OES-Environmental distributes metadata forms (questionnaires) to solicit information from developers involved in environmental monitoring around marine renewable energy project sites around the world. This page provides project descriptions, baseline assessment, post-installation monitoring, and links to available data and reports. Content is updated on an annual basis.

Swansea Tidal Lagoon

Project Site OES-Environmental

Title: Swansea Tidal Lagoon
Research End Date:
January 01, 2142
Technology Type:
Info Updated:
March 07, 2019
Project Status: 
Planned project
The turbines initially selected for the project at Swansea Bay were bi-directional, low head, Kaplan bulb hydro turbines manufactured by Andritz Hydro. The technology remains TBC.
Project Scale: 
Commercial scale pathfinder project
Installed Capacity: 
320 MW

The Swansea Bay Tidal Lagoon is currently stalled due to a lack of UK Government financial support. The 320MW pathfinder project aimed to provide a scalable blueprint for tidal lagoons, opening up the option of a fleet of larger UK tidal lagoons to generate renewable electricity.


To date, approximately £35 million has been spent on project development.  With the exception of a commercial loan from Welsh Government this has been financed privately.


The Project is situated at Swansea Port, approximately 2.2km southeast of Swansea city centre. The Lagoon will enclose part of Swansea Bay, from the eastern side of the River Tawe (western landfall) to the eastern edge of the Swansea University Bay Campus . The seawalls impounding the Lagoon will extend approximately 1.5km directly offshore from SUBC, adjacent to Crymlyn Burrows Site of Special Scientific Interest (SSSI). The seawalls will then extend in a southwest direction along the western boundary of the training wall of the River Neath Channel. A turbine and sluice gate housing structure will be located in the south west of the Lagoon, at an oblique angle to the dredged channel of the River Tawe. The seawall will then extend north towards Swansea Port, close to the mouth of the River Tawe, parallel but offset by 100m from the dredged channel for the River Tawe and Port of Swansea. In total, this will form an approximately 9.5km-long, U-shaped, seawall which will impound approximately 11.5km2 of the seabed, foreshore and intertidal area of Swansea Bay.


The hydro (water) turbines located within the turbine and sluice gate housing will be bi-directional, meaning they are able to generate power with flows of water in both directions (i.e. on both incoming and outgoing tides). There will be up to 16 turbines, each one around 7m in diameter, and all located permanently underwater. There will also be up to ten sluice gates; these are large gates which will be underwater and able to let seawater in and out of the Lagoon, and so controlling the water passing through the turbines, as required.


To generate electricity, as the sea starts to rise (flood tide) from low tide level, water is prevented from entering the Lagoon for an average of 2.5 hours, which creates a difference in water levels known as ‘head’. Once sufficient head has been reached, the water is allowed to flow into the Lagoon through the turbines, turning the runner (like a propeller) and generating electricity. This process is repeated on the ebb tide, where the water is prevented from leaving the Lagoon until there is sufficient head to start the process again.


Work was expected to start on site in 2018.  Construction of the entire project was estimated to take four years, with first power generated in year three.


The Project is situated at Swansea Port, approximately 2.2km southeast of Swansea city centre. The Lagoon will enclose part of Swansea Bay, from the eastern side of the River Tawe (western landfall) to the eastern edge of the new Swansea University Bay Campus (SUBC - previously known as the Science and Innovation Campus, and currently under construction) (eastern landfall). The seawalls impounding the Lagoon will extend approximately 1.5km directly offshore from SUBC, adjacent to Crymlyn Burrows Site of Special Scientific Interest (SSSI). The seawalls will then extend in a southwest direction along the western boundary of the training wall of the River Neath Channel. A turbine and sluice gate housing structure will be located in the south west of the Lagoon, at an oblique angle to the dredged channel of the River Tawe. The seawall will then extend north towards Swansea Port, close to the mouth of the River Tawe, parallel but offset by 100m from the dredged channel for the River Tawe and Port of Swansea. In total, this will form an approximately 9.5km-long, U-shaped, seawall which will impound approximately 11.5km2 of the seabed, foreshore and intertidal area of Swansea Bay.

Project Timeline: 

TLP received planning consent on June 09 2015, but in order for marine works to start the project also needs a marine licence from the Welsh government’s body in charge of sustainable management of its natural resources, Natural Resources Wales (NRW). In December 2016 it became apparent that NRW could deny a marine licence on the basis that the project would result in ‘major adverse effects’ as it was predicted, by NRW, to potentially kill 21% of salmon and 25% of sea trout every year.


TLP responded saying they had demonstrated minimal impacts on fish which was verified when their planning permission was awarded on the data that TLP provided in the EIA. TLP highlighted that their work has been peer reviewed and agreed by a host of world leading fish experts.


In January 2017, a report by former energy minister Charles Hendry ordered by the UK government recommended that tidal lagoons could play “a cost-effective role in the UK’s energy mix”, adding that there was “considerable value in a small pathfinder project”. If constructed, the project would provide enough power for 155,000 homes, or over 90% of homes in the Swansea Bay area.


In January 2018 the First Minister of the Welsh Government announced financial support for the project almost a year after the Hendry review recommended it be backed.


On the 25th of June 2018 the Department for Business, Energy & Industrial Strategy (BEIS) rejected the plan for the tidal lagoon in Swansea Bay, delivering a report to Parliament on the status of tidal lagoons with a cost-benefit analysis that indicated the project was too expensive compared with nuclear and offshore wind power. A follow-up audit of BEIS’ statement by TLP claimed that figures included in the statement were inaccurate by orders of magnitude.


An independent report published in August 2018 by financial experts Holistic Capital provided a set of recommendations for alternative delivery and financing models, stating that the tidal lagoon was a fundamentally strong proposition and an exceptional project that could provide clean power for generations to come.


In December 2018 eleven companies expressed their interest in the stalled project. Some have indicated they would deliver the entire project, which has an estimated £1.3 billion price tag, but with a different development and deal to the previous proposal. Other companies have said they want to be involved in delivering part of the project. It is not clear at present what role if any TLP might have going forward with the project.

Licensing Information: 

Swansea Bay Tidal Lagoon is planned to be an offshore generating station with more than 100MW of installed capacity and, as such, is considered a ‘nationally significant infrastructure project’ (NSIP) under the Planning Act 2008.


NSIPs are consented under a different system to that managed by local authorities, being managed instead by the UK’s Planning Inspectorate and consented by the relevant Secretary of State. The Project lies in Welsh waters, meaning a Marine Licence (for dredging and construction) is also required under the Marine & Coastal Access Act 2009. Marine Licence applications are determined by the Marine Licensing Team of Natural Resources Wales (NRW) on behalf of the Welsh Government.


The Project cannot go ahead without both consents. Planning consent was granted by the Secretary of State for Energy and Climate Change in June 2015.


A decision on the Marine Licence is outstanding.

Key Environmental Issues: 

These include potential impacts on fish, water quality, and changes to coastal processes and sediment transport in the area.


