Injurious affection to bungalow situated among agricultural land on Hampshire estate — Whether bungalow suffered damage from structural movement caused by construction of M3 some 900 ft away — By about nine months after completion of excavation of motorway cutting the bungalow walls had suffered cracking, the primary cause being rotation of the foundations due to differential drying-out of London clay subsoil — Date of cracking in dispute — Claimant’s contention that cause of shrinkage and drying-out was lowering of water table which in turn was attributable to construction of motorway causing reversal of flow, thereby reducing moisture at foundations — Extensive review of evidence of expert and other witnesses for both parties — Tribunal’s findings that cracking damage occurred suddenly in a fortnight some nine months after motorway excavation completed; that condition of fields between bungalow and motorway changed from extreme wetness and general unsuitability for cultivation to dryness and normality for cultivation; that corresponding change from wetness to dryness occurred in nearby ditches; and that there was a marked reduction in flow of springs — Experts, in tribunal’s view, had not given sufficient emphasis to interception of flow of surface water and ground water towards bungalow — If such interception were not responsible for damage, then only possible explanation was reversal of ground-water flow — Whatever the reason, tribunal concludes that damage was caused by motorway construction — ‘Lay logic’ — Award of agreed sum of £7,500
Rupert Jackson
(instructed by Walters Fladgate) appeared for the claimant; Michael Rich QC
(instructed by the Treasury Solicitor) for the acquiring authority.
Giving his
decision, MR WELLINGS said: This is a reference by consent for the
determination of the amount of compensation to which the claimant is entitled
for injurious affection to a bungalow belonging to her and alleged to be
attributable to the construction of the M3 motorway.
The bungalow
is known as Butterwood Bungalow. It is situate among agricultural land on what
may be called the Malmesbury Estate at Nateley Scures, Hampshire. The bungalow
was built in 1949 and was purchased by the Rt Hon the Earl of Malmesbury in
1954 and subsequently transferred by him to his wife, the claimant. Some of the
neighbouring land belongs to her in her own right, some of it is owned and
farmed by the heir to the title, Viscount Fitz-Harris, as tenant for life and
some of it is owned by Lord Malmesbury. As I understand it, the estate,
considered as a whole, is managed by him.
I need not be
specific as to the divisions between the respective parts of the estate nor as
to the titles thereto because it is accepted by the respondent, the Secretary
of State for Transport, that the bungalow was held together with land
compulsorily acquired for the purpose of the construction of the motorway,
which runs east to west in a cutting through Butter Wood some 900 ft to the
south of the bungalow, severing one part of the estate from the other.
The compulsory
purchase order was dated December 9 1968; notice to treat was served on the
relevant persons on December 9 1968 and entry was made on the land taken on
January 17 1969. Compensation in the sum of £9,340 for the land taken was
ultimately paid to the estate. That compensation included nothing for injurious
affection to the bungalow but, by an agreement in writing made on December 8
1980 between the claimant and the Secretary of State for Transport, the
parties, after appropriate recitals setting forth the respective contentions of
the parties, mentioning the payment of compensation for the land taken and
showing that the parties were in dispute as to the claim for compensation for
injurious affection, agreed to refer to the Lands Tribunal the following
questions:
(1) Whether the bungalow had
suffered damage by reason of structural movement caused by the construction of
the M3 motorway;
(2) If yes, what would have
been the additional compensation payable in respect of the prospect of such
damage if a claim therefor had been made by the claimant under section 7 of the
Compulsory Purchase Act 1965, upon the acquisition of land held with the
bungalow for the purpose of constructing the motorway.
The agreement
also contained a statement that the respondent does not dispute that it is
necessary to underpin the foundations of the bungalow and take other remedial
works specified in documents referred to in the statement. The second question,
referred to above, no longer arises because the parties, at the hearing,
through their counsel, agreed that if the answer to the first question referred
to the tribunal were in the affirmative, the claimant would be entitled to an
award of compensation for injurious affection in the sum of £7,500.
Since its
purchase by Lord Malmesbury in 1954, the bungalow has been occupied by Mr
Dennis Frank Gary, a general farmworker and building maintenance worker,
employed generally on the estate by Lord Malmesbury, and by Mr Gary’s wife,
Audrey Gary, and their family.
At the hearing
the parties were in agreement at least to this extent that:
(1) The subsoil beneath the
bungalow and indeed most if not all of the surrounding land consists of London
clay; and
(2) By September 15 1970 the
walls of the bungalow had suffered cracking; and
(3) The process of excavation
of the cutting in Butter Wood was begun in the summer of 1969 and completed by
the end of that year.
It was also common ground that the primary cause
of the cracking of the walls of the bungalow was rotation of its foundations,
it being agreed that such movement was caused by differential drying-out of the
subsoil, which drying-out was faster outside the bungalow than under it.
The details
relating to the cracking and its cause were not in all respects the subject of
agreement. The description which follows is taken from the evidence of Mr
William Dennis Stone (to whose evidence I shall refer subsequently in this
decision), whose description of these matters I accept. That description is as
follows:
(a) A horizontal crack is
present at the junction of the ceilings and the external walls. This crack
extends for the full perimeter of the building, having a minimum width of about
2mm in the living-room and a maximum width of about 8mm on the west wall of the
south bedroom.
(b) Vertical, or
approximately vertical, cracks, the result of horizontal movement, have
occurred in all walls except the west wall and the north wall of the
living-room.
(c) There is very little
significant cracking of any of the walls below dpc level and all vertical
cracks are wider at their upper ends, where they generally run into the roof,
than at their lower ends, which generally run into door or window openings.
(d) Adjacent to several
window and door openings a tapered crack has opened up between the frame and
the reveal, the taper increasing from the lower end towards the top.
(e) Since September 1970 the
floors have domed, causing distortions of internal door frames.
(f) The damage described
above is attributable to a rotation outwards of the external foundations of the
bungalow so as to cause the external walls to become out of vertical. The
amount of rotation was small but the amount of rotation necessary to produce a
crack of 1/4 in at ceiling level is small.
