QUEEN'S BENCH DIVISION
Strand, London, WC2A 2LL
B e f o r e :
| THE QUEEN
on the application of
THE HEATH & HAMPSTEAD SOCIETY
|- and -
|THE MAYOR AND COMMONALTY
AND CITIZENS OF THE CITY OF LONDON
(acting by THE HAMPSTEAD HEATH, HIGHGATE WOOD AND QUEEN'S PARK MANAGEMENT COMMITTEE
(and the PROJECTS SUB COMMITTEE))
|THE ENVIRONMENT AGENCY
(Transcript of the Handed Down Judgment of
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David Elvin QC and Richard Moules (instructed by Comptroller and City Solicitors Department) for the Defendant
William Upton (instructed by Legal Department (Exeter), Environment Agency) for the Interested Party
Hearing dates: 13th & 14th November 2014
Crown Copyright ©
Mrs Justice Lang:
i) An embankment dam requires a spillway to allow water to 'overflow' and pass safely downstream past the dam. Usually, this is via a channel, pipe or reinforced low portion of the bank. The capacity of the spillway must be sufficient to prevent the water level rising and going over the top of the dam.
ii) If the spillway has insufficient capacity, then in storm conditions the water may overtop the embankment dam. As the water flows down the face of the dam it accelerates and it has the power to rip grass cover from the soil or to erode the face of the dam.
iii) Where the face of the dam erodes there is a risk that the water in the reservoir behind the dam will break through and the dam will fail. Water would then be released from the dam with potentially catastrophic consequences.
iv) It is difficult to predict exactly how quickly a dam will fail, but once overtopping starts then a dam could fail within minutes. Failures could occur at any time and at short notice. Once erosion starts it is a self-perpetuating process that is virtually impossible to stop. It is thus important that the mechanisms for dam failure are eliminated.
v) When dams fail in built-up areas, it is likely lives will be lost. Dam breach releases a wall of water onto the community downstream, overwhelming any drainage system. The volume of water and velocity of flow can knock people and buildings over.
vi) The propensity of a dam to overtopping is indicated by a 'return period' that signifies the number of years which one would expect between floods equal or greater than the stated magnitude. Thus, if a dam is overtopped with a return period of a 1 in 20 flood then it would be expected to overtop on average once every 20 years. This is a theoretical exercise. In reality, severe floods may occur at any interval, and their frequency cannot be accurately predicted.
i) Each chain of ponds was considered as a whole system, so that increases in storage capacity could be focused in the least sensitive locations, in order to minimise increases in dam heights at more sensitive ponds and reducing residual works required elsewhere.
ii) The safety standard applied to each pond was the "Probable Maximum Flood" (PMF). Applying the Institution of Civil Engineers guidance 'Floods and Reservoir Safety' ("the ICE guidance"), this was the applicable standard for the three largest Category A ponds. It was anticipated that all the ponds would come within the scope of the RA 1975 once the amendments introduced by the Flood and Water Management Act 2010 were fully implemented.
iii) Tree loss was to be minimised
iv) The system would be passive, without reliance on any mechanical system or human intervention.
v) The engineering intervention would be balanced so as to minimise impact on the landscape.
i) Stock Pond: Restoration of the dam crest by up to 500 mm and a new open grass spillway, 21 m wide at base with side slopes of 1:12, at the right hand end of the dam, Two new 900 mm overflow pipes to run parallel to existing overflow pipe. Pond to be de-silted. New marginal planting. 23 - 26 trees lost.
ii) Kenwood Ladies' Bathing Pond: Restoration of the dam crest and a new open grass spillway, 24.6. m wide at the base with side slopes of 1:3, over the right hand part of the dam. Loss of 15 – 18 trees. Pond to be de-silted.
iii) Bird Sanctuary Pond: Minor restoration of the dam crest and relocation of the overflow pipe to the right hand end of the dam. No spillway but the slope downstream to the Model Boating Pond to be smoothed and lined with a turf reinforcement mat. Additional channel to be dug to enhanced wetland area and development and extension of existing reed bed. New wetland habitat constructed.
iv) Model Boating Pond: Raising the existing dam by 2.5 m with an earth embankment on the upstream side. New open grass upper spillway over the raised and existing dams at the right hand end. New island with a causeway to be formed around preserved trees. Loss of 8 to 9 trees. New footpath across dam and re-aligned west bank. Excavation of the west bank to obtain earth for construction of new dam, with consequent enlargement of the pond. Further borrow pit for top of hill west of pond; to be filled with silt from Highgate ponds.
