Atlas Properties Limited v Kapiti Coast District Council HC Wellington CP172/00

[2001] NZHC 1297

IN THE HIGH COURT OF NEW ZEALAND
WELLINGTON REGISTRY CP172/00

BETWEEN ATLAS PROPERTIES LIMITED a duly incorporated company having its registered office at Paraparaumu and carrying on business as Property Owner; R J & M B OPIE, both of Paraparaumu, Company Directors trading as ‘RURU INVESTMENTS’, SIGNFIX SYSTEMS LIMITED a duly incorporated company having its registered office at Auckland and carrying on business as manufacturers and suppliers of sign fixing components and steel banding products; ALLAN GRAY of Paraparaumu, Motor Engineer, trading as ALLAN GRAY MOTORS, KEN GRIFFITHS IMPORTS LIMITED a duly incorporated company having its registered office at Lower Hutt and carrying on business as importers; IVY ASHBY LIMITED, trading as ‘THE OLD FLAME’, a duly incorporated company having its registered office at Paraparaumu and carrying on business as restauranteurs; DAVID FRANCIS BETTERIDGE of Paraparaumu, Silversmith, trading as KAPITI SILVERWARE SPECIALIST
Plaintiffs

AND THE KAPITI COAST DISTRICT COUNCIL a local authority incorporated under the Local Government Act 1974
Defendant

Date of Hearing: 12-15 November; 21 November 2001

Date of Judgment: 19 December 2001

Counsel: P C Mitchell and A B A O’Brien for Plaintiffs
D J Heaney and S I Jameson for Defendant

JUDGMENT OF DURIE J

Solicitors:
Phillips Fox, Wellington for Plaintiffs
Heaney & Co, Auckland for Defendant

Introduction to the Case

[1] Several property owners, who are the plaintiffs, seek damages from the defendant, the Kapiti Coast District Council, for flood damage to their properties and possessions at Ihakara Street, Paraparaumu, and for associated business losses, as a result of a major storm on the night of 20-21 October 1998. The storm, based on past experience, was of a sort that might happen only once in a hundred years. The plaintiffs claim the Council was responsible for the damage. I will shortly explain why.

[2] With apologies to the exact labour of cartography, the lands and river most spoken of in the case may be shown diagrammatically as in Figure 1. The diagram depicts a quadrant of mainly farmland, circumscribed by the Wharemauku Stream to the North and West, as the stream passes to the West to the nearby sea. The quadrant is defined in the East by the straight run of Rimu Road. In the South it is prescribed by Ihakara Street and an imagined line from the end of that street to the stream. The plaintiffs’ lands and buildings lie on the North of Ihakara Street extending as far as a drain known as Drain 6 North. This is virtually the only part of the quadrant that is built on. Most else is low-lying, open farm country. The whole area is more low-lying than the lands outside the quadrant. That land is commercial or shopping land to the immediate East of Rimu Road and beyond, and is residential land to the South of Ihakara Street.

[3] Of the low-lying land in the quadrant, it is especially low around Ihakara Street. A lower point yet is on the North-Western corner of the properties owned by the plaintiffs, where Mr Murland, Director of the plaintiff Atlas Properties Ltd, has his business. Like Atlas he is at the very base of this part of the globe. I accept the evidence that taking a longitudinal line down Rimu Road, the fall to that part is discernible to the naked eve.

[4] The greater part of the quadrant is thus liable to flooding, as was proven on the night of 20 October, and few if any of the places were as liable to flooding as the places where the plaintiffs had their land, and Mr Murland especially. The plaintiffs described water depths of up to 600 mm on their properties with Mr Murland estimating 800 mm on his land at the shed on the Northern corner. That latter depth is not accepted in the Council’s evidence but there is no argument that depths in excess of 600 mm were possible.

[5] The plaintiffs sue the Council and with understandable reasons. Mr Murland thought that just by looking at the scene, as he did at 10.30 p.m. on the night of 20
October when peak flows were recorded, the natural passage of the water that swept down Wharemauku Stream towards Rimu Road was constricted by a culvert under that road. The culvert being too small for the torrent to pass on nature’s way, the torrent over-topped the South bank immediately before the culvert, the South bank being lower than the bank on the North. From there the water caroused over a shopping carpark then quickly ran down Rimu Road, which “flowed like a river” Mr Murland said. Whether via the duct of Rimu Road, or by sheeting across the farmland, the overflow water soon gathered at Ihakara Street. Although this was at night, Mr Murland was equipped to see as much as one could see at that time. Having been called by an on-site caretaker, he journeyed in a substantial four-wheel drive.

[6] The culvert under Rimu Road is an Armco multi-plate arch culvert with a span of 3.53 metres and a rise of 2.26 metres. Construction took place between November 1981 and March 1982 when Rimu Road was extended to the North beyond Ihakara Street. I refer to the culvert as the Armco culvert to distinguish it from the smaller, concrete culverts that service Drain 6 or the larger box culvert further up Wharemauku Stream under the State Highway. Whether or not the Armco culvert was constructed by a predecessor of the current Council, the current Council bears responsibility for it. The plaintiffs’ case is that even if the Council was unaware, at the time of construction, that the Armco culvert was inadequate for the reasonably anticipated volumes of water in the stream, the Council was soon informed. The plaintiffs contend that the Council became aware of the danger soon after construction, but nothing was done to enlarge the room for the water to pass.

[7] The contention on the Council’s behalf is that all that the Council did or did not do was reasonable in the circumstances and in the knowledge possessed at the time. In addition, the Council contends the plaintiffs’ area would have flooded in any event in a storm of the magnitude of that on 20 October 1998. The reference was not only or mainly to overflows of the stopbanks adjoining the farmland. More seriously, the Council contends, a large part of the open farmland, and Ihakara Street in particular, was a natural pooling area from the river backflow as it met the constraints of the open sea and as pressure built back to the confluence point where Drain 6 joined the stream. Of the water that entered the properties at Ihakara Street, it could not be said how much (if any) came from the backflow and how much from the overflow of the Armco culvert. However, in the Council’s view, it matters not. Whether the water came via the backflow of the stream or via the road, the amount of pooling at Ihakara Street would have been the same. Indeed, in the Council’s perception, having regard to the magnitude of the storm that night, had all the water flowed down nature’s path, as if there was no culvert or road at all to impede the natural progress, Ihakara Street would still have flooded to the same extent, and with the same consequential losses.

[8] The plaintiffs’ reject the natural phenomenon theory and remain focused on the evidence in relation to the Armco culvert itself, and a depression in the abutting South bank which directed any overflow to the South.

[9] In this case there is no dispute that the Armco culvert was unable to cope with the floodwaters of 20-21 October 1998. The Council’s own expert evidence is that the storm water generated a peak flow of 26.9 cumecs [fn 1 i.e. 26.9 cubic metres per second or 26.9m3/s] and that none of that would have spilled the banks en route to the culvert, for that part of the channel could have coped with the flow of 33 cumecs. However, just before the Armco culvert, the South bank lowers in height. The combined result of that and the size of the culvert is that only 14.5 cumecs would have passed through the culvert before the stream overflowed. Had the bank been up to the height that it now is, 15 cumecs could have passed, or more with water under pressure, but that was not the case on the night of 20 October. Consequentially, the overflow where Rimu Road crosses the stream was caused by a combination of the damming of waters by the roadfill with a culvert too small for the flow, and the escape route provided by the South bank depression. The excess thus overflowed the South bank to the carpark mentioned. Council’s expectations had been that any such overflow would have passed on a secondary flow channel along the east side of Rimu Road, across carparks associated with the shops there, to Drain 6 North. However, a driveway constructed to the carpark, in fact deflected the flow to Rimu Road.

[10] Further, there is no dispute that gravity would have taken the overflow down Rimu Road to the Western end of Ihakara Street as the natural low point in the area. Rimu Road descends to the South from RL 9.0m at the Wharemauku Stream [fn 2 i.e. Relative Level 9.0 metres, also referred to in evidence as Reduced Level.] to RL 5.61m at the Ihakara intersection and falls from there to RL 4.54m at the end of Ihakara Street. But for a hump at the intersection, the water may have passed further down Rimu Road to Drain 6 South.