Environmental Webpage: http://www.tidallagoonpower.com/environment/

Swansea Tidal Lagoon is located in United Kingdom.

Baseline Assessment: Swansea Tidal Lagoon

General Description:

An Environmental Impact Assessment has been carried out for the proposals. The Environmental Statement chapters can be downloaded from here

ReceptorStudy Description Design and Methods Results Status
  • Physical Processes

Metocean survey to measure currents, waves and turbidity

Placement of metocean measuring equipment at two sites within the lagoon to measure currents, waves and turbidity

At site 1 generally low current speeds with a maximum of 0.42 m/s were recorded. Faster flows were found to occur on the ebbing tide.


Flows at site 2 were found to be slightly faster reaching a maximum of 0.52 m/s.


Two sets of inshore wave roses were created from the data collected at the metocean deployment sites. Waves recorded at the metocean sites show clear evidence of sheltering from Mumbles Head to long period westerly waves, with the predominant wave direction orientated further to the south than seen at the Scarweather Buoy (located offshore), with much reduced wave heights in the shallower water. During the survey period the largest wave event at Site 1 had a significant wave height (Hs) of 1.7 m, an average zero crossing period (Tz) of 4.8s and a mean wave direction from 208°N. At Site 2, further offshore and in deeper water (but still within the lagoon footprint), the equivalent event resulted in a significant wave height of 1.87 m, Tz of 4.5s and a direction of 191°N.


At Site 1, it can be clearly seen that turbidity values are considerably greater during spring tides than neaps. This increase is driven principally by the slightly higher flow speeds experienced over the spring tides, which would appear to be sufficient to remobilise fine sediments (mud) from the seabed.


Turbidity was typically greatest at Site 2 during peak current speeds, approximately 2 hours either side of LW over spring tides.


Based on the converted values, the mean near-bed SSC values were moderate to high at both sites, with a mean of 113 mg/l at Site 1 and 54 mg/l at Site 2. The generally higher concentrations at Site 1 are likely to be a function of the shallower environment within the surf zone, which tends to retain concentrations above 50mg/l. In comparison, concentrations at Site 2 tend to indicate lower concentrations during calmer periods, suggesting that some material may locally drop out of suspension.

  • Benthos

Geophysical and benthic characterisation survey including sampling and particle size analysis

Survey area covers the proposed footprint of the lagoon

Evidence from the geophysical survey of the project footprint and the PSA analysis of surface samples, collected as part of the benthic sampling programme for the whole bay, identified that the seabed within the proposed footprint of the Lagoon is divisible into two distinct zones (east and west), separated by an irregular central strip, which represents an outcrop of hard sediments (interpreted as boulder clay). In the western part of the Lagoon footprint, the seabed sediments predominantly comprise sandy gravel and gravelly sand, often with a thin sand veneer. The geophysical survey further indicates that the gravel is particularly coarse at the shoreline to the east of the Swansea Dock entrance breakwaters. A preliminary geotechnical investigation for the Swansea Tidal Lagoon development (Atkins, 2013), which included a number of exploratory boreholes, vibrocores and cone penetration tests, indicates that the seabed sediments found across the western side of the lagoon footprint range in depth from around 0.25 to 0.8 m. Beneath these sediments are numerous layers of (medium) sandy sediments, with varying proportions of silt/ clay and gravel. The eastern half of the Lagoon footprint predominantly consists of sands (smooth and featureless) and slightly gravelly sands.

  • Fish

Intertidal and subtidal surveys: The aim of the surveys was to provide an up-to-date characterisation of fish resources in the study area.


Four surveys carried out over one year. Beach seine net (43m long by 4 m deep, with 6.5mm knotless mesh) set from a small rigid vessel and a riley push-net (1.5 m wide by 30 cm deep with 1 mm fry mesh) used from the shore. The subtidal surveys were carried out from a 12.1m mono-hull trawler using both otter and beam trawls.

A total of 55 species were captured during the site-specific intertidal and subtidal surveys. The fish population has an abundant pelagic fish community with relatively high numbers of sprat (42.6 %), herring (12.2 %) and sand smelt Atherina presbyter (4 %); these account annually for approximately 58 % of fish in Swansea Bay. The most abundant demersal species (whiting, bass Dicentrarchus labrax, pouting, lesser spotted dogfish Scyliorhinus canicula and poor cod) make up 14 % of the fish population; whilst benthic species (Goby species, plaice, grey gurnard, common sole, thornback ray Raja clavata, lesser sandeel Ammodytes tobianus, dab, sand goby Pomatoschistus minutus, hooknose Agonus cataphractus, solenette Buglossidium luteum, turbot and flounder) make up 24 % of the annual distribution of fish. The remaining 3 % of the annual fish population in Swansea Bay is composed of 37 species, each with an abundance of less than 0.1 %. The numbers of these fish are inflated by the appearance of juveniles during the summer months.


The Swansea Bay fish community showed seasonal fluctuations relating to movements of species between feeding, spawning and nursery areas. During summer a variety of species moved into shallow inshore (intertidal) areas to feed, whilst during winter fish migrated further offshore into deeper (subtidal) waters. These changes are as a direct consequence of temperature, ontogenic development and prey availability.


The shellfish community within Swansea Bay includes molluscs, crustaceans, echinoderms and cephalopods. A total of 38 species were captured during the four Quarterly site-specific intertidal and subtidal surveys. The ten most frequently caught species across the four quarterly surveys were: Brittle Star Ophiura ophiura found in the winter, spring and autumn surveys; ii. White furrow shell Abra alba found in the autumn survey with high abundance; iii. Moon Jellyfish Aurelia aurita found in the summer survey with high abundance; iv. Common starfish Asterias rubens found across all seasonal surveys; v. Shrimp Crangon spp. found across all seasonal surveys; vi. Prawn Palaemon spp. found across all seasonal surveys; vii. Common cockle Cerastoderma edule found in the autumn survey with high abundance; viii. Sea mouse Aphrodita aculeata found across all seasonal surveys; ix. Common hermit crab Pagurus bernhardus found across all seasonal surveys; x. Dog whelk Nucella lapillus found in the spring, summer and autumn surveys.

  • Birds

The objective of the surveys was to obtain site-specific data on the numbers of, and primary areas used by, birds within the Blackpill SSSI and River Neath WeBS count areas, with particular reference to the eastern area of the Bay.

Surveys were completed on a monthly basis over the winter period 2011/12 (October-March) and 2012/13 (September – March). These winter surveys were supplemented by counts in the east of the survey area (EE013-EE023; River Tawe - River Neath) over the summer period (April-August 2013)

During the field surveys and through literature review, various areas have been identified within Swansea Bay as being used by Divers and Grebes. These areas extend from Port Talbot Dock in the southeast, off Aberafan beach through to the waters off the Port of Swansea and heading out to Mumbles.


A large number of bird species were identified during the bird surveys, species are split into Waders & waterfowl, Gulls and Divers and Grebe. A list of these species can be found in table 11.9 of the Coastal Birds chapter of the ES.