v) Men's Bathing Pond: Raising of the existing dam by 1 m, using sheet piling clad with timber. Designed to repair existing leak in dam. New open grass spillway, 25 m wide, at the right hand end. Loss of 15 trees. Marginal planting and a small reed area.
vi) Highgate Pond No. 1: Raising of existing dam with a maximum 1.25 m high wall, using sheet piling clad with timber. A new open grass spillway, 64 m wide, at the right hand end. Return wall along one side. Loss of 5 to 16 trees. Extension of the existing reed beds
i) Vale of Health: Crest restoration up to 560 mm. New grass lined spillway at the western end, 5 m wide. Additional overflow pipe. 1 tree lost. Marginal planting.
ii) Viaduct. Crest restoration up to 180 mm. New grass lined spillway at the eastern end, 4 m wide and 1:12 side slopes. New overflow pipe. Removal of silt. Marginal planting on eastern edge. 4 – 6 trees lost.
iii) Catchpit: New flood storage dam 5.6 m high at the lowest point in the valley and 40 m wide at the widest point. Crest of the dam approximately 100 m. Slopes 1:3 upstream and 1:4 downstream. Spillway along the whole crest of the dam. Pipe under the dam to pass normal flow. Second pipe or overland flow and wetland area. Two new silt collection ponds upstream of the dam. Wetland scrapes and informal flow channels. Reed beds to be planted. 60 - 71 trees lost.
iv) Mixed bathing: Dam raised by 1 m, creating a new crest surface path 4 m wide. 1:1 slope of the upstream face, 1:3 on the downstream slope, Downstream slope to be reinforced with a mat. Spillway over the majority of the crest of the dam. Existing overflow pipe extended further. 7 trees lost. Silt removal. Marginal planting.
v) Hampstead No. 2: Crest restoration with a 0.2 m high edging. A new overflow with precast concrete box culvert/s at the western end with a drop inlet. Culvert route and width redesigned so that the plane trees on the dam are preserved. Loss of 1 - 2 trees. Marginal planting.
vi) Hampstead No. 1: New box culvert overflow over the embankment at eastern end. 5 trees lost. Marginal planting
Hampstead Heath Act 1871 (as amended)
"And whereas it would be of great advantage to the inhabitants of the Metropolis if the Heath were always kept uninclosed and unbuilt on, its natural aspect and state being as far as may be preserved, and if for that purpose the Heath were vested in the …. Board …"
"And whereas it is expedient that the Board be empowered to manage and regulate the Heath … and that all proper powers for the several purposes aforesaid be conferred on them ….."
"12. Heath to be kept open.
Subject to the provisions of this Act, the [Board] shall for ever keep the Heath open, uninclosed, and unbuilt on, except as regards such parts thereof as are at the passing of this Act inclosed or built on, and shall by all lawful means prevent, resist, and abate all encroachments and attempted encroachments on the Heath, and protect the Heath, and preserve it as an open space, and resist all proceedings tending to the inclosure or appropriation for any purpose of any part thereof. "
"15. Power to drain &c.
[The Board] shall by virtue of this Act have the following powers; …
To drain, level, and improve the Heath, as far only as may be in their judgment from time to time requisite, with a view to the use thereof for purposes of health and unrestricted exercise and recreation:
To plant trees and shrubs on the Heath for purposes of shelter or ornament, and to make temporary inclosures for the protection thereof."
"16. Preservation of turf, &c
[The Board] shall at all times preserve, as far as may be, the natural aspect and state of the Heath, and to that end shall protect the turf, gorse, heather, timber and other trees, shrubs, and brushwood thereon."
"18. Power to build Heath keepers lodges, &c.
Notwithstanding anything in this Act, the [Board] may erect from time to time on the Heath, and maintain, such convenient or ornamental buildings, of an elevation not more than twenty feet in any case, as they think requisite for the accommodation of Heath keepers, constables, or other officers, or for other public or useful purposes."
Reservoirs Act 1975
"A1 "Large raised reservoir": England and Wales
(1) In this Act "large raised reservoir" means—
(a) a large, raised structure designed or used for collecting and storing water, and
(b) a large, raised lake or other area capable of storing water which was created or enlarged by artificial means.
(2) A structure or area is "raised" if it is capable of holding water above the natural level of any part of the surrounding land.
(3) A raised structure or area is "large" if it is capable of holding 10,000 cubic metres of water above the natural level of any part of the surrounding land. …"
"10.— Periodical inspection of large raised reservoirs.
(1) The undertakers shall have any high-risk reservoir inspected from time to time by an independent qualified civil engineer ("the inspecting engineer") and obtain from him a report of the result of his inspection.
