Latest NatureScot Objection
Application For Consent Under Section 36 of The Electricity Act 1989 for construction and operation of Glean Earrach Pump Storage Scheme
I refer to the above case submitted in 2025, and its Additional Information submitted in 2026.
- Background
We have provided previous consultation responses dated 11 November 2025 and 19 January 2026. Since these responses we have continued liaison with the Applicant on several complex issues. The Applicant has provided additional information to address information gaps, and we can now provide our response to the outstanding matters. These matters are in respect to the River Moriston Special Area of Conservation (SAC) and Urquhart Bay Wood SAC.
The further detail that has been supplied to us over the intervening months has been submitted as Additional Information (AI) by the Applicant.
This letter should be read in conjunction with our previous letter of 11 November 2025 as this includes advice on Ness Woods SAC and Moray Firth SAC that is not repeated here and similarly, our letter of 19 January 2026 as this provides advice on the North Inverness Lochs Special Protection Area (SPA). These are attached for reference.
We also provide advice in respect to the AI grid connection assessment.
- Summary
As requested, we have undertaken an appraisal which considers the combined effects of the proposal and a seasonal variable weir at Dochfour which is not part of the current application.
We conclude the proposal could be progressed with appropriate changes and mitigation. However, in relation to the River Moriston SAC, because it could affect internationally important natural heritage interests, we object to this proposal unless it is amended and made subject to conditions so that the works are done strictly in accordance with the changes and mitigation detailed in our appraisal below.
In relation to the Urquhart Bay Wood SAC, there are natural heritage interests of international importance on the site, but our advice is that these will not be adversely affected by the proposal. The Applicant has provided further detail on the potential effects on Urquhart Bay Wood SAC, and we are satisfied that they have demonstrated beyond reasonable scientific doubt that as described the proposal will not adversely affect the integrity of the site.
This advice is based on our understanding that the proposed seasonal variable weir at Dochfour will be located, designed, constructed, operated and mitigated as described in the further information submitted by the applicant to NatureScot between February and August 2026, and submitted as AI1, and will be operational in advance of the pump storage hydro scheme commencing operations. If this is not the case, the conclusions of our appraisal would not apply, and you should reconsult us.
We will provide further advice on effects of the proposed variable weir when we are consulted on that application.
- Our advice
Appraisal for European sites
At your request, our appraisal is based on the proposal as described in the application, including the off-site seasonal variable weir at Dochfour the applicant proposes as mitigation for significant effects associated with water level variation in Loch Ness and downstream flows in the River Ness. The weir is not part of this application and has not yet been subject to a separate application. We understand it will be applied for by a third party who is yet to be identified. For clarity, we have not assessed the implications of Glen Earrach without the variable weir as described.
As previously advised in our response of 11th November 2025, guidance on Habitats Regulations Appraisal2 states that competent authorities must be sure that mitigation will be effective at the time they give their permission and that ‘each mitigation measure must be described in detail, with an explanation based on scientific evidence of how it will eliminate or reduce the adverse impacts which have been identified. Information should also be provided of how, when and by whom they will be implemented, and what arrangements will be put in place to monitor their effectiveness and take corrective measures if necessary’.
Therefore, in order to conduct a Habitats Regulations Appraisal (HRA) of this proposal the competent authority requires sufficient detail on the proposed weir to assess the implications for all the European sites that could be affected and determine whether it can be concluded with certainty and beyond reasonable scientific doubt that there will be no adverse effect on the sites’ integrity. In addition, the competent authority will need to be assured that the necessary legal and stakeholder agreements will be in place, and that the weir is consentable, to provide certainty that the required mitigation will be implemented.
- River Moriston Special Area of Conservation (SAC)
The River Moriston SAC is designated for Atlantic salmon and freshwater pearl mussel and lies approximately 8 km south-west of the proposed outfall/ intake.
The site’s status means that the requirements of the Conservation (Natural Habitats, &c.) Regulations 1994 as amended (the ‘Habitats Regulations’) apply or, for reserved matters, The Conservation of Habitats and Species Regulations 2017. Consequently, Energy Consents Unit is required to consider the effect of the proposal on the SAC before it can be consented (commonly known as Habitats Regulations Appraisal). The NatureScot website has a summary of the legislative requirements (see: https://www.nature.scot/doc/legislative-requirements-european-sites).
