The main component of a hydro system is a source of water that will provide a relatively constant supply. Other components typically include a pipeline (often referred to as a penstock) to connect the water source to the turbine, a turbine, generator and a ‘tailrace’ returning the water to the watercourse.
The government does not expect many applications for hydroelectric power generation to come forward. However, pumped hydro storage – transferring water from the upper reservoir to the lower reservoir through a turbine, generating power – is expected to grow significantly. Some of the information here refers specifically to considerations around pumped hydro storage.
Description of associated infrastructure
The infrastructure required for large scale hydropower systems includes a storage facility, large turbine, dam, generator and ancillary equipment and a connection to the electricity distribution network (i.e. grid).
The infrastructure required for small scale hydropower systems typically includes a building housing the turbine, generator and ancillary equipment (the ‘turbine house’) a connection to the electricity distribution network (i.e. the grid) or the user’s premises, a pipeline, often known as a penstock, to connect the intake to the turbine and a short open ‘headrace’ channel may be required between the intake and the pipeline.
Landscape and visual
Direct landscape impacts on the site
Direct landscape impacts on the site – for example loss of landscape features or change in the character of the site resulting from ground disturbances, construction activity, – for example the impact of headponds/tailponds, dams, weirs, leats, turbine houses, associated grid connection, power lines, and access tracks on the character of the landscape, as well as changes in water level, and appearance of waterfalls/ water features. Changes in the setting of a property may also have direct impacts on the significance of a place.
Indirect impacts on the landscape character of the surrounding area and setting of National Trust Properties
Indirect impacts on the landscape character of the surrounding area and setting NT properties – for example change in the character of adjacent landscapes as a result of the change in those landscapes, including changes in character/sense of place important to the property.
Direct impacts on views
Direct impacts on views – for example changes in views to and from NT properties and NT key views and vistas due to the introduction of dams, weirs, leats, turbine houses and associated power lines and changes in the visual appearance of waterfalls affected by water abstraction.
Direct landscape impacts on the site
Landscape and Visual Impact Assessment (LVIA). Effects on the special qualities and sensitivities of the landscape within the site, considering the landscape value the site provides to NT properties and to their setting. Analysis to be based on desk study, baseline assessment of site, field study and photography.
Use existing documents including Statement of Significance, Management Plans and other landscape evidence including Landscape Character Assessment.
Indirect impacts on the landscape character of the surrounding area and setting of National Trust Properties
Effects on the special qualities of the landscape and of the value provided to NT properties and their setting. Analysis to be based on desk study, baseline assessment of the surrounding landscape, field study and photography.
Consideration of NT properties in proximity to the site and their contribution to and significance within the surrounding landscape.
Use existing documents including Statement of Significance, Management Plans and other landscape evidence including Landscape Character Assessment.
Direct impacts on views
Effects on key views and designed vistas as identified by NT, considering the contribution of the site and surrounding landscape to the setting of relevant NT properties. Analysis to be based on desk study, ZTV, and may include photomontages of agreed viewpoints, field study and photography.
Potential receptors to assess include; visitors/tourists to NT properties including those travelling on routes to/from NT properties, residential receptors living within or in proximity to NT properties, recreational receptors on long distance walking or cycling routes within or in proximity to NT properties.
Effects on views, considering size/scale, geographical extent, and duration of the effect. Analysis to be based on desk study, ZTV, and may include photomontages of agreed viewpoints, field study and photography.
Direct landscape impacts on the site
The initial site selection and layout should take into account landscape scale and character. Consider watercourse locations which are already well screened with vegetation, minimising visibility of the installation. Selected sites should carefully consider proximity to sensitive landscapes, including from NT properties and settlements. Consideration should be given to the significance of the property, including key views and vistas, and the contribution of the setting to significance, as outlined in NT documents.
Incorporate screen planting (of a native, appropriate species) to conceal turbine house, considering opportunities for landscape enhancements in-line with long term plans as defined by NT management plans.
Where possible, consider the incorporation and restoration of old water related structures (mills, etc.). Design new elements to be as small as possible, ensure colour and materials of built elements are in keeping with local vernacular.
Bury pipeline and restore pipeline route after construction.