[11] I have mentioned a peak flow of 26.9 cumecs but of course that was not the flow throughout the entire time from 9.15 p.m. to 2.15 a.m. when, on rainfall statistics, the flood would have been most aggressive. During that time the estimated overflow on the South bank was probably about 13 cumecs. As the duct created by road kerbing is limited, the Council considered that up to half of that overflow would have sheeted across the farmland, but in any event the divided water would have regrouped at the Ihakara low point.

Introduction to the law

[12] The plaintiffs contend for rights of action in terms of the law of torts. This law provides for recovery of losses from certain injurious acts of others in breach of a duty or in contravention of a right. The right claimed to have been contravened in this case, was the plaintiffs’ right to be relieved of the nuisance of having one’s use and enjoyment of land taken away by an unwanted inundation. The injurious act complained of was the Council’s constructing and maintaining of a culvert that caused water to flow on other than nature’s course. In purported application of the law, the plaintiffs claim that the Council’s storm water system, with its restricting culvert and overflow point part way, effected such an interference with nature that in law, the Council is strictly liable, that is, liable even without the plaintiffs having any need to prove that the Council’s acts or omissions were at fault.

[13] If that is not accepted on a judicial interpretation of the law, then the plaintiffs claim that in law, the defendant is still strictly liable as it was reasonably foreseeable that the unnatural act of constricting nature’s arteries would result in an overflow that would inundate the plaintiffs’ land. In the third alternative the plaintiffs claim that the Council was simply negligent, that it was careless in constructing and then maintaining the culvert having regard to a duty of care that it owed to the plaintiffs; and that the Council ought reasonably to have foreseen that the culvert would cause an overflow and that the plaintiffs’ properties would be seriously affected as a result.

[14] Those claims are categorised under the separate headings of the Rule in Rylands v Fletcher, Nuisance and Negligence respectively. I will treat with those categories as ordained in practice even though they are not universally blessed in law. The learned authors of the Law of Torts in New Zealand (2nd Edition) consider, in Chapter 10, that a Rylands v Fletcher action is really an action in nuisance. They also contemplate as one of two prospective options in future development, at p 598, that negligence will become a pre-requisite of liability in all nuisance cases. However, in this instance the categories are not a barrier to the disposal of the case.

Statutory Defences

[15] Before coming to the various actions an affirmative statutory defence must be considered. Mr Jameson of counsel for the defendant argued that any right of action the plaintiffs may have under the headings of Rylands v Fletcher and Nuisance is excluded by s 148 of the Soil Conservation and Rivers Control Act 1941. That Act constitutes Catchment Boards with powers to undertake works to control or regulate the flow of water in drains or watercourses.

[16] Section 148(1) provides:

“(1) No Board shall be liable for injury to any land or other property caused without negligence of the Board by the accidental overflowing of any watercourse, or by the sudden breaking of any bank, dam, sluice. or reservoir made or maintained by the Board.”

[17] Mr Jameson submitted that the defendant was a Catchment Board upon the grounds that the definition of Catchment Board in s 2 of the Act included a territorial authority with jurisdiction in the relevant area and upon the further ground that the defendant was such an authority by virtue of the Local Government (Wellington Region) Reorganisation Order 1989 and an agreement with the Wellington Regional Council which delegated functions pursuant to s 125 of the Soil Conservation and Rivers Control Act. Mr Jameson submitted that the statutory arrangement was consistent with the observations of Lord Goff in Cambridge Water Co Ltd v Eastern Counties Leather plc [1994] 1 All ER 53 at 76 that the incidence and scope of strict liability for high risk operations should be set by Parliament rather than by the Court so that those involved in such activities would know where they stood.

[18] Mr Jameson argued that the wording of s 148 excluded the application of the Rule in Rylands v Fletcher and also the law of nuisance to the extent that liability is strict in terms of those laws. He submitted that on the basis of this section actions must depend upon proof of negligence.

[19] Mr Mitchell, counsel for the plaintiffs, submitted that the defendant was not such a Board. He submitted that Clauses 10 and 16 of the Local Government (Wellington Region) Reorganisation Order 1989, contrasted with Clauses 77 and 83 of that Order, clearly allocated functions to the Wellington Regional Council and not to the defendant. Section 125 of the Soil Conservation and Rivers Control Act provided for a power of delegation (and see also s 7 of the Soil Conservation and Rivers Control Amendment Act 1946). He submitted however that such delegations vested the administration of the stream in the defendant but did not thereby constitute the defendant as a Board.

[20] I should think that the transfer of responsibilities to the defendant under a statutory power to do so would effectively transfer the benefit of s 148 but I need not decide the point. I accept instead Mr Mitchell’s further arguments that the defendant was not acting as a Board, if it is a Board, in relation to the particular activity in question and that the injury was not the result of “an accidental overflowing” just as it was obviously not a “sudden breaking”. However my reasons expand upon the arguments that he gave. I consider first the question of “accidental overflowing”.

[21] On the evidence the overflowing of the Wharemauku watercourse was foreseen and was provided for. The dip in the South bank shortly before the bank abutted Rimu Road was for the purpose of taking any excess that could not pass through the culvert. Raymond O’Callaghan, engineer, was called by the plaintiffs as an expert witness with expertise in surface water design and control and in drainage design. He pointed to a report of 1990 when the shopping area to the south of the stream was undergoing development. This discussed the passage of the secondary flow from the overflow point near the culvert and the expectation that the secondary flow would pass down the eastern side of Rimu Road, next to the proposed shopping complex, to pass to Drain 6 North.

[22] Mr Gary Williams, a consulting engineer specialising in water and soil engineering, also referred to this secondary overflow area as having been recognised in reports to the Council. The same fact was acknowledged by expert witnesses for the Council. Dr Steven Joynes, a hydraulic modeller and developer of storm water management plans described the lowered height of the South bank as a “side spill weir that allows for secondary flow to pass down the Eastern side of Rimu Road”. He added “The intention of the flow path was to carry the water to Drain 6 North which would then return the flow to the Wharemauku Stream at a point downstream of the Rimu road culvert”. My view therefore is that the overflow to the South was not an accident but was part of a planned approach to watercourse management in the event of a stressed situation.

[23] More especially however, s 148 provides exemption only in respect of action taken or omitted by a Board in its capacity of a Board under the Act, and not to action taken or omitted by the same body when exercising its powers as a Council under the Local Government Act 1974. The objects of the Soil Conservation and Rivers Control Act 1941 are, in terms of s 10, to promote soil conservation, the prevention and mitigation of soil erosion, the prevention of damage by floods and the utilisation of lands in such manner as will tend towards the attainment of those objects. The general powers of the Board are framed to that end in s 126. The Boards may construct, reconstruct, alter, repair and maintain all such works as are necessary to control or regulate waterflows to, in or from watercourses or to lessen the likelihood of, or to control, overflows. The more particular powers in s 133 are likewise directed to the same intent. The common denominator for all is the provision of works to ensure free-flow. Here, the essential work that gave rise to concern is not at all of that kind, but was primarily directed to the formation of a road. The provision for water to pass through was incidental. The particular work, I find, is not a work under the Soil Conservation and Rivers Control Act, but a work undertaken by the Council, as a Council, in the exercise of powers under the Local Government Act. For those reasons I find that the statutory defence fails.

[24] Mr Mitchell made further and extensive submissions on the inapplicability of s 145, which provides for compensation, but it follows from the conclusion I have reached that s 145 does not apply.

[25] The defendant abandoned a further defence foreshadowed in its pleadings based upon the operation of part 5 of the Public Works Act 1981.

[26] Before now turning to each of the plaintiffs’ causes of action I record Mr Mitchell’s submission that his pleading of three separate causes of action was for conventional reasons. In line with that which I have previously indicated he submitted that following Cambridge Water Co Ltd (supra) the distinction between Rylands v Fletcher and nuisance was of little ultimate significance and that, in the light of Lord Cooke’s judgment in Delaware Mansions Ltd v The City of Westminster [2000] UKHL 55 (HL) the distinction between negligence and nuisance was secondary to the principal inquiry as to “the fair and just content and incidence of a neighbour’s duty”. He was nonetheless content to proceed on the distinct foundations which had been pleaded.

Rylands v Fletcher

[27] The rule that is traced to Rylands v Fletcher may be stated as follows. Where a person brings on to land and collects and keeps there any dangerous thing, for that person’s own purposes, which is likely to do mischief if it escapes, that person is prima facie answerable for all the damage which is the natural consequence of its escape. The rule applies where the use of the land was not natural, in which case the defendant will be liable notwithstanding that all reasonable care and skill has been taken to prevent the escape from occurring.