Our advice is that this proposal is likely to have a significant effect on the Atlantic salmon and freshwater pearl mussel qualifying interests of the River Moriston SAC.
Consequently, Energy Consents Unit, as competent authority, is required to carry out an appropriate assessment in view of the site’s conservation objectives for its qualifying interests. To help you do this, we have worked with the Applicant to ensure there is sufficient detail to inform your Appropriate Assessment, and we have conducted our own appraisal.
Atlantic salmon
In January 2026 we advised that the information submitted at that time did not demonstrate that the proposal could be constructed and operated without undermining the SAC’s conservation objective to restore the population as a viable component of the site, because of four impact pathways which could delay salmon migration and cause additional mortality.
These are repeated below with their original numbering, and we provide an update as to how the Applicant has addressed these and where the full detail can be found within the Applicant’s AI documentation.
a. Noise, disturbance and loss of access to fish passes during construction of the proposed Dochfour seasonal variable weir impeding migration.
The Applicant proposes to install two co-located temporary Chevron side baffle fish passes to facilitate upstream passage during the construction period. These are proposed to be installed before the start of works to modify the existing upstream passage route. We agree that the proposed arrangement provides appropriate attraction flows and water velocities to achieve an effective temporary passage solution for salmon migrating upstream.
During construction, smolt and kelt migration downstream is proposed to be facilitated by constructing two of the three proposed permanent downstream smolt passes, located adjacent to the Dochfour Lock gates (Smolt Pass Ref 1) and at the downstream end of the waste weir (Smolt Pass Ref 2), as the first step in the weir construction project. In addition, during installation of the proposed temporary upstream Chevron side baffle fish passes detailed above, two temporary downstream smolt passes adjacent to the temporary upstream fish passes are proposed to be installed, comprising suitably sized pipes with appropriate inlet profiles to control acceleration. The evidence presented shows it is possible in principle to design and operate smolt passes in a manner which will improve downstream passage for smolts, compared to the current situation.
The applicant proposes to avoid significant construction disturbance such that passage will be maintained throughout the construction period by means of the following measures:
•Planning the construction sequencing to ensure effective upstream and downstream passage at all times
•Based on advice on seasonal salmon migration activity at Ness Weir from Ness District Salmon Fishery Board, timing works with the potential to generate underwater noise disturbance (specifically impact piling) during November and December, with potential to extend the period to mid-October to mid-January subject to confirmation by the ECOW of low fish activity
•measures to limit underwater noise from construction activity
•commitment to a fallback response to apply precautionary construction controls should it not be possible to assess whether or not fish are exhibiting a sustained adverse response at the operational passage routes that is consistent with avoidance behaviour attributable to vibro-piling activity.
We agree that the proposed sequencing is appropriate to maintain fish passage; and the measures proposed to limit underwater noise and avoid significant disturbance represent best practice and are appropriate.
We conclude that the applicant has demonstrated it is possible in principle to construct the proposed Dochfour seasonal variable weir in a manner which ensures that salmon migration is not impeded during the construction period. Therefore, based on detail submitted by the Applicant (Ref 3), if the proposed weir is located, designed, constructed and mitigated as described by the applicant the conservation objective to restore the population as a viable component of the site would not be undermined by this impact pathway.
b. Changes to water levels in Loch Ness because of the operation of the scheme including the proposed seasonal variable weir
To ensure upstream migration, the applicants propose a vertical slot fish pass in one of two locations at the west end of Ness weir. Our independent hydrologist advisor confirmed that the Applicant’s approach was appropriate. We therefore conclude the applicant has demonstrated it is possible in principle to design and operate a new fish pass within the proposed modifications to Ness Weir in a manner that maintains effective passage for upstream migrating Atlantic salmon from the River Moriston SAC.
The applicants propose to improve on current arrangements for downstream passage for Atlantic salmon smolts and kelts by installing three separate smolt passes, located in the canal inlet channel immediately upstream of the Dochgarroch lock gates. Independent tilting gates are proposed on the entrances to each smolt pass to account for the fluctuating water levels controlled by the variable weir. The two existing smolt bywash channels would then be redundant and removed. In addition to these dedicated downstream passage routes, downstream migration would also be feasible via the new vertical slot fish pass described above. We agree with the Applicant’s approach and technical detail.
