Ipsofactoj.com: International Cases [2003] Part 5 Case 12 [NZCA]



Atlas Properties Ltd

- vs -

Kapiti District Council






20 JUNE 2002


Blanchard J


  1. The appellants are property owners in Ihakara Street, Paraparaumu who unsuccessfully sued the Kapiti Coast District Council for damage caused to their properties by waters from the flood-swollen Wharemauku Stream during a major storm on the night of 20-21 October 1998. As pleaded and run at trial in the High Court at Wellington before Durie J, the case for the appellants was that the problem was caused by the inadequate capacity of a road culvert over the stream in Rimu Road. Water which could not pass through the culvert diverted onto and across Rimu Road and ran to and ponded on the lowest adjacent land, which included the properties of the appellants (the properties).

  2. The Council had appreciated that in flood conditions the culvert would not be able to cope with all the floodwater and had made provision for the excess water to follow the course it did along the road. But then it was supposed to enter one or other of two drains which would take it back to the stream at a point beyond the properties and downstream from the culvert. The reason why this did not occur and why the water ended up on the properties will emerge shortly.

  3. At the trial it became apparent – the experts on both sides agreeing on this matter – that, even if there had been no culvert and no diversion of part of the water, the properties would still have been flooded. This would have happened because at a point on the other side of the properties the two drains from Rimu Road joined together on Council-owned land situated between the properties and the stream. There is a pipe through which water from the drains can then enter the stream. The experts agreed that because beyond that point i.e. lower down the stream, the bed is constricted, floodwaters in the quantity experienced on the night in question were unable to pass and consequently built up in the vicinity of the pipe and backflowed up the drain and also overtopped the stopbank which at that point is very low. This phenomenon actually contributed to the flooding of the properties. If all the water had been able to pass through the culvert the probability is that the backflow would have been much greater. Thus the same degree of flooding of the properties was, the experts agreed, inevitable even if the culvert had been adequate in capacity.

  4. The appellants had three causes of action – under the Rule in Rylands v Fletcher (1868) LR 3 HL 330, in nuisance and in negligence, but the claims under Rylands v Fletcher and in nuisance were pleaded and presented at trial only in relation to the culvert. So, primarily, was the claim in negligence and therefore almost all the evidence was directed to showing a breach of duty of care by the Council in respect of the culvert and the diversion of the water across Rimu Road. There was, however, a generalised pleading that the Council had failed, in breach of its duty of care to the appellants, to "provide, repair or maintain its stormwater drainage system so as to prevent the flooding of the plaintiffs’ properties during the storm".

  5. In this Court, Mr. Heaney for the respondent Council, conceded that this pleading, which was not particularised in any way, could be said to encompass an allegation of negligence by the Council in failing to take steps to prevent flooding of the properties by backflow of stream water up the pipe and the drains and by the overflowing of the low part of the stopbank. As will be seen, however, hardly any of the evidence and submissions were addressed to this question and, in particular, to whether the raising of the stopbank at this point and the installation of a one-way gate or flap on the pipe would have prevented or substantially mitigated the appellants’ flood damage if there had been no diversion of water at the culvert and it had all continued down the stream to the confluence with the drain.

  6. Nor, as will also be seen, did the evidence or the submissions do more than touch in an incidental way on the wider question, raised by the pleading of an inadequate stormwater drainage system, of the Council’s legal responsibilities to other property owners adjacent to the swollen steam and the possible effects on them if pressure on the swollen stream were not relieved by allowing it to backflow over and pond upon the Council’s land and the properties at the natural low point.


  7. Durie J said that he would bypass the first two causes of action and consider the case within the framework of negligence. He indicated, however, so far as the Rule in Rylands v Fletcher was concerned, that the Council had not had the purpose of accumulating or storing water on its land, but rather of allowing the water to pass through and so to proceed on its natural course. He said that an important component of nuisance is now the question of reasonable user of the defendant’s land, referring to the decisions of the House of Lords in Cambridge Water Co v Eastern Counties Leather Plc [1994] 2 AC 264 and in Delaware Mansions Ltd v Westminster City Council [2002] 1 AC 321, in the latter of which Lord Cooke of Thorndon had spoken of applying concepts of reasonableness between neighbours.

