Scottish Court of Session Decisions

OUTER HOUSE, COURT OF SESSION

[2016] CSOH 155

 

A423/11

OPINION OF LORD CLARK

In the cause

CHRISTIES PARKS LIMITED

Pursuer

against

SCOTTISH WATER

Defender

Pursuer:  Beynon;  Drummond Miller LLP

Defender:  Clancy QC;  BLM

4 November 2016

Introduction
[1]        Burnside Caravan Park is located on land near the village of Fochabers, in Moray.  The pursuer owns the land and operates the caravan park business. Mr Gordon Christie is the sole director and owner of the pursuer. The Burn of Fochabers runs through part of the caravan park. In 1976, the defender’s predecessors installed a mains water pipe to carry water across the land. The mains water pipe ran underground and crossed the burn, under its bed. On 4 September 2009, there was a flood. At the bottom of the left bank of the burn, the mains water pipe failed or disconnected. In several areas, including places close to the pipe crossing, the bed of the burn and substantial parts of the banks were damaged or partly washed away.

[2]        In this case, the pursuer seeks declarator that it is entitled to compensation in terms of section 10 of the Water (Scotland) Act 1980 for remedial works to certain parts of the bed and banks of the burn, and for related costs.  The sum sued for is £150,000. The pursuer claims that the damage to the parts of the bed and banks of the burn was a result of the negligent design of various aspects of the works carried out by the defender or its predecessors at the pipe crossing. Alternatively, the pursuer claims that the defender is responsible for the damage in terms of the law of nuisance. 

 

Background

[3]        Viewed on a map of the area, the strip of land on which Burnside Caravan Park is situated lies in a south-east to north–west direction.  Caravan pitches in the park are let out to members of the public and caravans can also be rented.  There are associated leisure facilities. 

[4]        The Burn of Fochabers flows in a south-east to north-west direction for the whole length of the park, in total for some 730 metres.  The burn enters the caravan park from the south-east, and initially runs through the caravan park, with caravan pitches on either side of the burn.  The mains water pipe crosses the burn in that part of the park.  After passing through that part, the burn forms the western boundary of the park.  The burn continues through Fochabers and eventually flows into the River Spey.

[5]        In their evidence, witnesses generally referred to the “right” and “left” banks of the burn.  By this, they meant the right and left bank as viewed when looking downstream in the direction of flow of the burn (that is, as viewed from the south-east, looking north-west).   I shall follow that general practice.   

[6]        Prior to 1903, weirs were constructed in the bed of the burn, between the park and the confluence of the burn with the River Spey, to provide protection of the channel of the burn against erosion as it passes the village of Fochabers.  These weirs have helped to maintain the stability of the channel of the burn from 1903 to the present time. 

[7]        In 1976, the defender’s predecessors installed the mains water pipe.  The defender has assumed responsibility for the works carried out by its predecessors and, for the sake of simplicity, when I refer to the defender that should be taken as including, where the context so requires, its predecessors.  The mains water pipe ran from west to east and crossed the burn, broadly at right angles to the burn.  The mains water pipe conveyed water across the park, from a reservoir located on land to the west of the park to another reservoir located outside the park to the east. 

[8]        The mains water pipe, which was 450 millimetres in diameter, was laid in horizontal sections under the ground until it reached near to the left bank of the burn.  In order for the pipe to cross beneath the burn, there was an underground joint close to the top of the left bank of the burn, where the pipe changed direction from the horizontal to run downwards at an angle within the left bank of the burn, down to a level beneath the bed of the burn.  It then arrived at another joint and changed direction again to run horizontally under the ground in the bed of the burn.  At the right bank, it reached another joint and changed direction from the horizontal to run at an angle back up within the right bank of the burn.  It reached the final joint under the top of the right bank and changed direction to run horizontally underground across and then out of the caravan park to the east. 

[9]        Part of the works of installation of the mains water pipe was a feature described as a “scour pipe”, which allowed drainage of water and debris from the mains water pipe.  To avoid confusion with the principal use of the word “scour” in the evidence, I shall refer to it as the drainage pipe.  A concrete anchor block was installed at the outlet of the drainage pipe, embedding the joint of that pipe in concrete.  No concrete anchor blocks were installed to secure the mains water pipe below the bed of the burn at the joints where there were directional change points.  The design and construction method for the installation of the mains water pipe was to use lengths of pipe joined together with socket and spigot joints under the bed of the burn, with a bolted compression joint at the change of direction at the bottom of the left bank of the burn.

[10]      Between 1980 and the mid-1990s, the defender installed a concrete slab across the burn, on top of the pipe. 

[11]      In July 1997, a major flood in the burn caused erosion of the bed of the burn, resulting in the pipe being exposed.  Following that flood, repairs were carried out by the defender in an attempt to provide protection for the pipe. The right bank of the burn had been eroded by the flood and was filled in by the defender, using granular material.  Wire metal baskets filled with rock, known as gabions, were installed by the defender.  The gabions were greater in height than the original channel.  No protection was provided downstream of the concrete slab against erosion or scour in the bed of the burn.

[12]      At various points in time between 1976 and 2000, the defender carried out works in connection with the pipe.  By 2000, the works carried out by the defender had begun to fail.  The concrete slab developed a crack.  An area of the bed of the burn was eroded or scoured, downstream of the pipe crossing.  This undercut the gabion on the left bank.  Erosion of the toe of the left bank was also evident.  No further works or repairs were carried out by the defender after 2000.

[13]      Prior to September 2009, if one followed the course of the burn from its entry to the caravan park in the south-east, the first structure one would have come to, of particular relevance to the present case, was a vehicle bridge.  It was used to allow vehicles to cross the burn, for example to tow caravans.

[14]      This vehicle bridge had two parallel tunnels through it, which carried the water downstream.  These tunnels were each made up of large concrete rings or pipe sections. The two tunnels were each five feet diameter and of some 18-21 feet in length.  In order to allow vehicles to cross, gravel was placed on top of the concrete rings and then tarmac was laid on top of the gravel.  To reduce the potential for wash-out of the gravel, walls made of concrete blocks were constructed across the burn at the upstream and downstream ends of the concrete rings, but leaving the openings of the rings or tunnels fully exposed so that the water could flow through.  In appearance, the vehicle bridge looked like a walled bridge across the burn, with two tunnels through it carrying the water downstream.

[15]      Parts of this vehicle bridge were washed away in the flood of 4 September 2009 and the banks of the burn at the location of the vehicle bridge were affected by erosion.  The damage to the vehicle bridge and the banks of the burn at its location forms no part of the pursuer’s claim, but the presence and effect of the vehicle bridge, and the damage to it and the banks, are relevant for the purposes of the expert evidence which I discuss below. 

[16]      The mains water pipe crossing installed by the defender in 1976 was located some distance downstream of the vehicle bridge.

[17]      In the flood of 4 September 2009, various structures were damaged (including the vehicle bridge). As noted above, during the flood, the mains water pipe failed or disconnected and water escaped from it. Parts of the bed and banks of the burn were damaged.

 

Procedural History
[18]      The matter came to proof on 19 March 2013, before Lord Jones.  The hearing had been set down for four days, but the evidence was not completed by 22 March 2013.  The proof was due to continue on 3 December 2013, but had to be adjourned because of the illness of a witness.  The matter came before the court once more on 28 October 2014 and the evidence was completed on 30 October 2014.  Thereafter the notes of evidence were extended and written submissions were lodged in the early part of 2015.

[19]      Following upon the untimely death of Lord Jones, by interlocutor dated 28 April 2016 the Inner House remitted the cause to a Lord Ordinary and gave certain powers and directions in that regard.  Having reviewed the case papers, I decided that the parties should have the opportunity to address me further, if so advised, on particular matters which I identified and on any points which they wished to add to their existing submissions.  Further written submissions were lodged by both parties. I was addressed on behalf of both parties at a hearing on 18 August 2016 and additional written submissions were lodged thereafter. I have considered all of the productions, including the expert reports and the video evidence of the flood, the transcripts of the evidence and all of the written submissions.  

[20]      The submissions focused on the issues relating to negligence. No separate submissions were made on nuisance.  Both parties proceeded upon the basis that the establishment of breach of duty for the purposes of negligence would suffice to establish culpa for the purposes of nuisance.  Both parties also accepted that if the claim in negligence succeeded then so too would the claim in nuisance, and if the negligence claim failed the claim in nuisance would also fail.  Having been invited to proceed in that manner, I have dealt with the claim based on negligence, but on the basis that the claim in nuisance stands or falls with it.

[21]      Against that background, I turn now to address the issues which arise in this case.  These can be identified as follows:

(1)        Has the pursuer established the existence of a duty of care owed by the defender and breach of that duty of care?

(2)        What is the damage which the pursuer claims was caused in September 2009 by the defender’s breach of duty?

(3)        Was that damage caused by a breach of duty by the defender?  

(4)        Was further damage, for which the defender is liable, caused after September 2009?

(5)        If the defender is liable, what losses are recoverable by the pursuer?

[22]      I now deal with these fives issues in turn. 

 

Issue 1:  Has the pursuer established the existence of a duty of care owed by the defender and breach of that duty of care?

 

[23]      As noted above, the claim is made in terms of section 10 of the Water (Scotland) Act 1980, which is in the following terms:

“10.  S (1) Subject to the provisions of this section, a local authority or Scottish Water shall make full compensation to any person who has sustained damage by reason of the exercise by them or it of any of their or its powers under this Act in relation to a matter as to which he has not himself been in default.

 

(1A)The escape of water, however caused, from one of Scottish Water’s communication or supply pipes or mains shall for the purposes of subsection (1) above be taken to have been brought about by the exercise by it of powers under this Act.”

 

[24]      It was common ground between the parties that a claim in terms of s 10(1) requires proof of actionability, in this case, fault:  University of Stirling v Central Regional Council 1992 SLT 79. 

[25]      The judgment in Campbell Construction Group Ltd v Scottish Water 2015 SLT (Sh Ct) 159 refers to strict liability arising in terms of s10(1A) of the Act. The pursuer submitted that this was incorrect and in particular that the decision failed to have proper regard to the requirement of actionability.  Thus, the pursuer did not seek to found on liability under s 10(1A) as being strict and, on the contrary, submitted that it must establish its case on fault.   The defender also argued that the sub-section did not introduce strict liability. Accordingly, the issue of whether strict liability arose was not before me.

[26]      Leaving aside the positions of the parties, there is one clear practical reason why the issue of whether the provision creates strict liability does not require further consideration in the present case.  If there is strict liability under s 10(1A), that can arise only in relation to damage caused by the escape of water from the mains water pipe.  The pursuer’s case is not founded on that mechanism alone – there is no discrete case based only on the failure of the pipe.  Rather, the pursuer asserts that the damage was caused by that failure in combination with the alleged failures in relation to the design, installation and maintenance of the pipe crossing works.  That combination of causes could not be the subject of strict liability under this provision.  I therefore proceed upon the basis that in this case the pursuer must establish fault and I reserve my opinion on whether s 10(1A) has the effect of creating strict liability.

[27]      The pursuer submitted that the test for breach of duty is that stated in Hunter v Hanley [1955] SC 200.  So, the pursuer’s case is that no civil engineer of ordinary competence, if taking reasonable care, would have proceeded in the manner in which the defender proceeded in the design, installation and further works of maintenance at the pipe crossing.  The defender did not demur to that being the appropriate test. 

[28]      In determining this first issue, three questions (or sub-issues) arise:

1.1       is the pursuer’s expert, Professor Fleming, properly qualified to opine on the content or breach of any duty of care owed by the defender?

1.2       does the scope of any duty of care owed by the defender encompass the avoidance of damage of the type claimed to have been suffered by the pursuer?

1.3       should the court accept Professor Fleming’s evidence and find that breach of duty has been established?