Mr Stone had
never seen outward rotation on such a scale as in the present case: usually it
is limited to one wall or side of a building.
Topography
The motorway,
which was completed in the early 1970s, runs, as I have stated, in a cutting in
an east-west direction south of the bungalow. The fence on the northern
boundary of the motorway is about 900 ft from the bungalow. The land between
that fence and the bungalow is on a ridge sloping downwards to the north and
the bungalow and falling away also on its western and eastern sides. Between
that fence and the bungalow there are two fields. The larger of the two is
nearer the fence and is called Bickmeads. The smaller of them is known as
Little Bickmeads and the two fields are separated by a ditch running east and
west. The bungalow, other buildings, Bickmeads and Little Bickmeads, the ditch
and other features of the locality are shown on the plan which is annexed to
this decision. Those features include the relevant section of the motorway,
various trees, a well, a lane on the west side of the two fields known as
Heather Row Lane, the bridge over the motorway to which that lane now leads and
the point of issue of certain springs.
Matters in
dispute
The date when
the cracking in the bungalow occurred is in issue. The claimant’s evidence is
that the cracking of the walls occurred suddenly in September 1970. The
claimant contends that the cause of the shrinkage and drying-out of the subsoil
under and in the vicinity of the bungalow was a lowering of the water table.
That contention is disputed. The claimant also contends, per Mr Stone, that the
lowering of the water table was attributable to the construction of the
motorway, the excavation for which, he said, caused the flow of the water
table, which previously had been from south to north, to be reversed and to
drain into the motorway, thereby reducing the moisture present at the
foundations of the bungalow. That contention is not accepted by the respondent.
It was common ground between the expert witnesses that the construction of the
motorway had intercepted and reduced the flow of surface water from south to
north in the direction of the bungalow, but neither expert thought that that
feature was the significant cause of the damage.
The witnesses
Mr Robert
Jackson, for the claimant, called Mr Dennis Frank Gary; the Rt Hon William
James, Earl of Malmesbury; Mr Geoffrey Ernest Mann FRICS, a partner in the firm
of Austin & Wyatt from 1947 to 1978 and now a consultant with that firm: Mr
William Dennis Stone BSc Eng (Lond) MICE and member of the Institution of Water
Engineers, senior partner in the firm of W D Stone Associates, consulting
civil, structural and services engineers; and Mrs Audrey Gary.
Mr Michael
Rich QC, for the respondent, called Mr David George Watts, who was employed as
clerk of works by the South Eastern Road Construction Unit during the
construction of the relevant part of the motorway from 1969 onwards; Mr Peter
John Butcher MICE, who had been assistant resident engineer for the M3
contract, Basingstoke — Frimley, and is now senior engineer in the South
Eastern Road Construction Unit; and Mr Jack Wrightman Ch Eng MICE, Fellow of
the Geological Society of London and member of the British Geotechnical
Society.
Summary of
oral evidence
A. Witnesses for the claimant
(1) Mr Gary: He was a bricklayer by trade
who originally had been employed by Lord Malmesbury as such but since April 9
1954 had been employed by him as a general farmworker and building maintenance
worker on the Malmesbury Estate. Since 1954 he and his wife had occupied the
bungalow. He had lived all his life, that is to say 50 years, in this area.
Before the motorway was built there had been no problem with cracking in the
bungalow. He first noticed the cracks on returning from holiday on September 15
1970 after he had been away for a fortnight. When he and his wife opened the
front door on returning from holiday plaster from cracks crashed on to the
floor. He informed Lord FitzHarris of the matter and he told him to report to
the Road Construction Unit, which he did two days later. On the instructions of
Mr Mann he fitted tell-tales. It was untrue that these cracks were old cracks.
They were new cracks. The cracks have got worse over the last 11 years. The
bungalow has not been decorated internally since 1970. That was in accordance
with orders given to him by Lord Malmesbury. In 1954 he built the barn (the
larger of the two buildings south-west of the bungalow).
The barn was
built as a piggery; it was built of hollow concrete blocks on solid
foundations. He built the structure but the roof was erected by a firm of
roofing engineers who had ensured that the tops of the walls were level before
putting on the roof. Since the excavation of the cutting for the motorway the
roof now falls 1 1/2 in towards the motorway and there are cracks in the walls
and floor. Before the coming of the motorway:
(1) Bickmeads and Little
Bickmeads and the ditches were wet all year round; hardly any use could be made
of them other than a little grazing from spring to late September; if tractors
were put on the fields they invariably got stuck; Heather Row Lane, until it
was tarmacadamed in 1955, was in effect a bog.
(2) There were four springs
which flowed powerfully and never dried up; he looked at them regularly.
Since the
coming of the motorway:
(1) The ditches were dry: the
ditch separating the Bickmeads fields was dry throughout the summer of 1971. It
became possible to graze cows on those fields all winter. That had been
impossible before the coming of the motorway. It was possible now to plough the
field. That had been impossible beforehand, although it had been possible in
about one year in seven years to break up the soil of the fields with a pan
buster in order to seed the land with grass seed.
(2) The springs were dried up
for the best part of the year and the main spring was non-existent until very
recently. The little springs were non-existent.
In 1972, on
the instructions of Mr Mann, he dug a trench, 5 ft 6 in deep, 20 ft long and 4
ft wide, alongside the path leading to the bungalow on its southern side and
between the bungalow and the oak trees. It remained open until 1975. It was
always dry except in heavy rain and even then it was not wet for long.
He remembered,
during the excavation of the cutting, seeing a big landslip. The slip was on
both sides of the cutting. If anything, it was worse on the northern side.
He redecorated
the bungalow twice between 1954 and 1970. Since 1954 there had been no change
in the vegetation in the vicinity of the bungalow other than the planting of
the poplar plantation.
(2) Lord Malmesbury: qualified as a
chartered surveyor in 1937. He was much experienced in farming and had been a
member of the local war agricultural executive committee. He had farmed the
Bickmeads fields until 1964 and thereafter they had been farmed by a tenant
farmer. He remembered the slip in the cutting. It was on both sides and was
substantial. The engineers were very worried.