  8. The Judge then considered the case in negligence. He noted, in particular, that the pleadings did not assert that the Council had been negligent in approving the subdivision of the properties. Nor was there a breach of the duty of care in the circumstances in which building permits had been issued. The main question, the Judge said, was whether there had been a breach of the duty of care in the Council’s failure to improve the culvert when it 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 properties. The culvert had been installed between late 1980 and early 1981 when Rimu Road was extended. By 1982 there was criticism of its capacity and consultants had recommended replacement or that a second culvert be added alongside. The Council had considered, however, that in the event of a flow larger than the culvert and the banks of the stream were able to accommodate there was, in effect, an escape path for the excess along the road to the drain. The Judge concluded that in 1982 the Council’s approach was reasonable. Then there had been a development of a major shopping facility in Rimu Road. Consultants had recommended that the culvert be replaced by a bridge by 1999. In fact, because of the expense involved, the bridge was not programmed (in 1998) into the Council’s capital works before 2002-2003. It had however been recognised that there was likely to be an overflow within a term of 20 years (i.e. in a 20 year flood) and that the drain was unlikely to be able to cope with the excess water. The Judge commented that from the evidence of relative levels it must have been plain that Ihakara Street would bear the burden of the result. The inference the Judge drew was that in its consideration of a secondary flow-path the Council had failed to have adequate regard for the impact on the properties. The resulting question, he said, was not whether the Council was entirely unmindful of the property owners but whether it should properly have provided sooner than it did in budgeting for an upgrade of the culvert. Durie J concluded, however, 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. He said that the Council had to balance a number of competing interests and there was no evidence that in seeking a balance the Council was acting irresponsibly. It was not therefore in breach of its duty and the action must fail.

  9. But, lest he be wrong in that conclusion, the Judge then considered whether flooding of the property was inevitable. The first point he made was that the storm, seen in historic terms, was unique. He noted Mr. Heaney’s submission that, even without the culvert and the associated ground work that impaired the flow at Rimu Road, the evidence had been that backflows from the lower reaches would have pushed up the drain to overflow onto the properties to the same extent as in fact happened on the night in question. The Judge said that he had found the evidence of the experts for the plaintiffs endeavouring to counteract this argument unconvincing. Because of the inevitability of a flood it was clear to him that the "but for" test was not satisfied; it could not be said that the culvert was the cause of the flooding when the flooding was inevitable in any event. He was therefore confirmed in his view that the Council was not liable in negligence.


  10. We have not found it necessary to consider the approach taken by the Judge to the legal issues before him as, although the claims under the Rule in Rylands v Fletcher and in nuisance were pursued in the written submissions in this Court, Mr. Mitchell accepted during oral argument that, on the basis of the experts’ conclusions concerning the backflow problem, to which those claims were not directed, they could not succeed. This backflow problem would have equally defeated a negligence claim restricted to the inadequacy of the culvert. As we have already noted, however, there was a generalised pleading alleging negligence in the Council’s management of its entire stormwater drainage system, which brings into question the Council’s treatment of the backflow problem itself. Nevertheless, the evidence adduced by the appellants at trial in respect of this alleged systemic negligence was deficient in two crucial respects.

  11. First, as to causation, the appellant did not show that the various measures suggested by experts during the trial for the improvement of the drainage system, such as upgrading the culvert, raising the stopbank and fitting the pipe with a gate, would actually (even in combination) have prevented the backflow and averted the flooding of the appellants’ properties.

  12. Secondly, as to the extent of this duty on the Council in respect of the stormwater drainage system, the appellants did not demonstrate that these suggested improvements could have protected during a storm of this magnitude both the appellants and other local landowners. The Council could not have been under a duty to take measures to protect the appellants if such measures would have merely transferred the flooding problem to other local landowners to whom the Council also owed a duty of care. Clearly the floodwaters had to go somewhere if they were prevented from backflowing at the drain and ponding as they did. The evidential focus, at trial, on the appellants’ properties in isolation diverted any real exploration of the necessarily interdependent nature of the Council’s obligations in respect of the entire stormwater drainage system.