Ensure site restoration upon decommissioning. Any landscape interventions should preserve the character of the site, in accordance with NT principals and associated NT management plans.
Indirect impacts on the landscape character of the surrounding area and setting of National Trust Properties
Ensure careful design of site layout and siting, considering impacts on views within, and in proximity to, the surrounding area and to the setting of NT properties.
Minimise visibility within the surrounding area of vehicular movement associated with the plant, using vegetation or fencing in character with the setting. Any fencing or vegetation is to be in character with surrounding landscape and relevant NT Management Plans.
Direct impacts on views
Minimise visibility of the development in key views and vistas as identified by the NT.
Consider screening opportunities, using vegetation and fencing in accordance with relevant NT guidance documents and Management Plans.
All impacts
“For non – EIA development:
Appraisal of impact of proposal on landscape character and visual amenity.
For EIA developments:
LVIA chapter within Environmental Statement as set out in the Guidelines for Landscape and Visual Impact Assessment Third Edition (GLVIA3). Assessment of impacts on visual receptors to be agreed in consultation with NT and relevant consultees. Key viewpoints to be agreed with Council, Natural England and Trust (where appropriate) at EIA Scoping stage.
Residential Visual Amenity Assessment (RVAA) where necessary – Assessment of impact from residential properties within 2km of development (to establish if infrastructure breaches ‘residential visual amenity threshold’).
Night-time lighting assessment where necessary (in addition to LVIA). Night time lighting to consider effect on overall character (e.g. in remote landscapes, dark sky reserves) as well as visual receptors.
Cumulative Landscape and Visual Amenity Assessment – assessment of additional cumulative effects that would arise when adding the Development to a baseline containing other existing large-scale developments (including wind and solar) or those that are the subject of a valid planning application within the 33 km search area (these equate to ‘Tier 1’ projects as set out in the Planning Inspectorate Advice Note 17).
Site selection and design chapter within Environmental Statement. Setting out the rationale behind the site selection, design objectives, the design evolution in response to different sensitivities and constraints, and any potential mitigation strategies.
‘Construction Method Statement’ and ‘Construction Environmental Management Plan’ (CEMP) which should include arrangements for implementation of various aspects of the works. The statement should also set out restoration of landscape earthworks, soils and surface vegetation after completion of construction, as well as restoration of any recreational elements.”
All impacts
Where landscape planting and/or fencing is considered appropriate to mitigate any adverse impacts monitoring of their establishment and maintenance should be secured.
DCLG (2004) PPS22 Planning for Renewable Energy Companion Guide.
Yorkshire Dales National Park Authority (2009) Small-Scale Hydro Feasibility Study.
Scottish Natural Heritage (2001) Guidelines on the Environmental Impacts of Wind farms and Small Scale Hydroelectric Schemes.
Scottish Natural Heritage (2015) Hydroelectric Schemes and the Natural Heritage.
Landscape Institute and the Institute of Environmental Management and Assessment (2013) Guidelines for Landscape and Visual Impact Assessment, Third Edition.
Landscape Institute (2023) Notes and Clarifications on aspects of the 3rd Edition Guidelines on Landscape and Visual Impact Assessment (GLVIA3).
Landscape Institute (2021) Assessing landscape value outside national designations. Technical Guidance Note 02/21.
Landscape Institute (2019) Visual Representation of Development Proposals – Technical Guidance Note 06/19.
Ecology (non-avian)
Direct impacts of hydropower operation on ecological receptors
Direct impacts of hydropower operation on ecological receptors (e.g. disturbance of habitats/species) from impact of altered hydrological regime e.g. plants, bryophytes and lichens (small scale hydro schemes often in ravines), disturbance to migratory patterns and death/injury of fish) and geomorphology e.g. sediment flows on river bed.
Direct impact of hydro-power construction on loss/displacement off ecological receptors
Direct impact of hydro-power construction on loss/displacement of ecological receptors (e.g. habitat loss and/or loss of plant or animal species, disturbance, fragmentation).
Opportunities for habitat management and enhancement
Opportunities for habitat management and enhancement e.g. fish re-stocking and bankside planting
Direct impacts of hydropower operation on ecological receptors
Desk study (data centre request).