He first knew
of and saw the cracks in the bungalow in September 1970. He knew of no cracks
in it before that date. If there had been any cracks Mr Gary would have
reported them to him. He remembered the trench dug by Mr Gary. He saw it a
number of times between 1972 and 1975. After rain there would be water in the
bottom of it but otherwise it was dry.
Before the
coming of the motorway the Bickmeads fields were almost a write-off, because
they were so wet. Only once, in 1959, were conditions sufficiently dry to
enable him to use the fields otherwise than as an exercise ground for cattle
and then only in the summer months. The ditches round the fields and in the
vicinity of the bungalow were running with water and were rarely dry. The war
agricultural executive committee never required a crop to be grown on the
Bickmeads fields.
Before the
coming of the motorway the ditch separating the two fields could not take the
flow of water; it was 2 ft in depth. The other ditches were always wet. Heather
Row Lane, until it was metalled, was awful.
After the
coming of the motorway, there was an astonishing change. The tenant farmer in
1970 and 1971 was running yearling stock on the fields, something which he had
never been able to do; the tenant farmer was able to do this even in winter and
was able to treat the fields as normal fields. Lord FitzHarris is able to do
the same now and obtain a reasonable grass crop. The ditches, even after heavy
rain, have very little water in them.
Before the
coming of the motorway two of the springs were strong and two were not so
strong. Since its coming their flow was much less. The poplars were planted in
1968 and 1969 as 15 in sets. They were very small when construction of the
motorway began.
A large
quantity of soil from the cutting was deposited in Ham Copse. It was of
miserable quality and the field in question had been a problem field ever since
and it had not been possible to obtain a satisfactory crop from it.
(3) Mr Mann: inspected the bungalow and
motorway cutting in October 1970 and decided where tell-tales should be put. In
1970 he went to the bungalow three times. The tell-tales all broke within a
short time of insertion. He could not recall any signs in the bungalow of
pre-existing cracks having been made good.
He was a
building surveyor and was experienced in field drainage with which he had been
dealing all his professional life. He came to the conclusion that the cracks in
the walls of the bungalow were due to the cutting having lowered the
water-table underneath the bungalow. The function of a field drain was to lower
the water table slightly so that the roots of crops did not get drowned when
the water table was very close to the surface. Clay was impermeable but it had
capillaries in it which pass water. Clay absorbs water. When a field on clay
gets waterlogged it sheds its water down the inclination and into vegetation.
The function of a field drain was thus to facilitate drainage so that the
surface water was absorbed by the top soil. It was not meant to dry out the
surface but to allow percolation to collect and run away more freely, the
surface remaining moist.
The depth of a
field drain on average was about 2 ft 3 in with a 3 in or 4 in pipe in it and 2
or 3 in of soil above the pipe. To take the drain deeper would not work because
water was held up by the density of the soil. The motorway acted as a huge
French drain.
Before the
coming of the motorway a great deal of water had been held in this land; the
excavation of the cutting let out the content. He believed that, although in
the vicinity of the bungalow the surface water drained from south to north, the
water beneath the surface drained in the opposite direction.
The trench
described by Mr Gary disclosed tree roots coming up to the foundations of the
bungalow and just touching the walls. This was unimportant because the trees in
question were of some age, between 80 and 100 years, and their water supply and
taproots were well established. The roots which he saw were of no consequence.
In November
1972 he carried out a test on the drain on the south side of the bungalow which
test revealed a leakage of approximately 2 gallons in 1 1/4 hours. The leakage
occurred on the top half of the perimeter of the drain and was not likely to
permeate the adjoining soil in ordinary usage. He regarded the leakage as of no
consequence. He ceased to regard the well as a control when he learned that it
had been polluted for a number of years by an overflow from the cesspit. The
foundations of the bungalow were less than current standards require but
nevertheless complied with the bye-laws when the bungalow was built.
(4) Mr Stone: the soil beneath the
foundations of the bungalow was clay. It was a clay of medium plasticity and
would shrink on drying and swell on wetting. The outward rotation of the
foundations was due to drying-out of the foundation soil; such movement was
comparatively common and occurred because the soil on the outside of the
building dried out faster than the soil which was covered by the building, thus
producing a slight differential vertical shrinkage of the soil beneath the
footings. The magnitude of the movement involved need not be great since, in
order to produce a crack at the wall/ceiling junction of, say, 5mm a differential
vertical movement under the footings of only about 1mm would be required and if
a thickness of clay of, say, 1 metre is affected a volumetric change of 1:1,000
is all that is required.
In February
1979 he caused four trial pits to be dug. They were all dug on a line running
north-south through the bungalow and extending southwards to the fence on the
northern side of the motorway. Trial pit no 1 was 92 yds north of the fence.
The soil was heavy clay and was quite dry. At the bottom of the hole there was
no more than a cupful of water. Trial pit no 2 was 95 yds north of trial pit no
1. No 3 was a further 65 yds to the north of no 2 and pit no 4 was 200 yds to
the north of the bungalow. All of the pits were 8 ft 6 in deep. They all
consisted of a dry yellow/orange clay with grey flecks inside. A very slow
seepage of water was noticed in pit no 2 about 3 in up from the bottom. There
was, on the top of that pit, about 2 in of topsoil which itself was quite
clayey but reasonably organic. In pit no 4 the water level was at 51 in below
ground level. On March 2 1979 the water level in pit no 1 was at a depth of 8
ft; that is to say, there were 6 in of water in the hole, but these
measurements were open to doubt because this pit collapsed as they were being
taken. Water was also found at a depth of 8 ft (6 in of water) in pit no 2, at
a depth of 7 ft (18 in of water) in pit no 3 and at a depth of 1 ft 3 in (6 ft
3 in of water) in pit no 4.