  13. The only relevant evidence on these matters was as follows.

  14. Mr. Williams, a consulting engineer called by the appellants, referred to a 1994 report to the Council from consultants which included a consideration of flood mitigation. He pointed out that the report highlighted the need to preserve existing flood storage areas "such as immediately downstream of [the drain]". The report had also noted the poor state of the channel, and in particular the haphazard nature of the existing stopbanks which were of uneven height, inconsistent from bank to bank and in profile along the stream, incomplete and often of poor construction. With reference to measures to mitigate the flood hazard in Ihakara Street, Mr. Williams observed in his written brief that a simple extension of the existing stopbank alongside the stream below Rimu Road to the outlet of the drain and the addition of a flapgate on the outlet end of what he called the culvert at the drain would prevent floodwaters entering the whole of "the current ponding area." He said there would still be local water from the two branches of the drain, but they drained quite small areas and some of the lower ("non-built on") part of the ponding area could be used to store that local water when the flapgate was closed because of high water levels in the stream. But, notably, Mr. Williams’ evidence did not address the question of the effectiveness of these suggested measures if the culvert were to be enlarged so that all of the floodwater came down the channel of the stream. Nor did he discuss the effect of the measures on urban and other areas downstream.

  15. In his oral evidence Mr. Williams said there was a stopbank from Rimu Road down the stream on its left bank towards the drain. He said there was a little gap where the drain came out on low ground. If the stopbank were extended across the drain and the outlet pipe had a flap gate on it, then that would prevent ponding water from going through all of the area from Rimu Road down the stream across a sandhill and to residential areas "all around" the southern branch of the drain. Again, however, he does not appear to have been asked about the situation on the assumption that the culvert was enlarged or removed.

  16. The appellants’ other expert witness, Mr. O’Callaghan, was referred in cross-examination to the confluence of the stream and the drain but said that he had never inspected it.

  17. Mr. Hickling, a consulting engineer called by the Council, referred in his evidence-in-chief to the overtopping of the stopbanks during times of high flow of the stream. In cross-examination it was put to him that Mr. Williams had said "with some recognition that it was very much a first blush view" that two obvious mitigation measures for the backflow problem would be the extension of the appropriate stopbank and the placing of some kind of gate on the drain outlet. Mr. Hickling agreed that those were options that were at least worth serious analysis and detailed design if done in conjunction with a culvert upgrading. But he added that undertaking those measures achieved nothing unless the bulk of the water could be got downstream through the channel, which is an obvious reference to the constriction problem. Later it was put to him by counsel for the appellants that Mr. Williams’ solutions were probably a good starting point. His response was that in principle they were, and that his firm had provided some preliminary indications for the Council of methods. He added that there was still another risk to the area from overflows from the State Highway culverts if they should surcharge. He agreed that the extension of the stopbank and the installation of a mechanism to stop water going back up the pipe were relatively small cost works compared with the installation of a bridge (at Rimu Road), but he said without the bridge they would not work (the implication being that with the bridge they might work) and that

    once one starts playing with things in the modern climate .... if one doesn’t go the whole hog and do it properly I believe one can be challenged so that if those stopbanks are to be upgraded they need to be upgraded to an agreed design storm with appropriate freeboards with resource consents uplifted that can show other potentially affected parties that their situation won’t be worsened by just doing a localised piece of work.

    It was put to him and he accepted that he was substantially in agreement with Mr. Williams when he said that one thing that should not be done was to proceed on a completely piecemeal basis. He also said that by taking away one weak point, one could create another "so if you’re the next door neighbour you get affected by my doing something on my property and one of our tasks is to ensure that when we look at a solution we identify those things and mitigate all in one burst.