  • Benthic Communities

Phase 1 habitat survey

Intertidal survey - The intertidal survey was conducted between Mean High Water Springs (MHWS) with the seaward boundary following Mean Low Water Springs (MLWS) (or as near as possible depending on surf and surge conditions). The surveys were undertaken on 14-15 January 2013 and 28-29 May 2013, at low water during spring tides


Subtidal survey - In order to gather benthic information across the range of different substrates within Swansea Bay, 27 samples were taken from within the footprint of the Lagoon and 22 samples were taken from the area surrounding the Lagoon, providing a total of 49 benthic samples. Three benthic grab samples were collected at each site using a refined compact 0.1m2 Hamon grab.

The survey noted the presence, distribution and condition of Sabellaria reefs adjacent to the Tawe Dock entrance. In addition, the survey confirmed the presence and distribution of any nationally important biotopes, protected habitats or rare species both here and across the intertidal area west of the River Tawe round to Mumbles Head.


The mapping was undertaken on foot. Aerial photography and satellite images were taken into the field to create sketch maps. Habitats in the area were mapped as polygons using the European Nature Information System (EUNIS) habitat classes to level 4 or 5. Biotopes, or other notable features, covering less than 5m2 were recorded using referenced target notes.


Area between River Tawe and River Neath

The upper limit of this rock habitat is dominated by lichens (corresponding to the biotopes LR.FLR.Lic.YG – yellow and grey lichens on supralittoral rock and LR.FLR.Lic.Ver.Ver – Verrucaria maura on very exposed to very sheltered upper littoral fringe rock) with the lower rock dominated by barnacles, limpets and other sea snails with occasional bands of seaweeds (LR.HLR.MusB.Sem.Sem - Semibalanus balanoides, Patella vulgata and Littorina spp. on exposed to moderately exposed or vertical sheltered eulittoral rock).


During the 2013 survey, at the far west of the rock wall close to the breakwater, two seaweed zones of Pelvetia canaliculata (channelled wrack seaweed) and Fucus spiralis (spiral wrack seaweed) were observed below the lichen dominated top shore (Figure 8.7, Volume 2). These correspond to the biotope codes LR.LLR.F.Pel – Pelvetia canaliculata on sheltered littoral fringe rock and LR.LLR.F.Fspi – Fucus spiralis on sheltered upper eulitoral rock, respectively. Zones of Enteromorpha and barnacle and limpet zones occurred below this.


In the far eastern section of the survey area the lower rock is dominated by barnacles, limpets and patches of green algae (LR.HLR.MusB.Sem.Sem and LR.HLR.MusB.Cht.Cht).


A variety of habitats were recorded throughout the lower intertidal with the majority focused in the western corner of the survey area, including a number of nationally protected habitats and species (e.g. S. alveolata and hydroid rockpools).


Subtidal ecology

In the vicinity of Swansea Bay, the sediments are best described as a mixture of circalittoral mud and sand with the respective composition of each varying spatially. These predictions are broadly consistent with previous descriptions of the Bay which outline the dynamic nature of the area and the high tidal range. This, along with the curved shape of the Bay which results in varied exposure, gives a range of sediments grading from gravely sand, through fine sand to sandy mud and muddy sand in the subtidal area.  There

was considerable variation in abundance and diversity of benthic invertebrate species recorded across Swansea Bay in the 2013 survey, with sediment type being the dominant factor in determining species composition of the subtidal areas. In general, more mobile areas of finer sand or mud tend to be of lower species abundance and diversity, whereas gravelly sand and cobbles support a higher diversity and abundance. Taxa belonging to the Phylum Annelida were generally found to dominate the benthic communities in terms of abundance, species diversity and total biomass.

  • Benthic Communities

Phase 1 habitats survey, including botanical survey

An extended phase 1 habitat survey of the terrestrial elements of the Project was begun during site visits between 27 November 2012 and 9 January 2013. The results of the initial survey were updated following repeated visits to the site through the spring and summer of 2013. JNCC 2010 habitat survey techniques were used, with habitats and other features of ecological interest being mapped and described using target notes.

Rocky shore (artificial)

The southern boundary of Swansea Docks comprises rock armoured sea defences and a 2m high concrete wall. The boulders forming the rock armouring are devoid of vegetation. The seaward face of the concrete wall supports very occasional plants of Stag’s-horn Plantain (Plantago coronopus), Rock Samphire (Crithmum maritimum) and Sea-purslane (Atriplex portulacoides) as well as a colony of approximately thirty plants of Golden-samphire (Inula crithmoides). The sheltered north-facing side of the wall, including sections of concrete hard-standing, have been colonised by species typically associated with rocky shorelines. In particular, cracks and crevices provided a foothold for Rock Sea-lavender (Limonium binervosum agg.), Sea-plantain (Plantago maritima), Stag’s-horn plantain, Creeping-bent (Agrostis stolonifera), Red Fescue (Festuca rubra), Common Couch (Elytrigia repens) as well as occasional plants of Sea-thrift (Armeria maritima) and Rock Samphire.



Sheltered habitat beside the River Neath, at the northern end of Baglan Burrows and eastern end of Crymlyn Burrows SSSI supports saltmarsh dominated by Sea-purslane. Other species dotted within the sward included Common Saltmarsh-grass (Puccinellia maritima), Sea Aster (Aster tripolium) and Common Cord-grass (Spartina anglica). At the fringes of more established areas of saltmarsh, compacted sediment associated with creeks and hollows also support a community dominated by Annual Sea-blight (Suaeda maritima) and Purple Glasswort (Salicornia ramosissima).


Sand dune

No strandline communities were evident during a site visit undertaken late in 2012, indicating that the foreshore dunes at Crymlyn Burrows SSSI had been eroded during winter storms. However, a strandline and embryonic dune community supporting a mix of Sand Couch (Elytrigia juncea), Marram, Prickly Sandwort, Sea Sandwort (Honckenya peploides) and Sea Rocket (Cakile maritima) re-formed during the summer months. In terms of National Vegetation Classification (NVC), the SD2 Honckenya peploides-Cakile maritima strandline community and SD4 Elymus farctus foredune communities best describe the species assemblages that have developed since the winter. However, in places the rhizomes of Marram have colonised this pioneer zone and locally a SD6a Ammophila arenaria mobile dune Elytrigia juncea sub-community appears to best describe the first band of vegetation.


The foredunes throughout Swansea Bay support vegetation overwhelmingly dominated by Marram, interspersed by bare sand attributable to the SD6d Ammophila arenaria mobile dune (typical sub-community) of the NVC.


Dunes set back from the foreshore become increasingly fixed in character comprising Marram, Red Fescue, Common Bent (Agrostis capillaris), Sand Cat’s-tail (Phleum arenarium) and Thyme-leaved Sandwort (Arenaria serpyllifolia).