The excavation
of the cutting caused a draw-down effect of the general water table on either
side of the carriageway and the effect of that draw-down would be noticeable at
the bungalow even though situated so far from the cutting. The distance at
which draw-down would be effective was entirely dependent on the porosity of
the soil and over so large an area this would vary. Small bands of porous soil
would increase the effective porosity of the soil quite disproportionately, the
effect being like a hole in a bucket; a small hole would, given time, allow the
bucket to empty completely. Without the presence of aquifers in the subsoil,
draw-down would not be noticeable at the bungalow because the greatest distance
in impermeable clay in which draw-down could be expected to be experienced
would be 10 times the depth of the cutting, that is to say, in the present
case, a distance of 300 ft. That being so, the aggregate length of aquifers
between the impermeable clay (if such be the case) in the vicinity of the
bungalow and the motorway need not exceed 600 ft.
Vegetation, by
its demand for subsoil moisture, was not the cause of the damage. Before the
construction of the motorway, equilibrium had been reached between the demand
for and replenishment of the subsoil moisture as was evident by the fact that
no subsidence took place during the years up to 1970, although several periods
of drought had been experienced. Had the tree roots, drains or other local
agencies been the prime cause of the settlement, the crack pattern would have
demonstrated this. The extensive cracking and general rotation of the walls
which had taken place
damage.
The subsoil
was in fact sufficiently porous to enable draw-down created by the motorway to
extend to beneath the bungalow and thereby to cause the damage. That view was
supported by the evidence of records relating to certain boreholes made on
behalf of the respondents prior to construction of the motorway and of the
analyses of soils found therein made on their behalf. In particular, the
witness referred to four boreholes as follows:
(1) BH362: West of the northern end of Heather
Row Bridge (constructed over the motorway: see plan annexed hereto);
(2) BH357: At the northern end of that bridge;
(3) BH367: In the centre of the carriageway,
approximately half way between the bridge and the line A — A shown on the plan;
(4) BH368: Along the line of the northern
motorway fence, further to the east.
Comparing the
levels shown in the borehole logs for those four boreholes as the depths at
which water was struck and at which standing water was found on the one hand
with the agreed levels of the invert of the drain at each borehole situation,
the water table had been lowered as follows: at
(a) BH362: by 19.68 ft;
(b) BH357: by 9.05 ft;
(c) BH367: by 9.28 ft;
(d) BH368: by 10.51 ft.
Mr Stone made
use of the respondent’s data and records showing the results of compaction and
other tests carried out on behalf of the respondent on samples of soil taken
from those four boreholes. From the descriptions of soils given in the records,
their liquid and plastic limits shown therein, their water content and angle of
friction therein specified and other features of those records, he drew the
inferences that:
(a) all the samples taken from the four
boreholes were water permeable;
(b) at the sites of the four boreholes there were
sandy layers or aquifers as follows:
(i) At BH357: a small section of sandy soil
above level 347.20 above Ordnance datum, but below that level there was clay
down to the bottom of the cutting;
(ii) At BH362: a substantial band of sandy soil
extending upwards from level 325.68 or thereabouts to beyond level 341.68;
(iii) At BH367: a substantial band of sandy soil
extending from level 330.94 upwards to level 355.94;
(iv) At BH368: two small pockets of sandy material
at level 341.68 and 350.98, those pockets being separated by clay.
Mr Stone
referred also to data relating to other boreholes made on behalf of the
respondent in or about this section of the motorway. The total picture was one
of a moderately plastic clay: not a highly plastic clay: of a granular
material: a silty sandy clay. The most useful borehole for determining the
water level beneath the bungalow was BH362, because at that borehole there was
a large sandy exposure in the side of the northern embankment of the motorway,
a large drop in water and the lowest drain position: 26 ft below the level of
the bungalow. A drop of 26 ft over a distance of about 900 ft was a fair old
drop. He concluded that the lenses or pockets of sand through which the cutting
was dug extended as far back as the bungalow. If that were right, the
consequence would be that the condition of the water table would form a type of
draw-down curve towards the motorway, the lowest point being the drain. Because
the sand outcrops in the side of the cutting and because abutment drains have
been provided in the sides of the cutting, the draw-down curve would be
moderated in time, so that it would reach its new equilibrium more quickly.
His views were
not belied by the geological map, which showed that the underlying Reading beds
dipped 1 in 70 to the north. There was no reason to believe that the London
clay also dipped to the north or, if it did so, that the aquifers in it also
drain to the north. London clay was not a stratified soil; it was fissured and
the fissures oriented at all angles. He had not come across a London clay which
was stratified. There was no evidence of any definite layer from the borehole
logs. His view was that there were pockets or lenses of sand in a general
background of a silty-sandy-clayey material, giving a low angle of friction and
low values of liquid and plastic limits.
During the
course of excavation for the cutting there were two landslips: as shown by the
respondent’s plans, one was 100 ft long and 32 ft wide and the other 225 ft
long and 40 ft wide. They occurred because the banks of the cutting were too
steep for the soil with its then water content. At the time of the slips there
was a great deal of water in the cutting.
Since the fall
of the land from the northern motorway fence was to the north, that is towards
the bungalow, the excavation of the cutting intercepted the flow of surface
water towards the bungalow. While the fall of the land was also east and west,
so that the higher land between the bungalow and the motorway was, as it were,
a ridge, the ditch separating the Bickmeads fields was shallow and surface
water, particularly, in heavy rain, would have percolated to the bungalow. In
the result, about 50% of the catchment area had been cut off. His assessment
was that the significant effect was not a surface water effect but a ground
water effect; that was the overriding consideration; but there was some surface
water effect. Several factors had come together: clay soil; surface water;
ground water. He believed that the construction of the motorway was the cause
of the damage to the bungalow and found support for that view in the following
matters:
(1) the fact that the
bungalow had stood satisfactorily for 23 years, including, as the agreed
evidence of local rainfall showed, several exceptionally dry periods before
1970;
(2) the suddenness with which
the cracking occurred;
(3) the nature of the damage
sustained and, more particularly, the rotation of the foundations of the walls
and the fact that it occurred in the foundations of all the walls rather than
one or two of them;
(4) the changes in the
conditions experienced in the Bickmead fields before and after the coming of
the motorway;
(5) the changes in the flows
of the springs before and after that event.