Phase 1 (or UK Habs) Habitat Survey..
Preliminary Ecological Appraisal (PEA) and Protected Species surveys (where recommended in PEA), e.g. otter, water vole, white-clawed crayfish.
Aquatic ecology surveys (aquatic and riparian habitats; aquatic macroinvertebrates; aquatic macrophytes; fish habitat assessment; aquatic invasive species survey).
Vascular and lower plant surveys.
Habitat Regulations Assessment is required if European Wildlife Sites (SPAs, SACs, Ramsar) are impacted.
Direct impact of hydro-power construction on loss/displacement off ecological receptors
Same as above.
Opportunities for habitat management and enhancement
Ecological mitigation and management plan.
Direct impacts of hydropower operation on ecological receptors
Ecological impacts can be mitigated through good design. The incorporation of fish passes and screens into the weir will allow free passage of migratory fish and other freshwater animals, and many turbines (i.e. low to medium head crossflow designs) can oxygenate river water, which will bring benefits to fish populations.
Measures such as pulsed flow or seasonal operating of the hydro scheme to avoid seasonal fish migration will also minimise impacts on breeding fish populations.
Small scale hydro schemes should avoid known core conservation areas for bryophytes and lichens. Certain bryophytes and lichens are specially protected under the Wildlife and Countryside Act 1981 (as amended, under Schedule 8).
CEMP measures can be prepared and developers should avoid construction during seasonal fish migration (varies for different fish species).
Direct impact of hydro-power construction on loss/displacement off ecological receptors
The construction of hydro schemes should be avoided during seasonal fish migration to ensure the safe passage of fish upstream/downstream. Well-designed schemes should also incorporate environmental improvements into the development through the restoration of natural riverside habitats that may be degraded or damaged during construction.
Protect water quality (e.g. prevention of pollution and sedimentation).
Restore habitat edges adjacent to water course.
Contain works to minimise disturbance footprint.
Opportunities for habitat management and enhancement
Prepare ecological mitigation and habitat management plan to identify the opportunities for habitat enhancement.
All impacts
For non-EIA development:
Preliminary Ecological Appraisal and an Ecological mitigation and management plan should be prepared.
For EIA development:
An Ecological Impact Assessment (EcIA) should be prepared, either alone or as part of an Ecology Chapter of an ES. Details of methodology and results of any protected species surveys and data search should be included.
Further information may be required:
– Biodiversity Net Gain report (England) or Net Biodiversity Benefit report (Wales).
– HRA (if required).
All impacts
An Ecological Monitoring Strategy should be prepared. Monitoring impact of small scale hydro schemes on bryophyte and lichen populations will help assist understanding of such impacts.
Environment Agency (2009) Good Practice Guidelines Annex to the Environment Agency Hydropower Handbook.
Salmon and Freshwater Fisheries Act (SFFA) (1975)
Water Framework Directive (2004)
NatureScot (2011) Commissioned Report 421 – Assessing the impacts of small scale hydroelectric schemes on rare bryophytes and lichens.
Ornithology
Direct impacts of hydropower operation on ecological receptors
Direct impacts of hydropower operation on ecological receptors (e.g. disturbance of habitats/species from impact of altered hydrological regime, disturbance to migratory patterns and death/injury of fish as prey species for feeding birds).
Direct impacts of hydro-power operation on ecological receptors
Direct impact of hydro-power construction on loss/displacement of ecological receptors (e.g. habitat loss and/or loss of bird species, disturbance, fragmentation).
Opportunities for habitat management and enhancement
Opportunities for habitat management and enhancement.
All impacts
Breeding Bird Survey.
Wintering Bird Survey.
Surveys for specific species may be required (PEA, set out in Ecology above, will inform choice of surveys), e.g. raptors, black grouse, moorland birds, divers and grebes etc.
Ornithology Mitigation and management Plan.
All impacts
CEMP measures.
Avoid construction impact during breeding season (March to August).
Pollution prevention measures during construction.
Creation of new and replacement wildlife habitats e.g. woodland.
Enhancement measures on impacted wetlands, e.g. nesting rafts.
All impacts
For non EIA development:
Preliminary Ornithological Appraisal.