The grassland communities associated with Swansea Docks, particularly in the vicinity of the seawall where they are subject to sea spray during rough weather conditions, support species of upper saltmarshes. In particular, a narrow fringe of grassland beside the seawall along the south-western boundary of Queens Dock is dominated by Red Fescue and Sea Couch with very occasional tussocks of Long-bracted Sedge (Carex extensa), Sea Rush and Sharp Rush.


Grassland habitat along the south-eastern end of the seawall is sandy in places and supports occasional Marram. Typically, the sward comprises Common Couch and Red Fescue with varying cover of species including Creeping-bent, Cock’s-foot (Dactylis glomerata), Yorkshire-fog, (Holcus lanatus), Ragwort (Senecio jacobaea), Wild Carrot (Daucus carota), Wild Parsnip (Pastinaca sativa), Restharrow, Perforated St John’s-wort (Hypericum perforatum), Ribwort Plantain, Oxeye Daisy (Leucanthemum vulgare), Common Knapweed (Centaurea nigra), Common Bird’s-foot-trefoil (Lotus corniculatus) and Kidney Vetch. Analysis of quadrat data suggests elements of this habitat is broadly comparable to SD8 Festuca rubra-Galium verum fixed dune grassland habitat of the NVC although it is probably best described as a coastal grassland community.


  • Terrestrial Ecology

Bat survey

A single surveyor (accompanied for reasons of health and safety) carried out each survey armed with a Pettersson D240x time expansion detector and Edirol R-09HR digital MP3 sound recorder. In addition, an automated bat detector (Anabat SD1 frequency division detector) was deployed for a minimum of four consecutive nights to coincide with each visit. Survey visits were undertaken on 16 May 2013, 5 July 2013 and 3 September 2013.

The first of three transect surveys targeting habitat at the western end of Queens Dock and including habitat beside the seawall was undertaken on 16 May 2013. The survey coincided with high tide. Bat activity on the landward side of the seawall was found to be very limited during the visit. However, foraging activity of both Common Pipistrelle and Soprano Pipistrelle was recorded alongside exposed rock armouring on the coastal side of the seawall. The first bats recorded during the survey appeared almost one hour after sunset suggesting roosts are distant from the study area.


Two further surveys on 5 July and 3 September 2013 identified similar activity by both Common and Soprano Pipistrelle bats, although a brief pass by a Noctule was also recorded by a static detector on 6 August 2013.


The September static detector survey identified further passes by Noctule, a species of Myotis and Nathusius Pipistrelle (Pipistrellus nathusii). Nathusius Pipistrelle passes were recorded on the nights of 3, 4 and 5 September 2013. Nathusius Pipistrelle are rarely recorded bats, with only 850 existing records for the UK and Ireland. It is a species that feeds on aquatic flies and is often associated with lakes and rivers (Russ, 2013).


No structures suitable for supporting roosting / hibernating bats were found that would be affected by the Project, including the electrical grid connection works, recorded during the field surveys.

  • Birds

Breeding bird survey

The breeding bird survey followed a methodology utilising a combination of defined transects routes supplemented by mapping of birds seen or heard using Common Bird Census (CBC) codes of the British Trust for Ornithology (BTO). Three survey visits during the bird breeding season (March-July/August) were undertaken.

Species recorded during breeding bird surveys in April, May and June 2013 included Carrion Crow (Corvus corone), Jackdaw (Corvus monedula), Cormorant (Phalacrocorax carbo), Mallard (Anas platyrhynchos), Gadwall (Anas strepera), Buzzard (Buteo buteo), Ringed Plover, Bullfinch (Pyrrhula pyrrhula), Blackbird (Turdus merula), Song Thrush (Turdus philomelos), Mistle Thrush (Turdus viscivorus), Wood Pigeon (Columba palumbus), Swallow (Hirundo rustica) and Common Sandpiper (Actitis hypoleucos).


Of these, Skylark, Linnet, Bullfinch, Dunnock, Lapwing, Ringed Plover, Song Thrush, Yellow Wagtail, Herring Gull and Black-headed Gull are section 42 NERC 2006 species. The records for Bullfinch, Yellow Wagtail and Black-headed Gull were flyover records.

  • Marine Mammals

Otter survey

A survey targeting specific areas within the wider study area which were considered to provide potential cover for Otters was undertaken. The survey concentrated on areas considered to be more likely to be subject to disturbance during construction and operation of the Project.

A survey targeted along the seawall and at the south-western end of Swansea Docks (Queens Dock) found evidence of Otters at two locations. Spraints were found under the landward end of a jetty and nearby beside the dock edge (within 20m) at the eastern end of Queens Dock. A sheltered area beneath the jetty was identified as having the potential to provide a laying-up location (a partially enclosed feature used by Otters for temporary refuge). However, September 2013 trail camera footage captured images of a dog investigating this potential laying-up location. If this is a regular occurrence, it is unlikely that the location would be used by Otters as a refuge.


Tar spots (small drops of faeces lacking solids such as fish bones) were also found at the firing-position of a Second World War pill box located within the seawall. The tar spots smelt strongly of Otter and suggest pill boxes provide access points through the seawall allowing movement from the docks to the coast.

  • Reptiles

Reptile survey

Survey effort for reptiles focused on grassland habitat to the south and west of Queens Dock where an absence of records existed. A series of artificial refugia (or ‘tins’) were deployed at potentially suitable reptile basking sites. The tins consisted of 50 x 50cm squares of heavy-duty roofing felt.

The reptile surveys confirmed the presence of Common Lizard within coastal grassland habitat alongside the seawall to the south of Queens Dock. Common Lizards were discovered in low numbers on eight of the eleven visits. On each of these occasions one to two individuals were recorded with the exception of a visit in late May 2013 when six individuals were recorded (four adults / two juveniles). Using the criteria of Froglife (1999) the discovery of 5-20 individuals of Common Lizard during any one survey visit is considered to represent a ‘Good’ population.


Open water with the potential to support breeding amphibians is limited within the study area for the Project. Irregularly inundated ditches and hollows at the northern edges of Crymlyn Burrows support wide ranging species, particularly Common Frog and Palmate Newt (URS, 2010b). However, the presence of Great Crested Newts is considered unlikely due to absence of suitable breeding ponds.

  • Invertebrates

Invertebrate survey

The invertebrate survey focused on investigating habitat associated with the estate of the Port of Swansea ("Docks Estate") largely comprising brown-field land supporting areas of hard-standing as well as grassland habitat and small areas of scrub. Two-intensive moth–trapping visits were undertaken in July and early August 2013. Incidental invertebrate records were also taken during botany and reptile survey visits.

Incidental records of invertebrates made during site visits to Swansea Docks, particularly during warm weather of June to August 2013 included the Small Heath, Large White, Green-veined White, Small Blue (Cupido minimus), Meadow Brown (Maniola jurtina) and Common Blue (Polyommatus icarus) butterflies, Common Field Grasshopper (Chorthippus brunneus) as well as a Click beetle (Agrypnus murinus) (a species associated with coastal grasslands).