(2) Unless it is at the time under the supervision of a construction engineer (or of an engineer acting under section 8 or 9 above) a high-risk reservoir must be inspected under this section at the times specified by regulations made by the Minister.
(3) As soon as practicable after an inspection under this section, the inspecting engineer shall make a report of the result of the inspection, including in it any recommendations he sees fit to make as to—
(a) the time of the next inspection;
(b) the maintenance of the reservoir;
(c) any measures required in the interests of safety and the period within which those measures must be taken.
(3A) If the inspecting engineer has not provided a report before the end of the period of 6 months beginning with the date of completion of the inspection, the engineer must—
notify the appropriate agency, and
provide a written statement of the reasons.
(4) An inspecting engineer shall consider the matters (if any) that need to be watched by the supervising engineer during the period before the next inspection of the reservoir under this section, and shall include in his report a note of any such matters.
(5) An inspecting engineer, when he makes his report, shall also give a certificate stating that the report does or does not include recommendations as to measures to be taken in the interests of safety or as to the maintenance of the reservoir, if it includes a recommendation as to the time of the next inspection, stating also the period within which he recommends the inspection should be made.
(5A) The undertaker must comply with a recommendation made under subsection (3)(b), unless the recommendation is the subject of a reference under section 19 and the reference has not been determined.
(6) Where an inspecting engineer includes in his report any recommendation as to measures to be taken in the interests of safety, then subject to any references of the matter to a referee in accordance with this Act the undertakers shall, within the period specified in the report, carry the recommendation into effect under the supervision of a qualified civil engineer; and that engineer shall give a certificate, as soon as he is satisfied it is so, that the recommendation has been carried into effect.
(6A) The inspecting engineer must include in the report of the inspection—
(a) a statement as to whether all of the safety measures recommended in the previous report under subsection (3)(c) have been taken, and
(b) either (i) recommendations to take any safety measure that has not yet been taken or (ii) an explanation of why it is no longer required.
(7) Where it appears to the enforcement authority, in the case of any high-risk reservoir,—
(a) that an inspection and report thereon have not been made as required by this section; or
(b) that the latest report of the inspecting engineer includes a recommendation as to measures to be taken in the interests of safety that has not been carried into effect as so required;
the authority may by written notice served on the undertakers require them within twenty-eight days after the date when the notice is served to appoint an independent qualified civil engineer to carry out an inspection under this section, unless an appointment has already been made, and (in either case) to notify the authority of the appointment or, as the case may be, require them to carry the recommendation into effect within a time specified in the notice.
(8) Where an enforcement authority propose to serve a notice under subsection (7) above requiring the undertakers to carry a recommendation into effect, the authority shall consult as to the time to be specified in the notice a civil engineer, being a qualified civil engineer for the purpose of supervising under subs. (6) above the carrying into effect of the recommendation.
(9) For purposes of this Act "independent" when used of a civil engineer in relation to a reservoir means —
(a) that he is not in the employment of the undertakers otherwise than in a consultant capacity; and
(b) that he was not the engineer responsible for the reservoir or any alteration to it as construction engineer, nor is connected with any such engineer as his partner, employer, employee or fellow employee in a civil engineering business.
The reference in this subs. to a construction engineer includes an engineer acting under section 8 or 9 above."
"12.— Supervision of large raised reservoirs.
(1) At all times when a high-risk reservoir is not under the supervision of a construction engineer, a qualified civil engineer ("the supervising engineer") shall be employed to supervise the reservoir and keep the undertakers advised of its behaviour in any respect that might affect safety, and to watch that the provisions of section 6(2) to (4) or section 9(2) above and of section 11 are observed and complied with and draw the attention of the undertakers to any breach of those provisions.
(2) It shall be the duty of the supervising engineer, so long as any matters are noted as matters that need to be watched by him in any annex to the final certificate for the reservoir or in the latest report of an inspecting engineer, to pay attention in particular to those matters and to give the undertakers not less often than once a year written statement of the action he has taken to do so.
(2A) The supervising engineer must provide the undertaker with a written statement of any steps taken to maintain the reservoir in accordance with the recommendations of the inspecting engineer under s. 10(3)(b).
(2B) The engineer must provide a statement under subs. (2A) at least once every 12 months.
(3) The supervising engineer shall recommend to the undertakers that the reservoir be inspected under s. 10 above, if at any time he thinks that such an inspection is called for.