 

Issue 1.1:     Professor Fleming’s suitability as an expert witness
[29]             The defender’s position was that Professor Fleming lacked the necessary professional experience to give a valid opinion on the quality of the design, installation or maintenance of the pipe crossing.  It was argued that he did not vouch his criticisms by reference to industry practice in respect of installations of this kind or to relevant codes of practice or professional guidelines.  It was also said that no individual engineers were criticised in the pursuer’s pleadings or evidence and that the duties alleged to have been breached are those owed by the defender and its predecessors, as entities.  These points were developed and added to in more detailed submissions. Reference was made to the decision of the Supreme Court in Kennedy v Cordia (Services) LLP 2016 SLT 209, [2016] UKSC 6.   

[30]      The pursuer’s position was that Professor Fleming’s evidence should be preferred to that of the witnesses led on behalf of the defender. This was on the basis of his more substantive academic and professional experience and the thoroughness of his reports, which, it was argued, contain opinions which he had tested by established principles of civil engineering. His expertise, acquired over a period of 45 years, as a chartered civil engineer was said to be vouched in his two reports and in his evidence.  That expertise, said the pursuer, relates essentially to river engineering and geomorphology. It covers the types and extent of river flooding and erosion and the ways that usual or ordinary civil engineering practice addresses such risks.  The fact that Professor Fleming has not designed a water mains pipe crossing was argued to be irrelevant.

 

Issue 1.1: Decision and reasons

[31]      Having regard to the decision of the Supreme Court in Kennedy v Cordia (Services) LLP and the authorities referred to therein, I am persuaded that Professor Fleming is suitably qualified and experienced to give evidence on the matters with which he dealt in his report and in his oral evidence.

[32]      In Kennedy, Lord Reed and Lord Hodge referred with approval to a South Australian case where it was said that the test was whether the expert has “acquired by study or experience sufficient knowledge of the subject to render his opinion of value in resolving the issues before the court” – The Queen v Bonython (1984) 38 SASR 45 (King CJ at 46).  In my view, that test is met in respect of Professor Fleming, on the basis of his evidence as to the knowledge he has acquired by study and by experience and the issues which arise in this case.  Those issues relate primarily to the causes and effects of erosion in the bed and banks of a watercourse (including the effect of flooding) and the nature of suitable and appropriate protection for the bed and banks of the watercourse.  Professor Fleming has specific experience of dealing with such issues in relation to repair works which he was commissioned to carry out prior to 1997 on the banks of the River Dee on the Balmoral Estate, where there had been massive flood damage at a place called Red Braes.  He was commissioned to design and replace the bank protection and he used heavy rock armour and geotextile material to protect the bank.  The fact that Professor Fleming has not himself designed a pipe crossing such as that involved in the present case is not, in my view, a reason to disregard his evidence or to cause little weight to be given to it.  While of no direct relevance to my decision, I note that the defender’s civil engineering expert witness, Dr Coghlan, also had no experience of designing or installing such a pipe crossing.

[33]      When Professor Fleming was asked how many of his publications were relevant to the subject matter of this litigation, he replied that, of his several hundred publications, a very large percentage were relevant and that 40% of them were centred on flooding. 

[34]      His experience included being vice-president of a company named Hydrocomp International, practising hydrology and engineering in assessing flood magnitude and flood processes.  He had also worked with the company EnviroCentre Ltd, dealing with flood risk assessments, and he was Chair of the Flood Commission which produced a report “Learning to Live with Rivers” and recommended improvements to design standards for flood risk assessment. 

[35]      While Professor Fleming referred to the Scottish Environmental Protection Agency (SEPA) Code of Practice from 2010, he also identified and relied upon reference material which was available in 1997 in relation to the design and construction of pipelines, including those underground.  He explained that these reference materials should have been known to a civil engineer of ordinary competence dealing with the maintenance work at the pipe crossing at the material time. He stated that he was taught, in his civil engineering degree between 1962 and 1966, the practice he had described. It would, he said, have been taught in most undergraduate civil engineering degree courses.

[36]      Dealing with whether he is qualified to speak on matters of geomorphology, he explained firstly that this formed part of his doctorate.  Secondly, his work had involved research and practice in understanding the subject of geomorphology as it affected rivers and catchments.  He had practised geomorphology throughout his career. His experience covered the management of erosion processes, flood risk assessment, and numerous projects on river restoration work involving the geomorphology of rivers affected by flood and scour.  In carrying out his analysis, Professor Fleming had considered stream power and flow rates and had applied formulae such as the Bagnold and Manning formulae, the latter of which had also been used by one of the defender’s experts, Dr Andrew Brookes.

[37]      The fact that he did not speak to the practice of water companies is not, in my view, of significance.  The parties each proceeded upon the basis that the relevant standard was that in Hunter v Hanley, which is about professional civil engineers rather than how companies might have behaved.  Moreover, it is implicit in the evidence of Professor Fleming that works of this nature ought to have been designed by a civil engineer.  It is difficult to see how else they could properly be designed. 

[38]      Accordingly, Professor Fleming, as a chartered civil engineer with experience of floods, erosion and river bank protection works, is suitably qualified and experienced to give expert evidence on the matters which arise in this case.

 

Issue 1.2          The scope of the duty of care
[39]      It was submitted by the defender that there has to be a connection between an alleged breach of duty and the mischief which the duty is supposed to protect against.  Reference was made to an observation by Lord Hoffman in Bank Bruxelles Lambert SA v Eagle Star Insurance Company Ltd [1997] AC 191, at 213 D and to MacLean v Caledonian MacBrayne Limited 2000 SC 74, at 76-77. 

[40]      It was further submitted by the defender that engineers who designed or modified installations like the pipe crossing would be concerned about their structural integrity.  The mischief they would take precautions against would be a failure of the structure, not the possibility that the presence of the structure would cause erosion.  The design or construction could be negligent if, but only if, it was not sufficiently robust to withstand a flood of a certain force.  To use Lord Hoffman’s phrase, a failure to take appropriate steps to prevent failure of the structure would, it was submitted, be what would make the engineer’s act (or omission) wrongful.  Any erosion caused by the presence of the structure, as opposed to its failure, would not be attributable to that act or omission. 

 

Issue 1.2: Decision and reasons

[41]      I have no difficulty in accepting that Scots Law recognises the principle founded upon by the defender.  However, in my view, this contention by the defender takes too narrow an approach to the scope of the duty of care in the present case.  In designing or modifying works related to the pipe crossing, the potential for those works to cause erosion and hence damage to the bed and banks of the burn would have been obvious.  Indeed, the gabions appear to have been installed by the defender in order to assist in limiting erosion to the banks; no other reason for putting them in place was mentioned in evidence.  The defender was not entitled to proceed upon the basis that the scope of its duty was limited to the integrity of the structure.  The avoidance of erosion caused by the design and presence of the structure and its effects on the bed and banks of the burn was within the scope of the defender’s duty.   

[42]      Accordingly, the duty of care owed by the defender extended to include avoiding damage to the pursuer’s property arising from the design, installation and maintenance of the works at the pipe crossing.

 

Issue 1.3          Was that duty of care breached?
[43]      The four steps which Professor Fleming stated should have been taken during the works done by the defender prior to September 2009 were as follows: 

(1)       Concrete should have been placed over the whole of the pipe, covering the pipe, on and under the surface, from bank to bank in the bed of the burn.

(2)       Rock armour or gabions should have been placed on either side of the burn, at the bottom of the bank where it meets the horizontal, for distances of 20 metres upstream and 20 metres downstream from the pipe crossing.

(3)       Geotextile material should have been placed under the gabions and up to the top of the banks of the burn.

(4)       Where the water coming over the concrete slab dropped down, protection against scour should have been installed, again by rock armour.

[44]      Professor Fleming assented to the proposition that the four steps he had described represented the usual or ordinary practice of civil engineers designing and carrying out works of maintenance in 1997 relative to a pipe crossing of this type and in this location.  He also agreed that any civil engineer, if taking reasonable care, would have adopted that practice when designing and implementing works in 1997, and in that regard he made reference to the works which he had undertaken in connection with the repairs to a river bank on the River Dee in Aberdeenshire prior to 1997. 

[45]      He further agreed that no civil engineer carrying out maintenance works in 1997 relative to this particular pipe, and in this particular context, would have failed to adopt this practice if he had been taking reasonable care.  When asked about the cost of such work, his response was that it wouldn’t be a high cost having regard to the infrastructure being protected.

[46]     In Professor Fleming’s opinion, if the works had been done as he suggested, the damage which occurred in September 2009 at the area around the pipe crossing would not have been sustained.

[47]      Professor Fleming went on to say that had concrete blocks been installed at the pipe joints at the sides of the bed of the burn, where the pipe changed direction, this would have resulted in the joint at the bottom of the left bank, where the pipe failed in the 4 September 2009 flood, being able to withstand the flood.  The drainage pipe had a concrete block at its joint and this survived the flood.

[48]      Professor Fleming explained that “scour” is the removal of sediment from the bed and banks of a river.  It is caused by energy from the flow of the water.  That energy is dependent on the velocity of the flow (which, in turn, is dependent on the slope of the river) and on the geometry of the river. 

[49]      Professor Fleming said that he had been informed by Mr Christie that, between 1976 and 1997, there were episodes when the pipe had been exposed because of scour. 

[50]      The photographs referred to in Professor Fleming’s evidence indicated to him that the defender had recognised that scour was taking place and had aimed to provide some pipe protection by creating a concrete slab across the top of the pipe and introducing gabions on either side of the channel as it was defined at that time.  Professor Fleming said that the concrete slab and the gabions above the buried pipe were a recognised way of protecting it.  His view was that the position of the pipe was “very shallow in relation to the depth of scour and was in the scour zone of the burn”.  It was normal, he said, to ensure that the gabions protect the pipe some distance upstream and some distance downstream. 

[51]      The photographs showed that the gabions were built above the level of the channel.  In Professor Fleming’s view, that was not a good practice, because they created an obstruction and changed the effective flow.  Downstream of a structure like the concrete slab, protection should have been installed, because as the water comes over the concrete slab, it drops on the opposite side and it causes a scour hole to form in the bed of the burn.  If the scour hole was not armoured and protected, it would cause undercutting of the upstream protection, undercutting of the gabions and undercutting at the concrete slab.  During Professor Fleming’s first site inspection, there was an indication that a scour hole had developed downstream of the protection works.  On one of the photographs (taken in the year 2000) it could be seen that the gabions had started to drop into the scour hole, which meant that the gabion protection was beginning to fail.

[52]      Professor Fleming expressed the view that the flood of 4 September 2009 created a blockage at the pipe crossing “caused by the obstruction created by the gabions and construction works installed in 1997”.  The blockage caused water to back up behind the concrete and gabion protection works, preventing trees and other debris moving down the burn.  This debris restricted the flow of water and caused it to find alternative routes across the whole width of the burn resulting in the undercutting of the banks and causing the high banks on the left side of the burn to fail. 

[53]      It was Professor Fleming’s opinion that, during the September 2009 flood event, the scour caused by the flood resulted in the exposure of the pipe at the bottom of the left bank of the burn where it changed direction, causing it to fail at the joint. 

[54]      Mr Hamish MacDonald is an asset planner for the defender and is also a chartered civil engineer. He confirmed that his investigations of the pipe crossing in 1998 and 2000 were only visual inspections.  He did not consider or investigate the adequacy or otherwise of the civil engineering design and installation of the pipe crossing, or the works carried out by the defenders’ predecessors in 1997, in the context of potential erosion of the banks on both sides of the burn

[55]      Dr Brian Coghlan, a civil engineer specialising in engineering hydrology, including flood risk hydrology, gave evidence as an expert witness for the defender. He was not asked in terms for his view as to whether or not the design of the works fell short of the standard of an ordinarily competent civil engineer exercising reasonable care.  However, in response to Professor Fleming’s views about negligence he stated: 

“It is reasonable to say that the original construction of the pipe crossing by Scottish Water’s predecessors did not meet the standards of best practice and was hence vulnerable to erosion and undermining in the area around the pipe, and locally on the banks on either side.”