The well,
which was 53 ft north-east from the corner of the bungalow, was no indicator of
the level of the water table beneath the bungalow because the sides of the well
were made of impermeable material and it was over 17 ft deep and in that depth
it must inevitably penetrate into permeable material — an aquifer — in order
that it might be supplied with water. The bottom of the well was probably 5 or
6 ft lower than the aquifer, since otherwise there would be no storage of
water. It was possible, and indeed probable, that the water level of the well
would fluctuate wildly without being related to the water level at the
bungalow. If the well were an indicator of the level of the water table under
the bungalow, he would have expected:
(a) 6 in of water in his
trial pits (because, as Mr Rich accepted, the bottoms of the pits were 6 in
lower than the level of the surface of the water in the well);
(b) the level in Mr Gary’s
trench to be the same as the water level at the well, but it was predominantly
dry;
(c) a correlation between
the well levels and the levels in the boreholes at the motorway, but there was
none.
The well
needed only a small catchment area in the garden of the bungalow itself. He
believed that the well levels were very much influenced by rainfall in its
immediate vicinity. A quarter of an inch of rain would shoot the level right
up. He believed that the aquifer supplying the well was in no way related to
the soil underneath the bungalow.
In
cross-examination, Mr Stone said that the foundations of the bungalow, though
complying with building regulations at the time of its construction, were
inadequate by modern standards. In practice they had proved sufficient for many
years. He would be surprised if there had been no cracking at all prior to
1970, but the prime cause of the cracking which he had seen was the rotatory
movement of the foundations of the walls and the doming of the floor. The
doming of the floor had occurred since his first inspection.
His trial pits
were intended to enable him to determine if the water table dipped in an
opposite direction to the general dip of the land, but the pits were not deep
enough. The amount of water in them did not indicate the level of the water
table. He preferred the evidence of the borehole logs because the boreholes had
been taken down to a
his theory with respect to the slope of the water table, he had rejected the
evidence afforded by them because the pits were not deep enough; he had not
mentioned his rejection of that evidence in his report.
Such evidence
as exists of an aquifer at the cutting is of a higher level than at the well or
the springs. This might be indicative of flow from south to north and onwards
east to west or continuing northwards. If the aquifers at the springs and the
well were interconnected, this would be contrary to his thesis. His view was
that such evidence as existed confirmed his thesis. Putting in the cutting
reversed the flow; it dried out the springs and the bungalow. If there were a
uniform level of aquifers the respondent’s view as to continued flow of ground
water after the coming of the motorway from south to north would be correct,
but that view would not be correct if there were, as he believed, a porous zone
or one aquifer on top of another. His opinion depended on there being a lower
level of issue at the motorway than at the springs. The standing water level
found at BH368 at level 339.99 OD, was higher than the level at the springs,
but the base of the motorway at level 320 OD was lower than that. The distance
from BH362 to the bungalow was 1,020 ft: twice the distance from the bungalow
to the springs. Before the coming of the motorway, rain falling between the
springs and the line of the motorway went towards the springs and the bungalow,
but the coming of the motorway reversed the process, because its base level was
below the level of the springs and of the bungalow. The balance of evidence was
of porous material in between.
There was a
high probability that before the coming of the motorway, the water in the water
table flowed in a northerly direction but that there was an appreciable
difference in level between the springs and the water table at the line of the
cutting, namely, 14.68 ft. After the coming of the motorway the flow of the
ground water would be to the lowest point, namely in the vicinity of BH362,
that is to say 26 ft lower than the level of the bungalow and 5 ft lower than
the level of the springs. In his opinion the excavation of the cutting reversed
the direction of flow.
(5) Mrs Gary: confirmed her husband’s
evidence with respect to the time at which the cracking in the walls of the
bungalow first appeared.
B. Witnesses for the
respondents
(1) Mr Watts: On September 24 1970 visited
the bungalow and prepared a record of cracks which he then saw. He expressed
the opinion that some of them were not of recent origin.
(2) Mr Butcher: had refreshed his memory
of events in 1969 and 1970 by looking at the site diary maintained by the South
Eastern Road Construction Unit (which diary was not produced) and the agreed
photographs. The earthworks in this part of the cutting were completed in October
1969. On April 8 1970 he noticed water seeping between French drains which had
already been laid and between chainages 61.2 and 61.4 (about 300 ft east of the
eastern edge of the southernmost Bickmeads field and south of the lowest point
between the bungalow and the carriageway). He was surprised that the drains
were not taking the water from the seepage away. There followed a landslip on
the south batter. He sought instructions from his headquarters but was advised
to leave things to develop. The slip got worse and became 200 ft long. The
seepage extended over a length of 300 ft. There was also a very soft wet patch
in the cutting extending 500 to 1,000 ft west of Heather Row Bridge.
In the summer
of 1970 remedial measures, including the installation of counterfort drains on
the north and south slopes, were taken. The slipped material was removed and
replaced by granular material. There was no similar slip on the northern slope.
In the roadworks contract, there was a provisional sum for counterfort drains
on both sides of the cutting. They were expensive items and would not have been
ordered if they had not been necessary. The slipped material, when removed,
revealed pockets of granular material in the sides of the southern embankment
remaining after the slip. There was no visible connection between the pockets
east to west. In the slipped material there was no continuous layer across the
motorway north to south. The slipped material was mingled with substantial tree
roots and other material and was so mixed in the process of removal that it was
not possible to detect a connection between pockets of granular material. The
discarded material was very wet indeed and very acid. Part of it was placed on
Lord Malmesbury’s field at Ham Copse.
He would have
expected the soil in the cutting to be wet but it was surprisingly wet even
before commencement of the roadworks notwithstanding the hilly nature of the
terrain. Two-thirds of the total material taken out of the cutting was
nevertheless used in the course of construction.
