Huge ecological impact from Thames estuary airport
The Airports Commission published yesterday a study assessing the environmental impacts of a new hub airport in the Thames estuary.
The ecological, habitat and wildlife impacts would be – in a word – huge.
“would result in a large scale direct habitat loss to Thames Estuary and Marshes SPA and Ramsar sites
would not be possible to mitigate in close proximity the sites mainly due to bird strike risk, geomorphology changes and flood risk,
A minimum of around 2130 hectares (ha) is likely to be needed for habitat compensation .. An upper estimate of 6800ha attempts to capture some of the potential indirect losses.
The road and rail links to the airport are also likely to result in additional direct losses to Natura 2000 sites and these are therefore likely to add to the total area required for compensation.”
The report also recognises the fact that it is never possible to fully replace the habitat and wildlife lost by compensation schemes. Surprisingly, the report does not point out that nearly all compensation schemes which seek to provide a particular habitat with its suite of species do so a cost to other habitats and species.
The ecology section of the summary report is reproduced below. The full report can be found at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/326986/impacts-study-1.pdf
Ecology section of report summary
While there would be no direct impacts on priority habitats as defined under the Habitats Directive, all the airport options proposed would result in a large scale direct habitat loss to Thames Estuary and Marshes SPA and Ramsar sites (as a minimum 24% & 27% of designation areas). Some sites would also involve direct loss to the Medway Marshes SPA and Ramsar sites (0-4% of designation areas).
Given the large scale of loss to the Natura 2000 sites, which would not be possible to mitigate in close proximity the sites mainly due to bird strike risk, geomorphology changes and flood risk, it is expected that any future appropriate assessment through the Habitats Regulations Assessment (HRA) would conclude that there are likely significant adverse effects on the Natura 2000 network.
Under the steps of the HRA process, the proposals would, therefore, be required to progress to the Alternatives Solutions test. The Competent Authority (Secretary of State for Transport) would need to be certain that no alternative solutions existed, had considered the best scientific knowledge and taken into account the representations of Natural England and Environment Agency. If this test is passed it would need to be demonstrated that the proposals were needed for Imperative Reasons of Overriding Public interest (IROPI).
In the event that the proposals were to be taken through the HRA alternative solution and IROPI steps, an acceptable package of compensatory measures would need to be developed. The compensatory measures would need to be created in advance and demonstrated to be adequate before losses occur. Key issues related to provision of adequate compensatory habitat include:
The compensation measures would need to allow for the full impact of the airport, including in-combination effects, on the Natura 2000 sitesThere are a range of additional sources of direct and indirect impacts, which can lead to further losses to the function of habitats in and around the Hoo Peninsula. These are difficult to measure at this stage without detailed assessment, field data or modelling and include:
– Bird strike management to reduce risk of bird strike to acceptable levels;
– Morphological changes to the estuary:
– Disturbance effects from airport operations and air traffic; and
– Compensation areas for other developments that are displaced.
A minimum of around 2130 hectares (ha) is likely to be needed for habitat compensation for the airport proposals and displacement of other compensatory habitat. An upper estimate of 6800ha attempts to capture some of the potential indirect losses. The road and rail links to the airport are also likely to result in additional direct losses to Natura 2000 sites and these are therefore likely to add to the total area required for compensation.
The compensatory habitat would need to be provided at least beyond the 13km safeguarding zone around the airport and it is recommended that habitat for birds is created beyond 20km.
Given the uncertainty with providing compensation habitat further afield it is likely that a ratio of gain for loss of greater than 1:1 would be required. Gain for loss ratios from other studies indicate that 2:1 and 3:1 ratios might be applied and possibly higher ratios might be appropriate where uncertainty is greater.
The Thames Estuary is part of a group of estuaries lying between the Suffolk coast and the eastern tip of the north Kent coast and is therefore the best area to focus on for potential compensation sites. There are several potential intertidal habitat creation sites associated with managed realignment policies along the Essex and Suffolk coast which would be the first area that should be considered. These potential land areas, however, are likely to reduce as constraints in terms of availability, suitability and additional impacts are considered. These would require significant study to determine realistic deliverability.
There is potential for providing adequate compensation in that it is technically possible, but the scale required is unprecedented in the UK to date and there is a high level of uncertainty given that the full requirement is yet to be understood. There is also significant uncertainty over the ability to deliver the functional quality of habitat to meet the needs of all species that might be affected. There is an added complexity in the ability to adequately provide the like for like combination of habitats – not just the habitat types in isolation but a mosaic of habitats for the requirements of some species.
The compensation habitat also needs to be provided in a geographic region which would support the species affected. In order to demonstrate deliverability, extensive studies would be needed over a large area and many years, including the affected site and the possible compensation sites. The uncertainty over successful compensation would remain until displacement occurs and sufficient long term monitoring data would need to be collected to demonstrate that compensation habitat had been successfully provided.
The cost of providing compensation habitat based on experience from other projects is estimated to be in the region of £70K to £100K per ha. Applying this to the indicative lower and upper ranges of compensatory habitat requirement and ratios from 1:1 up to 3:1, total costs could amount to £149million- £2.04billion.