[28] The plaintiffs contend that the storm water drainage system, including the Armco culvert beneath Rimu Road, constitutes a non-natural use of land and that the collecting and conveyance of water in bulk by that system is a dangerous thing which is likely to cause damage if it escapes. The water escaped, the Rimu Road culvert being inadequate for the task, and the plaintiffs submit that under this rule, the Council is liable for the consequential damage.

[29] The main argument for the plaintiffs was that water was inherently dangerous if allowed to escape and that the escape in this case was the inevitable consequence of the structure built by the Council.

[30] As was to be expected Mr Jameson stressed as the basis of liability under the rule that the defendant must have brought the dangerous thing onto the land which it controls and to have brought it there for its own purpose. He further submitted that the use of the stream for drainage is an ordinary and natural use of the land. In each of those respects I consider Mr Jameson is undoubtedly correct.

[31] In Rylands v Fletcher (1868) LR 3 HL 330; [1861-73] All ER Rep 1 the essential fault lay in the resolve of Messrs Ryland and Horrocks, mill owners, to maintain a reservoir to service their mill, and so to accumulate a dangerous body of water. In this case the Council constructed a culvert, not with the purpose of accumulating or storing water, even although that may have been its effect on the singular occasion of 20 October 1998, but with the purpose of allowing the water to pass through and so to proceed on its natural course. The real question in this case is whether the defendant was at fault in constructing a device which proved to be inadequate for the intended purpose of allowing the water to escape, and to that fact situation, the case of Rylands v Fletcher can have no application.

[32] Mr Jameson noted as an exceptional case, Green v Hamilton City Council (District Court, Hamilton, NP 921/98, March 2000) where Judge Willy confronted facts very similar to those in this proceeding. There, a culvert maintained by a Council failed to cope with an increased stream flow following heavy rainfall and created a bottleneck when the water could not escape. As a result the plaintiffs’ properties were flooded and they sued the Council under the Rule in Rylands v Fletcher and negligence. The Judge found the defendant Council liable in Rylands v Fletcher terms. He considered:

“The collection and conveyance of the stormwater from such a large urban area and channelling down a heavy modified watercourse is a non-natural user of the course of that stream. The stream is wholly on land owned by the defendant, and the water in it did escape onto the plaintiffs’ land causing the damage complained of. There was no act of God and nothing the plaintiffs did caused the escape.”

[33] Counsel very properly pointed out that Green was subject to an appeal. Since hearing counsel however, the defendant’s appeal has been struck out on the basis that the decision to appeal had been made by a delegate without authority.

[34] In that case as in this the Council did not have the purpose of accumulating or storing water but rather of allowing the water to pass through and so to proceed on its natural course. In Green, Judge Willy surpassed this difficulty by suggesting that Irvine v Dunedin City Council [1939] NZLR 741 (SC) was authority for the proposition that the Rule applies not only to accumulation of the non-natural use, but also to the carriage of substances over a defendant’s land. While Myers CJ did say this (at p 761) that was in the context of the carriage by pipes of water, gas and electricity which is a far cry from the present case.

[35] Significantly in all other cases cited by both counsel, those most analogous to the present case involve nuisance or negligence rather than the Rule in Rylands v Fletcher.

Nuisance

[36] Under this heading the plaintiffs contend that the flooding of their properties was a nuisance in that it interfered with the use and enjoyment of their land. They claim that the nuisance arose from the inadequacy of the defendant’s Rimu Road culvert to cope with water flows.

[37] As a broad starting point, I think it may be said that a private nuisance is an unreasonable interference with a person’s right to the use or enjoyment of land. In certain circumstances where the defendant has created the nuisance, liability may be strict. While there are similarities with the Rule in Rylands v Fletcher, historically Rylands v Fletcher has been concerned with isolated escapes, and nuisance with a continuing wrong although this is not invariably true. As was considered by the Court of Appeal in Hamilton v Papakura District Council [2000] 1 NZLR 265, to which Mr Mitchell referred, an isolated escape can give rise to a cause of action in nuisance. Examples cited by the Court were a water main bursting (Irvine & Co Ltd v Dunedin City Corporation [1939] NZLR 741), a blocked drain causing a flood (Pemberton v Bright [1960] 1 WLR 436 (CA)), and a gas explosion (Midwood & Co Ltd v Mayor, Aldermen And Citizens of Manchester [1905] 2 KB 597). The Court also noted the recognition in Read v J Lyons & Co Ltd [1947] AC 156 that nuisance usually focuses on the acts of the defendant, while Rylands v Fletcher consistently focuses on the event of an escape of some mischievous thing which the defendant brought onto his land.

[38] Liability in nuisance has been upheld when an inadequate culvert has caused flooding. In Greenock Corporation v Caledonian Rail Co [1917] AC 556 (HL) the appellants, with a view to creating a child’s playground, constructed a culvert in a stream that flowed through the town, and raised the level by placing material on the culvert. They also constructed a concrete paddling pool and dam at the mouth of the culvert, which seriously obstructed the free-flow of water. During high rainfall the stream flooded, damaging the respondent’s properties. In a passage approved by the House of Lords in Sedleigh-Denfield v O’Callaghan [1940] AC 880, Lord Finlay LC said, (at 572):

“It is the duty of any one who interferes with the course of a stream to see that the works which he substitutes for the channel provided by nature are adequate to carry off the water brought down even by extraordinary rainfall, and if damage results from the deficiency of the substitute which he has provided for the natural channel he will be liable. Such damage is not in the nature of dannum fatale, but is the direct result of the obstruction of a natural watercourse by the defenders’ works followed by heavy rain.”

[39] In Pemberton v Bright [1960] 1 WLR 436 (CA) the defendant Council widened a road under which ran a stream through a culvert. The Council extended the culvert 30 feet using a concrete pipe, which was left unprotected. For 30 years the Council’s workers periodically cleared the entrance of the culvert of debris. Following heavy rainfall, the entrance became blocked and the plaintiff’s land flooded. They sued in nuisance. The Court held (at 442):

“. . . the [defendants] created a potential nuisance which became an actual and actionable nuisance when, by reason of the entrance to the culvert being negligently left unprotected, it became blocked so that it dammed the water flowing in the stream and diverted it on to the plaintiff’s land.”

[40] However, an important component of nuisance is a reasonableness test. In Cambridge Water Co v Eastern Counties [1994] 2 AC 264 (HL) Lord Goff considered that strict liability in nuisance had been kept under control by the principle of the “reasonable user”. Thus, if the use of the land is reasonable, no liability for subsequent damage will follow, but if the use is unreasonable there will be liability even if all reasonable care had been taken. Similarly, in Delaware Mansions Ltd v The City of Westminster (supra) Lord Cooke (in his last judgment on the House of Lords) considered that:

“The answer to the issue (as to whether liability in nuisance followed damage caused by the encroachment of tree roots) falls to be found by applying the concepts of reasonableness between neighbours (real or figurative) which underlie much modern tort law and, more particularly, the law of nuisance.”

[41] Lord Cooke cited Sedleigh-Denfield, where the House of Lords had held that an occupier continues a nuisance if with knowledge of its existence he or she fails to take reasonable steps to end it, and Overseas Tankship (UK) Ltd v Miller Steamship Co Pty (1967] 1 AC 617 (PC), which imposed liability if “a reasonable man would have foreseen . . . and prevented the risk”. See also Goldman v Hargrave [1967] 1 AC 645 (PC), where it was suggested that it was necessary to consider what would be reasonable to expect of the defendant in the particular circumstances. The important point, as the learned Judge noted, is that all of these cases are directed to what a reasonable person in the shoes of the defendant would have done.

[42] The outcome appears to depend on that which is seen as the essential feature of the case. In Greenock, that feature was the introduction of a dam and paddling pool at the culvert mouth. In Pemberton it lay in the failure to protect a culvert that had a propensity to block. Here there were no such features. There was no interference with the channel save for the culvert itself and such small debris as the stream naturally carried had not previously caused particular concern. The work was not in itself unreasonable and was for a necessary roading purpose that was advantageous to the plaintiffs and all others in the area in providing additional access. The real questions here are whether the Council was careless in constructing the culvert, or was wrong in not enlarging the culvert when it appeared that the culvert might not be adequate for projected water flows. I think the case is primarily about negligence.

[43] Accordingly I bypass the first two causes of action and consider that the issues in this case properly fall to be determined within the framework of the third.