 

[56]      He added:

“It would certainly appear to me that the measures taken to maintain and repair the pipe crossing did not address the fundamental problems of erosion and scour of the bed of the burn, but merely consisted of short term/interim measures to address problems as they arose.  As discussed above this is an inevitable compromise after [sic] applied when time and money for a more root and branch approach is not available…

 

…As previously discussed, the original design and construction of the pipe crossing, and its subsequent maintenance falls short of the ideal.  However this should be seen in the context of decision-making in the real world, budgetary constraints.”

 

[57]      Mr Ian Burnett, another witness for the defender, is a civil engineer with a degree in civil engineering and a member of the Institution of Civil Engineers. He had been employed by the defender since 1991.  In 2009, he was manager of the Don region.  He first became concerned with the caravan park during the week after the September 2009 flood.  He did not visit the park until two or three months later.  Some clearance work had been carried out, but the mains water pipe was not operating.  During the course of telephone conversations with Mr Christie, he learned that Mr Christie’s view was that the erosion of the bed and banks of the burn were as a result of the pipe crossing and not as result of any flooding.  Mr Burnett and his colleagues were fairly clear at the outset that they did not think that the cause of the damage to the banks of the burn on the day of the incident resulted from the mains water pipe crossing.

[58]      In cross-examination, Mr Burnett was asked to comment on the four steps noted above which Professor Fleming had advanced in his reports and explained in his oral evidence.  The witness said that these were “the range of options in terms of things that can be done to improve the protection of the water main.”  The mains water pipe was, however, installed in 1976 and remained in place without any damage to itself until the incident of 2009.  There had been an incident in 1997 which, in his opinion, was significant.  The upstream bridge was washed away, but the mains water pipe crossing was not damaged.  In answer to the question whether he accepted that the four steps specified by Professor Fleming ought to have been taken, Mr Burnett said that the SEPA code of practice dated 2010, referred to by Professor Fleming, was well after the mains water pipe was installed.  It was installed in 1976, and while there were some significant flooding events between then and 2009, the mains water pipe remained intact but much larger structures, such as the upstream bridge, were washed away.

[59]      Against that evidential background, the pursuer submitted that the four steps identified by Professor Fleming should have been adopted when the works were done in 1997.  In any event, these steps should have been adopted in response to the later letters of complaint made on behalf of the pursuer.  There was a long history of erosion, failed repair and scour just downstream from the pipe crossing.

[60]      The defender submitted that the pursuer has failed to prove its allegations of negligence.  The defender argued that the individual criticisms made by Professor Fleming lacked merit.  Professor Fleming’s reference to the SEPA code of practice from 2010 was not relevant to the question of negligence in 1997, it was submitted.  Moreover, Dr Andrew Brookes (an expert witness for the defender) had explained that only in relatively recent times have a large number of geomorphologists been employed directly by consultants, water utilities and regulators to solve river erosion problems.

 

Issue 1.3: Decision and reasons
[61]      Professor Fleming’s evidence expressly addressed the test in Hunter v Hanley.  He explained the four steps which he said no civil engineer of ordinary competence carrying out maintenance works in 1997, on this pipe and in this particular context, would have failed to adopt, if taking reasonable care. His evidence was clear and well-reasoned.  There was no convincing evidence to the contrary.  Indeed, as I note in paragraphs 55 and 56 above, Dr Coghlan, one of the defender’s experts, accepted what might be regarded as some failings on the part of the defender, although not under reference to any particular test.  He was not asked to state his opinion, and did not do so, on whether the test in Hunter v Hanley was satisfied. He referred to budgetary constraints and said that he said he was offering a view on what “a reasonable water authority” would have done. While Dr Burnett disagreed with Professor Fleming in several respects, he is not an independent expert witness and in any event no detailed reasoning was given by him on the question of negligence.  His broad position was that the mains water pipe crossing had been installed in 1976 and remained intact until 2009 and that was sufficient.  In short, Professor Fleming’s evidence on breach of duty and the test in Hunter v Hanley had, in my view, no real contradictor.

[62]      In his oral evidence, Professor Fleming referred to the use of concrete blocks at pipe joints as a “desirable” feature, because under pressure the pipe will try to straighten itself.  Professor Fleming did not expressly offer the view that no engineer of ordinary competence, exercising reasonable care, designing or maintaining the pipe crossing would have failed to provide for concrete anchor blocks at the bottom of each bank.  However, read as a whole and in context, his evidence was to the effect that these concrete anchor blocks were really an alternative to the concreting over of the whole pipe, as a means of securing it, which on his evidence no engineer of ordinary competence exercising reasonable care would have failed to do.

[63]      In relation to the positioning of the gabions, Professor Fleming’s view was that these should have been placed at the bottom of the bank where it meets the horizontal. I understood him to mean that, so placed, they would not have trapped debris, at least to the extent that occurred in the September 2009 flood. On the question of using gabions, or rock armour, and geotextile material, Professor Fleming’s evidence was, as noted above, that this was the approach he had taken to deal with the erosion problem on the banks of the River Dee, prior to 1997. The practice which he described in his evidence had been taught in his undergraduate degree in civil engineering.

[64]      Accordingly, I am satisfied that the pursuer has established that the defender was in breach of its duty of care in the respects identified by Professor Fleming. 

 

Reasonable foreseeability
[65]      It is convenient to deal at this stage with the question of whether the kind of damage, principally by erosion, suffered by the pursuer to the bed and the banks of the burn was reasonably foreseeable. On the evidence, the lack of concrete protection, the limited number and positioning of gabions, and the absence of use of the geotextile, were all failures to limit the effects of erosion.  I also note that Dr Coghlan stated that:

“… the original construction of the pipe crossing by Scottish Water’s predecessors did not meet the standards of best practice and was hence vulnerable to erosion and undermining in the area around the pipe, and locally on the banks on either side.”

 

[66]      There was a history of erosion and of scour in the bed of the burn downstream from the pipe crossing.  The pursuer had also drawn the defender’s attention to issues of erosion at or near the pipe crossing, in correspondence in 1997 and 2000, which I discuss below.

[67]      Accordingly, it was reasonably foreseeable that erosion would be a consequence of a failure to take the measures identified by Professor Fleming.  In relation to the failure of the pipe, it is in my view clear as a matter of principle that water flowing under pressure from a failed or disconnected mains water pipe may cause erosion.  I deal later with the question of whether as a matter of fact the damage claimed by the pursuer was caused by any of these features.

 

Issue 2:  What is the damage which the pursuer claims was caused in September 2009 by the defender’s breach of duty?

 

Background: the flood in July 1997
[68]      It is helpful to consider firstly the effect of the flooding in 1997.  The relevance of the evidence on this point is partly for its historical context but also because it provides an insight into the nature and effect of an earlier episode of erosion of the banks of the burn. 

[69]      Mr Gordon Christie described the history of the defender’s involvement in works at the pipe crossing.  Within a year or so after the pipe crossing was installed in 1976, the pipe became exposed in the bed of the burn and the defender came back and put a concrete slab on top of the pipe, which helped to protect it.  Mr Christie said that whenever there was a mild sort of flood in the burn, there would be further erosion and the defender had to come and improve the works at the crossing on a number of occasions in the 1980s and 1990s.  These further works included placing stone pitching close to the large concrete block which secured the drainage pipe.  There were around four such visits by the defender prior to 1997.

[70]      Mr Christie’s recollection was that gabions were installed upstream from the concrete slab in the bed of the burn prior to 1997. That recollection was accepted by the pursuer as having been mistaken.  Parties are in agreement that the gabions were installed after the flood of 1 July 1997. 

[71]      Mr Christie described the flood in 1997 as a 1 in 10 year flood.  The right bank was washed away at the location of the pipe crossing, because it was “fairly soft material”.  The defender’s staff attended and backfilled the eroded area with gravel, tipped from lorries.  All the erosion in 1997 was on the right bank. The bank on the left side did not erode at all, because it comprised the stiffer boulder clay which originally formed both banks of the burn. 

[72]      Mr Christie said that the work undertaken by the defender after the flood of 1997 was carried out in the spring.  Later that year, in or about November, a letter was sent on behalf of the pursuer to the defender expressing a concern about the state of the pipe crossing, because there was some erosion at that location.  Mr Christie sent a further letter, dated 30 June 2000, expressing concern “once again” about “water erosion at the Fochabers Burn where it passes through our Caravan Site”.  In that letter, Mr Christie recorded that it had been noticed that the bank was eroded where the mains water pipe crossed the burn and asked that one of the defender’s engineers should investigate and detail the required remedial work.  There was an acknowledgement from the defender, stating that it would let Mr Christie know of the findings after an inspection.  There was no further contact from the defender.

[73]      Mr Christie said that the vehicle bridge had been replaced four or five times between 1997 and 2009 and he accepted the general proposition that the flood in 1997 caused erosion to both banks of the burn as it passed through the caravan park. His evidence of damage at or around the pipe crossing at that time was, as noted above, that only the right bank was damaged.

[74]      Professor Fleming accepted that the erosion of the banks prior to 1997 was nothing to do with the pipe crossing.  He also agreed that in July 1997 there was a major flood which caused channel erosion.  When it was put to him that, if there was erosion upstream of the pipe crossing as a direct result of the 1997 flood, that could not have been caused by the gabions, he agreed. His position was that it was the sheer volume of the flood in 1997 that caused the erosion to the banks, both upstream and downstream of the pipe crossing, at that time.

[75]      The defender’s witness Hamish MacDonald had visually inspected the pipe crossing in 1998, following the flood in 1997 and a complaint on behalf of the pursuer about erosion at the pipe crossing.  Erosion near the pipe crossing appeared to him to be the worst part.  He noted erosion of the left bank, but was of the view that this had been occurring for a very long time and was probably an ongoing process.  He also looked at the pipe crossing in 2000.  In essence, his view was that he saw no need for any work to be done at the pipe crossing in 1998 or 2000 and felt that the pipe crossing was not affecting the banks.

[76]      The pursuer does not make any positive case that the erosion which occurred in 1997 was caused by the presence or effect of the pipe crossing works done prior to that date.  Indeed, the questions put to Professor Fleming on the issue of negligence by the defender specifically used 1997 as the relevant time.  The gabions were not installed until after the flood of 1 July 1997 and it was accepted that erosion at that time cannot be attributed to their presence. 

[77]      I accept Mr Christie’s evidence as to the nature of the damage caused by the 1997 flood. I therefore conclude that a substantial flood in July 1997 caused erosion to the right bank of the burn.  The defender filled in the eroded areas.  The flood also caused the then existing vehicle bridge, upstream of the pipe crossing, to be swept away. 

[78]      The events in 1997 demonstrate that flooding of reasonable severity could of itself cause erosion in this burn and to its banks.  That is a factor to be borne in mind when assessing the cause of damage in September 2009. However, and in my opinion of some importance, the left bank of the burn was not damaged by erosion as a result of the flood in 1997.

 

The damage in September 2009

[79]      Mr Christie explained that, on 4 September 2009, erosion had caused a large circular hole near to the pipe crossing, which he put down to the effects of outflow from the failure of the pipe, rather than the flow in the burn itself.  He described it as “strange erosion”.  He went on to say that there was no further erosion to the left bank, apart from the circular erosion, which extended to some 10-15 metres on either side of the pipe crossing on that bank, upstream and downstream.  On the right bank, the erosion was most severe at the location of the pipe crossing, and extended about 10 metres downstream, but some 30‑35 metres upstream.

