Exposure to flood risk is an increasingly live issue in developing and trading property. If it cannot be insured against, and no public authority will take adequate flood prevention measures, there is really only one option left to the landowner, which is to construct its own flood defences.

The recent case of Environment Agency v Afshin Payravi (2007) serves as a reminder that it is unwise to do even this, unless in consultation with the appropriate authority.

Regulatory bodies

In practice, landowners usually have to deal with the Environment Agency (‘EA’), in relation to a ‘main river’ (designated as such under the Water Resources Act 1991). If dealing with a tidal river, there will usually be a body with specific responsibility for it, eg the Port of London Authority in relation to the Thames.

Other watercourses not designated as main rivers usually fall under the control of the local authority. The EA is increasingly using its power to designate watercourses as main rivers, so as to give it a greater degree of control over development on flood plains and the likelihood is that in most cases the landowner will be concerned with a ‘main river’.

Role of Environment Agency

The Water Resources Act 1991 gives the EA wide-ranging powers in relation to the maintenance and improvement of main rivers (including the construction of flood defences), in order to ensure the efficient passage of flood flow and to manage water levels.

At the same time, it restricts what affected landowners can do without the EA’s consent; specifically, for present purposes, s.109(3) provides that “no structure designed to contain or divert the floodwaters of any part of a main river” shall be erected or altered without consent.

A DIY flood defence

What happens where a landowner goes ahead and constructs flood defences without obtaining the required consent? Mr Afshin Payravi, of North London, did just that. His garden, in common with those of his neighbours, backed onto the Deans Brook, which is designated as a main river. It was at risk of occasional flooding, and to guard against this Mr Payravi erected shuttering up to two metres high along the river footage, back-filled with a considerable amount of spoil from an extension being built at his home.

The failure to obtain consent was a breach, not only of s.109(3), but also of the EA’s Thames Region Land Drainage Byelaws 1981. The EA considered that the works actually increased flood risk, and served a notice requiring that they be removed.

As Mr Payravi failed to do so, he was prosecuted, and fined £2,000 plus costs of £1,500. It should be noted that while the fines imposed in any particular case may not be substantial, the EA can require removal of unauthorised flood defences, which may involve much greater costs.

There was no legal novelty or complexity to the decision, but it emphasises the fact that landowners’ common law rights are now highly circumscribed, and presumably it was with a view to raising awareness of this that the EA issued a press release about the case. The EA publishes a booklet, “Living On The Edge”, which contains guidance on the rights and responsibilities of those whose land adjoins a river. 

Aftermath of a tragedy

So what of the position at common law? A case in 2004, Arscott and Others v The Coal Authority and Merthyr Tydfil County Borough Council, reviewed the relevant authorities quite comprehensively.

The background to the case was the Aberfan disaster of 1966, in which part of a coal waste tip above the village of Aberfan collapsed onto the village school, killing 116 children and 28 adults.

In the aftermath of the disaster there was considerable public pressure to remove all coal tips in the vicinity. The Council owned a large recreation area known as the Grove Fields, which was susceptible to flooding from the River Taff which ran alongside it.

It was decided to deposit the waste from the tips there, thus removing the tips and simultaneously improving the drainage of the Grove Fields. In the event, the Grove Fields were raised in level by some 10-12 feet, and a much-improved facility resulted.

It may seem unsurprising that one of the outcomes was flooding elsewhere, namely the housing estate where the claimants’ homes were situated. Predicting the precise behaviour of flood waters is difficult, though, and in fact flooding of the estate was held not to have been reasonably foreseeable. It could only have been predicted by using computer modelling techniques which were hardly imaginable at the time the work was done.

Common enemy rule

In defence to an action for nuisance brought by the aggrieved residents, the authority and the council relied on the so-called “common enemy” rule.

The basis of this is the idea that the flood waters represent an common enemy to all landowners at risk, who are each entitled to take action to defend their property without reference to the consequences to each other.

As the judge expressed it: “…an owner or occupier of land is entitled to use or develop his land so as to prevent flood waters coming on to his land. If, in times of flood, waters which would have entered his land in consequence damage another’s land – that does not provide a cause of action in nuisance.”

The rule operated so as to provide the authority and the council with a defence to the claim. As a point of interest, when the case came to the Court of Appeal the review of the authorities identified two limitations to the rule (though neither applied in the circumstances of the case):

  • Works that impede or interfere with the established watercourse of the river do not fall within this rule, and may well therefore give rise to liability in nuisance.
  • The common enemy rule addresses prevention, not remedy; if the flood waters have already, or will in any event, come onto the land, taking measures which cause the water to flow from it onto someone else’s land will be an actionable nuisance.

In the Court’s view, these limitations exemplify the balance which the law of nuisance seeks to strike between private right and public interest. To quote the first instance judge: “Sometime the public will regard the result of this as attractive – sometimes not. It is though soundly based.”

This balance, moreover, in the Court of Appeal’s view, satisfied the requirements of the Convention on Human Rights, and a challenge to the law based on the Human Rights Act 1998 therefore also failed.

Going through the proper channels

The common law, then, is very helpful to the landowner who wants to set up his own flood defences. However, the Payravi case illustrates all too clearly that the common law is not the only factor here: the landowner must also obtain all necessary statutory consents to the work, and in particular involve the EA.

In the Arscott case, the predecessor body had been involved throughout the process, and its deliberations featured prominently in the evidence before the court as to what was reasonably foreseeable.

The lesson is that compliance with the regulatory framework is not only necessary in itself, but is likely to stand the landowner in good stead in the event of subsequent nuisance claims.