The Surrounding Moat of Stonehenge I
"… provide the necessary firm foundation on which to build
future theories and to construct new research designs, for as
with any archaeological site, the project has raised questions
which will require an answer in the future.�
("Stonehenge in its Landscape", English Heritage, 1995, p.492)
This hypothesis differs from others in that it views Stonehenge as being
surrounded by a water-filled moat rather than by a dry quarry-ditch as is
commonly believed to be the case.  The realization that the Ditch of Stonehenge I
may have been a reservoir grew out of research into a larger hypothesis
concerning the transport of the stones, one requirement of which is that a large
supply of water needed to be available at the level of Stonehenge.  It is one of
many conditions required by the hypothesis that are confirmed by the records of
various archaeological excavations in and around Stonehenge.  However, a model
of Stonehenge surrounded by a water filled moat (as opposed to a dry
quarry/ditch) is noteworthy for its own sake, since it contrasts substantially with
any view of the monument previously proposed.

If, as claimed by many writers, the surrounding ditch of Stonehenge I were
nothing more than a dry quarry ditch, many of its features have gone without
reasonable and coordinated explanation.  There has not been a single unified
theory that has explained many of the conditions known to exist in the ditch.  
Only when viewed as a major and important part of the original monument of
Stonehenge I do the various pieces of the puzzle fit together to form a single and
coordinated view of the surrounding ditch/moat.

Until now, it has been supposed that the ditch surrounding Stonehenge I was
nothing more than a dry, ugly, quarry/ditch whose sole purpose was to supply
material for the building of the surrounding bank. Writers too numerous to
mention have claimed that it is only the bank that was important and that the
ditch was merely the inevitable by-product of the building of the bank.
R.J.C.Atkinson “Stonehenge�, 1965, p.23 writes:
“Irregular ditches of this kind, like the outline of a string of very badly made sausages, are
characteristic of neolithic earthworks in southern England. Their apparently unfinished state
does not mean that the work was abandoned before it was completed, but that the builders
regarded the ditch merely as a quarry for material to build the bank. It was the bank which was
the important element of the earthwork, and the ditch had no meaning, in itself as a structural
or symbolic feature.�
However, there is considerable evidence that the surrounding ditch ranked
at least equally with the bank in its importance to the structure of
Stonehenge I.
Thanks to the discoveries of Col. William Hawley during his excavations of the 1920s in
combination with other known conditions at Stonehenge, it can be said with some measure
of certainty that the surrounding ditch of Stonehenge was originally a moat, filled with
water that flowed from an inlet at the northwest to an outlet at the east, and which, except
for the causeway at the northeast, encompassed the entire site of Stonehenge I.
The surrounding moat of Stonehenge
comprises three distinct parts:
1. The northwest reservoir occupies the north and west quadrants of the
ditch. It extends from the northeast causeway to the southwest point of the
ditch – about 180 degrees of the periphery.  It includes the northwest
inlet where water flows into the moat (possibly from an elevated aqueduct)
and flows southward. The water level of the northwest reservoir is
maintained by a
barrier/weir across the moat at the southwest over which
the water flows into the south quadrant.
2. The south quadrant comprises several basins through which the water flows filling each
basin to the level of a barrier/weir over which it flows into the next and lower basin to its
east.
A twelve feet wide causeway cuts across the moat at the south.  A
culvert through the
causeway allows the water to flow from west to east through the causeway.  The culvert is
below the surface of the water and keeps the water level equal on both sides of the
causeway. The
water level at the causeway is maintained by a barrier/weir some distance
(about 40 feet) to the east of the causeway. The water overflows the barrier into the east
quadrant.
The northern and southern quadrants are on sloping ground requiring the barrier/weirs at
the south to provide the several pools along that quadrant and requiring embankments
(dikes) on both sides of the moat at the north.  The water level at the west, south and east is
below the ground level at those locations, but the water level at the north, because of the
sloping ground, is higher than the ground level and so dikes are required to contain the
water there. The bank that surrounds the site just inside the moat provides the required dike
on the inner side of the moat.  There is also an outer bank at the north
(a counterscarp) that
provides the required dike on the outer side of the moat.  This north counterscarp is the
only
real counterscarp at Stonehenge; the low bank outside the other three quarters of the
ditch/moat is insignificant compared with this major feature at the north.  Obviously, due to
the slope of the land, the north is the only area where such a bank is required of a moat.