Negligence

[44] Here the plaintiffs contend that the defendant was negligent in constructing or maintaining the Armco culvert when that culvert was inadequate to cope with a f1ow of water of a scale commensurate with that which flowed on 20 October 1998, and when such a flow ought properly to have been predicted and provided for.

[45] The tort of negligence consists of a breach of a duty of care owed to another as a result of which that other suffers loss. The first question is whether the Council owed the plaintiffs a duty of care.

Was a duty of care owed?

[46] There is no doubt that the Council owed the plaintiffs a duty of care, and that the relationship between them was sufficiently proximate. However I understood Mr Mitchell to submit that it informs the standard of care that was necessary to prevent damage, to consider the particular duty owed to the plaintiffs in this case. In the process some side issues are settled.

[47] Mr Mitchell traced the relationship between the defendant and the first named plaintiff from an occasion in 1973 when Mr Murland and others, or a company with which they were involved, sought to subdivide the land at Ihakara Street. I accept that in so approving that subdivision, the Council, or a forebear from whom responsibilities have passed, must be taken to have considered the suitability of the land for that purpose having regard to the prospect of inundation.

[48] I understand from a question I put to a Council witness that the statutory source of power and responsibility was then s 23 of the Counties Amendment Act 1961. It matters not if the Municipal Corporations Act in fact applied as for the purposes of the present discussion the principles there are the same. Section 23(1) provided that when a scheme plan of subdivision is submitted for approval the Council shall refuse to approve the scheme plan if it is of the opinion, amongst other things, that the land is not suitable for subdivision. In sub-section (3) it was provided that without limiting the grounds upon which the Council may decide that the land is not suitable for subdivision, the Council, in deciding, shall take into consideration, amongst other things, any danger that may exist of the land being inundated or may require the owner to make provision for the same. Similar provisions would later appear in s 274 of the Local Government Act 1974 and, under the current regime, in s 106 of the Resource Management Act 1991.

[49] I need not go to the point of whether the Council was obliged to undertake an exhaustive inquiry to satisfy the requirements of the Counties Amendment Act. I doubt that it was so obliged. In this case the plaintiffs’ pleadings did not assert that the Council was negligent in approving the sub-divisional plans and the question is solely for the purpose of considering whether the Council knew or ought to have known that the plaintiffs’ land was liable to inundation. In this case, some few months after the request for an approval was made, Council approved the plan, but subject to ten conditions. These included compliance with processes under the Water and Soil Conservation Act 1967 for the discharge of water from the property and satisfactory provision for storm water drainage. In the application, the applicant had provided that all peat was to be removed and was to be replaced by suitable material. Further, a drainage easement was provided for what is now Drain 6 North. The adequacy of site drains to Drain 6 North was the subject of further correspondence. At the same time provision was required for certain building sites to be above a prescribed level in relation to those drains.

[50] No evidence was adduced to suggest that the Council was remiss in the performance of its duties having regard to the standard of the day. Equally, there is no evidence that the sub-divider was neglectful in informing the Council of the relevant facts. Clearly, both parties knew the land was low-lying and both sought special provisions to accommodate that fact. Final approval, after the conditions had been met, came much later in January 1977 when the plan, as revised, was sealed.

[51] The next development in the parties’ relationship was in the approval of building sites, for one may deem that in so approving, the Council considered those sites to be reasonably secure from what the heavens might provide. Approvals were not in fact sought until 1985, 1987 and 1988 beginning with G.H. Murland Limited in 1985. In the interim, in 1981 and 1982, Rimu Road had been extended to link to other roads in the north and the Armco culvert at the meeting of Rimu Road and Wharemauku Stream, had been installed.

[52] By that time the Local Government Act 1974 applied along with the Local Government Amendment Act 1979 as amended in 1983. Section 641(2) of the Local Government Amendment Act 1979, as amended in 1983, provided that the Council shall refuse to grant a building permit if in the opinion of the Council -

“(a) The land on which a building is proposed to be erected or altered, or any part of the land, is not suitable for the purpose of erecting the building . . .; or

(b) The land, or any part of it, is subject to erosion or subsidence or slippage, or inundation by the sea or by a river, stream, or lake or by any other source;

. . .

unless the Council is satisfied that provision has been made or is to be made for the protection of the land from erosion or subsidence or slippage or inundation.”

[53] The harmonisation of s 641 of the Local Government Act and s 23(1) of the Counties Amendment Act is not easy to achieve. The question of flooding had already been visited in 1973. What would have happened then had there been a flood in the interim? Approvals would have been given and in reliance upon those approvals an expenditure would have been incurred. How then could permits be reasonably refused except upon a requirement that provision be made for further protection? In similar vein, how could the Council have refused to seal a sub-divisional plan on account of new facts emerging, if the conditions of its original approval had been met? In the case of sealing a sub-divisional plan the position seems relatively clear that approvals once given cannot be taken away unless the necessary work has not been completed. In the case of building permits I should think that in terms of s 641 of the Local Government Amendment Act the Council would be obliged to refuse a permit unless further works could be undertaken and were undertaken to remove or ameliorate any new found malady.

[54] In this case there were in fact new circumstances. The first was “an occurrence” in 1976 that saw Drain 6 North flooding back from its confluence with Wharemauku Stream. Whatever the full nature and extent of the “occurrence”‘ may have been, no evidence has been adduced to show that it resulted in any flooding of the plaintiffs’ properties or that as a result of that “occurrence” the Council ought properly to have formed an opinion that a permit should not issue. Equally there is no evidence that the applicants for permits expressed concerns at that time about the 1976 “occurrence” or that they proposed any amendments or approvements to the existing drainage scheme.

[55] The second item of new material was that in 1982, the Council had been made aware of a report that questioned the efficacy of the Armco culvert on Rimu Road. The question then is whether the Council was remiss in issuing building permits having regard to that report, or was neglectful of its duties in not thereupon enlarging the passage that the culvert provided for the water in the Wharemauku Stream.

[56] That question arises later in this judgment. For the present I note that no claim is made for breach of statutory duty. Any breach that may have been inferred in evidence, in respect of the approval of the sub-divisional plan, would not be sustainable on the facts as they were known at the time in my assessment, that assessment being based upon such evidence as is now available. This matter was addressed by leading counsel for the defendant, Mr Heaney. I accept his submission that any action in respect of the approval of building permits would be ousted by s 91 of the Building Act 1991. This provides:

(1) Except to the extent provided in sub-section (2) of this section, the provisions of the Limitation Act 1950 apply to civil proceedings against any person where those proceedings arise from -

(a) Any building work associated with the design, construction, alteration, demolition, or removal of any building; or

(b) The exercise of any function under this Act or any previous enactment relating to the construction, alteration, demolition, or removal of that building.

(2) Civil proceedings relating to any building work may not be brought against any person 10 years or more after the date of the Act or omission on which the proceedings are based.”

The time limit imposed has now passed.

[57] There was much argument on the matters I have mentioned but they can now be set aside. All that needs to be noted at this juncture is as follows:

• First, in addition to any duty of care to property owners generally, I am satisfied that the Council owed a particular duty of care to the plaintiffs arising out of the Council’s approval of the relevant sub-divisional plans and the Council’s issuing of building permits:

• Secondly, it informs the duty of care so owed that in so approving and issuing, the Council was enjoined by statute to consider the prospect of flooding of the subject lands and the works necessary to provide a protective measure.

Breach of duty of care

[58] The main question in the plaintiffs’ case has been whether the Council was in breach of its duty of care to the plaintiffs in failing to improve upon the Armco culvert beneath the place where Rimu Road was extended across the Wharemauku Stream, when the Council knew or ought to have known that the culvert was likely to so restrict the flow of water in the stream as to cause a secondary flow which would flood the plaintiffs’ land. In this case there were large volumes of evidence relevant to this matter much of which was reviewed extensively in counsels’ closing submissions. I will simply set out the main facts as I find them to be in the light of counsels’ submissions.

Culvert design and installation

[59] The Armco culvert was designed some time before August 1979, which was some 6 years after the Council had approved the Ihakara Street sub-division knowing that the land there was low-lying. The file for the design of the culvert cannot now be located but a photograph shows that the construction material was to hand, by August 1979, so that the design must have been done earlier. In now assessing the appropriate degree of care in arranging for the Armco culvert, it is helpful to recall the caution of the Court of Appeal in Askin v Knox [1989] 1 NZLR 248 that matters are to be determined according to the state of knowledge at the time.

