Hydropower schemes affecting designated sites, protected species and supporting habitat

You will need to determine whether any part of your hydropower scheme, or its operation, is likely to affect a site designated for nature conservation or protected species and their habitats. If it is likely then you will need to carry out a detailed evaluation of your schemes’ environmental impacts to accompany your licence application. You will need to consider impacts during both construction and operation of the scheme which includes changes to river flows.

We place much stricter limits on how much water may be abstracted in these sites to protect flow sensitive ecology and are also likely to require a very high standard of environmental design for a scheme. Licence applications may be refused if there is a risk that designated species and habitats cannot be adequately protected from a hydropower development.

Read more about flow sensitive ecology in Abstraction rates for hydropower

Designated sites

Designated sites in Wales include rivers, streams and water dependent wetland habitats.

Site designations include:

  • Special Areas of Conservation (SAC)
  • candidate Special Areas of Conservation (cSAC)
  • possible Special Areas of Conservation (pSAC)
  • Special Protection Areas (SPA)
  • candidate Special Protection Areas (SPAs)
  • potential Special Protection Areas (pSPA)
  • wetland sites designated under the International Convention for the Conservation of Wetlands (Ramsar sites)
  • Sites of Special Scientific Interest (SSSI)
  • WFD Water Bodies at High Ecological Status (HES) or Quality Elements at high status
  • Geological Conservation Review (GCR) sites
  • National Nature Reserves (NNRs)
  • Marine Conservation Zones (MCZs)

Sites are designated for nature conservation due to the presence of nationally and internationally rare species, habitats, geological/geomorphological characteristics and ecological communities, all collectively known as features.

Some features may be sensitive to changes in river flow – these will mostly be within the river channel, banks or riparian zone. Some flow sensitive features include terrestrial species and habitats near streams that require high levels of humidity (i.e. Oceanic woodlands and associated species of mosses and liverworts).

Designated site features that are sensitive to changes in flow include:

  • Old sessile oakwoods with Ilex and Blechnum
  • Western/Atlantic (oceanic) bryophyte assemblages
  • Killarney fern Trichomanes speciosum
  • Atlantic salmon Salmo salar
  • Allis shad Alosa alosa
  • Twaite shad Alosa fallax
  • Sea lamprey Petromyzon marinus
  • River lamprey Lampetra fluviatilis
  • Brook lamprey Lampetra planeri
  • Bullhead Cottus gobio
  • Eel Anguilla anguilla
  • Freshwater pearl mussel Margaritifera margaritifera
  • White-clawed crayfish Austropotamobius pallipes
  • Otter Lutra lutra
  • Water vole Arvicola terrestris

Designated sites are assessed for the conservation status of their features and have conservation objectives describing how the features should be protected and maintained.

If a proposed impoundment or abstraction is proposed within, or likely to affect a designated site, then applicants will be required to carry out ecological surveys and an impact assessment, presented in an Environmental Statement, to determine how the scheme may affect the designated features and their conservation status. The assessment should show:

  • the notified features of the site that are likely to be affected;
  • the mechanism and scale of likely impacts;
  • the measures that could be implemented to avoid or reduce damage to the notified features;
  • the measures that are proposed to compensate for any damage that cannot be mitigated.

We will use this information in the licence determination process to make a detailed evaluation of the impacts of a proposed scheme.

Special Areas of Conservation (SAC)

Hydropower schemes likely to affect a Special Area of Conservation, Special Protection Area or Ramsar wetland sites are subject to special scrutiny under Regulation 61 of the Conservation of Habitats and Species Regulations 2017 (referred to as the Habitats Regulations) as these sites protect our most important species and habitats.

A Habitats Regulations Assessment (HRA) will need to be carried out and will consider impacts of a proposed scheme both alone and in-combination with other plans or projects. We will carry out Habitats Regulations and in-combination assessments using the information that you have provided. It is important for applicants to understand that it is not only the impacts of their own scheme that will determine the outcome of these assessments where protected sites are concerned. A Habitats Regulations Assessment will need to be carried out for the purposes of both abstraction and impoundment licencing and any associated planning consent.

An applicant will need to demonstrate that the proposed development will not adversely affect the integrity of the site/s concerned. Proposals must be submitted with full details of all the measures that will be put in place to protect the designated features of the site, taking account of the site’s conservation objectives and condition status. It is a legal requirement of the Habitats Regulations that developers provide all the information necessary to allow a Habitats Regulations Assessment to be undertaken.

