Hydropower

If, as most people now accept, global warming is a reality, surely any way of producing renewable natural energy to help reduce our carbon footprint would hugely benefit the planet?

Tidal energy is a reliable source of energy, providing power for around 10 hours a day, when the tide is flooding and ebbing. However, building the equipment to harness this energy can be very expensive, and devastating to life up and down stream of the development.

Severn Barrage Proposal

A project that can harness the energy created by the second biggest tidal surge in the world, eventually providing up to 5% of the country’s total electricity requirements, should, in theory, be supported by us all. However, closer inspection of the environmental impact of such a massive scheme is leaving fisheries interests and conservationists in a cold sweat and, indeed, it is even being questioned as to its legality. Are we seriously suggesting that we should try and mitigate the affects of global warming on the ecology of our planet by designing projects which, in their own right, heavily impact precious habitats and their dependent species? Isn’t that the ultimate indictment of the way we are managing our natural resources, and shouldn’t it act as a wake-up call to those with a genuine interest in such issues, that we must do all in our power to stop this sort of madness continuing in our name?

The Government feasibility study into the controversial Severn Barrage proposal is now under way. The study is set to investigate the practicality, both economically and environmentally, of building a barrage between England and Wales. It is predicted the £15 billion project would produce up to 5 per cent of UK energy; however this would come at a huge environmental cost, with the loss of important wildlife migration corridors, including fish, and intertidal habitats.

The Severn Estuary is a globally unique system, with the second highest tidal range in the world, second only to the Bay of Fundy in Nova Scotia. It is one of the most important and highly protected sites in Britain. The Estuary is extremely important for migratory fish, on their way to freshwater spawning sites in the SAC designated Rivers of the Usk and Wye, and returning to the sea. These fish include species protected under the EU Habitats Directive; salmon, allis and twaite shad, sea and river lamprey, as well the socio-economically important sea trout, and endangered eel. The Sustainable Development Commission (SDC) report concluded that the local populations of all these species could face extinction with the creation of a barrage, which would act as a physical barrier to movement and would also result in environmental and water quality changes.

On October 1st 2007, the Sustainable Development Commission published its report into the feasibility of a Severn Barrage, and in it they acknowledged that the barrage could affect fish populations in a number of ways:

• It would create a barrier to migratory fish – salmon, sea trout, shad, lamprey and eels
• The Environment Agency estimates a ‘high to very high’ mortality for migrating salmonids passing through the generating turbines
• Important marine species would have spawning and feeding areas impacted – bass and mullet amongst them
• Water quality would be seriously affected, including oxygen levels, turbidity and the build up of contaminants trapped above the barrage
• Noise and pollution levels will rise significantly during the construction period, with a massive carbon footprint before even an amp of electricity is generated

However, the report also stated: “Further detailed studies would be required of the possible impacts on (fish) species, especially those which are designated (under EU law) or of commercial or recreational importance.” The reference to ‘recreational’ importance is a satisfactory conclusion to some hard lobbying by fisheries interests, and at least acknowledges the importance of angling to the region within such a huge concept as the Severn Barrage.

Severn estuary is also hugely important for its intertidal habitats, which are designated under the EU Birds Directive, as key feeding and roosting habitats for a wide variety of bird species. For example the world famous Slimbridge refuge, home to over 60,000 water birds, which feed on the mud flats at low water, could also be affected by the development of a Severn Barrage.

Intertidal habitats are also now widely recognised as vital habitats for fish, by providing feeding, refugia and nursery areas for juvenile fish. Intertidal habitats are dynamic environments, which are utilised by both freshwater and marine fish species, depending on the tidal and freshwater flows. In addition, intertidal habitats deliver a range of other invaluable environmental services, such as nutrient and carbon storage, and flood and storm defence (see: Intertidal Habitat).

Under EU law, the loss of wetland areas lost to the barrage would have to be replaced by developing compensatory sites elsewhere. However, mitigating environmental damage through compensatory habitat on this scale is very concerning. Recreating intertidal habitat for small-scale port developments may be a workable solution, but to try and reimburse the destruction of an entire ecosystem is completely untenable. Replicating lost salmon and sea trout runs would be impossible, as would the creation of additional safe havens for the other impacted fish species, both migratory and marine.

The environmental changes within the estuary associated with the barrage could also significantly impact important commercial marine species utilising in the estuary, such as bass, mullet, pollock, sole, flounders and sprat.

The S&TA, was one of eight UK NGO’s (others included WWF, RSPB and National Trust) to commission a study by Frontier Economics, to analyse the barrier proposal. The report concluded that the barrage would be an expensive way of generating renewable electricity compared to alterative technologies also capable of meeting the Governments renewable targets. This report highlights that economically, as well as environmentally the Severn barrage is not justified.

Whilst we appreciate the urgent need to address climate change, we do not believe the irreversible damage to important natural habitats and species, which would result from the Severn barrage, can constitute a sustainable solution. We urge the government to investigate other smaller ‘green’ energy options which could increase renewable energy, but at far less environmental risk.

S&TA believes the Severn Barrage to be non-sustainable. Suffice it to say that, with our environmental partners, we will do all in our power to see that funds are spent in a more cost effective way, and without the extreme impacts on our ecology that some others seem prepared to accept. The S&TA is representing these fisheries views in the current rounds of stakeholder workshops, as part of the Severn Estuary Tidal Power Feasibility Study.

For further information see;

Hydropower Briefing Paper
Fish Passage Briefing Paper
Hansard Report on Hydropower and Fish Passage Debate
S&TA Humber River Basin Management Response
Severn Tidal Power Feasibility Study Update (2008)
Frontier Economics (2008).
BERR. (2008). Severn Tidal Power Q&A
Parsons Brinckerhoff (2008). Strategic Environmental Assessment of proposals for Tidal Power development in the Severn Estuary.