eels in Ireland. Read more here.


Armstrong GS, Aprahamian MW, Fewings GA, Gough PJ, Reader NA, Varallo PV. (2004) Environment agency fish pass manual: guidance notes on the legislation, selection and approval of fish passes in England and Wales. Environment Agency, Llys Afon, Hawthorn Rise, Haverfordwest, Pembrokeshire, SA61 2BQ, Wales, UK.

  • DVWK (2002) Fish Passes. Design, Dimensions and Monitoring. Food and Agriculture Organization of the United Nations. Deutscher Verband für Wasserwirtschaft und Kulturbau e.V. (DVWK)  Rome, 2002.
  • Hardisty MW (1986) Petromyzontiforma. In: Holcik J (ed). The freshwater fishes of Europe. Aula-Verlag, Wiesbaden.

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