  18. Dr Joynes, a civil engineer, was also called for the Council. He expressed the opinion that a floodgate at the confluence of the drain with the stream "would do nothing to prevent overtopping of the stopbanks during such high flows". He went on:

    It might then be suggested that higher stopbanking may have been able to prevent waters escaping from the Wharemauku Stream. However, the ability to stopbank is restricted by other factors such as road levels, junctions with tributary drains and other structures (i.e. the building structure over the stream at Coastlands).

    In designing mitigation works, Council must always be mindful of simply transferring the problem to another area. Aside from the problem of storage of local runoff should [the drain] have a floodgate added to it, should the Wharemauku Stream have higher stopbanks constructed along its length in the vicinity of the Ihakara Street subdivision then this may simply have caused more excessive flooding to other areas.

    Dr Joynes was not cross-examined on this subject.

  19. Mr. Mitchell, for the appellants, took us to various passages in reports to the Council over the years but was not able to refer to anything dealing with the present question. We have, however, noted in the Stormwater and Flood Plan Management Study prepared by Connell Wagner Ltd in February 1994, under the heading "Flood Management Philosophies", the observation that as the lower reaches of the catchment would be the areas affected most significantly by the option of allowing for all design flows to get quickly and efficiently to the main stream and then to the sea by upgrading the stream and stopbanks and those areas are heavily urbanised, it was considered that a compromise of waterway improvement and retention of ponding areas to allow bank overtopping in controlled areas was the most appropriate flood management option for the catchment. "This option would allow filling local low areas which are not defined as providing significant flood attenuation". Later in the report there was the following passage:

    As this analysis has demonstrated, peak flows in the Wharemauku Catchment are significantly affected by storage during the rarer storm events, particularly along the main stream channel. Future development is likely to eliminate a large portion of this storage, if not all of it, unless provisions are made to preserve the ponding areas, within the planning controls.

  20. We have been provided with copies of the closing submissions made to the Judge. Understandably, on the basis of the relevant evidence, of which we have given a fairly full account, counsel for the appellants spent very little time on the allegation of negligence relating to the backflow problem. There was plainly an insufficient foundation in the evidence properly to support the allegation. There was no more than bare assertion, unsupported by calculations, that the suggested remedies would in combination provide a cure for the backflow flooding if all the water were to come down the stream to the point where it is affected by the narrowing of its bed; and as the allegation was directed to a failure of the respondent’s system for dealing with floodwaters in the catchment of the stream, which, on the evidence, relied in part on the availability of ponding areas, the appellants needed at least to put before the Court evidence which raised a serious question about the respondent’s need to use the area adjacent to the drain for this purpose when stormwater levels rose in the stream. The Council obviously had recognised the problem but it was also conscious of the consequences for downstream areas if the stream were unable to pond at the drain. There is nothing in the evidence directed at showing that a solution which met the Council’s legal obligations to other landowners was readily available but not acted upon.

  21. The appellants have therefore failed to prove negligence by the respondent in relation to flooding of their properties caused by the backflow of the stream. As inundation of their properties on the night of 20-21 October 1998 would have occurred even if there had been no diversion of water at the culvert and it has not been shown that it could and would have been avoided or significantly mitigated by the carrying out of the suggested works on the stopbank and drain – so that flooding of the properties was inevitable regardless of the deficiencies in the culvert – the claim in negligence must fail on that basis alone. And as indicated above, it also failed on the particular pleading.


  22. The appeal is accordingly dismissed with costs to the respondent in the sum of $5,000 together with its reasonable disbursements to be fixed if necessary by the Registrar.


Rylands v Fletcher (1868) LR 3 HL 330; Cambridge Water Co v Eastern Counties Leather Plc [1994] 2 AC 264; Delaware Mansions Ltd v Westminster City Council [2002] 1 AC 321

Authors and other references

Connell Wagner Ltd, "Stormwater and Flood Plan Management Study"


PC Mitchell and JF Jacobs for Appellants (instructed by Phillip Fox, Wellington)

DJ Heaney and SI Jameson for Respondent (instructed by Heaney & Co, Auckland)

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