SPS Position on Fawley desalination plant

Southern Water (SW) believe that new sources of fresh water are needed to mitigate the risk of future water shortages driven by increasing population and more frequent extreme weather events. At such times, the amount of fresh river water that SW can now take from the county’s two main rivers, the Test and Itchen, has been restricted by the Environment Agency in order to safeguard river water quality.

Southern Water’s “Water for Life – Hampshire” programme has been considering a selection of options for creating greater resilience in their network to cover these expected shortfalls.

Three options have been investigated by SW. The first involved the transfer of existing water supplies by new pipelines, either from Portsmouth Water’s proposed Havant Thicket reservoir, or from outside the region, from Wessex Water or from Bristol Water. The second option was for the development of new waste water recycling facilities at either Budds Farm or Peel Common waste water treatment works while the third option was for the construction of a desalination plant to extract fresh water from sea water on the Solent shore.

During the preparation of their Water Resources Management Plan in 2018, SW selected ‘desalination’ as their preferred option following “extensive consultation with customers and stakeholders”. The extent of residential customer consultation was limited, amounting to just 100 customers and a ‘future customer’ group of 60 school children.

Earlier this year, Southern Water issued a ‘Consultation Brochure’ stating that their decision was to build a desalination plant near Ashlett Creek, Fawley. The ‘Water for Life – Hampshire Consultation Brochure’ is, therefore, the first real opportunity that the wider public community has had to pass comment on either the selection of ‘desalination’ as the preferred option and specifically, the choice of Ashlett Creek as the location for the development.

The brochure can be viewed by clicking the image below:

Southern Water – ‘Water for Life – Hampshire’ Consultation Brochure

Solent Protection Society has written a three-page letter to Southern Water, detailing our concerns about the direction being taken by Southern Water, with particular regard to the specific proposal to build and operate a desalination plant near Ashlett Creek.

Our main points are:

Environmental impact: The Water for Life Consultation Brochure does not consider the impact of an intrusive desalination plant on the visual amenity of Ashlett Creek or the shoreline environment and habitat.  Furthermore, it does not explain exactly where the plant would be, the area of development or the height of the buildings.  It is difficult to make any detailed response to the proposal without more information on the location of the particular site, the size of the plant, its impact on the local community, the noise impact during construction and while in use and, most importantly, the effect on the local environment and its wildlife. We believe that no amount of replanting and remodelling of the present saltmarsh and seabed will mitigate any development of this type.

The Beckton Desalination plant on the Thames Estuary. Photo – Acciona US

Proposed Capacity: Given the lack of detailed evidence in support of the Southern Water ‘Base Case’, we question the proposed capacity of the desalination plant. In the Consultation Brochure, they write that they “now have a shortfall of about 190 million litres of water per day during a 1-in-200-year drought event.” However, nowhere is it made clear how a ‘190 ML/D’ shortfall during a one-in-200 year event translates to a firm requirement for a 75 ML/D capacity desalination plant that will only be required during periods of shortfall. The consulting brochure states that: “Supply and demand computer modelling is still ongoing and is helping us understand how often the desalination plant would be required and the maximum flows during severe and extreme droughts”.

Impact on marine life: While wildlife in the sea is at risk of being sucked into the intake pipes or caught on the filter screens, the greatest impact to marine life would probably arise from the discharge of warm brine.  This can be damaging to marine life on and in the sea bed.  The amount of brine produced is often 150% of the volume of freshwater produced and in addition, the discharge often includes other chemicals which are toxic to marine life such as chlorine, used to control bacteria. 

Carbon neutrality: We question whether Desalination should be the preferred option, wherever it might be located.  It would be expensive to build and in operation would consume a large amount of energy which, for the foreseeable future, would still be sourced from conventional power stations.  At a time when our national priority should be to reduce global warming, the proposed desalination plant will increase the country’s output of CO2 instead of reducing it.  We question how this would be compatible with Southern Water’s statement (on page 7 of their brochure) that they have committed to become carbon neutral by 2030.

In summary

Solent Protection Society believe that there are clearly important outstanding considerations for the environment and its marine habitats that would make any Desalination plant unacceptable in the Solent region.  We consider that the alternative schemes should be re-examined while Southern Water accelerate their plans to reduce leaks of water in the existing network.

There is insufficient information to establish whether the other schemes would have marine implications but we would welcome the opportunity to examine them when further detail is available.

Ashlett Creek, Fawley (photographer Graham Rabbitts), and Lepe Beach (photographer Chris Edmonds)

Other reading:

“Londonist” Blog – Observations on the Thames estuary desalination plant at Beckton |