[80]      Mr Christie also explained that two footbridges (one of which was located in the caravan park) as well as the West Street bridge in Fochabers were also lost in the flood in September 2009. 

[81]      Professor Fleming stated that the right bank had been filled in with non-cohesive material in earlier works by the defender and as a result was particularly badly damaged in the flood of September 2009. 

[82]      The defender’s witness Hamish MacDonald said that when he went back in October 2009 to view the position at the pipe crossing after the flood, the left bank looked “enormously different” and “it looked like a crater”.  He explained that instead of the channel that the burn had followed before, “it was just one great big opening that we were standing on the edge of and looking across this much wider chasm than there had been there before.”  He described it as “like a big, large, almost circular area.”  “What had happened”, he said, “had very much affected both sides.”  Also, the banks were affected both upstream and downstream of the crossing.  It was difficult to estimate how close the damage extended in relation to the vehicle bridge, but it extended from the pipe crossing “a few tens of metres”, again both upstream and downstream. 

[83]      Martin Dunbar, a witness for the defender, was Scottish Water’s Team Manager for Networks Grampian in 2009.  He explained that six water mains involving burn crossings had failed on 4 September 2009.  In relation to the caravan park, when he inspected it he found that the worst damage was at the pipe crossing.  Mr Dunbar saw lots of trees or debris and pieces of concrete in the burn. Most of the debris was around the location of the pipe crossing.

[84]      The witness said that “the bridge was obviously gone and there was debris lying roundabout the area where the water main crosses the burn.”  He said that he had walked up the burn as far as where the vehicle bridge had been and downstream from the pipe crossing, but not too far.  There was damage to the banks upstream and downstream of the vehicle bridge.  The worst bit of damage was at the left bank just where the pipe crosses.  There didn't appear to him to be much damage, if any, downstream of the pipe crossing. 

 

Issue 2: Decisions and reasons

[85]      The evidence shows that after the flood in September 2009, at the location of the pipe crossing, there was a circular or crater-like erosion of some 10-15 metres on either side of the pipe crossing on each bank.  The left bank was eroded to that extent, but there was no further erosion on that bank.  The right bank also suffered the circular or crater-like erosion, but it was also affected by erosion both upstream and downstream to the extent of a total of some 40-45 metres. 

[86]      The graphic descriptions by the witnesses of the scale and nature of the erosion at the location of the pipe-crossing shows that it was distinctive.  This is potentially indicative of particular issues at that location.  Also, as noted earlier, the left bank had not been affected by erosion as a result of the flood of 1997: something had caused substantial erosion of the left bank in the area of the pipe crossing in September 2009.

 

Issue 3:  Was this damage caused by a breach of duty by the defender?
[87]      In essence, the competing positions of the parties can be summarised as follows. The pursuer contends that the damage was caused by the defender’s breach of duty in failing to take the steps identified by Professor Fleming. In addition, that breach of duty resulted in the failure of the pipe at the pipe crossing and the escape of water from the failed pipe under pressure contributed to the damage. The defender contends that the damage was caused by factors unrelated to the pipe crossing or the failure of the pipe. These factors were the natural (geomorphological) effects of the flood, taken along with issues arising from the presence of the vehicle bridge and the damage to it. In addition, the defender’s position was that the failure of the pipe did not in any material way contribute to the damage.

[88]      In evaluating the expert evidence on these competing contentions, it is convenient to discuss this third issue under four sub-headings:

            3.1       the consequences of the breach of duty;

            3.2       the natural effect of the flood;

            3.3       the vehicle bridge;

            3.4       the failure of the pipe.

 

Issue 3.1      The consequences of the breach of duty

[89]     Professor Fleming’s position was that:

“The pipe failure together with the fluvial flood of September 2009 caused an exceptional flow resulting in major damage at the pipe crossing and downstream.  This damage would be greater due to the instability and unsuitability of the pipe crossing design and the pipe protection works installed.”

 

[90]      In brief, his view was that the design failures had resulted in scour of the bed of the burn at the pipe crossing, affecting the banks and causing the exposure and failure of the pipe. The banks were unprotected by sufficient gabions and geotextile material. The failures by the defender had, he maintained, resulted in a blockage at the pipe crossing, which contributed to the damage, as did the flow of water from the failed pipe.

[91]      In relation to the blockage at the pipe crossing, he said that prior to September 2009, significant failure was taking place at the pipe crossing where the gabions had collapsed into a scour pool formed below the pipe crossing works.  In his first report, Professor Fleming explained that during the September 2009 flood the blockage at the pipe crossing caused water to back up behind the concrete slab and the gabion baskets.  This blockage resulted in the water finding alternative routes and undercutting the high banks on the left side, which then failed. 

[92]     Dr Andrew Brookes, one of the defender’s expert witnesses, gave his profession as a scientist with a civil engineering firm and his specialism as geomorphology. He explained that, as a geomorphologist, he looked at the processes that create rivers, how they adjust naturally and, in particular, how they adjust due to man’s impact.  This included the causes and effects of river erosion problems. Dr Brookes disagreed with Professor Fleming’s view that in the September 2009 flood there was a blockage by debris at the pipe crossing, caused by the features there.  Dr Brookes was of the view that the blockage of the burn could have occurred at this point without the presence of an exposed pipe crossing and/or gabions.  Also, his understanding was that debris from the destroyed vehicle bridge was carried downstream and may have played a part in the blockage. 

[93]      In short, Dr Brookes’ position was that the flood was exceptional and that the damage to the bed and the banks was due to the flood as a natural cause, taken along with the issues relating to the vehicle bridge, (discussed below).

[94]      The other expert witness for the pursuer was Dr Brian Coghlan.  His position on the question of whether the pipe crossing installation made a contribution to the erosion which occurred in the flood in September 2009, was that he did not think it possible to be categorical on that matter.  He thought that there was a possibility that there was some contribution, but there was certainly no evidence, to his mind, that this was the major cause.  In actual fact, the mains water pipe and its surrounding bedding may have been damaged by the collapse of the vehicle bridge. 

[95]      The extent of the damage caused by any erosion around the failed pipe, in his opinion, would be relatively localised.  He said that this was borne out by the photographs, which showed limited erosion below the pipe.  It was not extensive.  The undermining of the banks was extensive, down both sides for a considerable length, including upstream of the vehicle bridge.  This was, in his view, clearly related to the flow through or over the vehicle bridge and through the section of the burn where the banks were damaged.  It was primarily due to the flood event and not due to the presence or construction details of the pipe crossing or failure of the pipe. 

 

Issue 3.1: Decision and reasons
[96]      It is noteworthy that among the principal areas of damage to the banks of the burn in September 2009 were those locations at which man-made structures had been installed.  In particular, the vehicle bridge in the caravan park and the West Street bridge in Fochabers were affected by mechanisms whereby flood water, requiring to find its way downstream, eroded the banks around the structures.  The other significant area of erosion was of course at and around the pipe crossing, another man-made structure. 

[97]      While I appreciate that Professor Fleming did say that not all of the erosion which occurred in, or as a result, of the September 2009 flood was caused by the pipe crossing or its failure, his position was that the damage for which the pursuer sought compensation would have been avoided had the defender implemented the four steps which he stated were required.  These included use of protective measures, gabions and geotextile material, which would in his opinion have prevented the damage.  The real issue therefore is whether the erosion would still have occurred in September 2009 had these four steps been taken. In my opinion, that issue is not addressed in any cogent fashion in the evidence of defender’s witnesses. Dr Brookes referred to the use of stone pitching and said that the banks would have collapsed in any event. He also referred to a weir or gabion across the burn at the pipe crossing and said that a “knickpoint” (discussed below) would have threatened the integrity of the gabion or other type of protection. He also said that geo-fabric is unlikely to be effective for bank collapse caused by continued downwards migration of a knickpoint.  In my view, Dr Brookes did not give a systematic or full consideration and critique of Professor Fleming’s view that the four steps spoken to by him would have prevented the damage. Moreover, Dr Coghlan does not address this issue in any adequate manner.

[98]      It was also the defender’s position that there was no significant scour of the bed below the pipe crossing during the flood.   However, on the evidence, whatever the depth of the scour hole, there was a sufficient removal of material from the bed of the burn to cause the pipe to uncouple or fail at the joint at the lower point of the left bank.

[99]      I also accept that it is on balance more likely than not that there was a build-up of debris at the pipe crossing and that this caused the flowing flood water to find its way around the blockage and to cause erosion.  I reach that view on the basis that the gabions and the pipe (exposed when erosion scoured the bed of the burn) were located in positions such as would trap debris and that there was clear evidence of substantial debris being carried down the burn during the flood and being seen at that location.  Over time, at least one gabion had partially collapsed into the burn, creating further potential for blocking.  The evidence supports the view that debris at the pipe crossing after the flood was present due to the blockage.

[100] Accordingly, I conclude that the damage suffered on 4 September 2009 was a consequence of the defender’s breach of duty.

 

Issue 3.2    The natural effect of the flood

[101]    Professor Fleming accepted that where the burn flows through the caravan park it is geomorphologically very active, as Dr Brookes had said.  One consequence is that floods will cause erosion.  Again agreeing with Dr Brookes, he accepted that the potential for erosion was high but, he added, that is why it should have been taken into account in 1997 by those designing the works.  Commenting further on the report of Dr Brookes, Professor Fleming disagreed with the view that the damage in September 2009 which is the subject of the claim was caused by the flood itself and was not a result of the works at the pipe crossing or the failure of the mains pipe.  Professor Fleming’s position was that any knickpoint at the pipe crossing was due to the installation of the concrete slab and the gabions.  These features actually created the knickpoint because scour formed underneath or below the channel, downstream of the concrete slab. 

[102]    Professor Fleming also disagreed with the views of Dr Brookes on the flow rate of the burn during the flood, for reasons which he explained. He also disagreed with Dr Brookes on stream power in the burn, and said that Dr Brookes’ calculation of stream power (500 watts to 1000 watts per square metre) represented very high energy.  These figures were, Professor Fleming said, more consistent with steep mountainous channels.  Professor Fleming’s estimates were in the range of 178 watts to 186 watts per square metre, which he described as high to medium energy.  He had used the Bagnold formula.  Its purpose is to calculate the power of a flow in a stream, in relation to its geomorphology, and also in relation to its capacity to erode the banks and bed of a river.  In carrying out this exercise, Professor Fleming sought to demonstrate why the figures he arrived at were much lower than those shown by Dr Brookes. 

[103]    Dr Brookes explained that the Burn of Fochabers, from just upstream of the replacement vehicle bridge in the Burnside Caravan Park to its junction with the River Spey, was and is being affected by erosion processes.  This section of the burn could be described as an incised or incising channel.  The defining characteristic of incised channels is that they have undergone, or are undergoing, bed level lowering.  This results from an excess of stream power relative to the amount of sediment supplied to the stream. 

[104]    He explained the concepts of “knickzone” and “knickpoint” thus: 

“a knickzone extends over a larger geographical area because it’s the zone at which there is instability.  Within that zone there may be individual knickpoints which are the erosion front, as we call it, or the point of erosion at any point in time, and that can progress upstream during a flood, for example”. 

 

[105]    Thus, knickpoints were points of incision or erosion within a knickzone, being the way in which the bed lowers itself. A knickpoint can migrate upstream and, if it does, will therefore expose or undermine structures.

[106]    In Dr Brookes’ view, a knickpoint had migrated upstream to a position underneath the mains water pipe on 4 September 2009, as a result of the flood.  With erosion of the bed of the burn, even a very strong bank could become unstable.  It is, he said, the erosion of the bed that causes the bank to pass the critical point into instability.  He disagreed with the proposition of Professor Fleming that the knickpoint at the pipe crossing was caused by the fall of water over the concrete slab installed by the defender. 