The invertebrate surveys recorded a relatively diverse fauna of common or locally common species, reflecting the mosaic of semi-natural habitats present. A review of the habitat preferences and food plants associated with the section 42 NERC 2006 and localised species found during the 2013 surveys suggested a correlation with coastal grasslands communities present within the docks.

Reports and Papers

All detailed survey reports can be found in the relevant ES chapters and appendices which can be downloaded from here

Post-Installation Monitoring: Swansea Tidal Lagoon

General Description:

Additional data will be collected to support the validation of each of the impact assessments in the Environmental Statement. In addition, as a first of a kind project, data will also be collected to manage uncertainty and to provide further understanding of the Project and its interaction with the environment. The results of the monitoring will be reported through the Adaptive Environmental Management Plan (AEMP) process to the relevant stakeholders through which, and where necessary, appropriate adaptation in monitoring and/or management measures can be implemented. The developer plans to undertake pre-construction, construction and operational monitoring. The information provided below focuses on construction and operational monitoring. Proposed pre-construction monitoring is included where deemed appropriate. Please note, as this environmental management plan is an adaptive document it may have changed since submission to Tethys. The wording below reflects the latest position at the time of writing (June 2016).

ReceptorMonitoring Program Description Design and Methods Results Status
  • Physical Processes

Multi-beam bathymetric surveys and side-scan sonar to monitor broad scale changes within Swansea Bay

Multi-beam bathymetric and side scan sonar surveys will be used to detect any broad scale changes in bathymetry as a result of the project. The area offshore between Mumbles Head and Sker Point, extending to the offshore disposal grounds will form the extent of the wider study area.  Prior to construction, data from 2017 UKHO surveys of this area will be supplemented by site specific survey to provide coverage across the whole area.  A 100m line spacing will be used across sensitive receptors and 200m line spacing elsewhere. Targeted surveys will be then be undertaken in year 3 of marine construction and years 1, 5 and 10 operation. Data will be reported and reviewed through the AEMP process.

  • Physical Processes

Fixed point photographic record along  the lagoon walls

Photographic record at fixed points, of 100m spacing, along the external faces of the western and eastern lagoon walls, and the internal face of the eastern lagoon wall will be undertaken. The photographs are to observe potential erosion or accretion of sediment in the immediate areas of the structure and to provide a visual record of any changes observed. The photography is not meant to be a quantitative assessment, but provides a qualitative record of changes as the lagoon wall is constructed and over the years of operation which can be used to inform the assessment of intertidal changes and associated effects on sensitive receptors identified, including adjacent to Crymlyn Burrows SSSI where the potential for accretion of sediment was predicted along the external eastern lagoon wall.


Photographs to be taken in both the spring and autumn during the marine construction period. Repeat photographs will be taken spring and autumn post-construction for the first five years of operation, to monitor any changes in sediment accretion/erosion.  If notable adverse weather occurs such as high intensity storms, additional photographic records will be taken, as considered necessary, by the lagoon operators to inform lagoon maintenance activity.   Photographs will be taken from the top of the lagoon wall facing out to sea or into the lagoon (eastern breakwater). At each location three photos will be taken to provide left, right and seaward or lagoon shots.


The photographic record will be analysed and reported to NRW, CCSC and NPTCBC on an annual basis, through the AEMP process.

  • Bathymetry

Bathymetric surveys and Argus silt meter to monitor siltation within the lagoon

The ES for the Project predicted that during operation, sedimentation will occur within the Lagoon footprint, as a result of water being held within the lagoon to allow generation.  The objective of the surveys is to monitor extent and rates of sedimentation within the lagoon footprint, to increase understanding of lagoon operation, to provide evidence and advice on operational procedures and to inform fleet lagoon developments.


A multibeam echosounder bathymetric survey will be undertaken of the lagoon footprint immediately following completion of lagoon construction ‘out survey’. The survey will be undertaken by the appointed contractor to provide an updated construction baseline.


Surveys within the operational lagoon are proposed annually for the first three years of operation, with the frequency to be reviewed thereafter to tie in with anticipated maintenance regime as determined by the operators of the lagoon.


An Argus Silt Meter will be deployed to measure deposition/turbidity profiles within the lagoon. The survey will be carried out during year 1 of operation.

  • Coastline

Monitoring changes in the intertidal area using beach profiles, Rapid Geomorphological Assessment (RGA) and sediments

Historically beach profiles within Swansea Bay have been monitored by Swansea and Carmarthen Bay Coastal Engineering Group (SCBCEG) either once or twice a year. A high level overview of existing data gathered by SCBCEG for the sites within Swansea Bay between Mumbles and Kenfig Burrows was undertaken for the EIA.  Subsequent to this, detailed analysis of historic data has been carried out by University of Wales Trinity St David's (UWTSD) on behalf of TLSB, to determine recorded variation at each profile. A software has been developed by UWTSD, such that future beach level data can easily be compared against the historic data to detect change outside that previously recorded. 


In autumn 2015 TLSB commissioned a pilot survey of the sites and subsequently commenced annual monitoring of 31 sites in Spring 2016.   The results of the annual surveys and analysis will be contained in the AEMP Annual Monitoring Report. Where appropriate the annual report will make recommendation for beach management.


Annual targeted sediment samples have also been included in the beach monitoring surveys.  PSA data is classified according to Folk (1954) and any changes in classification over the years will be reviewed.


Finally, RGA will be undertaken along dune frontage where present. 


Data from the coastal process monitoring will also be reviewed in combination with data collected from other subject areas such as marine ecology, coastal birds and coastal ecology and the results will be reported through the AEMP process.

  • Physical Processes

High resolution aerial survey

Initial high resolution aerial survey between Mumbles Head and Sker Point was undertaken in Autumn 2014. Further high-resolution aerial survey data of the coastal zone in Swansea Bay using a photogrammetric-grade, multispectral camera will be acquired prior to construction.  Data from this survey will provide information on potential changes in substrate distribution, broad scale beach changes (movement of sandbars), intertidal habitats and beach profiles.


Further surveys will then be undertaken in year 3 of marine construction and year 1 and 5 of operation.  Data will be reported in the relevant survey year and will be reviewed through the AEMP process.

  • Physical Processes

Wave reflection and currents

It is proposed that Nortek Acoustic Wave and Current (AWAC) devices will be deployed at

two locations over three months in the winter in the first year of lagoon operation.  The AWAC devices will collect data on waves, water levels, current profiles and suspended sediment (acoustic backscatter), combined with Optical Back Scatter (OBS) for suspended sediment (turbidity). The devices will be deployed to obtain three months of oceanographic field data at two locations in the first year of operation. Site 2 is located within the lagoon footprint.  Site 1 is to be re-positioned in the west of Swansea Bay to examine residual flows in this area.

  • Physical Processes

Currents from turbines and sluice gates

Data will be collected across the turbine and sluice gate housing structure to provide spatial current data using a vessel mounted Acoustic Doppler Current Profiler (ADCP).