3. The east quadrant is on relatively level ground and forms a single reservoir extending
from the southeast point of the moat to the eastern side of the northeast causeway.  The east
quadrant of the moat includes the
outlet through which the water flows from the moat and
is directed into Stonehenge Bottom via a
trench stretching eastward from Stonehenge.
The writers of "Stonehenge in its Landscape" refer to the irregularity of the ditch at the
south.  It is noted that the ditch is more segmented at the south and that the depth of the floor
of the ditch changes from one segment to the next and that barriers separate the segments
when there is a change in the floor levels.   Actually these changes in the elevation of the
ditch floor are not surprising, since the surface slopes, and the elevation of the surface
changes correspondingly.  Strategically placed barrier/weirs maintain the water levels of the
various basins along the southern quadrant.  When the purpose of the ditch as a moat is
taken into account, it is to be expected that the sloping southern quadrant will be divided
into distinct segments.  It is not surprising then that Col. William Hawley found barriers of
chalk separating the segments.

No barrier/weirs are required in the other three quarters of the moat, and none have been
discovered there.  The north and west quadrants have not been excavated, and so it has not
been determined whether any barriers exist there.  At some time in the future, non-invasive
means may be developed and applied to determine the conditions of the moat at the north
and west.  If this moat hypothesis is correct it is unlikely that any barriers will be found
there, since none are required.
     The irregularity of the ditch pointed out by K.E.Walker in "Stonehenge in its
Landscape", p.65,  is particularly pertinent to this discussion, since conditions are just as
expected of a moat on that landscape.
Walker also comments on the importance of Col.
William Hawley's work.

There is no counterscarp required at the west, south and east and there is none such as the
counterscarp at the north.  There is, however, a low outer bank composed of material (sod,
soil and turf) removed from the site of the moat prior to digging out of the chalk and the
building of the bank, presumedly so the bank would be built of only clean chalk from the
lower levels of the ditch, but the counterscarp at the north is more substantial than the low
outer bank and is composed of the same clean chalk as is the inner bank.  There is no doubt
that the counterscarp at the north represents a major effort of labor and was important to
the monument
R.J.C.Atkinson, "Stonehenge", 1990, p.25, writes:
Besides the main bank on the inner side, there are slight but indubitable traces of an outer, or
counterscarp, bank as well, which can best be seen immediately north (that is, anti-clockwise)
from the entrance to the earthwork.  Curiously enough, this feature has seldom previously
been recorded, and has otherwise passed unnoticed, although it must once have been
substantial, with a width of perhaps 8 ft and a height of 30 in., since excavation has shown that
here, as under the main bank, the surface of the natural chalk has been protected from
weathering.
The authors of "Stonehenge in its Landscape"
English Heritage, 1995 express the hope that
their publication may:
 The Flint Layer
Since the bedrock underlying the site is quite permeable, it was necessary to provide sealant
to the bottom of the moat.  A sealant composed of a mixture of clay and chalk with
considerable quantities of
struck flint added has been applied to the bottom and into crevices
on the bottom.  Col. William Hawley refers often to a “flint layerâ€�, and to a layer of â
€œpurposely applied foot trampled clayey mudâ€� (compo) filling crevices and covering the
bottom of the ditch directly atop the natural chalk bottom of the ditch. This durable
material, compo mixed with flint, is taken (here) to represent an effective means of sealing
the bottom of the moat, much the same as clay is applied today to the bottoms of canals and
reservoirs in the area around Stonehenge.
Col. William Hawley refers often to a ‘ubiquitous layer’ of ‘foot trampled
clayey mud’ with ‘much struck flint’ mixed in and ‘purposely applied’.  
It is known as the “flint layerâ€�.  There is no doubt that the bottom of the moat was
deliberately lined with the artificial, concrete-like material (compo) and that it provided
a seal to the bottom of the moat against water seepage, whether or not that was the
reason for it.  Whatever the intended purpose of the flint layer, it may not be argued that
permeability of the underlying rock precludes the possibility of a moat.