[107]    He also believed that the vena contracta effect could have caused degradation and hence lowering of the bed, with associated collapse of the banks.  The vena contracta effect is the acceleration of water in a watercourse through a narrowing of the channel, such as bridge or similar structure.  He added that the artificial straightening of a section of the burn, which had been done many years before, would assist in causing knickpoints to migrate upstream.

[108]    He explained:

“It is my view that the flood in Fochabers Burn was locally a geomorphologically effective flood, causing rapid channel change at specific locations.  Where incision had already started in the knickzone reach containing the Scottish Water Pipeline then my view is that flows at that point were mainly in bank in the 4 September 2009 flood (due to the enlarged size of the channel) causing accelerated erosion.”

 

[109]    Dr Brookes was asked in cross-examination about whether he was undertaking consultancy work for the defender independently of giving expert evidence in court and replied “Yes, we are very much consultants for them.  I do work for them, yes, but not the same individuals”.  His employer, Jacobs UK Ltd, had framework agreements with the defender. The work he had carried out for the defender, from 2009, included recommendations on reservoir discontinuities, and review of a report on a pipeline in a floodplain, as to whether it would or would not be vulnerable to erosion.

[110]    In the opinion of the other expert witness for the defender, Dr Coghlan, all of the damage to the bed and banks of the burn in September 2009 was a consequence of the flood and ongoing erosion processes. 

[111]    Dr Coghlan’s view was that the effect of a large flood coming down the burn should be compared to what he regarded as the relatively small amount of water escaping from the failed pipe and causing localised damage. This indicated to him that the banks and bed and, in fact, the collapse of the vehicle bridge, were caused by the flood and by inherent problems with the vehicle bridge structure.  The localised damage could partly be caused by the escape of water from the failed pipe, but it could equally be contributed to or caused by other effects, and that would include the turbulent flow of water coming either through or over the vehicle bridge.  He referred to the fact that undermining or other failure mechanisms had caused the loss of previous vehicle bridges in the caravan park.

[112]    In his opinion, the loss of the vehicle bridge, and associated damage, was a consequence of ongoing erosion processes. The damage to the pipe crossing was another consequence of the same underlying problem, rather than a cause of the damage to the pursuer’s property. 

[113]    While he considered that there were some errors in Professor Fleming’s approach to estimating the flow rate, his own analysis in his report resulted in a similar conclusion, with peak flows of between 5 and 10 cubic metres per second (m³/s).  In relation to the return period of the flood on 4 September 2009, his initial view was that it might have been above or below 1 in 10 years.  He said in his oral evidence that additional information subsequently obtained from SEPA indicated that the return period would actually have been significantly more than 1 in 10 years. But, in his view, flood return periods were not that relevant.  It was theoretically possible to have a worse outcome from a 1 in 10 year flood than from, for example, a 1 in 20 year flood.  He had no comment on the points made by Dr Brookes or Professor Fleming about stream power.

 

Issue 3.2: Decision and reasons
[114]    The pursuer submitted that the evidence of Dr Brookes should be given little weight, as it lacked objectivity in view of his previous involvement with the defender. In my opinion, this criticism is not made out.  I note that in Kennedy v Cordia (Services) LLP the test on this issue is whether the witness is being impartial in his or her presentation and assessment of the evidence. 

[115]    While I accept that it may have been desirable for the previous involvement of Dr Brookes in projects undertaken by the defender in Scotland to have been disclosed by him in his reports, I do not consider that the mere fact that he and his employer had previously carried out such projects for the defender is itself sufficient to taint the objectivity of his evidence.  There was no good reason, taken up with the witness, as to why his impartiality should be questioned. For example, there was no suggestion of any personal friendship or relationship between Dr Brookes and any particular staff of the defender, let alone anyone with any role or responsibility in the present matter.  Nor was it suggested that Dr Brookes had personally benefited from work done for the defender.   No specific instances of alleged impartiality were identified in his evidence or put to him. Whether or not any such factors might affect the objectivity of an expert will depend upon the whole circumstances, but they do not feature here. I am therefore not persuaded that the evidence of Dr Brookes should be given less weight on the grounds submitted by the pursuer.

[116]    However, on this issue I again prefer the evidence of Professor Fleming. His conclusions as to flow rate were broadly supported by the evidence of the defender’s expert, Dr Coghlan. These conclusions were more reliably explained than those of Dr Brookes. Professor Fleming’s calculations on flow rate resulted in a figure for peak flow of between 4.66 m³/s and 5.84 m³/s. His figures on stream power and flow rate were supported by his calculations using the Bagnold formula and the Manning formula.  On those figures, this was not an exceptional flood, but was something to be expected once in every five to ten years.

[117]    In contrast, Dr Brookes modified his original view on flow rate of 90 m³/s to 40 m³/s and then to 20 m³/s.  No sufficiently detailed working was shown by him for his figures.  A flow of 90 m³/s would have needed two metres of rainfall in 31 hours.  As Professor Fleming explained, this was not realistic or indeed physically possible. Also, Dr Brookes had calculated his figure of 40 m³/s at the point of confluence of the burn with the River Spey, which Professor Fleming did not consider to be the appropriate location because of the flow from the burn “piling up” against the flow in the River Spey.

[118]    On stream power, again there was no full and detailed explanation of the workings used by Dr Brookes, in contrast to Professor Fleming’s explanation about his use of the Bagnold formula.  On flood frequency, Professor Fleming’s finding of a 1 in 5 year to a 1 in 10 year flood event was broadly supported in Dr Coghlan’s report. 

[119]    In my opinion, the evidence of Dr Brookes was to some extent undermined by his changes of view on flow rate from 90 m³/s, to 40 m³/s, at the confluence with the River Spey, and then to 20 m³/s in the burn, without evidence of his detailed workings and without any other sufficiently cogent explanation.  In the result, he apparently proceeded on the basis that this was an exceptional flood event. 

[120]    Overall, I am not persuaded by the evidence of the defender’s witnesses that the flood on 4 September 2009 was an exceptional flood event. I regard it as of significance that there was, in my view, no persuasive explanation from the defender’s witnesses for the crater-like erosion to the left bank on this occasion, which had not occurred in earlier flood events.  In addition, as noted above, the defender’s experts did not in my opinion give convincing reasons that the natural flood would have caused the damage which is the subject of the claim, had the four steps identified by Professor Fleming been implemented.

 

Issue 3.3:  The vehicle bridge

[121]    The precise distance between the vehicle bridge and the pipe crossing was in dispute.  Several different figures were given by witnesses, including Mr Christie, based on their own impressions. Professor Fleming was taken to a figure in his report which showed the results from a survey and, from that, he said that there was a distance in excess of 100 metres between the vehicle bridge and the pipe crossing.

[122]    The next point in dispute was the extent of the vehicle bridge’s failure during the flood of September 2009. Mr Christie’s evidence was that the roadway of the vehicle bridge had been partly washed away, the gravel on top of the pipes had been washed out and during the flood the concrete pipes were under the flow of water, but the pipes were still very substantially in place in the bed of the burn.  About one half of the concrete block walls had, he said, been washed into the burn, within several feet of their original location.  Water had found its way behind the concrete block walls and had eroded a large area on the left bank.  Mr Christie could see the bank falling into the burn and saw a septic tank being washed away.  Mr Christie stated that he saw part of one of the concrete rings from the vehicle bridge at the pipe crossing.

[123]    As is noted above, Dr Brookes and Dr Coghlan appear to have proceeded upon the basis that the vehicle bridge had been substantially destroyed.

[124]    The parties also disagreed as to whether the vehicle bridge caused any erosion to the bed or banks of the burn during the flood of September 2009, either before or after it failed. Two contributory factors were identified by the defender, the first being the vena contracta effect and the second being a surge of water and debris that would follow from the collapse of the vehicle bridge.

[125]    Professor Fleming accepted that the vena contracta effect could cause erosion for tens of metres downstream of a structure.  Responding to the suggestion that it was the build-up of water at the vehicle bridge that may well account for the damage at the location of the pipe crossing, he said that he didn’t necessarily agree, adding that Dr Brookes took the bridge as being only 20 metres upstream when in fact it was 100 metres away, a distance which, as is noted above, Professor Fleming stated was based on an accurate survey by a professional surveyor.

[126]    Professor Fleming said that the damage to the banks in the section of the burn between the vehicle bridge and the pipe crossing was not the same as the damage at the location of the vehicle bridge and the pipe crossing, which he said is “where my conclusion comes from”.  I take this to mean that the degree of erosion at or around these locations was, in his opinion, different in appearance, and at least partly in causal mechanism, from that in between the locations.

[127]    Dr Brookes stated that it was possible that the vehicle bridge could have caused a blockage and/or contributed to the erosion of the banks downstream and at the location of pipe crossing.  He explained the vena contracta effect caused by the vehicle bridge, and that this would create accelerated flow causing bed and bank change up to 85 metres further downstream.  In his view, the vena contracta effect would have caused some erosion during the flood.

[128]    Dr Brookes also thought that the build-up of debris at the vehicle bridge followed by its failure may well have caused a surge of water which was part of the primary cause of erosion, along with the natural knickzone effect and the vena contracta effect of the bridge. 

[129]    It was therefore the defender’s position that, in addition to the natural flood, the vena contracta effect and a surge of turbulent water and the displacement of debris downstream when the bridge failed would have caused the failure of the pipe and erosion of the bed and banks of the burn.

 

Issue 3.3: Decision and reasons
[130]    In my view, there is no clear basis in the evidence for concluding that the presence of the vehicle bridge upstream of the pipe crossing had any causal relationship with the erosion at and around the pipe crossing.  I am not persuaded that there was a complete or even very substantial failure of the vehicle bridge, such that a sudden surge of water would have occurred. 

[131]    The defender’s experts proceeded upon the basis that the flood of 4 September 2009 effectively destroyed the vehicle bridge in the caravan park.  Before the failure of the bridge, its parapet walls were over-topped by the flood waters, and, the defender submitted, the flood waters completely filled the culvert pipes before they failed and were washed from their position as installed.  It was said that much of the concrete block structure and the gravel with which it was infilled were washed away.  In my opinion, this goes further than the evidence allows.  On the clear evidence of Mr Christie, which was not materially contradicted, the extent of damage to the vehicle bridge was not as major as the defender’s witnesses stated.  He accepted that there was a piece of one of the concrete rings found at the crossing after the flood, but otherwise spoke to simply the tarmac and gravel and perhaps half of the concrete blocks being washed away, with the blocks remaining close to the vehicle bridge and the concrete tunnels remaining very largely in place.

[132]    I accept that the vena contracta effect can cause scour or erosion for tens of metres downstream.  However, in view of Professor Fleming’s evidence, based on the survey, of a distance of 100 metres between the vehicle bridge and the pipe crossing, there is no real basis in the evidence for the view that the vena contracta effect could cause damage of the particular nature and scale that was witnessed to the banks of the burn that distance downstream.  This is supported by the absence of evidence of comparable damage in the area between the two structures.  I therefore reach the view that the vena contracta effect is not significant in the present context and does not explain the damage caused at and around the location of the pipe crossing.

[133]    In any event, Professor Fleming’s position was that the alleged failure of the vehicle bridge upstream would not have impacted on the pipe crossing if the pipe crossing had been properly constructed with the provision of bank protection and pipe protection works he had identified in his four required steps. Again, this point was not adequately or convincingly addressed by the defender’s witnesses. They looked at whether the vehicle bridge and the damage to it might have had an impact on the banks downstream, but did not in any satisfactory way address the question of whether that impact might have been avoided at or around the location of the pipe crossing had the four steps listed by Professor Fleming been taken.