For EIA development:
An Ornithological Impact Assessment can be prepared as the Ornithology Chapter in an ES. Technical Appendices should include bird survey methodology and results.
Further documents that may be needed for non-EIA and EIA development include:
– Habitat Regulations Assessment Screening Report and Appropriate Assessment.
– Ornithology Mitigation and Management Plan.
– Monitoring Plan.
All impacts
An Ornithology Monitoring Strategy should be prepared.
Environment Agency (2009) Good Practice Guidelines Annex to the Environment Agency Hydropower Handbook.
Salmon and Freshwater Fisheries Act (SFFA) (1975)
Water Framework Directive (2004)
NatureScot (2011) Commissioned Report 421 – Assessing the impacts of small scale hydroelectric schemes on rare bryophytes and lichens.
Historic environment (built heritage, archaeology and historic landscapes)
Potential embedded design and mitigation measures
Physical impacts (loss or truncation) to above-ground heritage assets (buildings, landscape components) and buried heritage assets (archaeological deposits and features, including undiscovered archaeology and paleoenvironmental remains). May be opportunities for sustainable re-use of historic water mill buildings for small-scale run-of-river schemes, and potentially historic leat structures, etc. – but needs careful design and strong understanding of significance of structures.
Erosion and gradual decline of submerged heritage assets
Erosion and gradual decline of submerged heritage assets through water action in schemes which entail damming watercourse or creation of pumped storage reservoir.
Harm to the significance of assets arising from change in their setting
Harm (negative impact) to the significance of assets arising from change in their setting (e.g. interruption of visual, functional, symbolic or historic relationships; effects as a consequence of noise, vibration)
NB. Effects as a consequence of setting change are direct, as they directly affect the heritage significance of the asset.
Impacts on wider historic character.
Harm to historic landscape character
Harm to historic landscape character, including by flooding and submerging key components.
All impacts
Understanding of significance of assets potentially affected is vital prior to determining impacts/potential impacts. Historic environment desk-based assessment (HEA), in line with associated CIfA Standard and Guidance, informing ES chapter or as a standalone supporting document for the application (non-EIA cases) or other appropriate document (e.g. in Wales a Heritage Impact Assessment (HIA) following associated Cadw guidance is to be produced in the scenario that the application directly affects (i.e. is in) a historic asset).
HEA/HIA to include walkover survey of construction footprint and micrositing allowance, and prospection for assets potentially affected within the redline boundary. Designated assets to be assessed for sensitivity to the proposed change within the ZTV, along with non-designated assets of high importance. The potential for views of the development in combination with assets also need to be considered with the assistance of the ZTV.
Depending on the nature and location of the site, local authority archaeologists may require pre-consent evaluation field work (non-intrusive such as geophysical survey or intrusive trial trenches) to fully understand significance of assets subject to potential direct physical effects, fulfil information requirements for determination and provide the basis for an appropriate mitigation strategy (including redesign of proposals where assets are to be preserved in situ). This work is to be undertaken in line with relevant guidance (e.g. CIfA, HE).
Assessment methodology is to be in line with 2021 ‘Principles of Cultural Heritage Impact Assessment in the UK’, as industry-standard guidance developed and promoted by the relevant professional institutes for the historic environment and EIS. It is to meet relevant Historic England or Cadw guidance. Assessment of heritage significance should be transparently articulated (i.e. in line with Historic England or Cadw ‘Conservation Principles’, or equivalent heritage values set out in national planning polices (e.g. NPPF)). The assessment is to use a transparent articulation of impacts and effects, making it clear what effects are significant effects in EIA terms and why, to enable consistent judgement across topics. In England, these are to be expressed in terms of whether and what level of harm arises so the tests in NPPF can be applied by the decision maker.
Clear evidence of the design process and solutions explored to avoid/minimise effects are to be provided in the ES and DAS.
All impacts
Design and locate main structures and associated infrastructure to avoid physical impacts and harm due to setting change affecting significance on identified heritage assets, such as siting turbine houses where they will be least obtrusive and/or hidden by natural contours or blend into natural/man made environment. Avoid impacts and preserve features in situ wherever possible.