How to find out if your scheme affects a designated site

You can find out if your proposed hydropower scheme is located in or near a designated site, and the features for which a site is designated, by looking at the maps and site designations available on our website 

or see the Welsh Government DataMapWales

Protected species and habitats

Protected species and habitats may also be present within or outside a site designated for nature conservation and receive special legal protection under environmental law. These include species and habitats listed in section 7 of the Environment (Wales) Act 2016. Some of these will be sensitive to the construction of hydropower schemes and changes to river flow caused by their operation.

Read more about When you need a protected species licence

When will we require protected species surveys?

Recognising that we aim to protect the whole riverine ecosystem, the limits we place on abstractions for hydropower for Zones 2 and 3 will usually be adequate to support most flow sensitive, protected species and habitats within a depleted reach including brown trout (Salmo trutta), otter (Lutra lutra), water vole (Arvicola terrestris) and bryophytes.

We will require higher levels of flow protection for sites where freshwater pearl mussel (Margaritifera margaritifera), native white clawed crayfish (Austropotamobius pallipes) and very rare flow sensitive bryophytes are found to be present.

Native white-clawed crayfish are restricted to catchments in mid and south Wales where water quality and other factors are suitable for their survival, with particularly important populations in the River Wye and its tributaries on the Welsh borders. If your proposed scheme is in one of these catchments, please contact us and we will advise whether you will need to undertake a survey for these species.

Freshwater pearl mussel (Margaritifera margaritifera)

You will not normally need to carry out surveys for rare bryophytes, unless you are proposing a development within a designated site where protected bryophyte species are present. There may be exceptions where we will require surveys to be undertaken outside of designated sites. We will advise you after we have received your application if a bryophyte survey will be necessary for proposals in Zone 2 or Zone 3.

Supporting habitats

For the purposes of licensing abstractions and impoundments for hydropower we define supporting habitats as being those beyond the boundaries of SACs and SPAs that support mobile features of those sites for all or part of their life cycle. This could include tributaries to, or the upstream and downstream catchments of designated river sites. Several rivers in Wales are designated for Atlantic salmon (Salmo salar) and this species can often be found further upstream than the SAC boundaries.  In such cases, the Habitats Regulations will apply to any hydropower schemes that potentially impact on water courses in a way that would affect the integrity of habitats that support salmon. We apply the same restrictions to hydropower abstractions in Supporting Habitats as we do for those located in or affecting designated sites.

Atlantic salmon are notified features for the following riverine SACs:

  • River Dee & Bala Lake
  • River Teifi
  • River Usk
  • River Wye

Any rivers or streams upstream of these sites are supporting habitat unless it can be shown that the location for a proposed hydropower scheme is not accessible to migratory salmon now or in the future as part of a river restoration project. Access may be restricted by natural or man-made barriers downstream such as weirs, falls or culvert / bridge footings.

Applicants will need to provide us with evidence of impassable barriers to upstream migration if they wish to demonstrate that a reach affected by a hydropower scheme does not qualify as supporting habitat.

Salmon spawning grounds

Although salmon is a protected species, its’ populations are in considerable decline in Welsh rivers. The restrictions we place on hydropower abstractions outside designated sites and supporting habitats are designed to protect habitats and flow conditions for salmon except for salmon spawning grounds. These are areas of clean gravels and cobbles on the river bed in which salmon lay their eggs. The channel and flow conditions that create and maintain the gravels and cobbles of spawning grounds mean that they can be very sensitive to changes in flow. Intakes and outfalls for hydropower schemes should therefore be located to avoid salmon spawning grounds. We will apply the same restrictions to hydropower abstractions affecting existing or potential salmon spawning grounds as we do for those located in or affecting designated sites and supporting habitats.

Developers should determine whether the reach affected by a potential hydropower development is accessible to migratory salmon. As with supporting habitat, this could be determined from local knowledge or include an assessment of whether there are impassable barriers to upstream migration that prevent salmon from reaching the hydropower site. A survey should also be carried out to find out if there are any areas of clean gravel within the river reach that will be affected by a proposed hydropower development. If present, then there may be existing spawning areas or have the potential for a spawning site if the reach is accessible by salmon.

Read about licensing weirs for hydropower schemes

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