 

Issue 3.4:   The failure of the pipe

[134]    Mr Christie said that, in conversations with engineers employed by the defender, he had been told that the pressure in the pipe was 16 bar.  Mr Christie later said that he was told by the defender’s engineers in 2012 that the pressure in the pipe in 2009 was 12 bar. 

[135]    In Professor Fleming’s view, due to the high pressure jet caused by the pipe failure on 4 September 2009, a large scour hole was formed on the left bank:

“When failure of the pipe occurred, a massive force of water was released against the left bank, causing severe bank erosion, bank cutting and bank failure”.

 

[136]    As noted above, Professor Fleming also assumed that the water in the mains originated at the River Spey.  On his understanding, pressure was applied to the water in the pipe by means of a pump.

[137]    In cross-examination, it was put to Professor Fleming that in fact the water in the mains pipe came from the Badentinan water tank, which is a supply reservoir located 7 kilometres from the caravan park. It was further put to him that the pressure in the pipe was of the order of 7 bar and that water had flowed from the failed pipe for a seven hour period from about 4am until 11am on the morning of the flood.  The pressure arose from the fact that the Badentinan water tank was at a height. He was not aware of these points. But Professor Fleming rejected the idea that it was appropriate to average the outflow from the pipe over a period of 7 hours.  He said that there would be high pressure at the outset of the pipe failure and that it would decline.  He explained that when the pipe fractured or failed, the figures he had calculated were for the flow rate “that will take place at that instant, and it wouldn’t take very long for that quantity of water at that flow rate to cause the damage which I’ve observed on site”.  While there would be a drop in the head of pressure in the Badentinan water tank resulting from a reduction in the volume of water in it, this would not be that significant, “so there is going to be a fair amount of head still jetting out of the pipe”. 

[138]    Professor Fleming repeated his view that “the failure of the pipe exacerbated the erosion on the left bank” and added that he was much more interested in the energy available to be dissipated at the instant the failure took place (rather than over an extended period) because that is when most of the damage would be done.

[139]    He was interested in the velocity of the flow from the pipe and the energy that velocity had in terms of erosion of the bank.   He referred to burst water mains causing vertical jets “of 100 feet high into the air.  They can lift cars off the road and they can destroy pavements and roads”.

[140]    He said that the jet of water from the failed pipe in the burn would probably not be visible to people there at the time “because it was under a flood”.  However, he disagreed with the view that the presence of flood water at the failed pipe junction would deflect or absorb the effect of the jet of water.  He reiterated his view that “in the initial stage there will be a high flow at high velocity, and then it will reduce as the reservoir discharges”. 

[141]    Professor Fleming’s view was that even if the pressure was 7 bar this would give a velocity of 27 metres per second and would add an additional 4 m³/s or thereabouts in flow rate, which added to 5.84 m³/s would give nearly 10 m³/s.  This represented a 1 in 75 year to 1 in 100 year flood event, which is what he now believed happened. When it was put to him, in the context of pressure being 7 bar, that one had to take account of the head loss in the pipe distribution system upstream from the failure, he said:

“The head loss in the pipe system will lead to a reduction in the flow, but you’re starting off with an initial pressure.  That pressure will dissipate as the pipe empties.  I’m talking about the point of the instantaneous failure of the pipe and the combined flows and the velocities experienced in the burn at the pipe crossing, and my conclusion is that the two factors caused erosion of the pipe crossing.  One, the natural alluvial flood, the 5 to 10 year return period and, second, the failure of the pipe which added to that erosion of the bank on the left side”. 

 

[142]    He stated that he could not accept that the discharge of the reservoir from the failed pipe into the burn at the pipe crossing did not contribute to some flood damage.

[143]    Accordingly, even if the pressure was of the order of 7 bar, Professor Fleming adhered to his view that the failure of the pipe would have contributed to the erosion. On his analysis, there was perhaps a one hour period during which the failed pipe made a significant contribution to the flow.  But he repeatedly emphasised the effect of erosion at the instant of failure, and I take his reference to the contribution from the failed pipe during the one hour period to relate to its contribution to the general flow of water in the burn during the flood.

[144]    Dr Brookes explained that he had spoken with some pipeline engineers about the issue of flow from the failed pipe. There was, he stated, an instantaneous moment at which a pipe breaks when there may be an enhanced pressure coming out.  Asked what the duration of the instantaneous effect was, he referred back to his recollection of the discussion with the pipeline engineers and said it was a matter of seconds or minutes while the pressure is released from the pipe.  Once that pressure was released, it was then a much lesser flow, perhaps as low as 0.25 m³/s (250 litres per second).  In his professional view, the flow from the failed pipe was an infinitesimally small contribution compared with the overall flow going through the channel in the flood. 

[145]    He explained that the photographic evidence produced did not lead him to believe that the pipe crossing caused any significant erosion to the adjacent bed or banks.  Rather, he believed that the pipe was a victim of the significant mechanisms of erosion he had described earlier.  The burst water main in itself could have caused some localised erosion, particularly in the first few seconds whilst the pressure was released from the pipe.  However, the photographs provided suggested to him that the pipe was only locally fractured (that is, it was not a clean break) and there was no significant bed scour attributable to that failure of the pipe.

[146]    Dr Brookes said that he was not qualified to talk about the bar pressure and its impact, but he could see no evidence close to the failed part of the pipe that caused him to think that, whatever the bar pressure, there was significant erosion due to that cause alone. 

[147]    Dr Coghlan stated that the “slight depression” around the location of the fracture of the mains water pipe might be the limited damage caused by the failure of the pipe.  In his view, bank failure due to pipe failure was highly unlikely.  From the photographs, the flow from the failed pipe would tend to be upwards rather than towards one of the banks.  Further, in his view, “There is no evidence of excessive localised scour around the area of the fracture itself, only a more generalised erosion of the bed in the area of the pipe as well as upstream and downstream.”

[148]    Dr Coghlan disagreed with Professor Fleming’s views expressed in his report regarding the outflow from the failed pipe.  Taking the position as being that there was a flow out of the Badentinan water tank of 6,300 cubic metres over the 7 hour period (from 4am until 11am on 4 September 2009) the average flow was of the order of 0.25 m³/s.  If Professor Fleming’s flow rate figure in his report was used, the tank would have emptied in 1.5 hours, but in fact it took 7 hours. 

[149]    The figure of 7.7 bar for pressure within the pipe, which Dr Coghlan had used, was given to him by staff of the defender.  In relation to the position immediately after failure of the pipe, he said there were two possible scenarios.  Firstly, that the complete fracture or failure occurred instantaneously, in which case the high pressure of 7.7 bar would rapidly drop to the final pressure and the flow rate that comes out of the pipe would not be significantly more than 250 to 270 litres per second.  The timescale envisaged for this rapid drop, depending on how the break occurred and the pipe material characteristics, was likely to have been a very short period of time, possibly a fraction of a second.  Secondly, the other scenario that he could envisage was that the fracture would gradually open up and, in this scenario, the pressure would take longer to recede and the flow would gradually increase but at no time would it be likely to increase above the figure of 250 to 270 litres per second.  Even if this was the case, the likelihood is that it would be a relatively gradual process, which would only have taken a few minutes, at most.  He stated that “… we know that during the entire seven-hour event, the drop in the, the reservoir, the upstream end was gradual and steady”.

[150]    Hamish MacDonald accepted that it may be that the crater-like or circular damage to the banks at the pipe crossing was caused by a jet of water from the pipe.  He said in re-examination that he did not imagine that the pipe joint would have burst before the land in which it was located had been eroded, but added that he would be speculating.

[151]    Mr Burnett did not consider that the damage to the banks was caused by the failure of the mains water pipe or as a result of any erosion due to the presence and design of the pipe crossing.

[152]    Martin Dunbar explained that the Badentinan water tank is located 2-3 miles away from the pipe crossing and positioned at a higher elevation than the park.  The pressure in the pipe would have been 7.7 bar which equals 77 metres of head, the difference in height between the source and where the pipe failed being some 77 metres. 

[153]    Mr Dunbar further explained that the capacity of the Badentinan water tank was 45 mega litres (45 million litres, which equals 45,000 cubic metres in volume) and at the time when the pipe failed it was 80% to 84% full.  He stated that the defender had the telemetry information and that the level in the tank dropped by 14% between 4am and 11am.  This was because of the ruptured main.  The pipe was able to cope with up to 16 bar in pressure.  The water in the pipe was not pumped, and the pressure of 7.7 bar was a result of the difference in elevation and thus was caused by gravity.  Head loss due to friction (caused by the water in the mains pipe running past the inner surface of the pipe) might make the pressure 7.5 or 7.3 bar.

 

Issue 3.4: Decision and reasons
[154]    It is common ground that the mains water pipe failed at the lower joint on the left bank of the burn.  This occurred because the 5.5 metre horizontal section of the pipe in the bed of the burn, and beneath the concrete slab, sank due to the bed of the burn being eroded or scoured.  This resulted in the joint between that section of the pipe and the diagonal section which ran up within the left bank dislocating or failing, resulting in an outflow of water from the pipe.  The failure of the joint caused water to escape under pressure.  As noted, the diameter of the pipe was 450 millimetres.

[155]    On day five of the proof, the defender moved to lodge the telemetry records for the Badentinan water tank.  The motion was refused and therefore the evidence on the matter was oral testimony. Given the nature of his job, and what he might therefore be reasonably expected to know, I accept Mr Dunbar’s evidence that the total capacity of the Badentinan water tank in September 2009 was 45,000 cubic metres, and that, at the time of the failure of the pipe, it was about 80% to 84% full.  I also accept that the failure of the pipe occurred at about 4am on 4 September 2009 and that between then and around 11am, when the flow was shut off, the volume of water in the tank had dropped by some 14%. 

[156]    The pursuer submitted that the defender’s witnesses were unable to say whether or not the Badentinan water tank was refilled during the period between 4 am and 11 am and that, therefore, the evidence as to the amount of water which was discharged from it during that period cannot be relied upon.  Mr Dunbar was asked whether or not it was the case that the reduction in the level of the Badentinan water tank of about 14% was attributable to the pipe failure at the park, and he said that it was.  He agreed that it was matter of arithmetic to calculate how much water had flowed out of the reservoir, down the main and out of the failed pipe during the period in question. As to the rate at which the water flowed through the pipe between 4am and 11am, he said that one could probably make a calculation on how much water was escaping based on how much the reservoir dropped.  In my view, Mr Dunbar’s evidence on this matter must imply that water was not flowing into the Badentinan water tank during that period. 

[157]    I therefore accept the evidence of Mr Dunbar concerning the reduction in volume of water in the Badentinan water tank and that this was attributable to the failure of the pipe at the caravan park.  It also seems to me that, proceeding upon the basis that the tank was not topping up, the calculation made by Dr Coghlan is correct.  This was to the effect that, taking the reduction in volume and the time over which that reduction took place, the average flow rate from the failed pipe was of the order of 0.25 m³/s.

[158]    In the absence of good and detailed evidence about the source and content of the things allegedly said to Mr Christie about pressure in the pipe, I am unable to give much weight to this evidence.  I accept the evidence of Mr Dunbar to the effect that the likely pressure at the point of failure of the pipe was between 7.3 bar and 7.7 bar. He was in a better position than any other witness to give evidence on this matter. For that reason, one of the assumptions originally made by Professor Fleming (pressure of 15 bar) was unfounded.  Accordingly, Professor Fleming’s observations in his report as to the rate of flow from the failed pipe were incorrect.  However, in his oral evidence Professor Fleming was of the view that even if the pressure was around 7 bar, the velocity and flow rate of water emanating from the failed pipe at the instant of failure would still have been sufficient to contribute to the erosion at the pipe crossing.