On September
24 1970 he was present at the bungalow when Mr Watts made his record of cracks
and supervised the making of that record. He inspected the cracks. They
appeared to be of different ages: some newer and some older. Some were insignificant:
hairline. Some were wider and longer and more serious. Approximately one year
later he returned to the bungalow and annotated Mr Watts’ original record with
what he found on that occasion. The cracking had not become substantially worse
but had changed noticeably: some of it had widened and some of it had
lengthened; some had even diminished in size. On being referred to a letter
dated October 22 1971 written on behalf of the South Eastern Road Construction
Unit to Mr Mann stating that the facts contained in the first two paragraphs of
Mr Mann’s letter dated October 19 1971 were not disputed (which paragraph
asserted that the subsidence was caused by reduction of water in the subsoil
occasioned by the construction of the motorway; referred to the glass
tell-tales; the fact that they had broken; and asserted that in the period from
August 1971 to October 1971 the structure had moved considerably, as was
evidenced by the increase in the size of the numerous cracks that were visible
in the structure), he said that not all the cracking was structurally
significant.
(3) Mr Wrightman: first inspected the
bungalow and its vicinity in 1979. He had had no experience of a water table in
London clay having been affected by a motorway cutting at so great a distance
as 900 ft. He would be surprised if the effect extended much beyond the line of
the fence. For the motorway to have affected the bungalow there needed to be a
change in the level of the ground water regime at the bungalow such as to cause
a significant change in stress in the soil under the bungalow. By ‘change’ in
the level of the ground water regime he meant something more than a mere
temporary change, a change of some duration. Further, for the motorway to have
affected the bungalow the ground water regime at the bungalow needed to have
been such, prior to construction, that it had an overriding ability to keep the
London clay beneath the foundations at an equilibrium moisture content, despite
all the processes of wetting and drying caused by rainfall, drought and
vegetation.
In May 1979 he
caused two trial pits to be opened against the foundations of the bungalow on
its south-west and north-east elevations. Some roots were found in each pit.
For the water
table to flow southwards beyond the fence line of the motorway a material other
than London clay between the motorway and the bungalow would have been
necessary. In his opinion, no such material existed because:
(1) the line of section on the geological map is
at right angles to the line of strike where the London clay appears; the
section at the bottom of the map shows a dip of the London clay to the
north-east at an angle of about one degree;
(2) that section represents a slice through the
whole lithology between the canal and the plateau;
(3) the London clay was laid in a reasonably
large estuary, the deposits being invariably laid level: the gradients are very
flat;
(4) when once a deposit was laid and tilted one
degree northwards, the whole of that zone would be so tilted;
(5) of the
level (agreed to be 325 ft above OD) of the springs;
(6) of the level (agreed to be 327.36 ft above
OD) to which the well was driven.
The level of
the bottom of the well pointed to the existence of an aquifer there; it tied up
with the geological depth and with the slope of the surface of the ground
(namely, 1 in 70 to the north). There must also be a sand lens outcropping at
the springs issue consistent with the depth in the whole stratum; he could not
say that the aquifer
extensive aquifer under the whole area, but whether it was directly connected
with the well or indirectly with the motorway he could not say: he inferred the
existence of such an aquifer from the data from Mr Stone’s trial pits.
In May 1979 he
looked at the springs after heavy rain. The higher of them was certainly
running well on that occasion. He noticed also that the counterfort drains on
the northern side of the motorway were dry. Since the springs were running and
the well was reasonably high on the same occasion, he inferred that the aquifer
dipped to the north.
Also the
evidence from Mr Stone’s trial pits indicated to him that the water did not
flow towards the cutting: water flows downhill. That evidence was likely to be
superior as information than the boring records because the boreholes were
probably lined and the pits were not. He thought that the pits gave a
reasonably reliable picture of the water table there now and he concluded that
the water levels in the pits were not dissimilar to those in the boreholes. If
there had been another trial pit between the most southerly pit and the head of
the cutting the evidence from the pits would have been more satisfactory.
From the
evidence of the boreholes and that of Mr Butcher, it was clear that there was
water in the sand seams at the cutting, but there would appear to have been
very little head-pressure there. In one or two of the boreholes there seems to
have been some pressure but it appeared to vary from borehole to borehole.
Therefore, while there was an aquifer at the cutting, the permeability of the
material in it was not very high. He did not agree with the conclusions which
Mr Stone drew from the analyses of the samples taken from the boreholes.
He thought
that such slips as had occurred had probably been activated by seepage
pressures. If it were right that the slips occurred only on the south side of
the cutting and that the aquifer dipped from south to north, the pressure head
would be on the south side; although he did not regard that as absolutely
conclusive. From the evidence of Mr Butcher, he thought that the aquifer was a
weak aquifer which could only transmit water relatively slowly.
Surface water
from the northern fence of the motorway would trickle down the ridge to the
ditch separating the Bickmeads fields, which was the low point, and then fall
away east-west on either side of the ridge. The falls to the east and west were
rather more substantial than to the north and south. In consequence, the motorway
had not interfered with drainage of surface water to the bungalow.
The well acted
as a good tell-tale of the ground water at the bungalow. The correlation
between the figures relating to rainfall and the level of the water surface in
the well (which were agreed) told him that the ground water regime was very
much influenced by rainfall. There had been no long-term drop in the level of
the surface of water in the well and he could not see that there had been a
long-term depression of the water table.
He thought it
most unlikely that there had been a sudden appearance of cracking in the
bungalow. On his first inspection he approached the matter with an open mind
but, on meeting Mr Gary, he had said to him: ‘these cracks have been here for
donkey’s years’, but that Mr Gary had said that that was not for him to say. Mr
Wrightman got the impression that Mr Gary was only too well aware that there
had been some cracking previously. He accepted that broadly there had been a
marked increase in cracking between 1970 and 1971. He did not know what the
cause of the cracking was.