The survey will focus on three identified survey areas:

a) Inside the lagoon focusing on the inlet;

b) Inside the lagoon looking at the general flow pattern; and

c) Outside lagoon flows.


Surveys will be undertaken over a flood – ebb tidal cycle once on a spring tide and once on a neap tide. This would provide spatial current data as opposed to fixed point temporal data which is collected by the AWAC deployments. The spatial ADCP survey could also be used to provide more detailed information on flow patterns within the lagoon as a whole, as well as to measure backscatter intensity, which would provide an indication of turbidity in the water column.

  • Water Quality

Bacteriological water quality within the lagoon.

With the proposed extension of the DCWW Waste Water Treatment Works LSO to discharge outside of the lagoon, the key bacterial load into the lagoon will be removed and 'excellent' water quality (as defined by the BWD, 2006) is predicted within the impounded area. This monitoring will confirm whether this ‘excellent’ water quality has been achieved and the routine data will be used to inform and manage uses within the lagoon.


Lagoon tidal cycle bacterial monitoring (Faecal indicator organisms, FIO) - during operation, water quality samples will be taken at hourly intervals over a full tidal cycle (13 hours). The survey will be repeated for dry weather and wet weather conditions and over spring and neap tides in summer and winter, for the first year of operation.


Routine water quality sampling in lagoon - during operation, water quality samples taken at fortnightly intervals between 1 October and 14 May, and then weekly in the bathing season (as set out within the revised BWD), from 15 May to 30 September, for the first year of operation. Depending on monitoring results and future use of the lagoon as a bathing water, ongoing surveys will only be undertaken within the bathing season (from 15 May to 30 September).

  • Water Quality

Nutrient levels within the Neath Estuary, Tawe Estuary and Swansea Bay; and to monitor chlorophyll levels within the Lagoon

The primary reasons for the monitoring are three fold:

1) to monitor the nutrient levels within the Neath and Tawe Estuaries during pre-construction, construction and operation and within Swansea Bay once the lagoon is operational;

2) to monitor Chlorophyll levels within the lagoon once operational; and

3) to inform and validate the WFD compliance assessment.   


Dissolved Inorganic Nitrogen (DIN) sampling commenced within the Neath and Tawe estuaries during July 2015. Data on temperature, conductivity, salinity, dissolved oxygen and turbidity was also recorded. Sampling is undertaken monthly pre-construction.  Sampling will also be undertaken monthly during offshore construction and the first two years of operation.  A sample will be collected at the western extent of the lagoon, outside of the breakwater, once the Project is operational. 


Chlorophyll will be also sampled within the lagoon at three inshore monitoring locations, monthly for the first two years of operation. Results will be reported within the project AEMP.

  • Intertidal Ecology

Surveys of seawalls – to monitor colonisation of the lagoon breakwater, the success of intertidal biodiversity offsetting measures and the presence of  invasive species

Intertidal and subtidal transect, quadrat, rocky shore, rockpool and UAV (drone) surveys  

will be undertaken on the lagoon breakwater and intertidal areas within the lagoon footprint (including translocation and biodiversity offsetting measures).  In addition, intertidal and subtidal transect and quadrat surveys by drop down camera will be undertaken of the lagoon breakwater and biodiversity offsetting measures. 


Surveys will be undertaken each spring and autumn during marine construction commencing in the first spring or autumn after the placement of each offsetting measure (and during summer for the S. alveolata UAV surveys). During operation, surveys will be undertaken spring and autumn each year for the first three years.


Results of any marine INNS monitoring will be reported to inform the Marine Biosecurity Risk Assessment (MBRA). Transects will be located along the internal sections of the breakwater, however, where feasible, external transects will also be established where health and safety considerations allow. Control (reference) sites will also be monitored to examine natural variation. Surveys will also consider rocky shore macroalgae in accordance with WFD-UKTAG (2014) guidance and a taxon list for macroalgal species will be recorded.

  • Intertidal Ecology

Sabellaria aveolata

Monitoring will be undertaken of the Port and Tawe Sabellaria alveolata reefs within Swansea Bay. a range of baseline surveys will initially be undertaken as follows:


Reef UAV (drone) surveys: high resolution aerial imagery and topographical data will be collected to establish a baseline of the Tawe and Port reefs (and the reference reefs Afan, Dunraven and Porthcawl) as well as establishing the distribution of each reef formation across each reef. 


Reef quadrat and core sampling surveys: Rapid assessment (presence/absence) of the key epifaunal species associated with S. alveolata reef set out in the SAC Regulation 33(2) Advice document (Natural England and Countryside Council for Wales, 2009), and adapted based on the Site Characterisation survey findings, will be undertaken prior to construction. Quadrat surveys as well as collection of a series of small cores (5 cm in diameter) at 3 locations within each reef category on each reef will be used to determine the average number of live S. alveolata worms and associated infaunal assemblages within each reef formation and health category.


Water sampling survey – plankton larvae and water quality (food): Baseline monitoring of S. alveolata plankton larvae within the water column has been undertaken (May 2016 – May 2017).


Drone surveys and reef quadrat and core sampling surveys will be repeated throughout marine construction and for the first 3 years of operation at the Port and Tawe reefs and at the reference reefs:


Water sampling survey – larval supply and water quality (food) surveys will be undertaken monthly in Year 2 of operation.

  • Invertebrates


Targeted oyster dredge trawls within the footprint of the lagoon will be undertaken prior to marine construction. These works will form part of the marine contract package for the construction of the Lagoon.  Any native oyster collected will be transferred to a safe location for the duration of construction. Once the lagoon is complete the oysters will be relocated.


The successful production of offspring from oysters is affected by many variables, including site specific factors and the condition of the oysters. As such the oyster enhancement programme will be adapted.


The production of spat in hatcheries is a well-documented process. However, the physiological condition of oysters differs and the process has to be trialled and optimised. The preliminary aim is to stock 3-5 discrete areas inside the Lagoon with oysters from spatting ponds introduced and/or a hatchery. The exact location depends on sediment and hydrodynamic conditions within the lagoon. It is anticipated that there will be suitable subtidal areas, but possibly also intertidal areas; in Swansea Bay native oysters are naturally found in lower intertidal areas, although in low numbers.


The growth and survival of oysters inside the lagoon will be monitored and recorded. The extent to which the created oyster reefs support biodiversity compared with other habitats will be assessed.

  • Intertidal Ecology

Broadscale changes in intertidal marine ecology

Following the high resolution aerial survey an intertidal biotope map will be produced using the aerial imagery. Subsequent to this intertidal benthic ecology surveys will be undertaken to ground-truth the aerial imagery between February to June (inclusive) prior to marine construction, and in years 1 and 5 of operation.


In addition, walkover surveys will be undertaken to identify any presence of opportunistic macroalgae and algal mats in the western part of Swansea Bay. Walkover surveys will be undertaken in the first three years of operation in year 5 operation.