Where assessment suggests that archaeological potential is high, mitigation strategy should be informed by field evaluation – geophysical survey (where ground conditions allow) and/or trial trenching, in line with an approved WSI.
Where physical impacts to non-designated assets cannot be avoided, preservation by record can be acceptable, but must be undertaken in line with a Written Scheme of Investigation (WSI), approved by the LPA archaeological adviser. The programme of fieldwork should be secured by condition, and the necessary funding from the developer for analysis of excavation outcomes, analysis of environmental samples, finds etc., deposition of archive material and processed finds, and publication in a periodical commensurate with the significance of the evidence recovered, must be secured by legal agreement.
Where significant archaeological, built heritage or historic landscape complexities are involved in the delivery of the project, the Applicant should undertake to provide an Archaeological Clerk of Works (ACoW) or Historic Environment Clerk of Works to monitor ground-breaking work in sensitive areas, advise on mitigation requirements and deal effectively with any previously unrecognised assets identified during construction.
For large-scale schemes, beyond site selection and design being informed by a strong understanding of the historic environment, there is likely to be little further mitigation possible for effects related to setting change or harm to historic landscape. There may be potential for landscape design solutions to aid integration of small-scale schemes. These are to be designed in a way that does not give rise to additional impacts, but works with existing historic landscape structure, and the palette of landscape materials. Examples of this include designing turbine houses to have a low profile, incorporating local building materials and using appropriate landscaping to further soften the appearance.
All impacts
For non EIA development: Input on effects to historic assets prepared by historic environment specialist in Design and Access Statement.
Appropriate historic environment reports explaining baseline and effects to assets (e.g. HEA (incl. setting assessment), geophysical survey report, trial trenching report, geoarchaeological assessment, historic buildings assessment, HIA, WSI).
For EIA development:
-Input on effects to historic assets prepared by historic environment specialist in Design and Access Statement.
Monitoring by relevant curatorial authority (e.g. LPA archaeological advisor, conservation officer; HE/Cadw officer, HED) to ensure agreed mitigation works are being undertaken in line with the approved WSI, or archaeological excavation license (for works in Northern Ireland). This process may take several years where archaeological investigation is required as any specialist analyses and post-excavation works must be concluded before reporting can be completed and published, at which point the monitor certify that they have been completed in line with the WSI.
Chartered Institute for Archaeologists (CIfA) (2020) Standard and Guidance for historic environment desk-based assessment.
IEMA, IHBC & CIfA (2021) Principles of Cultural Heritage Impact Assessment in the UK.
CIfA (2020) Standard and guidance for archaeological geophysical survey.
CIfA (2020) Standard and guidance for archaeological field evaluation.
Historic England (2014) Micro-Hydroelectric Power and the Historic Environment.
Historic England (2015) Managing Significance in Decision-Taking in the Historic Environment: Good Practice Advice in Planning Note 2.
Historic England (2017) The Setting of Heritage Assets: Historic Environment: Good Practice Advice in Planning Note 3.
Historic England (2019) Statements of Heritage Significance: Analysing Significance in Heritage Assets Historic England Advice Note 12.
Cadw (2017) Heritage Impact Assessment in Wales.
Cadw, Countryside Council for Wales & ICOMOS (2007) Guide to Good Practice on Using the Register of Landscapes of Historic Interest in Wales in the Planning and Development Process Second Edition.
Cadw (2017) Setting of Historic Assets in Wales.
Welsh Government (2017) Technical Advice Note 24: The Historic Environment.
Department for Communities (2018) Guidance on Setting and the Historic Environment for Northern Ireland.
Department for Communities (2019) Guidance on making changes to Listed Buildings: Making a better application for listed building consent for Northern Ireland.
Department for Infrastructure (2019) Best Practice Guidance to PPS 23 ‘Assessing Enabling Development for the Conservation of Significant Places.
Department of the Environment (2009) Best Practice Guidance to Planning Policy Statement 18 ‘Renewable Energy’.
Hydrology, hydrogeology and water sources
Impacts during construction on local watercourses
Impacts during construction on local watercourses (e.g. from pollution, erosion, sedimentation, impediments to flow or increased surface water run off), particularly where soil is disposed (Pumped Hydro Storage (PHS)).