[60] The greater evidence is that in 1979, the installation of the Armco culvert would have been seen as regular in respect of other than a main highway - and this was not a main highway. Very little existed to indicate a need for special caution. No records suggested that the Ihakara Street area, though low-lying, was particularly or especially flood prone. It was known to be peat land, which is indicative of past swamping, but then most of the Kapiti Coast is characterised as peat land discoverable in the furrows of sand dunes. Nonetheless the greater area from Ihakara Street to the coast had been heavily developed for housing and all that had been done without marked, untoward results. Mr Murland, in his evidence, had not known Ihakara Street to have been flooded before 1998 yet he had had the land for 20-25 years and his father had owned it before then.

[61] Records discovered in the proceedings disclosed an “occurrence” in 1976, which I have already mentioned, when Drain 6 had backflowed in a storm, but it is more telling that this was described as a “new occurrence’, as Mr Heaney emphasised in his submissions, and no note was made of any flooding of the land. Another flood report, in 1980, related to overflows downstream in the main residential areas. This did not affect the subject land, although it did lead to doubts about the efficacy of another culvert in another place. The problem there, however, was that the culvert provided poor entry for the stream and here, the culvert was “straight on”. The Armco culvert was finally installed between late 1980 and early 1981 when the construction of Rimu Road was brought to completion.

[62] Civil engineer Brian Hickling deposed that many local authorities did not have the formalised planning documents of today to manage construction works affecting water flows. The fledgling Kapiti Coast Borough, formed in late 1974 from parts of earlier counties, was no exception. The Council had inherited little in the way of infrastructure. For example, reticulated sewerage was introduced only between 1981 and 1983. For such smaller authorities culverts were not uncommon and there were no general planning codes to suggest an alternative. Mr Hickling’s conclusion that there was nothing unreasonable in the Council’s approach when the culvert was designed and was laid, is supported by the evidence.

1982 criticism of the culvert’s capacity

[63] However, in the same period that this culvert was laid, new emphasis to storm water management followed floods in the Hutt Valley in December 1976. While that was quite removed from the Kapiti Coast, the floods did result in new codes or guidelines, produced separately by the Institute of Engineers in December 1980, as a guide to smaller local authorities and the profession generally, and by the Wellington City Corporation in 1982.

[64] Such codes were not available when the Kapiti Council completed its Rimu Road design but in about 1980, the Council engaged engineering consultants to advise on storm water management. General advice and technical data were released by the consultants at different times and reference was made to design standards for various flows. It seems to have been as a consequence of that, that the borough engineer sought a specific assessment of the new Armco culvert that had just been put in place.

[65] Mr Mitchell relied on the consultant’s response of 29 April 1982 as indicating that from that point, the Council ought to have taken positive steps to have the culvert replaced or another culvert installed alongside.

[66] The Council’s consultants reported that the culvert, when assessed in relation to the abutting riverbanks, would need less than a two year design flow, while the waterway upstream carried a design flow of 20 years. The culvert was thus seen as a significant constraint. The consultants recommended replacement or that a second culvert be added alongside.

[67] The consultants’ reports from the early 1980s marked the introduction to the Kapiti Coast of a planned approach to storm water management. In that approach waterways are examined for their capacity to manage flows of various strengths having regard to the anticipated frequency of a range of flow intensities. In the absence of historic core data from the measuring of actual flows, the consultants had necessarily to project the frequency of different flow intensities from an examination of catchment characteristics, rainfall statistics and the like. For the purposes of this case it saves upon elaboration to adopt a measure much mentioned in evidence whereby a flow likely to recur about once every 5 years is expressed as Q5. Q is an old established symbol for a quantity of water discharge, usually measured in cumecs, or cubic metres per second.

[68] In the case of the Armco culvert on Rimu Road, the consultants considered, in 1982, that the culvert, having regard to the height of the abutting banks, could cope with no more than Q2, when a standard of Q20 ought to apply. Raising the banks would increase the quantity of water and take the capacity nearer to the Q20 standard. The stream was otherwise capable of handling that standard. The more preferable course however, was to replace the whole with a bridge or to put another culvert alongside.

[69] The Council appears to have considered that the constriction provided by the culvert did not present too large a problem. In the event of a flow larger than that which the culvert and banks were able to accommodate, there was, in effect, an escape path for the excess. There was room for the overflow to pass over the South bank on a secondary flow path down what were then paddocks on the Eastern side of Rimu Road. From there it would pass to Drain 6 North where it would flow on to the Wharemauku Stream. Accordingly, at some time between 1982 and 1990, the South bank was raised so as to increase the flow through the culvert, but a depression was maintained near to Rimu Road to allow for an overflow to pass on the secondary flow path described.

[70] Some years later the consultants considered that the culvert was in fact capable of managing Q20. In addition however there were also doubts as to the capacity of the secondary flow path to perform to expectations. All that was later however. The first question is whether the Council’s response to the 1982 reports of doing no more than raising the bank a little and then allowing for a secondary flow path, was reasonable at the time.

[71] On the evidence. I accept Mr Heaney’s submission that a number of considerations weigh against an expectation that a reasonable Council would have acted with some sense of immediacy to plan in a manner that the consultants had suggested. Putting the matter in terms of my own findings:

(a) There were no particular statutory requirements or settled planning documents to compel the Council to adopt a more rigorous stance than the normal standards of a reasonable person in such a situation.

(b) Reasonable care does not require a Pavlovian response to a consultant’s every recommendation for, if it did, ratepayers would be exposed to undue burdens and councillors would be surcharged from office on a flow of Q3. At most a Council might plan having regard to competing demands. At this distant point in time it is not possible to say what all those demands may have been.

(c) Regard has then to be had to any sense of urgency that the consultants themselves may have expressed in making their recommendations. Upon reading the 1982 report, I find a sense of urgency is singularly lacking. The problem was exposed but was not expressed in any such graphic way as may have stimulated the Council to some more extraordinary speed. Instead, interim measures were suggested.

(d) A planned approach to floodwater management based on future projections was new. It would eventually substitute for the old approach of relying on past history. Here, past history gave no particular cause for concern. In many respects the Kapiti Council was entering upon an optimum planning approach well ahead of councils of similar size and circumstance but nonetheless, one cannot expect a rapid mind shift from the old way of viewing things.

(e) The consultants’ previous interim reports had already indicated that the new planning methodology was indeed new and the science was not exact. In this case, emperical methodologies were required for reasons that I have explained. These depended upon the resolution of a range of uncertain variables and no single method of testing had gained ascendancy.

(f) Studies were ongoing and further reports were projected with improvements in assessing the likely flows in the district, their frequency and the capacity of existing waterways and drains to cope.

(g) While new planning methodologies may rapidly lead to new codes for future construction, a different set of criteria must prevail for existing, non-complying works.

(h) Finally, the Council had an emergency plan for the excess water to pass on a secondary flow path to Drain 6 North. There is nothing in the evidence to suggest that at the time, the emergency plan might be questionable. Secondary flow paths were common.

[72] I am drawn to the view that in 1982, the Council’s approach, in deferring matters pending further examination and reports, in reliance upon a secondary flow path, was reasonable. It does not appear as mere neglect but rather, as a calculated decision made in the context that studies in the area were new and further examination would be conducted.

Developments 1982-1998

[73] The subsequent period to 1990 saw ongoing discussions for the development of the whole of the paddock area south of the culvert to provide for major shopping facilities with extensive carparks. All was to be linked to pre-existing complexes to the north of the river by vehicle bridges and a covered pedestrian bridge built into the malls on either side.

[74] The Council was concerned to protect the secondary flow path over the sealed carparks and to ensure that the new buildings were removed from that path and had floor levels above the maximum height of the anticipated flow. At the same time, the south bank of the river was raised, as earlier described. It was raised from RL 7.8 to RL 8.2 to increase the flow to the culvert while maintaining provision for any overflow from a major storm to pass to the south.

[75] Contemporaneously the science of hydrometric analysis advanced. This was aided by the measurement of real flows by means of gauging equipment, installed in 1980, at a weir shortly upstream from the Armco culvert.

[76] In 1990 the Manawatu-Wanganui Regional Council, with the advantage of new data and insights, completed a fresh flood frequency analysis for the district. From this the consultants’ 1982 analysis had indeed been conservative. It transpired that the culvert and bank was in fact adequate for a Q20 design. Had this been known in 1982 then clearly, the Council’s position would have been justified on the basis of expert views.