  • Benthos

Benthic surveys to monitor broad scale changes in subtidal ecology within Swansea Bay

Baseline subtidal benthic surveys will be undertaken inside and outside the lagoon footprint within Swansea Bay, prior to marine construction and then ongoing subtidal benthic sampling surveys are proposed in year 1 and 5 of lagoon operation. The surveys are to be conducted between February and June (inclusive) of the relevant year.


The sampling sites have been positioned to provide representative samples from the key substrates and habitats present in line with a Before-After-Control-Impact (BACI) approach, and based on the primary and secondary impact zones of the Project as recommended by Ware and Kenny (2011). 


Analysis of the samples will follow WFD-UKTAG (2014) guidance, with the samples collected during the sampling campaigns being sieved through a 1mm mesh. Within the lagoon footprint where finer sediments may be expected, a 0.5mm mesh will also be used together with the 1mm mesh. The need for on‐going double sieving of samples within the lagoon footprint will then be reviewed as part of the AEMP review process.  The findings will be analysed together with the results of the coastal processes studies to examine the effects of the Project. 


Native and marine INNS will also be recorded through the above surveys and reported through the project AEMP process.

  • Fish

Fish surveys to monitor any broad-scale changes in fish fauna assemblage within Swansea Bay and gain an understanding of the fish diversity associated with the breakwater.

The ES predicted that the lagoon may have an effect on fish populations in Swansea Bay, primarily through habitat modification and potential changes to bed composition, as a result of changes to the hydraulic regime. This could lead to broad-scale changes in fish assemblages. The ES also reported that the lagoon breakwater will introduce rocky reef habitat which may increase fish and shellfish biodiversity, potentially improving ecological and ecosystem diversity within Swansea Bay post construction.


Intertidal and subtidal fish baseline surveys have been undertaken in autumn 2015 and autumn 2016 and will be repeated in the autumn prior to marine construction.

The methodologies and sampling locations used for the pre-construction surveys are the same as those used for the EIA.


The intertidal and subtidal fish surveys would be repeated in the autumn during operation. The surveys would commence when the intertidal and subtidal benthic ecology reaches an equilibrium status, following marine construction and early operation. The surveys which will take place over an approximately 5-year period, aim to gather data to detect any broad-scale changes post-construction with sufficient confidence and power levels.


Drop down camera surveys are also proposed to be undertaken during the operation of the Project, to record fish associated with the lagoon wall, and where possible to identify behaviours that occur as a result of the structure, to inform fleet lagoon projects. Drop down camera surveys will be undertaken as part of marine ecology surveys. In addition to this survey, data collected from anglers using the lagoon wall will be recorded where possible. Angling catch data would be utilised to further understand fish population diversity within the vicinity of the lagoon, such data would inform a qualitative view in terms of species present and the identification of any new species to the area.

  • Fish

Herring spawning

The provision of spawning media on the foot of the Western landfall was proposed within the ES to provide further diversity of spawning habitat and to mitigate the potential losses under the lagoon wall. With consideration of the application of such mitigation measures, the ES concluded impacts would be not significant. The ES also concluded that the breakwaters of the lagoon would provide a range of suitable spawning habitat which would be available for any spawning herring following construction of the Project and this was considered a potential positive impact of the Project. However, to confirm the implementation of the mitigation, targeted surveys are proposed.


Baseline ichthyoplankton Monitoring Trawls have been undertaken February to April 2015, February to April 2016 and January to April 2017. To date no evidence of herring spawning within the bay has been recorded. Survey will also be undertaken February to April in year 2 of operation.  If herring larvae are recorded in any samples, the location of herring spawning will be determined using the Langrangian particle tracking model.


In addition, intertidal and subtidal transect and quadrat surveys will be undertaken by drop-down camera. The surveys will be of the lagoon seawall and targeted surveys of biodiversity offsetting measures. The drop down camera survey will be undertaken to examine the condition (presence and extent) of the herring spawning media provided. The presence of any herring in the vicinity of the media will also be recorded for information.

Herring spawning

  • Fish

Surveys in development

Further fish monitoring proposals are in development in consultation with the relevant advisors associated with the project Marine Licence determination. These surveys are likely to include but will not be limited to:

  • Monitoring in the vicinity of the turbine house and sluice gates
  • Fish telemetry studies
  • Monitoring of migratory species in rivers


This section will therefore be updated once this process is completed.

  • Fish and Fisheries


Angling catch data would be utilised to further understand fish population diversity within the vicinity of the lagoon. Data would inform a qualitative view in terms of species present and the identification of any new species to the area.


In addition, it is proposed to hold angling competitions and for information about fishing effort and fish caught e.g. numbers, species, size, etc. to be recorded.

  • Marine Mammals

Harbour porpoise usage surveys

A long-term acoustic monitoring programme for harbour porpoises has being established in the proposed Lagoon footprint and the wider Swansea Bay area. These surveys commenced in 2014, to examine the use of Swansea Bay by harbour porpoises, and to determine if there are any seasonal patterns to usage.


Baseline data using C-PODs has been collected at up to six sites within Swansea Bay since February 2014. The data collected from the CPODs were discussed and reviewed with NRW(A) in July 2015 and the layout revised to allow monitoring over a gradient at increasing distances from the source of potential impacts.  The on-going baseline monitoring comprises the deployment of four C-PODs at the following locations: Mumbles Head, DCWW outfall extension, Kenfig Patches and Scarweather Sands.


The surveillance data collected will be used to understand variability in site usage by harbour porpoise while taking into account factors such as time of day, time of year, tidal state and phase of the Project. Interim reports will be prepared following each CPOD deployment period (approximately 3-4 monthly) summarising the data collected.


In depth analysis of the data will take place at the end of each phase of the Project, i.e. pre-construction, construction and at intervals throughout operation. These will include information on harbour porpoise trends in use of the area (for example in relation to time of day or tide) and include comparisons between deployment locations, periods and phases of the Project.


Monitoring will continue during construction and operation. The results of the surveys will be reported through the project AEMP process and will be used to inform the subsequent monitoring strategies.

  • Marine Mammals

Monitoring marine mammal interaction with the turbine house/sluice gate structures

The purpose of the monitoring is to record marine mammal presence in close proximity to the turbine and sluice gate housing structure, and if required, to verify the effectiveness of Acoustic deterrent devices (ADDs) or Acoustic Startle Response systems (ASRs) in reducing marine mammal presence in close proximity to the turbine and sluice gate housing structure and to also to reduce the risk of entrapment within the lagoon.


Review of potential monitoring and mitigation systems for marine mammals has been undertaken and the use of a detect and deter system utilising active tracking such as sonar, in combination with Acoustic Deterrent Devices (ADD) or Acoustic Startle Response systems (ASRs) was identified as a potential monitoring system for the Project. Turbine monitoring is necessarily adaptive and will therefore be managed through the AEMP as set out within this Objective.