Direct impacts during operation through alterations to the hydrological regime of watercourse
Direct impacts during operation through alterations to the hydrological regime of watercourse. This could also lead to increased flood risk.
Discharging of water
Discharging of water of an altered quality or temperature than the received water will affect the biodiversity of aquatic flora and fauna. In particular, pumping of water to the upper reservoir will result in increased temperatures (PHS).
Direct impact of flow depletion
Direct impact of flow depletion which can cause erosion to banks.
All impacts
Assessment of the existing status of, and impacts of the proposed project on water quality, water resources and physical characteristics of the water environment.
Preparation of flood risk assessment.
Prepare Environmental Management Plan (including use of silt traps) to be submitted to determining authority prior to construction, see Ecology above.
Impacts during construction on local watercourses
Implement good pollution prevention practices based on Natural Resources Wales guidelines and CIRIA documents.
Design of the PHS scheme should include intake and outfall locations that avoid or minimise adverse impacts.
Direct impacts during operation through alterations to the hydrological regime of watercourse
Same as above
Discharging of water
Specific measures to minimise fish impingement and the discharge of excessive heat to receiving waters.
Direct impact of flow depletion
Design intake and outfall to minimise erosion.
All impacts
For non-EIA development:
Consultation with the Environment Agency and relevant licenses i.e. water abstraction license.
For EIA development:
A hydrology and hydrogeology chapter within an ES must be prepared.
Further documents that may be needed include:
– Flood Risk Assessment
All impacts
Ongoing monitoring of pollution levels, water quality and changes in hydraulic variations.
Department for Energy Security and Net Zero (2023) Draft NPS for Renewable Energy.
Centre for Ecology and Hydrology (2006) Flood Estimation Handbook CD-ROM V2.0.
Welsh Government (2021) Technical Advice Note 15: Development, Flood Risk and Coastal Erosion.
CIRIA (2002) Control of Water Pollution from Construction Sites – Guide to Good Practice on Site.
Water Framework Directive (2004)
Noise and vibration
Increase in noise levels at nearby sensitive receptors during operation
Increase in noise levels at nearby sensitive receptors during operation (e.g. noise emitted from the turbine and generator).
Blasting
There may be considerable noise in the construction phase, if blasting is required to create reservoirs and penstocks (PHS).
All impacts
An assessment of construction noise should be undertaken in accordance with British Standard (BS 5228-1) which provides guidance on a range of considerations relating to construction noise including the legislative framework, general control measures, example methods for estimating construction noise levels and example criteria which may be considered when assessing the significance of any effects. Similarly, part 2 (BS 5228-2) provides general guidance on legislation, prediction, control and assessment criteria for construction vibration.
Operational noise should be assessed in accordance with ETSU-R-97. Good practice in the application of the ETSU-R-97 methodology is set out in Institute of Acoustics Good Practice Guide to the Application of ETSU-R-97 (IOA GPG).
All impacts
Design of turbine house to incorporate acoustic insulation materials.
Explore how noise impacts can be reduced through the scheme siting and by using natural screening.
Set limits on noise emissions through planning conditions.
All impacts
For non-EIA development:
A Noise Impact Assessment will likely be required.
For EIA development:
A noise chapter is likely to be included within an ES.
All impacts
Monitoring of noise sensitive receptors may be required if feedback from residential dwellings is negative.
Welsh Government (1997) Technical Advice Note 11: Noise.
Department for Energy Security and Net Zero (2023) Draft NPS for Renewable Energy.
The British Standards (2014) Code of practice for noise and vibration control on construction and Open Sites, Part 1 Noise and Part 2 Vibration.
Traffic and transport
Increase in vehicle movements on local roads during construction
Increase in vehicle movements on local roads during construction.
Change in transport requirements for excavated materials and building requirements
Change in transport requirements for excavated materials and building components.
All impacts
Transport and Traffic Impact Assessment should be prepared.
All impacts
Prepare a Traffic Management Plan which will include measures for vehicle sharing, avoidance of HGV deliveries during peak periods etc.
Define most suitable road access routes.
Arrange timing of movement to avoid sensitive periods.
Consider if waterways transport by barge can be used in construction phases.