The matter of “compo�, “flint�, “reservoirs�, and “sealant� is not without
modern parallel.  Here is a link to Arthur Becket’s
http://www.dewponds.info/biblio_spirit_of_the_downs.htm, about dewponds that bear
remarkable similarities to the Stonehenge moat.  It seems that many “dewpondsâ€� exist on
the chalk plains of southern England.  These are artificially made ponds most of which are
situated at the tops of hills and have no streams or springs feeding into them, yet they manage to
stay filled with water, even after ponds at lower elevations go dry.  The dewponds run dry only
when their sealants fail or during most severe draughts.

The ponds often serve to provide the water requirements for several hundred head of sheep and
cattle.  The linings of the bottoms of these dewponds are identical in many respects to the linings
of the Stonehenge moat.  The linings are composed of puddled compo containing much flint and
are applied in layers directly on the chalk floor of the pond.  The mix of compo and flint is used to
fill any cracks or crevices in the floors of the ponds just as it is in the floor of the moat.  The
compo and flint is quite effective in preventing leakage from the ponds.  It is made quite clear in
Becket’s article that flint is an important ingredient of the sealant, just as Col. William
Hawley emphasized the flint layer at the bottom of the moat.  While some of the ponds are known
to be modern (nineteenth century), some are believed to have neolithic origin (that view is
unconfirmed, however).
More About Dewponds: (
Link 1) (Link 2) (Link 3)
The authors of "Stonehenge in its Landscape", English Heritage, 1995, p.68 suggest that
the flint layer may represent scraps left over from the
“opportunistic knapping� of
flint discovered in the process of the digging of the ditch.  
There is some argument
against the flint layer having been the result of opportunistic knapping, however.
   The Dark Layer
As occurs on the bottoms of bodies of water (ponds, rivers, canals and moats etc.) there is
resting directly on the bottom of the moat a
dark layer of decayed organic matter.  Col.
William Hawley reports this ‘ubiquitous dark layer’ throughout his excavations of
the ditch. At some places the dark layer was as thick as 8 inches and rested directly on the
bottom or, as usual, directly on top of a ‘purposely applied’ layer of compacted
trampled clayey mud (compo) that covers the bottom.  This dark layer resting on top of the
layer of compo and below the primary fill is interpreted to be the natural deposit of organic
sediment that invariably accumulates at the bottoms of such bodies of water.
Col. Hawley refers to the "very organic" nature of the dark layer and the possibility of
"wood in it".  This compares with the kind of sediment that
accumulates on the bottoms of
impoundments behind weirs.
The deep craters at the terminals of the ditch to either side of the northeast causeway have
given rise to speculation by some writers.  It is suggested by the authors of "Stonehenge in
its Landscape", English Heritage, 1995, p.109 that the reason for the craters being
different from the rest of the ditch may relate to the
social status of the diggers.  Another
possibility may be:, since the ditch is the source of the chalk for the bank, and since more
material would be required at the ends of the bank if it were to wrap around the ends so as
to enclose the ends of the ditch within the bank, that the deeper craters at the ends of the
ditch could be accounted for by the requirement of a larger amount of material there. How
else could the material for the extra length of bank be obtained than to go deeper?
Apparently the bank did indeed originally wrap around the ends of the ditch and was at a
later time deliberately redeposited back into the ditch.   Col. William Hawley reports
finding
deliberately redeposited chalk near the ends of the ditch on both sides of the
northeast causeway.
Deep Craters
The most efficient method of providing the required weirs in the southern
quadrant was to simply leave the natural material undisturbed wherever the
weirs were needed.  Since the natural material is chalk and, since the chalk is
subject to rather rapid erosion by the flow of water, the weirs are protected by
a
layer of clay on the tops and sides of them.   The soft chalk would have been
eroded rapidly by the water passing over it, whereas a layer of clay would have
withstood the effects of the water and indeed the clay has endured and was
evident to Col. William Hawley in the 1920s.
Clay on Barriers
Southwest Barrier
The barrier at the southwest point of the moat determines the water level in the
northwest reservoir. At the end of his digging, Col. William Hawley reports a condition
unlike any he had encountered up to that point.  
Segment 28, the final segment of Col.