The need and type of monitoring system required will continue to be developed in consultation with relevant advisors taking into consideration: Research into other deployed marine renewable devices now and in the future and their effects on marine mammals.  Additional research and development into detect and deter systems that will be suitable for use for the Project will also be reviewed and this will include any updates to designs of the devices, development of detection and deterrent systems, appropriate field trials and installation requirements on the Project, to ensure that they will be an effective form of mitigation; and noise data for Project specific turbines.


Discussions are ongoing with relevant advisors regarding the final operational monitoring system and this will be established and agreed prior to operation of the Project.

  • Marine Mammals

Marine noise monitoring

Mitigation proposals for impact piling are described fully in Chapter 23 of the ES. These include the use of the JNCC (2010) protocol for piling activities (soft start procedure) if impact piling is required, the presence of a Marine Mammal Observer and the use of passive acoustic monitoring.

The primary reasons for monitoring are as follows:

  • To collect construction noise data primarily for percussive piling to increase knowledge of marine noise associated with construction of tidal lagoon projects and more generally, for marine developments; and
  • To collect marine noise data generated from variable speed turbines to inform other objectives, within the Project AEMP, and to increase knowledge for fleet tidal lagoon projects.


Marine noise data will be collected and compared with the values used within the ES for construction plant and activities, and the operational turbines.


Baseline underwater noise measurements undertaken in April 2013 at five locations around Swansea Bay for the Project EIA.   Monitoring of construction-related sound emissions for percussive piling will be undertaken.  Surveys will also consider noise arising from dredging works and rock armour placement activities. During operation, noise monitoring of the bulb turbines at varying distances will be undertaken with data collected across the tidal operating regime.

  • Sea and Shorebirds

High tide and low tide counts

The primary reason for surveys are as follows:

 To qualitatively understand potential changes in bird numbers and any possible re-distribution within Swansea Bay as a result of the Project, with particular focus on sanderling and ringed plover features of Blackpill SSSI; and to understand potential links between changes in beach habitat, intertidal biotopes and numbers of sanderling and ringed plover in the Bay, with particular focus on Blackpill SSSI.  As such a programme of surveys has been developed to further understand bird numbers and distribution within the Bay, with particular focus on sanderling and ringed plover.

Baseline surveys include:


·         WeBS style mid-tide counts – over passage period and winter period, August 2014 to May 2015 and from August 2015 to May 2016;

·         High-tide (core) and Low-tide WeBS counts - over passage period and winter period, August 2014 to May 2015 and from August 2015 to May 2016;

·         Over-wintering High-tide (core) WeBS count and Low-tide WeBS counts completed on a monthly basis (October 2011 – March 2012, September 2012 – March 2013). Additional surveys carried out in the east of the survey area (between the River Tawe and River Neath) in the summer of 2013 (April-August 2013). The 2014/15 surveys covered the same area as that undertaken for the ES i.e. from Mumbles Head round to Baglan Bay. The 2015/16 survey area was extended to cover Aberafan Sands, in particular to assess the use of the habitat by sanderling, which have been regularly recorded in numbers of national importance in other areas of Swansea Bay.


The following surveys will be undertaken during construction and operation:


High-tide (core) and Low-tide WeBS counts  – Monthly over the passage and winter period every other year during construction, starting during (terrestrial) construction. All surveys to cover the existing WeBS count sectors (in line with ES) and to be extended to include Aberafan Sands; and

High-tide (core) and Low-tide WeBS counts – Monthly over the passage and winter period during operation in years 1, 3, 5, 7 and 10. All surveys to cover the existing WeBS count sectors (in line with ES) and to be extended to include Aberafan Sands.

  • Coastline

Monitoring of the frontal dune system of Crymlyn Burrows SSSI

The frontal dune system of Crymlyn Burrows SSSI will be monitored to understand if any changes to habitat condition or extent can be linked to the Project through associated changes in coastal processes. Information gathered will be used to inform decisions over management practices of the SSSI dune frontage and management of the artificial dune system created within the Project footprint.


A frontal dune survey undertaken in June 2015 provides a detailed baseline survey. During the frontal dune survey vegetation mapping, fixed transects and quadrat data will be collected. Other features such as notable plants, invasive species and strandline invertebrates will be recorded where present.  The survey will be repeated in late spring/early summer prior to marine construction of the western breakwater.


A further survey will be undertaken prior to construction of the eastern breakwater with further surveys undertaken in years 1, 3, 5, 7 and 10 of operation (after which a substantive review will be undertaken). Surveys to be undertaken during late spring/early summer. Coastal process survey results will inform the review of data and data will be reported through the AEMP process.

  • Coastline

Monitoring dune systems of Swansea Bay Site of Importance for Nature Conservation (SINC)

An initial baseline dune condition survey (vegetation mapping, fixed quadrats, and recording of other features) was undertaken in June 2015.  The survey will be repeated in late spring/early summer prior to marine construction. Beach level and RGA data for the area will be reviewed.  Further dune condition surveys will be undertaken in the event that the data review indicates erosion/stabilisation of dune frontage outside natural variation.

  • Coastline

Surveillance of habitat creation areas within the lagoon

Surveillance of features created within the lagoon will commence in the year following completion of the construction of the habitats or in year 1 of operation, whichever is sooner. Surveys include:


·         Vegetation and habitat condition surveys of new habitat to determine colonisation and eventual condition of the habitats in the year following completion of the construction of the habitats or in year 1 of operation, whichever is sooner, then in years 1 (if required), 3, 5, 7 and 10 of operation (when a substantive review will take place).

·         Terrestrial invertebrate surveys of the created coastal grassland and dune habitats at a frequency determined by the suitability of the habitats to support invertebrates. These surveys will commence in the year following completion of the construction of the habitats or in year 1 of operation, whichever is sooner, then in year 1 of operation (if required) and repeated in years 3, 5, 7 and 10;

·         Strandline invertebrate surveys of new beach along the beach creation area at the same frequency of the terrestrial invertebrate surveys; and

Reptile surveys between April and October in years 5, 7 and 10 of operation of the restored/created grassland habitats after which a substantive review will take place.

  • Terrestrial Ecology


In order to confirm the continued use of foraging habitat by bats, it is proposed that remote bat detectors (anabats) are deployed for at least a week duration, bi-annually (between May and September), for three years post-construction. In addition, use of the lagoon wall by foraging bats could also be determined over the same time period using a hand-held bat detector.

  • Marine Mammals


Proposed mitigation measures to ensure potential impact to Otters is minimised include avoidance of light spill onto open water of the docks and exclusion of high risk construction areas whilst maintaining access for Otters between the docks estate and coastline. These proposals will require monitoring during the construction phase.

Reports and Papers

Adaptive Environmental Monitoring Programme, 2014.

The Adaptive Environmental Management Plan, is a live document designed to monitor the project and its interactions with the environment throughout its 120 year generating life. Since the close of the examination and DCO Consent the document has been updated in consultation with relevant statutory advisors. The information contained within this datasheet reflects the latest position. However, there is potential for the monitoring surveys listed within these sections to change and the text provided does not represent the final text. Currently it is anticipated that the final AEMP will be formally submitted in January 2018.

Research N/A
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