He agreed with
Mr Stone to this extent, that the motorway created a new point of drainage in
addition to all the other points of drainage existing in the vicinity; it was
an extremely effective drain, if water could get to it. He could not offer an
explanation for the change in the springs other than the possibility that the
aquifer or aquifers feeding the springs drained into the motorway drain. He
agreed with Mr Stone that the top of the water table at the line of the
motorway at the sites of BHs 362, 357, 367 and 368 had been lowered by
respectively 19.68 ft, 9.05 ft, 9.28 ft and 10.51 ft. If the boreholes had been
lined it was possible that the drop in the water table effected by the motorway
might have been even greater than those figures.
While he
accepted that the flow of the ground water at the motorway now entered the
drain constituted by it, particularly in periods of heavy rain, he did not
accept that the flow of the ground water, which previously was from south to
north, had been reversed. He did not agree that such granular material as did
exist between the bungalow and the motorway could be described as sand. It was
a very different kettle of fish from sand. If it constituted an aquifer it was
not a very efficient one. The motorway interrupted the aquifer but it flowed
from south to north.
He could not
explain why the trench dug by Mr Gary remained dry except after rain.
On being
asked, in re-examination, to explain the cause of the cracking in the bungalow,
assuming that it had occurred suddenly, he said that he thought that it might
have been thermal cracking due to the kitchen stove cooling off while Mr and
Mrs Gary were away on holiday. Alternatively a change of regime in the garden might
have caused it.
In answer to
questions from me, he said that the mature trees had been long established and
that they must have substantial taproots. He said further that it was possible
that the motorway had interrupted some of the water which otherwise would have
flowed to the bungalow; it was a possibility but a remote one.
Submissions
Mr Rich
[counsel for the respondent] said that the water regime of the locality could
have been affected by the motorway cutting only by the interception of surface
water or by an influence on the ground water through an aquifer. On the
evidence, any possible effect from the interception of surface water was
negligible and it followed that the damage suffered by the bungalow could not
have been caused by the motorway unless the ground water at the bungalow was
sufficiently connected to the cutting by an aquifer or aquifers so as to enable
the water table at the bungalow to be drawn down over a distance of 1,200 ft to
BH362 or over 1,000 ft to the nearest point of the carriageway. Mr Stone relied
upon what he alleged was the draw-down effect of the water table and not
interception of the surface water. The case ought not to depend on whether the
cracks in the walls of the bungalow were new or old; it depended on proof and
the onus of proof was on the claimant. The newness of the cracks was the
foundation of the opinion of both Mr Mann and Mr Stone that there must be a
causal relationship between the cutting and the damage suffered by the
bungalow. That led them to rejection of the contrary evidence which their
expertise should have told them would have probative force. Mr Stone had dug
trial pits in order to investigate the movement of the ground water after
construction of the motorway. He discovered that it contradicted his theory. He
was frank about that but he did not reject the theory but the evidence. Mr
Stone’s and Mr Mann’s evidence consisted of sweeping generalisations without
any attempt to determine the cause of the damage. That approach was specious.
The parties nevertheless had to rely upon the evidence of experts, since it
would have been much too expensive to attempt to ascertain the cause of the
damage and the existence or otherwise of aquifers and the depth of the water
table by physical means such as by the use of boreholes. The approach of Mr
Mann and Mr Stone was unscientific: a kind of lay logic. I ought to prefer the
evidence of Mr Butcher and Mr Wrightman.
Mr Jackson
[counsel for the claimant] submitted that, while Mr Stone’s main theme was that
the flow of the ground water had been reversed as a result of the coming of the
motorway, I ought not to overlook the interception by the motorway cutting of
the flow of the surface water. If, as Mr Wrightman said, the flow of the ground
water from south to north had not been reversed, that flow, like the flow of
the surface water, had also been intercepted by the motorway cutting. That was
a matter which had not been relied upon by Mr Stone but he, Mr Jackson, was, as
advocate, entitled nevertheless to rely upon it. Mr Rich, at this point in the
argument, interjected that Mr Stone had ignored this point. Mr Jackson replied
that, nevertheless, on the evidence of Mr Wrightman, the cutting had
intercepted the flow northwards towards the bungalow of both the surface water
and the ground water. It was a very likely inference that that interception had
caused a lowering of the water table under the bungalow. He took that point in
the alternative to Mr Stone’s
evidence he asked me to accept.
I have
inspected the bungalow and much of the locality.
Some findings
of fact
I find the
following facts:
(1) Although there may have been some minor
cracking, not readily apparent in the plaster of some of the walls of the
bungalow before 1970, the damage as described by Mr Stone (which description I
have set out earlier in this decision) occurred suddenly in the fortnight ended
September 15 1970.
(2) The condition of the Bickmeads fields changed
from one of extreme wetness and general unsuitability for cultivation before
the coming of the motorway to one of dryness and normality, so far as
cultivation is concerned, thereafter.
(3) There was a corresponding marked change from
wetness to dryness before and after the coming of the motorway in the ditches
separating and surrounding the fields and the bungalow.
(4) There was a marked reduction in the flow of
the springs after the coming of the motorway compared with the situation before
that event.
Decision
This is a
difficult case and the difficulty lies in the decision of the parties to leave
what are essentially questions of primary fact to be determined by the evidence
of expert witnesses rather than by physical evidence as to the depth of the
water table at various times, the existence of aquifers and the direction of
flow of the ground water. No doubt the course which the parties have taken
involves less expenditure of money than might otherwise be the case and for
that reason is to be understood. I must therefore do the best I can in the
circumstances.
What was the
cause of the differential drying of the subsoil under and in the vicinity of
the bungalow? As I understand his
evidence, Mr Wrightman did not attempt to answer this question except
negatively. His concern was to demonstrate, so far as he could, that Mr Stone’s
theory with respect to the flow of the ground water was wrong. He did not offer
any positive solution as to the cause of the damage. It is true that in his
report and in his evidence he threw out speculatively some suggestions as to
possible causes, but he did not investigate them with any degree of
seriousness.