[159]    To focus on the average rate of flow over the seven hour period does not in my opinion assist with the question of the immediate impact of the failure or bursting of the pipe.  Professor Fleming gave graphic evidence about the effects of burst water mains in other circumstances.  All of the experts agreed that there would be an instantaneous release of water from the failed pipe, at pressure, albeit they did not agree as to its precise duration or effect.  Professor Fleming was clear that the energy dissipated at the instant of failure would be significant and would have contributed to the damage that was done to the left bank of the burn. I accept that evidence. I found his reasoning persuasive and his conclusion fits with the nature and scale of the damage to the left bank of the burn. The evidence for the defender tended to focus instead on the average rate of flow and the contribution of the water exiting from the failed pipe to the general flow in the burn during the flood.

 [160]   The defender submitted that the evidence of Professor Fleming on this matter was unreliable.  It was said that he gave no proper scientific explanation and that his evidence was non-specific and essentially anecdotal.  However, Professor Fleming gave evidence as to the calculation of velocity and flow rate and he focused upon the instant of failure.  In fact, all of the expert witnesses agreed that at the instant of failure of the pipe water would exit from it at a higher velocity than the average over an extended period.

[161]    The defender further submitted that Professor Fleming did not have the expert knowledge or experience to say that, if the mains water pipe failed in these circumstances, it would cause erosion of the kind identified.  I have dealt earlier with Professor Fleming’s experience and qualifications and in my opinion these allow him to give expert evidence on the effect of the failure of the pipe

[162]    Overall, therefore, I am of the view that Professor Fleming’s evidence is to be preferred.  I have taken into account that he had initially proceeded upon the basis of higher rates for pressure and for flow but when the alternative figures were pointed out to him he adhered to his view about the immediate effects of the release of pressure. 

[163]    The defender’s experts did not explain in any sufficiently cogent fashion why the release of pressure in that instant would not be enough to contribute to the damage to the banks of the burn.  Dr Brookes effectively acknowledged that he was not well-placed to give expert evidence on that matter. Indeed, as I have noted, there is also some acknowledgement in his and Dr Coghlan’s evidence that, at least for a very short period, the release of water would be at a high pressure.  Moreover, the nature and scale of the damage, particularly at the left bank, as noted above, fits with the idea that an additional mechanism to the natural effect of the flood contributed to the erosion at the location of the pipe crossing. Dr Coghlan also proceeded upon the basis that there was only a “slight depression” at the location of failure, which understates the factual position.

[164]    The defender also submitted that flow from the failed pipe would be in one direction only, namely down the angled section of pipe and towards the bed of the burn.  It would not, argued the defender, have jetted in the direction of the left bank and so it could not possibly account for damage to the left bank and the bed of the burn or to both banks.  It was said that a massive natural flood was covering the pipe when it failed. 

[165]    It was Professor Fleming’s clear evidence that such an escape of water had indeed contributed to the erosion to the banks of the burn, and I accept that conclusion.

[166]    Photographs of the pipe were taken after the defender’s contractors had cleared the debris at the pipe crossing, following the flood.  They had taken away the concrete slab that covered the pipe and removed the mass concrete block (which had anchored the drainage pipe).  The scene had therefore been disturbed.  In any event, Professor Fleming was aware of the locations of the pipe sections as shown in the photographs and it appears to me to be unrealistic to suggest that he had failed to have regard to this in giving his evidence.  The precise arrangement and proximity to one another of the failed sections at the immediate point of failure is not known, but in light of the evidence there is no basis for assuming that any sudden release of pressurised water from that failure point would have had no impact on the left bank.

[167]    The defender criticised Professor Fleming’s evidence that increased flooding downstream from the pipe crossing, all the way to the River Spey, could be seen in the YouTube video evidence of the flood in Fochabers at the West Street bridge. While there may be some force in that criticism, it does not affect Professor Fleming’s conclusions as to the immediate effect of failure of the pipe and its contribution to erosion at the pipe crossing. 

[168]    The defender also argued that the engineering work, which Professor Fleming said should have been carried out, would not have prevented the separation of the two pipe sections and hence would not have prevented any water jet erosion which resulted from the failure of the pipe.  In my opinion, that is incorrect.  I accept Professor Fleming’s view that the failure to install the necessary protection resulted in the pipe being exposed and failing in the manner described above. 

[169]      In summary, on issue 3, my conclusion is that the damage was caused as a result of the failure by the defenders to take the steps identified by Professor Fleming. The defender’s breach of duty also resulted in the failure of the pipe, which contributed to the damage. The damage was therefore not caused by natural causes or other factors unrelated to the pipe crossing.

 

Issue 4:  Was further damage, for which the defender is liable, caused after September 2009?

 

[170]    Mr Christie stated that, during the course of exposing the pipe after the September 2009 flood, the defenders’ contractors dug out the gravel in the bed of the burn “at least three foot all the way down, 30 metres”.  The witness estimated that they must have dug out at least 1,500 tons of material “which made a substantial difference to the bed of the burn”. 

[171]    While Mr Christie made clear in his evidence, on several occasions, that this excavation and consequent lowering of the bed of the burn took place, the other evidence in the case did not support that position.  Mr Dunbar had no knowledge of the defender having at any stage actually excavated the bed of the burn in the aftermath of the flood on 4 September 2009. If that had happened, he would have expected to know about it. On his evidence, the defender had no reason to excavate a section of the base of the burn downstream of the pipe crossing. He was not aware of the defender having at any stage instructed contractors to excavate a 3 to 4 feet deep trench 30 metres downstream of the pipe crossing and he  confirmed that there was no likelihood that someone else on the defender’s staff would have given that instruction without him knowing about it. He accepted in cross-examination that the contractor had been instructed to remove the debris to see what damage had been done to the bed of the burn.

[172]    Professor Fleming was asked about this matter in the course of his evidence in chief, and in essence he did not know “the situation at the time”. He understood from Mr Christie that the area was levelled and smoothed off, which built up and replaced some of the eroded material in the September 2009 flood, but then when the November 2009 flood came it exposed the pipe again. Accordingly, Professor Fleming had no knowledge of the suggestion that excavation of 3 to 4 feet of the bed of the burn for the length spoken to by Mr Christie had in fact occurred, and did not provide any support for it having taken place.

 

Issue 4: Decision and reasons
[173]    The absence of any support for Mr Christie’s evidence as to the excavation of the bed of the burn makes that evidence difficult to accept. Professor Fleming’s evidence is not consistent with Mr Christie’s own position. There was some excavation to expose the pipe, but beyond that the position is unclear. Mr Christie certainly understood that the further excavation required to be addressed by remedial works and it was clear from his evidence that some of the remedial works which are the subject of the claim were undertaken for that purpose. However, even if excavation to the extent spoken to by Mr Christie had occurred, it was not, on any view, a consequence of the original breach of duty by the defender. There is no basis in the evidence for concluding that this constituted a separate act of negligence on the part of the defender. Professor Fleming does not address this question and so does not offer any view to the effect that it was negligent of the defender to excavate the bed of the burn.

[174]    A central feature of the present case is the existence of detailed and complex expert evidence about the causes and effects of flooding, the removal and deposition of material, and erosion of the banks and bed of the burn. Without evidence addressing the point, I cannot speculate as to whether removal of material from the bed of the burn, to the extent that this occurred, was a further negligent act.

[175]    The defender further submitted that, even if the contractors engaged by the defender had excavated the bed of the burn to the depth that Mr Christie suggested, this was not something for which it had been shown that the defender was vicariously liable.  I agree.  No evidence was led by the pursuer, and no detailed submissions were made, which could justify a finding of vicarious liability on the part of the defender for the acts of its contractor.

[176]    Accordingly, this part of the pursuer’s claim does not succeed.

 

Issue 5:  What are the recoverable losses?
[177]    Mr Christie explained that the pursuer was seeking the costs of the repair works carried out over a length of some 130 metres of the banks.  (In other parts of his evidence, this figure varied between 138 metres and 126 metres).  He assented to the proposition that he was seeking “the costs of reinstatement relative to the failed pipe itself, the blockage around the pipe crossing area and… the damage caused by the works done between the first flood and the second incident in November 2009”.  He also said that the pursuer was claiming for works done in respect of 5 out of 7 weirs. 

[178]    The pursuer’s claim comprises the recovery of the costs of (i) temporary works (£29,486.02); (ii) permanent reinstatement works (£72,532.50); (iii) lost management time not claimed in earlier sums (£28,000); and (iv) miscellaneous items (£2,250). Interest is also sought from various dates.

 

Issue 5: Decision and reasons
[179]    Before turning to analyse these individual aspects of the claim, the losses must of course be restricted to those actually caused as a result of the defender’s breach of duty. I make two points in that regard.

[180]    Firstly, it appears to be clear from the evidence that the damage to the banks at and around the pipe crossing after the September 2009 flood extended to some 10-15 metres on either side of the pipe crossing on the left bank, that is a maximum of 30 metres, and then on the right bank extended to 40-45 metres (10 metres downstream of the pipe crossing and the rest upstream of it).  Even allowing for rock armour to be placed further upstream and further downstream of the damaged areas of the banks, at least some of the remainder of the 130 metres or so stretch of the burn, on which work was carried out and is the subject of the claim, must include other works. These include the works done to remedy the alleged lowering of the bed of the burn caused by excavation carried out by the defender’s contractors.  I have held that the defender is not liable for those costs, as it has not been shown that they were incurred as a result of a breach of duty by the defender.

[181]    Secondly, Mr Christie gave evidence that five new weirs were installed in the stretch of the burn mentioned above.  Even if these works were not done as a consequence of the alleged excavation of the bed of the burn, in order for the cost to be recoverable the pursuer would require to show that the weirs had to be installed as a consequence of the breach of duty by the defender.  This was not established by the evidence.  Further, Professor Fleming stated that the remedial works, including the weirs, had stabilised the burn. It was never a requirement of the defender’s works in 1997 or thereafter that these should result in stabilisation of the burn. While the weirs may assist in limiting the potential for future erosion, by putting a check on the gradient of the slopes, no clear link was established between the defender’s failures and the need to install weirs.  Moreover, Professor Fleming made no suggestion that it was negligent of the defender not to have installed weirs.

[182]    Therefore, the pursuer has failed to establish that all of the works and resulting costs comprised in its claim for payment of £126,790.52 resulted from the breaches of duty by the defender.

[183]    The passages in the evidence of Mr Christie where he described the two sets of temporary works and the permanent reinstatement works were not entirely clear.  Given that he was dealing with the claim as a whole, that may be understandable, but it makes it difficult to identify with absolute precision those elements of the remedial works which were caused by the alleged excavation of the bed of the burn or by other matters not arising from the defender’s breach of duty.

[184]    Against that background, I now turn to deal with the individual elements in the claim and under each sub-heading I shall state the reasons for my conclusions.

 

TEMPORARY WORKS
[185]    Part of the claim is for two sets of what were described as temporary works.

These temporary work items are dealt with in various invoices lodged as productions. The sequence of events spoken to by Mr Christie was that the alleged excavation of the bed took place after the September flood and thereafter the first set of temporary works were undertaken, including the use of rock armour to install weirs.  Some rock armour was also placed at the right bank. Mr Christie spoke to the damaging effects of the November flood, because of the excavation of the bed of the burn, and explained that the pursuer had to “beef up” the weirs and the bridge foundations with rock armour. 

[186]    The work the contractors allegedly did in excavating the bed of the burn, said Mr Christie, “caused a substantial increase in the amount of repairs that had to be undertaken”.  The invoices which relate to the first set of temporary works included, for example, the hire of a digger from 2 November 2009 until December 2009.  The invoices also showed the purchase of rock armour from Limehillock Quarries, along with “type 1 sub‑base” which was used as infill. 

[187]    Mr Christie explained in his evidence that both sets of temporary works were essentially for the same purpose.  He supervised the temporary works, this being part of the management time claim. While the oral evidence of Mr Christie led by pursuer was not particularly clear, it is consistent with the temporary works being required for the reasons averred by the pursuer. These were stated to be the defender’s works in exposing the pipe and allegedly lowering the bed of the burn and the effects of the second flood incident of 1 November 2009.