William Hawley’s excavations was found to be much shallower than any others.  It
is at the southwest point of the moat beyond which the ground surface levels off and the
northwest reservoir begins.  At the point where Hawley ended his work the ditch was a
mere 18� below surface, but by probing, Hawley discovered that shortly the ditch
returned to the normal depth.  Hawley reports the filling of the ditch to be of “great
hardness� and that the “The level chalk bottom looks as if it had been patted
down by feet passing over it.� – a condition Hawley reports finding throughout his
excavations of the ditch – and there were “… a few flint chips on the bottom�.
This final segment, #28, of Col. William Hawley’s excavations is interpreted
as the barrier/weir at the southwest that maintains the water level in the
northwest reservoir.  It would have provided a water level in the reservoir
somewhat less than 18â€� below ground level.  The water would have
overflowed the western end of the barrier and flowed down the sloping surface
and into the basin of segment 27, somewhat lower than segment 28.  In modern
times the shallow depth of the ditch at segment 28 probably led to its becoming a
thoroughfare and possibly to the great hardness of the surface, or possibly the
surface may have been deliberately made hard by the builders to prevent erosion
by the flow of water over it.  In any case it would seem that the 'foot patted'
bottom of the ditch was deliberately conditioned to withstand erosion.
There are no barriers in the eastern quadrant.  Since the eastern section of the
moat lies on level ground, no barrier/weirs are required there and so none are
expected.  The eastern reservoir includes the lowest point on the periphery of
the monument and so an outlet from the moat is required there.  There is an
outward opening of the ditch at the lowest point to allow for the flow of water
from the ditch. From the exact point where the outlet needs to be and
evidenced by
obvious cropmarkings a, now filled in, trench leads off from the
edge of the moat and runs downward toward Stonehenge Bottom.
Eastern Quadrant
The Inlet
As mentioned above, water would have been fed into the moat at the northwest
inlet
, possibly from an elevated aqueduct.  This ditch/moat theory is a part of a
larger theory that requires the moat, or at least some body of water at the
elevation and location of Stonehenge.  The moat has become apparent as the
result of research into that larger theory.  For now, we may say that there is,
externally, compelling reason to believe that the water was fed into the moat
from an elevated aqueduct.  There is also within the moat some indication that
the water entered the moat from some height, as from a waterfall.
When water falls, as with all falling matter, of course, it develops some momentum the
velocity of which, due to the acceleration of gravity, depends on the distance it falls.  The
water falling into the reservoir will create turbulence and will stir up any small or light
particles on the bottom of the reservoir and carry them away with the current.  They will
be carried away in the direction of the flow, as will other particles that happen to be on
the bottom as the turbulent waters pass over them.  The washing away of the small and
light particles will create a
depression (plunge pool) on the bottom of the reservoir, and
the depression will be elongated in the direction of the flow.  The size of the depression
will depend on the height from which the water falls, the depth of the water in the plunge
pool, the rate of flow, the nature of the rock, etc. The larger and heavier chunks will
remain and will occupy less space than was occupied by both the large and the small
particles.  This is all very obvious and no one should have a problem with it.  It is just that
it is important to the idea of an elevated aqueduct feeding water into the moat. It is the
kind of evidence that should be expected of such a system. Amazingly, even after fifty
centuries, there is clear evidence at the inlet of exactly the shape of depression to be
expected if water had fed into the moat from some height.
In his book “Beyond Stonehenge�, 1973, Gerald S. Hawkins published the elevations
at Stonehenge at one-foot intervals.  The map of elevation contours has proven invaluable
to the development of this theory and especially in verifying the expected elongated
depression at the inlet.  The map also indicates the subtle differences in elevations that
verify the need for diking at the north and for barriers at the south.
STAY TUNED
Below is such a theory:  
Thanks go to English Heritage, Gerald S. Hawkins,
R.J.C.Atkinson, Col. William Hawley, Christopher
Chippindale, and the many researchers and writers
of Stonehenge without whose work this hypothesis
would not have been possible.
To be continued
This article is dedicated to the memory of Professor Gerald S. Hawkins who freely
provided help in the form of information, suggestions, advice and encouragement,
over the years, in the development of this hypothesis.
THANKS TO ALL FOR YOUR KIND ATTENTION

                             
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