We therefore conclude the applicant has demonstrated it is possible in principle to design and operate new fish passes within the proposed modifications to Ness Weir in a manner that maintains effective passage for downstream migrating Atlantic salmon from the River Moriston SAC.
Monitoring will be required to show whether the new upstream and downstream fish passage opportunities are operating effectively, and thus whether adjustments, for example to control systems, are required. The applicants present a range of monitoring options, which provide reassurance effective monitoring would be possible.
Overall, we conclude that the applicant has demonstrated it is possible in principle to locate, design, operate and mitigate the proposed Dochfour seasonal variable weir in a manner which ensures that salmon migration will not be impeded due to changes to water levels in Loch Ness because of the operation of the scheme including the proposed seasonal variable weir.
Therefore, based on the information submitted by the applicant(Ref 4), if the proposed weir is located, designed, operated and mitigated as described by the applicant, and will be
operational in advance of the pump storage hydro scheme commencing operations, the conservation objective to restore the population as a viable component of the site would not be undermined by this impact pathway.
c. Changes to winter flow regime in the River Ness, including an increased rate of water level change, impeding salmon migration up and down river
The Application submission(Ref 5) provides an assessment of hydropeaking effects on the River Ness based on the approach set out in Bakken et al (2023)(Ref 6). It assesses that operation of the Proposed Development, taking into account the combined influence of Loch na Cathrach and Loch Kemp PSH operations as well as the existing Foyers PSH, falls within the Small (Green) category under the total impact assessment, with a moderate hydropeaking effect and low vulnerability. Having considered this assessment, we agree that changes to the winter flow regime will not significantly impede downstream and upstream migration of salmon from the River Moriston SAC. We therefore conclude this pathway will not undermine the conservation objective to restore the population as a viable component of the site.
d. Acoustic fish barrier proposed between weir and canal impeding salmon migration
The Applicant’s submission (Ref 7) confirms that an acoustic barrier is just one of a number of non-physical deterrents under consideration, and that the most appropriate option will be investigated further and selected later in consultation with us and other stakeholders.
We agree that details of non-physical deterrent(s) can be finalised later in consultation with us, provided the new downstream fish passage arrangements at the weir are designed to maintain or improve downstream passage of Atlantic salmon smolts and kelts independently of the addition of any non-physical deterrents.
We therefore conclude it is possible in principle to construct the proposed Dochfour seasonal variable weir in a manner which avoids any acoustic fish barrier proposed between weir and canal impeding salmon migration and thus that the conservation objective to restore the population as a viable component of the site would not be undermined by this impact pathway.
In addition, the original application information submitted did not demonstrate that the proposal could operate without undermining the site’s conservation objective to restore the habitats supporting Atlantic salmon within the site and availability of food, as a result of the following impact pathway:
e. Changes to the water level regime in Loch Ness affecting salmon spawning habitat in the lower reaches of the River Moriston
Based on the report of the site visit7, we agree that the lower reaches of the River Moriston have very little, or any, spawning potential. We therefore conclude this pathway will not undermine the conservation objective to restore the habitats supporting Atlantic salmon within the site and availability of food.
References
1 Applicant’s 2026 AI submissions relating to Glen Moriston SAC and Urquhart Bay Wood SAC – available on ECU case
2 https://op.europa.eu/en/publication-detail/-/publication/11e4ee91-2a8a-11e9-8d04-01aa75ed71a1
3 ECU00005121 – Additional Information (AI) 3.28 – NatureScot – River Moriston points a and b – March – 2026
4 ECU00005121 – Additional Information (AI) 3.28 – NatureScot – River Moriston points a and b – March – 2026
5 ECU00005121 – _Additional Information (AI) 3.15 – NatureScot – River Moriston point c – Feb 2026
6 Bakken, T.H., Harby, A., Forseth, T., Ugedal, O., Sauterleute, J.F., Halleraker, J.H. & Alfredsen, K. (2023). Classification of hydropeaking impacts on Atlantic salmon populations in regulated rivers. River Research and Applications, 39(3), 313–325.
7 ECU00005121 – _Additional Information (AI) 3.17 – NatureScot – River Moriston points d and e – February – 2026