[77] Nonetheless the Council’s consultants remained cautious and were not convinced that the Regional Council was entirely correct. Armed with yet more material and the additional studies of others, the consultants advised the Council, in 1994, that the constriction would not in fact match Q20 standards. They put the reality at somewhere above Q15. On that basis they recommended that the culvert be replaced by a bridge within 5 years, that is, by 1999. A bridge would provide a design flow possibly as high as Q100.

[78] However, a bridge would also represent a marked expense but in 1998, a bridge was programmed into the Council’s capital works for 2002-2003.

[79] The position of the plaintiffs was put by Raymond O’Callaghan, an engineer with expertise in water design, and Gary Williams, a consulting engineer specialising in water and soil engineering. They argued that the Council ought to have been aware from the early 1980s that a Q20 standard should apply. They pointed to design guidelines from the Institute of Engineers in December 1980 (pertinent to the flooding of buildings), and local authority design codes from July 1981. For these purposes they argued that Rimu Road was to be regarded as a primary road. However, in this case, the Council’s consultants had been urging no less. The real problem lay in assessing the rate of flow that would equate a Q20 design for this particular catchment and stream.

[80] The plaintiffs’ experts also pointed to the fact that the Council itself had insisted upon a Q20 standard for the shopping complex developers on the lands South-East of the Rimu Road culvert. More particularly the Council had required full bridges. Again, an insistence on standards for new works, according to the scientific wisdom of the day, is reasonable, but the variables are not the same when it comes to considering existing works. There, the real question is the time that should be allowed having regard to the cost. For example, should a city’s buildings be found to be less than adequate on the basis of new earthquake standards, there can be no requirement for old buildings to be replaced except within a reasonable timeframe.

[81] The councillor’s advice to the developers, in 1986, that replacement of the culvert was not a priority, must be seen in that context, in my view, together with the fact that there was a contingency plan for an overflow in the event of a major flood.

[82] All this has also to be seen in the context that the early 1990s marks a national movement for a greater level in protection from flooding, exemplified in the Resource Management Act 1991 and subsequent building codes. A movement is nonetheless a movement, being something that strengthens with experience. I was not alerted to any particular fixed standards that were hard and fast law.

[83] The plaintiffs’ evidence is further that during this time, the Council ought properly to have appreciated that the secondary flow path was inadequate to convey the excess water, in a major storm, to Drain 6 North and so to join the Wharemauku Stream. Mr O’Callaghan considered that by 1991 the New Zealand Building Industry Authority Code, and the Council’s own code of practice, obliged the Council to bring the secondary flow path into consideration in its water management planning. I do not think that that was ever disputed. Nor was it disputed that the Council in fact had the secondary flow path in mind. The Council required the developer of the new shopping lands to provide for the secondary flow path to continue over the area to be designated for carparks and to site buildings to stand beyond that path.

[84] The real problems were two-fold. First, was Drain 6 North capable of receiving the additional water? Second, would the configuration in fact lead the flow to Drain 6 North, or would it cause the flow to bypass that drain and flow direct to Ihakara Street? Mr Williams thought it would be obvious to even an untrained person, simply by looking at the land, that the secondary flow would pass direct to Ihakara Street.

[85] In a report to the developers of 1990, the Council’s consultants estimated the likely amount of spill on a maximum flow at Q20, an amount that would vary according to whatever height was finally settled upon for the south bank weir. Using maximum anticipated flows the consultants predicted that the bulk would pass along the secondary flow path but with some sheeting across to Rimu Road. The assumption appears to have been however, that all would pass to Drain 6 North at the South-Western corner of the developers’ land. However, the consultants did go on to recognise that Drain 6 North would have difficulty in coping with the excess. It was anticipated that the water would pool in the South-West corner of the development site.

[86] Since the focus of the report was on the impacts that this might have for the developers, no mention was made of the possible impacts for Ihakara Street owners. In looking at the report, the assumption appears to have been that while there would be pooling in the South-West corner, that pool would not become so large as to invade above the floor levels of the developers’ proposed new buildings. That still left quite a question mark over what would happen to the water as it built up. Where would it go? The logical answer, on the evidence now available, is that it would go to Ihakara Street, by whatever route.

[87] Counsel variously assessed the evidence as to the true quantity of water that might overflow the South bank on the maximum flow to be predicted within a term of 20 years. I think the position is simply that there is considerable room for speculation. Too much depends upon the collation of real data for feeding into scientific minds. It has also to be brought into account that the consultants themselves have operated from a conservative position in order to minimise risk. Even allowing for differences as to true quantity however, it can be said that on the state of the science as applied to this case, it was expected that there would be an overflow within a term of 20 years and that the drain to deal with the likely overflow, was unlikely to cope. From the evidence of relative levels it must have been plain that Ihakara Street would bear the burden of the result.

[88] The inference is that in its consideration of a secondary flow path in 1990, the Council failed to have adequate regard to the impact on Ihakara Street property owners. The resulting question however is not whether the Council was entirely unmindful of the Ihakara Street owners at that time. The question is whether the Council should properly have provided sooner than it did, assuming that it was aware of the risk to Ihakara Street, in budgeting for an upgrade of the Armco culvert.

[89] No evidence was given as to the various demands upon the Council’s funds at this time. The only evidence is that of Blair Murray, the Council’s storm water engineer since about 1993, as to current demands. Mr Murray deposed that the Council is presently engaged in a cost-benefit analysis for approximately 100 storm water projects within the Kapiti region. These comprise about $10 million worth of works to be prioritised into a capital works programme over the next 20 years. Current funding is in the vicinity of $1.8 million for 2001-2002.

[90] The essential question is a question of law as to both the imposition of a duty of care in these circumstances and the appropriate standard of care required. I have already mentioned the conclusions of Lord Cooke in Delaware Mansions and the opinion adopted there that liability would be imposed if “a reasonable man would have foreseen . . . and prevented the risk”. In addition Mr Jameson for the defendant drew upon Anns v Merton London Borough Council [1978] AC 728 at 751-752 and the judgment of Richardson J in Fleming v Securities Commission [1995] 2 NZLR 514 at 526 to stress the two-stage approach required and most especially the second broad field of inquiry as to whether there are any policy considerations that tend to negate or restrict a duty in any particular case. He submitted the more operational the alleged cause of the harm the more likely a duty of care will exist (citing Stachniak v County of Thorchild; Camploops v Neilson [1984] 2 SCR, 5 WWR 1 (SCC)) while pure policy decisions are much less likely to be subject to such a duty.

[91] Mr Mitchell submitted that the facts of this case are a very long way from what he termed the “policy-operational dichotomy”. He submitted that the matters which led to this flooding have always been within the operational purview of the defendant.

[92] I have already given my findings on the facts on the basis of the evidence and in the process I have expressed some view. In the circumstances of this case the following passage from Goldman v Hargrave (supra at 656-657) appears most apposite:

“So far it has been possible to consider the existence of a duty, in general terms; but the matter cannot be left there without some definition of the scope of his duty. How far does it go? What is the standard of the effort required? What is the position as regards expenditure? It is not enough to say merely that these must be “reasonable” since what is reasonable to one man may be very unreasonable, and indeed ruinous, to another: the law must take account of the fact that the occupier on whom the duty is cast, has, ex hypothesi, had this hazard thrust on him through no seeking or fault of his own. His interest, and his resources whether physical or material, may be of a very modest character either in relation to the magnitude of the hazard, or as compared with those of his threatened neighbour. A rule which required of him in such unsought circumstances in his neighbour’s interest a physical effort of which he is not capable, or an excessive expenditure of money, would be unenforceable or unjust. One may say in general terms that the existence of a duty must be based on knowledge of the hazard, ability to foresee the consequences of not checking or removing it, and the ability to abate it. Moreover in many cases, as for example in Scrutton LJ’s ([1924] 1 KB at p 357) hypothetical case of stamping out a fire, or the present case, where the hazard could have been removed with little effort and no expenditure, no problem arises; but other cases may not be so simple. In such situations the standard ought to be to require of the occupier what it is reasonable to expect of him in his individual circumstances. Thus, less must be expected of the infirm than of the able bodied: the owner of small property where a hazard arises which threatens a neighbour with substantial interests should not have to do so much as one with larger interests of his own at stake and greater resources to protect them: if the small owner does what he can and promptly calls on his neighbour to provide additional resources, he may be held to have done his duty: he should not be liable unless it is clearly proved that he could, and reasonably in his individual circumstance should, have done more. This approach to a difficult matter is in fact that which the courts in their more recent decisions have taken.”