(4) Where it appears to the enforcement authority that a high-risk reservoir is not for the time being under the supervision either of a construction engineer or of a supervising engineer, the authority may by written notice served on the undertakers require them within twenty-eight days after the date the notice is served to appoint a supervising engineer and to notify the authority of the appointment or, if the reservoir is at that date under the supervision of a construction engineer or of a supervising engineer, to notify the authority of that fact.
(5) Reference in this section to a construction engineer include an engineer acting under s. 8 or 9 above.
(6) The supervising engineer may direct the undertaker to carry out a visual inspection of the reservoir at specified intervals for the purpose of identifying anything that might affect the safety of the reservoir.
(7) The undertaker must notify the supervising engineer of—
(a) each visual inspection that is carried out, and
(b) anything noticed in the course of it.
(8) The Minister may issue guidance about supervision in accordance with this section (and may take compliance into account when making decisions under s. 4)."
The Flood and Water Management Act 2010
i) was not concerned with absolute or near safety, but with a level of safety that was reasonable in all the circumstances;
ii) was to be read as subject to and qualified by the City's statutory duties not to build on and to preserve the natural aspect and state of the Heath pursuant to the Heath Act, which were contravened by the proposals;
iii) did not require that "measures" only involve physical engineering and a "passive system" when active measures such as early warning systems and human intervention could ameliorate risk;
iv) did not exclude consideration of safety measures in place under regimes outside the RA 1975;
v) did require consideration of the historical, social, ecological value of the Heath that will be disturbed or harmed by the proposals.
i) The flood warning mechanisms in place, including under the Civil Contingencies Act 2004 and the 2010 Act, will provide warning of possible flood and dam breach far in excess of the maximum 40 minute time frame which led the Defendant to proceed on the basis of "no warning".
ii) It was perverse to assume that the dams would collapse with little or no warning. The Defendant's own assessment was that breach would not occur immediately but only several hours after the start of the probable maximum flood.
iii) In the event of a probable maximum flood, surface water would already have overwhelmed the sewerage system, causing widespread flooding, and risk to life.
iv) The Defendant's quantitative risk assessment concluded that in the event of a probable maximum flood, some 1,100 deaths would occur through flooding from water overtopping the dams prior to a single dam breach.
v) The prior flooding, whether from surface water or overtopping, would already have prompted warnings and evacuation measures, long before any dam breach.
The purpose of the Reservoirs Act 1975
"An Act to make further provision against escapes of water from large reservoirs or from lakes or lochs artificially created or enlarged." (emphasis added)
"I hope that this important safety measure will be received with …. general approval …it is well recognised on all sides that we need to protect the public safety, particularly in respect of reservoirs holding large amounts of water ….
The existing legislation on reservoir safety is contained in the Reservoirs (Safety Provisions) Act 1930. That Act was the result of two unfortunate experiences in 1925 which resulted in serious loss of life.... In Scotland, five people were drowned …. When a reservoir overflowed during a storm and destroyed the dam. The cause of the accident was found to be faulty design ….In the Welsh disaster, 16 people lost their lives when the dam collapsed as a result of poor construction.
Therefore, Parliament at that time decided that measures were needed, and the 1930 Act was introduced. We have relied on that Act since that time, and it has served us reasonably well for 45 years. But it is clear, as a result of the growing demand for water, and because there are now larger and larger man-made lakes and reservoirs to contain the water ….that we need to strengthen further the safety provisions governing reservoirs.
I can best illustrate the need to do this by giving the world picture. We estimate that there are 10,000 in the world over 45 ft high …. On average, during the past 40 years, one such dam has failed every 15 months, claiming an average of 40 victims each. That is the measure of the concern which the House is called upon to express and the reason for this measure, in the face of those figures we would be accused of great complacency if we did not from time to time review our existing legislation and strengthen it where necessary.
The worst of these cases occurred in 1963 at Vajont, Italy, where a landslide into the reservoir caused 42 million cubic metres of water to splash over the dam and nearly 3,000 people lost their lives. That shows the tremendous, destructive force of water and the need for maximum safety measures. That tragedy, together with the others I have mentioned …. led to our own Institution of Civil Engineers to …produce its report on reservoir safety 1966 which proposed revisions for the 1930 Act. It is that set of circumstances which brings us here today, to consider those proposals and the conclusions of the government arising from them.
The 1930 Act has proved to be workable and desirable. But one serious weakness is that there is no adequate provision to ensure that the Act is complied with…..The Government agree with the Institution that that is not a satisfactory situation. The law should be tightened to provide an absolute obligation on anyone holding a reservoir or lake … to ensure the safety of the reservoir at all times."
"the proposals not only cover all the major water undertakers of the country but include old mill dams, fishing lochs and lakes, ornamental lakes, and so on. Over 230 such lakes and lochs and amenity recreation lakes in this country … come within the ambit of the legislation."
