Heath ponds judicial review: High Court told dams are an ‘exceptional case’

Marc Hutchinson, Heath and Hampstead Society chairman, discussed the ponds project with then Environ

Marc Hutchinson, Heath and Hampstead Society chairman, discussed the ponds project with then Environment Secretary Owen Patterson (right) earlier this year. Picture: Polly Hancock - Credit: Polly Hancock

The Hampstead Heath ponds are an “exceptional case” and should not be treated like any other reservoirs, the High Court heard today.

The ponds project should be blocked because it will “seriously disfigure the Heath” and has not been produced on a “sound legal basis”, Stephen Tromans QC said.

Mr Tromans was laying out the case against the £15million ponds project on the first day of a judicial review hearing, which has been adjourned until tomorrow morning.

He argued that the ponds should be regarded as a special case and not subjected to the same standards of safety as newly built dams.

He said: “The dams withstood the worst the weather could throw at them for the past 250 years, including a very extreme storm in 1975 which experts estimated as being a more than 1-in-10,000-year storm in severity...

“They should have been considered an exceptional case because of a number of factors – historical and community importance, the statutory protection under the Hampstead Heath Act, and because they are unlike a large commercial reservoir.”

Mr Troman is appearing for the Heath and Hampstead Society, which is seeking to block the City of London Corporation’s scheme to radically alter the Heath’s landscape to prevent the dams failing in an extreme storm.

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The legal battle hinges on whether the City and its advisers are right to interpret reservoir legislation as requiring the “virtual elimination” of any risk from dam collapse.

This has been taken to mean that the ponds and their dams must be redesigned to withstand what is called the “probably maximum flood” (PMF) – an event with a 1-in-400,000 probability of occurring in any year.

The City argues that the ponds should be treated like any other reservoir and that this high safety requirement outweighs other considerations.

Mr Troman said: “The PMF is essentially the worst downpour that anyone can conceive – an unimaginably severe weather event.

“I can’t imagine what it would be like, and I doubt if anyone else can.”

He described the 1975 Reservoir Act, one of the key pieces of legislation covering the ponds, as being a “dog’s breakfast of an Act”.

The standard of “virtually eliminating” risk comes from guidance issued by the Institution of Civil Engineers, rather than directly from legislation.

Mr Troman criticised the “elevation” of this guidance into an “inflexible requirement” by the City.

He claimed that, in doing so, the City has failed to follow the Hampstead Heath Act of 1871, which protects the Heath’s “natural aspect and state”.

Mr Troman said: “Clearly this guidance carries significant weight, but the point is it’s guidance, it’s not an inflexible set of standards. At the end of the day, an engineer must exercise judgement.”

He added: “This is guidance framed to be applied potentially for all dams, however we would say that common sense suggests that one is going to apply it in a different way if looking at a new dam, than if looking at retro-fitting – at very severe environmental cost – works to an existing set of dams.”

Mr Troman also argued that any emergency flood safety measures which are in place, such as early warning systems, should not have been ignored by the City.

He also noted that, while the ponds project deals with a 1-in-400,000 risk, the sewers are only designed to cope with a 1-in-30-year flood.

He added: “It’s not quite as clear cut as simply stating that risk in each case has to be virtually eliminated.

“We say there are very strong material considerations which mean [the guidance] should be departed from.

“One should carry out a risk assessment of looking at what the consequences would be, but that assessment should take into account all the measures which are in place to protect life.”

Thousands of people are opposing the ponds project, including the vast majority who responded to a public consultation carried out by the City.

The work is currently due to begin in January and is estimated to last nearly two years, until October 2016.

If it goes ahead, heavy duty vehicles including five-tonne tankers, nine-tonne dumpers and a 90-tonne crane will make thousands of trips in and out of four entrances to the Heath.

Twelve ponds across the Heath will undergo works for between four and 33 weeks each, including the three bathing ponds. The ladies’ pond will be shut from mid-February 2016 until mid-May 2016.

Mr Troman will continue his case tomorrow morning before the City gives its response.