[93] Standing back from the matter and seeking a broad overview I have come to the conclusion that the Council’s actions in planning for a bridge to replace the culvert in the not too distant future, was reasonable having regard to the presumed competing demands on the Council and its assessment of those demands against the risk inherent in the existing floodwater scheme. The Council had to balance a number of competing interests and there is no evidence that in seeking a balance the Council was acting irresponsibly. The evidence is rather that the Council was concerned to take a responsible approach. I find therefore that the Council was not in breach of its duty and that the action must fail.

[94] If I am wrong in that conclusion then I have also to consider a question of “fatal inevitability” under the further heading of causation.

Causation

[95] The storm of 20 October 1998 appears to have caught everyone by surprise except for the more cautious hydro-analysts. The storm, along a large section of the coast from Wanganui to Wellington, caused a degree of damage and disruption of a scale that no one, in evidence, could recall. It also claimed one life. An assessment from the Wellington Regional Council was that the storm over-topped Q100.

[96] I am inclined to accept the Wellington Regional Council’s conclusion notwithstanding that the Kapiti Council’s consultants hastened to advise the Council to rank the storm at about Q40. However, as I understand the evidence, the consultants’ assessment of Q40 was a computed result, simply incorporating the flow into the relatively brief expanse of recorded real flows from 1980 and so adjusting averages. It is thus, once more, a conservative position for future planning, rather than an attempt at recording history.

[97] The fact remains, nonetheless, that the 20 October 1998 storm, seen in historic terms, was unique, as far as historic records go. It also provides sound evidence, in real terms, and without the necessary artifices of planning, that the culvert had in fact served close enough to the design period of 20 years without causing more than the one surcharge as predicted within that timeframe.

[98] Accordingly, in reverting to the reality, and leaving aside the safety mechanisms for sound future planning. Mr Heaney submitted for the defendant that even without the culvert and the associated ground work that impeded the flow at Rimu Road, and had the stream flowed precisely on nature’s path, without restriction, the flood of Ihakara Street would still have occurred. The reason lies, in the Council’s expert evidence, in its assessment that backflows from the lower reaches would have pushed up Drain 6 to overflow onto the plaintiffs’ properties at Ihakara Street, to the same extent as in fact happened on the night in question.

[99] That evidence focused upon a combination of factors. The flow rate, at its maximum for 5 hours from 9.15 p.m. to 2.15 a.m., and peaking at 26.9 cumecs at 11.45 p.m., was one contributing factor. The relative levels of the land at the Drain 6 confluence, the drain levels at Ihakara Street. and the anticipated flood levels as assessed in 1994 on a lesser flow of 26 cumecs, was another factor. Further to be drawn into the mix is old evidence of backflow propensities. The phenomenon was noted in a report of 1982 which recommended flap gates for the Drain 6 outlet. (The flap gates were seen to generate other difficulties). Further support for backflow potentialities was the recording of that fact in respect of Drain 6 in 1976, although no damage was reported on that occasion.

[100] Major support however lies in a further unique event that in the week after the major storm of 20 October there was another storm, of much lesser magnitude, but significant for the further information that it gave. The flow then, speaking comparatively, was a mere 14.3 cumecs. That was large nonetheless. On that occasion there was no overflowing at the culvert and all the water passed on nature’s course. However, even at that flow rate, the water backed up in Drain 6 and Ihakara Street was again subjected to flooding. Certainly the flooding was not of the same order, but the significance of the event is in the proof of the point.

[101] On the evidence the facility for Drain 6 North to overtop in the North West corner of the plaintiffs’ properties, is matched by the facility for Drain 6 South to feed back water from an equivalent position in the South, through a drain pipe that normally operated to take water away.

[102] Experts for the plaintiffs endeavoured to counteract this argument. It was unconvincing, in my view, in all respects but one. The North, West and Southern perimeters had bunds at the edges of the drains. “Bunds” is a term which appears to have been imported into New Zealand by military engineers who settled here after serving in the Imperial Militia in India. There the term describes a solid embankment, dam or dyke. In New Zealand context, I think it must stand for something closer to a rough mounding of earth to similar effect. Mr Murland deposed that he developed the bunds that now exist in the North and South aspects of the Ihakara Street development. He said he did this by chance when bulldozing earth and vegetation while preparing for the sub-division. He did not know the origin of the more crucial Western bund. He thought the Council probably put it there when forming Ihakara Street. The Council’s records shed no light. In any event it existed. From the evidence of de-watering after the storm, the fact appears to be that the bund tended to lock the pool of water into place, to the extent that the West bund had to be cut open to assist the de-watering process.

[103] The question is whether, as the plaintiffs contend, the bunds, and the West bund especially, were sufficient to keep the backflow out. The question raised some difficulties at first, but upon examination I am drawn to the conclusion that despite any arrest that the West bund may have provided for a time, to any backflow over the land, the bund could not have stopped the discharge to the plaintiffs’ properties at the North-West and South-West corners. Rampant water, being all id without super-ego, must journey to its own low destination. On the evidence, I consider the balance of probabilities is rather clearly in favour of the backflow travelling to the Ihakara low points and filling in the plaintiffs’ properties from there. I am satisfied that the fill from the backflow would have equalled the fill that came from the culvert on 20 October. From whichever source the water came, gravity would still determine the water plane. I accept the evidence for the Council, that irrespective of the culvert, and any inadequacies of the secondary flow path, the flooding of the plaintiffs’ properties would have occurred to the extent that it did.

[104] The law on this matter is not without difficulties. These difficulties have not been assisted by the fact that counsel, while addressing the facts in some detail and while citing numerous authorities in all other areas, cited no authorities in asserting as to the law under this heading. However, as I see the position, the starting point for determining whether a defendant caused the plaintiff’s loss is the generally accepted “but for” test, which asks whether the harm to the plaintiff would have happened “but for” the tortious acts of the defendant. Because of the inevitability of the flood, it is clear that the “but for” test is not satisfied. However, this is not the end of the matter. The function of the “but for” test is not to allocate legal responsibility, but simply to “act as a preliminary filter and eliminate the irrelevant”: Winfield and Jolowicz on Tort (14ed, 1994), 148. Normally a negative answer to the test will determine the issue, but where there is more than one cause, each sufficient in itself, the “but for” test is by itself inadequate: March v EMH Stramere Pty Ltd (1991) 99 ALR 423.

[105] The damage in this case is indivisible, in the sense that it is unclear whether the flooding resulted from the overflow at the culvert or the backflow. In such cases, policy considerations, in the sense of the justice of the case, may be helpful in determining causation. For example, if two persons separately light fires which later combine to damage the property of a third, and either fire would have been sufficient to cause the whole of the damage, it seems unjust that the persons who lit the fire escape liability on a “but for” test. In Pryce v Small (1909) 11 GLR 508 (SC) Denniston J suggested, obiter, that while the authors of each fire are not properly termed “joint tortfeasors”, each may, if the effect of each fire is indistinguishable, be liable for the entire damage. Similarly, where two motorcyclists drove past a horse at the same moment, causing it to bolt and the plaintiff to fall off, it was held that both caused the loss: Cory v Havener 65 NE 69 (1902).

[106] The case is no different, it would seem, where tortious and non-tortious causes combine to produce the damage. The policy questions applicable when two tortfeasors seek to blame the other are not necessarily the same, but courts have been willing to similarly modify the “but for” test. An example is Bonnington Castings Ltd v Wardlaw [1956] AC 613, where the House of Lords was faced with a plaintiff who contracted a disease via inhalation of silica dust from two sources, in respect of one of which the defendant was in breach of statutory duty. Because it was the atmosphere inhaled by Mr Wardlaw that caused his illness, it was impossible to resolve the components of that atmosphere into particles caused by the fault of the appellants and particles not so caused, as if they were separate and independent factors in the illness. The real question was whether the breach of duty materially contributed to the plaintiff’s loss, and the defendant was therefore liable for the whole loss unless the de minimis principle applied.