[188]    In these circumstances, the pursuer has not established a causal link between the defender’s negligence and the reasons for incurring the costs of the temporary works, with the exception of fencing and electrical costs (discussed below) and possibly the cost of some rock armour on the right bank. However, Mr Christie did not in any clear way distinguish between the placing of rock armour in the bed of burn, as weirs, and the use of rock armour on the banks. Mr Christie stated that the vast majority of the rock armour was installed by R & C Murray Ltd and not as part of the temporary works. While it therefore appears that a relatively small amount of rock armour to the right bank of the burn was installed as part of the temporary works, I have no basis in the evidence for estimating its cost. Moreover, it was not explained in the pursuer’s evidence that this rock armour on the bank was within the range (20 metres upstream and 20 metres downstream of the area to be protected) which Professor Fleming spoke to as being required. The costs of the temporary works, other than fencing and electrical costs, are therefore not recoverable.

[189]    The claim for the cost of fencing was in respect of fencing put in to protect people in the park from the steep banks created after the flood.  The defender submitted that the evidence from Mr Christie was too sketchy to establish this part of the claim. Also, the total meterage of fencing claimed was excessive.  However, on the pursuer’s evidence, only that part of the fencing costs which relates to the areas said to have been damaged by the defender’s breach of duty was claimed for, and the sum invoiced (£4,584) was restricted to a sum for fencing and electrics of £3,348.  Accepting that evidence, I hold these costs to be recoverable.

 

PERMANENT REINSTATEMENT WORKS
[190]    I turn now to the reinstatement works and their costs. The central elements of the reinstatement costs are (i) a payment of £48,882.55 made to R & C Murray Ltd, the contractor which carried out the reinstatement works, and (ii) a payment of £23,650 for civil engineering design works carried out by A F Cruden Associates Ltd.  Reference was made in the evidence of Mr Christie to these invoices. Two drawings were prepared by A F Cruden and these show the nature and extent of the reinstatement works. They show four positions for rock armour weirs and the areas where additional rock armour protection along the banks of the burn was to be placed, where extreme erosion had occurred. R & C Murray Ltd carried out the works as stated on these drawings.

[191]    The invoice from R & C Murray Ltd gives a fairly detailed breakdown of their costs. By far the largest element in the cost is the sum of £32,216.55 for “infill material placed and graded onto bank at severely eroded areas adjacent the burst water main. Fill material to be angular binding crushed rock.” On this narrative, this work relates directly to the damage caused by the defender’s breach of duty and there was no suggestion that it did not. In relation to rock armour, the invoice distinguishes between rock armour placed on the banks and rock armour placed within the burn at five positions, the latter apparently being the weirs spoken to by Mr Christie in his evidence.

[192]    I note that in respect of the rock armour placed on the banks of the burn, the cost is £8,535.20. This rock armour occupies, according to the drawings, a length of approximately 60m on each bank. Having regard to the evidence of Professor Fleming that the rock armour (or gabions) initially installed by the defender should have extended to 20m upstream and 20m downstream of the pipe crossing, the rock armour required for the remedial works should reasonably include those distances from damaged areas. Given the extent of the damaged areas, I conclude that the rock armour placed on the banks of the burn by R & C Murray Ltd was indeed required in order to deal with the effects of the defender’s negligence. The other items in the invoice, apart from the rock armour placed within the burn and the random rocks, also appear to me to fall within that category.

[193]    I conclude therefore that the elements of the R & C Murray Ltd invoice which do not relate to the works required as a result the defender’s negligence comprise the costs of the rock armour placed within the burn at five positions and the cost of placing the random rocks, the total sum being £4494.60. Deducting that sum from the total figure in the invoice of £48,882.55 gives £44,387.95.

[194]    There was no detailed evidence as to how the costs in the A F Cruden invoice were arrived at.  As a starting point, given that the works done by R & C Murray Ltd were based on the drawings by A F Cruden, a similar apportionment to that just done above might be appropriate. However, I note that one of the two design drawings relates solely to the weirs. I therefore consider that it is appropriate to proceed on the basis that a greater percentage deduction than that made in respect of the R & C Murray Ltd invoice requires to be made from the sum paid to A F Cruden. Mr Christie’s evidence was that A F Cruden were employed to produce a scheme to stabilise the bed and banks in the burn, including in respect of the alleged excavation of the bed of the burn.  For example, he said that some of the rock armour shown on the A F Cruden drawing formed a substantial weir because there was a big drop caused where the burn was dug out.  Thus, a significant part of the work by A F Cruden related to weirs but another significant part related to the damage caused by the defender’s breach of duty. On the limited evidence available, it is therefore reasonable to approach matters on the basis that one half of the A F Cruden cost was indeed in respect of work arising from the defender’s breach of duty. Thus, 50% of the cost in the A F Cruden invoice is recoverable. This results in a figure of £11,825.

 

MANAGEMENT TIME
[195]    Mr Christie explained that the first part of the management time aspect of the pursuer’s claim was based on 56 hours of his time, at £80 an hour.  He explained that this amount of time dealt with arranging for the hire of the digger, organising the work to install the weirs and project managing the repairs to the burn. It also covered meeting with the defender’s representatives and with the pursuer’s consulting engineer and dealing with letters and the claim for compensation. He said that 40 hours out of the 56 hours were spent meeting the defender’s representatives.  This claim for 56 hours of time was the subject of an invoice by Christies of Scotland Ltd, another company owned by Mr Christie.  In my opinion, only the 40 hours spent in meeting with the defender’s representatives is recoverable, since the claim in respect of the temporary works fails for the reasons I have given above and thus no sum is recoverable for management time spent on their organisation or supervision.

[196]    The pursuer also claimed in respect of further management time of Mr Christie, in the sum of £28,000, and hence for a further 350 hours of management time. 

[197]    I accept that Mr Christie must have been required to spend a considerable number of hours in dealing with the issues which arose as a result of the breaches of duty by the defender.  However, Mr Christie’s estimate of the total number of hours was not reliable. He gave various figures and said that the figure of 400 hours in total was a “rough guess”.  This would represent fifty 8 hour days, devoted entirely to dealing with the consequences of the breach of duty. Without a clear and cogent explanation, this appears disproportionate and excessive. The record of meetings and other activities in the document which Mr Christie produced covered 175 hours, in addition to the 56 hours mentioned in the earlier invoice. This record covered the period until the end of 2011. His evidence was that the management time spent after that date related to “preparing for the case and things”. I therefore conclude that the figure of 175 hours is the appropriate starting point for the second part of the management time claim.

[198]    In relation to the management time aspect of the claim, I was referred to one authority, by the defender:  Standard Chartered Bank v Pakistan National Shipping Corporation (no 3) [2001] 1 All ER (Comm) 822.  The defender submitted that as a matter of law in order to succeed with an employee’s time claim the pursuer must show that there has been significant disruption of the pursuer’s business or loss of profit or increased expenditure incurred by them. It was said that the pursuer has not proved any of these elements in this case.

[199]    In my view, the defender’s contention based on Standard Chartered Bank is not well-founded.  Mr Christie gave evidence that because he was spending time on matters related to the repair and reinstatement works, he couldn’t do other projects.  He identified the other projects which were delayed.  This provides sufficient evidence of the diversion of his time causing disruption to the business to justify the claim in respect of management time. 

[200]    No evidence was led to the effect that the hourly rate claimed by Mr Christie (£80) was excessive nor was that suggested to him in cross examination.  Having regard to the evidence and the absence of challenge, I consider it to be a reasonable rate.

[201]    In relation to the question of whether the pursuer is entitled to recover in respect of the time spent by Mr Christie in preparing for giving evidence at a proof which was ultimately discharged, and in respect of the days on which the proof actually ran, no direct authority was referred to by either party.  My opinion is that these costs are not recoverable.  If they were, then in every litigation where an employee or manager had to meet solicitors or counsel or prepare for a hearing, such costs would be able to be claimed and indeed would continue to accrue throughout the litigation. Without being directed to any clear basis in principle or authority, I am unable to find that a management time claim extends to time spent preparing the claim for damages or to time spent in court or in preparing for the proof.

[202]    I note that there is reference, in the document vouching the second part of the claim for management time, to time spent consulting with solicitors or counsel and preparing the claim or dealing with other matters which were not properly explained.  From the document, I calculate that 52 hours falls into that category. I therefore deduct that 52 hours from the second aspect of the management time claim (175 hours), leaving 123 hours. Added to the 40 hours from the first invoice, this gives a total figure for recoverable management time of 163 hours.

[203]    Of these 163 hours, 45 hours are claimed for what is described as “supervise works to completion”. I have already excluded from the first part of the management time claim the time spent on supervision of the temporary works.  Based on the limited material available, I consider that the appropriate course is to seek to apportion the 45 hours to reflect the fact that a portion of the second aspect of the management time claim can reasonably be inferred to have been spent on non-recoverable matters. Therefore, I take the totality of the sums claimed by the pursuer in respect of the two invoices for the permanent reinstatement works (£72,532.55), identify the portion of these which is not recoverable on the basis of my views as expressed above (£16,319.60), and arrive at the percentage which is recoverable (77.5%, rounded). Applying that percentage to the claim for 45 hours of management time in supervising the works, at £80 per hour, gives £2,790. Adding the other 118 hours of the management time claim (valued at £9,440) gives a total figure of £12,230.

 

MISCELLANEOUS ITEMS
[204]    The pursuer also claims the arrangement fees (£750)  for a bank overdraft for a sister company, Christies of Fochabers (Chemists) Ltd, which borrowed money for the repair works.  The pursuer further seeks recovery of fees (£1,500) paid to a Chartered Engineer, Mr Moir, who advised on the repairs.  The pursuer also argued that the SEPA licence was required because of the works and that its date and the involvement of A F Cruden confirmed this fact.

[205]    In relation to the bank fees and the fee for the services of Hamish Moir, I consider that these are recoverable in principle but should be apportioned for the reasons given above.  I apply the same apportionment (77.5%) to the total for these claims (£2250) on the basis that a portion of them relates to costs which are not recoverable. This gives a figure of £1,743.75.

[206]    As to the SEPA licence, it was not suggested in evidence that the SEPA licence would not have been required, or would have cost any less, if the only works being done were works other than those properly recoverable and included in the claim. There was no reason given as why the works in relation to weirs would not have required a SEPA licence.  Thus, the pursuer has not established that the licence was required only in relation to works which form part of the recoverable items of expenditure.  Accordingly, I am not persuaded that this part of the claim can succeed. 

[207]    I summarise my calculations of the sums recoverable and the interest due on these sums as follows:

1.         Temporary works (excluding fencing and electrical works): nil.

2.         Fencing and electrical works: £3,348, with interest at 4% per annum from 30 April 2010.

3.         Reinstatement works: £56,212.95, with interest at 4% per annum from 15 May 2011.

4.         Management time: £12,230, with interest at 4% per annum from 1 July 2012.

5.         Bank fees: £581.25, with interest at 4% per annum from 15 May 2011.

6.         Hamish Moir fee: £1,162.50, with interest at 4% per annum from 1 March 2011. 

 

Disposal

[208]    For the foregoing reasons, I shall sustain the pursuer’s first and second pleas-in-law. I also propose to sustain the pursuer’s third plea-in-law, to the extent of the total of the sums listed above (£73,534.70). I shall also sustain the fourth plea-in-law for the defender and repel the remainder of the defender’s pleas. However, before pronouncing an interlocutor I will put the case out by order, to allow parties to check and confirm the arithmetical calculations I have made and the dates from which interest should run. In the meantime, I reserve all questions of expenses.