"It re-enacts and strengthens the Reservoirs (Safety Provisions) Act 1930….I am sure the whole House will be united in its wish to make effective provision for the safety of reservoirs and for the protection of the public and their property."
Standards of safety
The accidental, uncontrolled escape of water from an impounding or other reservoir can threaten life and property. Greater security is required against dam failure where there is a severe threat of a loss of life and extensive damage and a lower security where the threat is less severe. All dams should be assessed for the consequences of failure, and the categories shown in Table 1 indicate the degree of security required of a dam and the likely effects of the failure of the main dam … by which the reservoir is retained….
Category A dams
It is considered that public opinion will not accept conscious design for a specific threat to a community, even though it tolerates to an extent both random and accidental loss of life. Consequently, no dam above a village or town should be designed knowingly with a finite chance of a disastrous breach due to the under-provision of spillway capacity. A community in this context is considered to be not less than about 10 persons who could be affected; it is considered that inspection of any valley will soon reveal whether the presence of a hamlet, school or other social group means that a dam at its head should be in category A…..
Category B dams
Category B(i) is intended to refer to inhabitants of isolated houses and, for example, to operatives in treatment works immediately below a dam and in other places of work in the flood path…Category B(ii) refers to extensive damage, including erosion of agricultural soils and the severing of main road or rail communications.
Category C dams
Category C covers situations with negligible risk to human life and so includes flood-threatened areas that are "inhabited" only spasmodically; e.g. footpaths across the flood plain and playing fields. In addition this category also covers loss of livestock and crops.
Category D dams
Many small reservoirs with low earth dams may cause no real problem .. if they wash out. These special cases, many of which are ornamental lakes, kept full for aesthetic reasons, are given a separate category where they pose no significant threat to life or property."
"Table 1 is designed to take account of those factors which are weighed together by panel engineers both for the design of new dams and for dam inspections. Its main intentions are to ensure that, where a community could be endangered by the breach of a dam, the risk of any breach caused by a flood is virtually eliminated. However, where there is no community at risk, expenditure on safety works should be kept to a scale justified by the risk."
"The fundamental principle [of the 1930 Act] is that only a qualified civil engineer can provide the professional expertise required to ensure the safety of the reservoir structure. A qualified civil engineer within the terms of the Act is an engineer who has been appointed by the Secretary of State, on the advice of a special committee of the Institution, to a panel specifically constituted for the purposes of the Act…."
"reservoir construction and supervision is a highly technical subject and this Bill is not concerned with the details of civil engineering. It provides the legislative framework in which those best fitted to decide on technical matters – the qualified engineers – may operate."
"4.2.1 Guidance on Supervision
Defra does not intend to issue statutory guidance on the supervision of reservoirs. We consider that the legislation is sufficient taken with non-statutory guidance produced in collaboration with the Institution of Civil Engineers (ICE) in the form of "A guide to the Reservoirs Act 1975". This guidance document is being revised by a working group at the ICE at the request of Ministers to reflect the amendments to the legislation and to reflect any changes in practice since its original publication in 2000. It should not be forgotten that civil engineers qualified under the 1975 Act are expected to demonstrate high professional standards to maintain this qualification."
Recommendations made under the RA 1975
The HHA 1871
"a dreary desert prospect of hideous pits and shapeless heaps as far as the view extends over the hill itself, with a few miserable furze-bushes here and there, a ragged tuft of dusty ling, or some wretched weed content to grow in its degraded situation, but without one square yard of verdant turf for a baby to roll upon…. The very body of the earth had been cut away to an amazing depth… holes are scooped out …. thirty feet or forty feet deep…."
"The judge did not accept this construction of the Act and neither do I. Section 36 is specifically concerned with the preservation of the natural state of the commons and in particular with the grassland, gorse, heath and trees which grow there….But s.36 is essentially ancillary to s.34 in that any encroachment or building on the Common will necessarily interfere with the existing landscape. It would be odd if any powers which the Conservators may have under s.34 are nonetheless absolutely excluded by the provisions of s.36. One would expect the legislative scheme to be that which the Conservators should be under a duty to preserve the natural state of whatever parts of the Common they are obliged to maintain as open space under s.34. It seems to me that the natural construction of the words "as far as may be" in s.36 is " as far as required under the Act". I do not accept Mr McCracken's argument that s.36 provides an independent, absolute, and unrelated duty which would have the effect of making the scheme under s.34 largely irrelevant."
Other emergency provision for floods
The Defendant's decision