Environmental impacts - Falmouth Docks Redevelopment Proposal

This is a summary of some of the environmental impacts of the proposed redevelopment of Falmouth Docks. These can also have a material impact on the town and Cornwall through their effects on our local economy amenity and health, which all rely on the health of our natural environment.

The marine ecosystems near the docks are nationally important, supporting England’s largest and best maerl beds, extensive seagrass meadows and kelp forests, the Fal’s unique and important sustainable native oyster fishery, seabird species, marine mammals including dolphins, porpoises, whales and seals, and commercial fish and shellfish species including lobster, crab, scallop, bass, pollack and thornback rays. They also support peoples’ amenity, health and wellbeing through being near, on and in the water, and countless businesses dependent on clean waters and our natural environment. The contaminants mercury, zinc, lead, copper, Polycyclic Aromatic Hydrocarbons (or PAHs), di-butly tin and tri-butyl tin (or TBT) have been found at the site at levels far exceeding those deemed safe for disposal at sea. TBT can bioaccumulate in molluscs and cause shell deformations, metabolic and cell stress and larval motalities, so poses a particular risk to the oyster, clam, lobster, and scallop fisheries. PAHs can cause DNA damage, oxidative stress and endocrine disruption, leading to cancer, reproductive failure, and developmental disorders.

The current application assesses the risks associated with the development based on modelling that uses very few measurements of contaminant levels and sediment and water flows and understates the operational impacts and the cumulative effect of all impacts taken together.

On contaminant measurements:

The site has an area of around 32 football pitches and a proposed dredge volume of around 250 olympic size swimming pools across which just 21 cores have been taken and sampled in a few places to provide 81 sample points in total. Contamination has been found in excess of thresholds for disposal at sea in 16 of these 21 cores and at a number of different depths. This very coarse sampling will have informed the estimate for how contamination is distributed across the whole site, which will affect both the modeling of contaminant spread and the risk of disposing excessively contaminated material at sea.

One sample found at depth and shown to exceed the level for disposal at sea has been discounted as anomalous and without proposing any further testing to validate this, despite this being modelled to be an area of high sediment deposition which could conceivably have buried contaminants. No explicit commitment or condition has yet been put forward to further test dredge materials prior to disposal.

On sediment and water flows:

The modelling of sediment and contaminant spread does not include resuspension of sediments, freshwater input or a range of weather conditions. Cornwall is subject to regular and extreme storms and conditions can change quickly, so newly exposed sediment mid-dredge or already suspended sediment due to dredging just passed could spread more significantly than modelled with greater adverse effects, and further spread contaminants. Fishers have also queried the tidal modelling due to their experience of flows in the multiple bodies of water that come together close to the docks, and the need for still conditions for Oyster reproduction, neither of which are consistent with the current tidal modelling.

Modelling of sediment spread as provided in planning documentation predicts large variations over the course of a day, with notable peaks. The same variation in time has not been provided for contamination levels. Contaminants including TBT have a environmental quality standard for maximum allowable concentration (MAC EQS). The planning documentation is only presenting time averaged values for predicted TBT contamination. The peak predicted values should also be provided and compared to the MAC EQS to demonstrate to what extent the models predict this will be exceeded outside of the site boundary.

While more modelling and some mitigation has been conducted for the dredge itself, the impact of disposal at sea has received less attention. Only the suspension and deposition of sediment has been considered in the vicinity of the disposal ground, not the spread of contaminants. As discussed earlier, the coarse sampling means that some of what is disposed of at sea may exceed the contamination safety threshold. The site is near the special area of conservation and fishing grounds which may then be adversely affected.

On operational impacts:

The environmental risks associated with each part of the development – the dredging, piling and construction, disposal of dredge materials, future operations of the port, are addressed in isolation in the application and many of them are claimed to have negligible or minor impact. The risk of sediment and contaminant spread during the dredging is identified as the one area with sufficiently high risk to merit mitigations, rather than considering the cumulative impact of all parts of the development together.

The operational impacts are also considerably understated. Regarding the impact from cruise, the applicant claims that the impact will not be much greater than at present. But the cruise passenger numbers on which most of the claimed economic benefits of the development are based forecast an increase from 45,000 a year in 2023 to 200,000 in 2030. Despite this, no estimate of the air pollution effects has been provided. There can also be marine pollution from scrubber wastewater – where scrubbers capture air pollutants which are instead disposed of at sea, and with greywater which can be filled with detergents and microplastics. It is believed that the regulation of these pollution sources is currently very lax.

Recommendations

If the development is to proceed further, the following measures are proposed to address some of the above issues:

• Further contaminant sampling before commencing works. Particularly in under sampled areas and in the vicinity of the contaminated sample claimed to be anomalous.
• In-situ testing of tidal flows and sediment spread in a range of conditions (including storm-like conditions) before commencing works to evaluate accuracy of sediment plume and transport modelling.
• Publication of peak contamination levels predicted by the existing models (particularly of TBT), and the extent to which this peak exceeds the MAC EQS.
• Full evaluation of operational impacts and monitoring and active management conditions to limit and compensate for their negative impacts.
• Putting in place effective monitoring and active management measures, as proposed by Natural England in their letter of May 2026.
• Habitat monitoring prior, during and after construction (as proposed by Natural England for after construction) with active management to pause works should adverse effects on marine life be identified.
• Dredge material to be handled with care to avoid leakage, and all dredge material considered for disposal at sea to be sampled for contaminants, with excessively contaminated material separated for disposal elsewhere.

Relevant documents

These comments are all based on the planning application documents, available on the Cornwall Council planning portal - application number PA25/01598 - under the Documents tab.

Of particular relevance are the documents uploaded on 10th September 2026 labelled "HRA - Habitat Regulations Assessment" (by Ramboll UK Limited) and "Consultee Comment" (by Natural England).