I agree with
Mr Stone, for the reasons given by him, that vegetation did not cause the
damage. Its taproots and other roots had been long established, which explains
also why the vegetation has continued to thrive. Some roots were found in Mr
Gary’s trench in 1972 and in the trial pits ordered to be dug by Mr Wrightman
in 1979 (long after the occurrence of the damage). Tree roots would hardly have
caused the rotational movement of the foundations of all four walls, even if
they would have caused rotational movement at all (which is most doubtful).
I cannot see
that there is any evidence whatsoever to link the damage sustained at the bungalow
with the cooling down of the stove during the period of Mr and Mrs Gary’s
holiday in September 1970 or that there is any evidence whatsoever of a change
in the regime in the garden. While there were periods of drought in the
vicinity before 1970, there appears to have been none sufficiently proximate to
the damage to have been responsible for it. I am not satisfied that damage
ought to be attributed to the shallow foundations of the bungalow.
The suddenness
with which the damage occurred, its nature and severity and the remarkable
changes in the Bickmeads fields, in the ditches and in the flow of the springs
after the coming of the motorway, compared with the pre-existing situation,
cannot be explained by reference to such common place occurrences as those
which I have mentioned. What, then, did cause the damage? In my judgment the only possible inference is
that an event occurred which caused the level of water table at the bungalow to
be lowered for a period which was more than just temporary. According to the
evidence, the reduction in level need not have been very great.
While there
would appear to have been no noticeable long-term drop in the water level at
the well since the motorway was constructed, I agree with Mr Stone, for the
reasons given by him, that the well was no indicator of the level of the water
table beneath the bungalow. Until at least 1971 or thereabouts, when main
drainage was installed at the bungalow, the well was no indicator of anything
because it was polluted until that event by an overflow from the septic tank.
The experts were in agreement that the levels of the water in the well would
respond rapidly to changes in rainfall. It may be, therefore, that the aquifer
supplying the well is unrelated to any aquifer supplying the springs or leading
to or from the bungalow and the motorway.
Mr Stone’s
thesis as to the reversal of the flow of the ground water and the draw-down
effect of the motorway cutting is undoubtedly bold. It is contradicted by such
information as is to be derived from Mr Stone’s own trial pits, but that
information is rather bleak. The pits were plainly not deep enough. Trial pit
no 4 was so far from the bungalow as to be of limited usefulness and trial pit
no 1 collapsed. It would have been better, as Mr Wrightman said, if another pit
between trial pit no 1 and the northern fence of the motorway had been dug. On
the other hand, it seems to me that the figures which Mr Stone managed to
derive from the boring records and other documents relating to BHS357, 362, 367
and 368 give valuable support to Mr Stone. Those figures are now agreed. It is
also agreed that the cutting created a new point of drainage of the most
effective kind if water could get to it. There is no doubt that there was a lot
of water in the roadworks in the cutting after the land slip occurred (even if
that slip was confined to the south batter, as to which I am not entirely
sure).
I find the
point which Mr Wrightman seeks to derive from the dip of one degree to the
north of the underlying London clay shown on the geological map difficult to
decide because there is no firm physical evidence relating to it. If I must
decide the point, then I prefer the opinion of Mr Stone relating to it and
therefore reject it. However, there is no doubt whatsoever that before the
coming of the motorway both the ground water and the surface water flowed from
south to north in the direction of the bungalow. Furthermore, as I understand
the evidence of Mr Wrightman, he did not dispute that at all material times
there was an aquifer in the land between the bungalow and the motorway,
although he thought it was a weak aquifer.
In these
circumstances, if Mr Stone’s opinion with respect to the reversal of the flow
of the ground water is not to be accepted, what caused the lowering of the
water table at the bungalow? If I were
to reject that opinion, it would be my view, after prolonged thought about this
matter, that the experts have not given sufficient emphasis to two matters:
(1) the interception by the motorway cutting of
the flow of surface water from south to north and;
(2) the interception by it of the flow of ground
water from south to north or
to the two
matters considered together.
In my view,
some of the surface water prior to the coming of the motorway must have percolated
to the bungalow, notwithstanding that the ridge over which it flowed falls away
to the east and west. Such percolation was inevitable because the ditch
separating the Bickmeads fields was shallow. It was necessarily shallow,
because as Mr Mann said, it would not otherwise have performed adequately its
function as a land drain. Mr Stone said that about 50% of the catchment area
for surface water had been cut off. It appears to me that that was a major
event in itself. If to that loss there be added the loss of ground water which
had previously percolated from the south towards the bungalow but which, after
the coming of the motorway, was diverted into the drain created by the cutting,
the event which caused the lowering of the water table at the bungalow is, in
my opinion, sufficiently explained. If that is not right, if the interception
of surface water or ground water was not responsible for the matters in
question, then the only possible explanation, in my judgment, is that Mr
Stone’s thesis of reversal of flow of the ground water and draw-down of it into
the motorway cutting is correct.
Thus, for one
reason or another, I conclude that the damage sustained to the bungalow, which
damage I have previously described, was caused by the construction of the M3
motorway. It may be that, in reaching this conclusion, I have been guilty of
using what Mr Rich described as lay logic, but that would seem to be the
correct approach: see per Lord Reid in McGhee v National Coal Board
[1973] 1 WLR 1 at p5, where he said:
It has often
been said that the legal concept of causation is not based on logic or
philosophy. It is based on the practical way in which the ordinary man’s mind
works in the everyday affairs of life.
For these
reasons I award to the claimant the sum of £7,500, together with surveyor’s
fees on scale 5(a) of the professional scales of the Royal Institution of
Chartered Surveyors. The respondent will pay the claimant’s costs of the
proceedings such costs if not agreed to be taxed by the Registrar of the Lands
Tribunal on the High Court Scale.
I congratulate
counsel on their admirable grasp of the complexities of this case and thank
them for their able advocacy.
The editor
acknowledges the assistance of Mr G A Campbell FRICS, of Austin & Wyatt, in
the preparation of the plan.