All impacts
For EIA development:
An Access, Traffic and Transport chapter within the ES would be required. This would typically include a Transport assessment (TA) as an appendix.
All impacts
Maintenance of site access post construction including site entrances and exit points. Additionally, a construction management plan may be secured by condition.
Institute of Environmental Assessment (1993) Guidelines for the Environmental Assessment of Road Traffic.
Institution of Highways and Transportation (1994) Guidelines for Traffic Impact Assessment.
Soils/Geography
Alterations to landscape hydrology and habitat loss
Soil removal for infrastructure causing alterations to landscape hydrology and habitat loss.
Reduction of the movement of sediment and changing patterns of sediment transfer
Natural channels or physical habitats can be reduced or their development stopped by the reduction of the movement of sediment and changing patterns of sediment transfer.
Alterations to landscape hydrology and habitat loss
See Ecology above.
Reduction of the movement of sediment and changing patterns of sediment transfer
Geomorphology assessment may be needed.
Alterations to landscape hydrology and habitat loss
Where the project is likely to have effects on biodiversity the applicant should undertake an assessment as required in the Environmental Statement.
Design measures should be included through PHS schemes that improve local biodiversity (including through habitat creation and/or enhancement, fish restocking, and bankside planting. Some turbines may also assist in increasing dissolved oxygen levels)
Reduction of the movement of sediment and changing patterns of sediment transfer
Bed or bank reinforcement measures.
Alterations to landscape hydrology and habitat loss
See Ecology above.
Reduction of the movement of sediment and changing patterns of sediment transfer
For non-EIA development:
Feasibility study and ground investigation works should be undertaken.
All impacts
Unlikely to need monitoring post construction.
Environment Agency (2009) Good Practice Guidelines Annex to the Environment Agency Hydropower Handbook.
Salmon and Freshwater Fisheries Act (SFFA) (1975)
Water Framework Directive (2004)
NatureScot (2011) Commissioned Report 421 – Assessing the impacts of small scale hydroelectric schemes on rare bryophytes and lichens.
Socio-economic
Disruption to public footpaths during construction
Recreation: Disruption to public footpaths during construction (e.g. from pipeline routes that follow existing footpath routes along a river) and PHS schemes are likely to be located in hilly or mountainous areas and are likely to have specific impacts on recreation. Impacts on the landscape and water courses could have adverse impacts on recreational activities such as water sports (e.g., canoeing) and fishing.
Impact on nearby fisheries
Impact on nearby fisheries (e.g. disturbance to seasonal fish migration, commercial income).
Impact on navigation
Impact on navigation, creating hazards or barriers.
Disruption to public footpaths during construction
An Outdoor Access Management Plan and full assessment taking into account views of relevant bodies could be undertaken.
Impact on nearby fisheries
See Ecology above.
Impact on navigation
Consultation with users of the waterways.
Disruption to public footpaths during construction
Bury pipeline and restore pipeline route after construction.
PHS schemes should be designed to minimise impacts on existing recreational activities. It may be possible for the PHS scheme to be designed in such a way that these activities can be enhanced.
Impact on nearby fisheries
Avoid construction during seasonal fish migration (varies for different fish species).
Adjustment of the seasonal operating schedule of the hydro scheme.
Incorporate fish passes and screens into weir to allow free passage of migratory fish.
Impact on navigation
None likely.
Disruption to public footpaths during construction
For EIA development: A socio-economics chapter of the ES could be prepared if required. These are often included as stand alone reports separate from the ES.
Recreation and Access Management Plans.
Impact on nearby fisheries
See Ecology above.
Additionally a Fish pass and Screen approval from the Environment Agency may be required.
Impact on navigation
None likely.
All impacts
Unlikely to need monitoring post construction.
Welsh Government (2016) Guidance for Local Authorities on Public Rights of Way.
Department for Energy Security and Net Zero (2023) Draft NPS for Renewable Energy.
Environment Agency (2009) Good Practice Guidelines Annex to the Environment Agency Hydropower Handbook.
Salmon and Freshwater Fisheries Act (SFFA) (1975)
Water Framework Directive (2004)
NatureScot (2011) Commissioned Report 421 – Assessing the impacts of small scale hydroelectric schemes on rare bryophytes and lichens.