[107] There is also support in the cases for the proposition that where only one cause operates, but it is inevitable that another would have done the same thing a little later, while the first is the operating cause rendering the defendant liable the damages may be discounted. In Smith v Cawdle Fen, Ely (Cambridge Commissioners [1938] 4 All ER 64 (KBD)) very similar facts to the present case arose. The plaintiff’s lands had been damaged by flooding, and the main cause was that the banks of a river were too low. Four days after the flood, abnormal tides and weather combined to cause water to rush over the rivers banks again, something that was not due to any fault of the defendants. This also would have flooded the plaintiff’s land.

[108] While it was unnecessary to do so, the Council having been found not liable for the initial flooding, Du Parcq J considered that it would be no answer to a claim for damages for destroying something that it would be destroyed four days later. However, this would affect quantum, because the “expectation of life” would have to be taken into account. To borrow the example given by the learned Judge, if a man is killed by someone’s negligence on Monday but had been sentenced to die the following Wednesday, it would be strange if his estate could recover the same damages as if he had been a person with a likelihood of along life.

[109] In the New Zealand context the test for causation was considered in Sew Hoy & Sons Ltd v Coopers & Lybrand [1996] 1 NZLR 392 (CA), where the appellant said that by giving an unqualified audit certificate to company accounts which showed a profit, the auditors had caused the company to carry on business instead of closing down. McKay J confirmed that causation means more than the mere creation of the opportunity to incur loss, but to say that it was decided by an application of common sense was not to provide a test, but to point out that it was a jury question. Henry J suggested that the question was whether, on a broad and common sense view, the loss suffered is to be attributed to the breach of duty of care. Thomas J considered that it was a mistake to think that the causation issue could be answered by a single question, or in one step. He said (at 408-409):

“The basic question remains whether there is a causal connection between the defendant’s default and the plaintiff’s loss . . . the answer to this question will not be resolved by the application of a formula but by the application of a Judge’s common sense. The Judge needs to stand back from the case, examine the facts closely, and then decide whether there is a causal link between the default and the loss in issue which can be identified and supported by reasoned argument.”

[110] The House of Lords’ decision in Bonnington can be distinguished from the present case. There are a number of similarities between the present case and this one, in particular that there was a tortious and a non-tortious event that was said to have resulted in the harm, and the harm itself was indivisible. However, there was no express finding that the non-tortious cause would have been sufficient in itself to cause the plaintiff’s illness. Rather Bonnington was a case in which the whole of the polluted atmosphere in the plaintiff’s place of employment caused the disease. While it was accepted that the non-tortious cause resulted in most of the disease-causing particles entering the air, and that the contribution of pollution for which the appellants were responsible was small, it was continuous over a long period. Significantly, Lord Keith of Avonholm considered that the particles inhaled from each source acted cumulatively, and had it not been for this cumulative effect, the respondent may not have contracted the disease when he did, if he contracted it at all. Lord Reid also considered that it was the combined effect that caused the respondent’s disease.

[111] In this case, in contrast, I have concluded that the flooding was inevitable, regardless of what the Council did. In Smith v Cawdle Fen, Ely (Cambridge Commissioners) the King’s Bench considered that inevitability of damage due to a subsequent non-tortious event did not by itself preclude the possibility that an earlier tortious event could be considered a cause. However, that statement was obiter and had not been the subject of argument by counsel. Second, the non-tortious event in that case happened four days after the tortious event, and it was thus easier to isolate the actual cause of the harm. A finding that an event four days later reduced the cause of the harm to being merely incidental would have been problematic, because it would then have raised the question as to where, in terms of time, the line was to be drawn. Common sense dictated that because the plaintiff would have had the use of the flooded land for four days had the defendant not acted negligently, it should be compensated for that loss. In the present case, however, the flooding from both sources, the culvert and the backflow, happened in fairly short order. As a matter of commonsense, I think it would be pretentious to hold that the culvert was the cause, when the flooding was inevitable in any event. The conclusion to which I come is that the Council should not be liable for the tort of negligence, if it was in fact negligent.

Quantum

[112] For the defendant, Mr Heaney submitted that the plaintiffs have failed to prove each item of loss in respect of each plaintiff as detailed in the statement of claim. That claimed and that accepted by the defendant as proven, was:

Claimed	Accepted
Ken Griffiths Imports	$173,937.77	$60,616.30
Signfix Systems	$88,987.62	$53,266.18
Opie	$13,142.91	$3,413.50
Alan Gray Motors	$9,745.92	$ 4,295.57
Kapiti Silverware	$24,474.41	$5,445.00
Atlas Properties	$11,523.00	$11,523.00
Ivy Ashby Ltd	$2,157.77	$2,157.77

[113] On the basis of those submissions the defendant claims that the damages should be reduced from the amount claimed, $323,969.40 to $140,717.32.

[114] The main challenge is to the loss of profits claims which constituted the greater parts of the claims of Ken Griffiths Imports and Signfix Systems as assessed by the insurance company’s loss of profits accountant. Mr Heaney submitted that the defendant obtained concessions from the plaintiffs’ expert that such claims were not supported by the evidence. Mr Heaney explained in submissions that the defendant Council, taking the view that councils have not been historically liable for flood damage, had not insured against this loss in the usual way. The Council was merely part of a co-operative risk sharing scheme amongst certain councils. Presumably the defendant feels unable to work on any give and take understanding that might otherwise apply between insurers.

[115] Mr Mitchell submitted that the insurance assessor reached his conclusions based on a range of factors and that the amounts claimed were accepted by an experience loss adjuster and payment was recommended. Such a recommendation being reasonable it should be accepted by the Court, he submitted, as loss adjusters are unlikely to recommend payment unless satisfied that the loss was incurred. The first question, as Mr Mitchell submitted, was whether there was, on the balance of probability, material lost. Because there is no doubt that the damage and loss was significant, quantification must be a matter of commercial judgment and reality, and that the inability to get mathematical precision on quantum does not remove the loss. Further, evidence from the plaintiffs was that their uninsured losses had not been claimed.

[116] The basic principle to be applied when calculating tortious damages is that the plaintiff should be placed in the same position as if the loss had not be suffered: Czarnikow v Koufos (The Heron II) [1969] AC 350, 420 (HL). As a further general principle, proof of damage is an essential element of most torts, and if a plaintiff is unable to prove any loss caused by the tort, no remedy is available.

[117] In Bonham-Carter v Hyde Park Hotel Ltd (1948) 64 TLR 177, 178) Lord Goddard CJ said:

“Plaintiffs must understand that, if they bring actions for damages, it is for them to prove their damage; it is not enough to write down particulars and, so to speak, throw them at the head of the court, saying: ‘This is what I have lost, I ask you to give me these damages’. They have to prove it.”

[118] The nature of such proof was considered in Ashcroft v Curtin [1971] 3 All ER 1208 (CA). The plaintiff had established his own successful one-man business. Injuries negligently inflicted by the defendant had undoubtedly resulted in damage to the business, as the plaintiff was unable to continue working in the same way he used to. Unfortunately the accounts kept by the plaintiff were woefully inadequate, so that loss of profitability was impossible to determine. However, Edmund Davies LJ (CA) was reluctant to award no damages, as this would be unjust to the plaintiff. It would mean that, in the words of Holroyd Pearce LJ in Daniels v Jones [1961] 3 All ER 24, 28, “arithmetic has failed to provide the answer which commonsense demands”. The conclusion the Judge reached was that while the probability was that some loss of profitability resulted from the plaintiff’s accident, it was quite impossible to quantify it. However, it was considered improbable that the amount lost was anything like the amount awarded by the Court below, so it was reduced.

[119] This case is focused on but one of many localities seriously affected by the storm in question. Some relaxation of the normal standards of inspection and recording may have been necessary for prompt payments to all of those affected. In these circumstances I consider the Court should trust to the experienced eye of expert assessors unless it is plain that they were remiss in the performance of responsibility. In this case the assessor impressed as to his large experience and to his regular detailed investigation. But for the decisions earlier that negligence and causation have not been proved, I would have accepted the amount claimed.

Conclusion

[120] Judgment is for the defendant and no award is made. Instead the defendant is awarded costs on the basis of category 2 band B. In interlocutory stages counsel then appearing for the plaintiffs had asked that I record that Mr Heaney had insisted upon calling each plaintiff to be cross-examined on their briefs in relation to quantum. I am satisfied that Mr Heaney had good cause to so insist. Although the decision is against him on that point, his arguments were merited and I do not make any reduction in the costs awarded.