12 NATURAL BOUNDARIES
Boundaries present themselves
in one of two forms, either as natural or artificial boundaries. Natural
boundaries are ambulatory in nature and the doctrine of accretion asserts
that they may move in position providing that change is imperceptible
Natural boundaries are those
evidenced by naturally occurring phenomena such as the seacoast, inland
waters and mountain ranges. The most common natural boundaries dealt with
by surveyors in South Australia are defined by the mean high water mark
(MHWM), or the centre line or banks of streams. Surveyors also deal with
boundaries created parallel to natural boundaries (150 link reserves);
such boundaries are generally not ambulatory.
Water boundaries are classified
as being either riparian (streams) or littoral (shores, that is lakes
or the sea and its inlets). It should be noted that the term riparian
is commonly used to include littoral boundaries; unless otherwise specified
this section shall do the same.
In South Australia disputes
over riparian rights are rare as there is a relatively small proportion
of land parcels with natural boundaries, due to the lack of substantial
watercourses and fresh water lakes.
sections 12 and 19 for natural boundary plan requirements.
This section refers to some
legislation relevant to the ownership of the seabed and the bed of the
River Murray. As there is no specific legislation relating to the surveying
of natural boundaries the following common law rulings and discussion
has been presented to assist understanding.
BOUNDARY DEFINITIONS AND PRINCIPLES
Mean High Water Mark
v Chambers is the precedent generally adopted for the extent of
parcels bounded by tidal waters. This case was to resolve the question
of the landward extent of the Crown's right to the seashore.
While this judgement confirmed the extent as MHWM (also known as medium
high water mark or ordinary high water mark, OHMW) it was somewhat imprecise
in defining MHWM. The judgement refers to:
point of the shore therefore is about four days in every week, i.e.,
for the most part of the year, reached and covered by the tides.
average of these medium tides in each quarter of a lunar revolution
during the year...
line of the medium high tide between the springs and the neaps. All
land below that line is more often than not covered at high water, and
so may justly be said, in the language of Lord Hale, to be covered by
the ordinary flux of the sea. This cannot be said of any land above
on this case has come from the Crown Solicitor (DL 3533/1967):
misunderstanding has subsequently arisen from the Lord Chancellor's
reference to "the medium high tide between the springs and the
neaps". The words underlined are descriptive only and are not,
in my view, juristically definitive: they could, without changing the
meaning of the passage in which they occur, have been omitted. The highwater
mark of the ordinary tides, not the average of spring
and neap tides, fixes the boundary.
Hallmann (1994, para. 13.40)
lands are bounded by tidal waters, the common law rule is that the boundary
is the mean high-water mark, ie. the mean of all high tides including
the spring and neap tides taken over a sufficiently long period...
if the extent of the Crown's right to the seashore is MHWM then any land
alienated from the Crown abutting the seashore, unless otherwise described,
extends to MHWM. 'Low water mark' is a description of a boundary where
it is clearly intended that parcels extend over part of the seashore.
It is quite common to find that
the line located for the coast on early surveys of waterfront parcels
was some distance inland from MHWM. In many cases this is not attributable
to the ambulatory nature of the MHWM. The position located by these surveyors
was often a line (sometimes labelled) of edge of vegetation, accumulation
of debris, cliff edge or top of bank. Redefinition of the seaward boundary
of a coastal parcel inland from MHWM would probably require evidence of
intention by the Crown to retain a strip of land between that parcel and
Halsbury's (1998, para.355-14015)
land is described as abutting a tidal
river, it is presumed, as
with the seashore, that the mean high water mark constitutes the boundary.
The common law distinguishes between tidal
rivers and non-tidal
Where the river is a tidal
the land forming the bed and channel
through which the river runs, the alveus 19,
belongs to the Crown up to the mean high water mark.
the absence of any specific legislative definition, 'tidal waters' means
those in which the tide ebbs and flows under the gravitational influence
of the sun and the moon.
Hallmann (para. 4.4) clarifies
tides must be in evidence for more than half of each and every year.
Waters that do not answer that description, or waters that are only
intermittently tidal so at times to be naturally cut off from the sea,
are deemed at law to be non-tidal waters...
Anecdotal evidence suggests
that prior to the construction of the Murray mouth barrages, salt water
at times reached as far up the river as Mannum. Furthermore, it is thought
that the river may have been influenced by the ebb and flow of tides as
far upstream as Blanchetown.
of the Sea Bed
Raven v Keane confirms
the extent, and status, of the foreshore : 'The
foreshore, that part of the seashore between ordinary high-water mark
and low-water mark, prima facie belongs to the Crown.'
Under Section 15 of the Harbors
and Navigation Act 1993 adjacent
land is vested in fee simple in the Minister. Section
4 includes in the definition of adjacent land:
extending from the low water mark on the seashore to the nearest road
or section boundary, or to a distance of 50 metres from high water mark
(whichever is the lesser distance)...
Section 18 (4) provides that
this land: "...if within the area of a council but not within a harbor
- under the care, control and management of the council..."
Land vested in the Minister
under Section 15 also includes land underlying the territorial
sea adjacent to the State. Under the Seas and Submerged
Lands Act 1973 the territorial sea extends seaward for three nautical
miles from low water mark, agreed baselines, or from bay closing lines
joining the headlands at the mouth of true bays.
In relation to Council boundaries
the Crown Solicitor (HB 1059/25) advised that:
proper interpretation to be placed upon the words "coast",
"seacoast", or "seashore" where they, or any of
them, are used, without being defined, to fix the seaward boundary ...
of a Municipality or a District Council District, is that the
boundary extends to low water mark... [italics added].
times the boundaries of some National Parks have been extended to lowest
astronomical tide. Lowest astronomical tide is
defined as the lowest height of the surface of the sea which can be predicted
to occur under average meteorological conditions and under any combination
of astronomical conditions.
METHODS FOR DETERMINING MHWM
An obvious point is expressed
by the Manual of the NSW Integrated Survey Grid (1976, para 22.4):
'The determination of the limit of mean high water presents no difficulty
when the foreshore is steep. On flat grades and where mangrove swamps
exist, great care is necessary.'
Where it is necessary to locate on
site the present position of MHWM the following methods should be considered.
It is recommended that surveyors utilise the current year's
SA Government Tide Tables (available from
SA , 108 North Terrace Adelaide). These tables
provide instructions for tidal predictions. Where additional tidal information
is required beyond that in the Tide Tables:
- consult Australian National Tide Tables 1(ANTT),
- seek advice from Flinders Ports Pty Ltd.
The main methods utilise a value
which is the average of all the high tides for the local area. This value
can be observed at the appropriate time or set out using the relationship
between the tide gauge and height control. The two main methods shall
be referred to as:
- observing the water's edge, and
- setting out the MHWM contour.
The advantage of observing the
water's edge is that at appropriate times the MHWM is self evident. A
problem with this method is that it is only suitable in calm conditions;
at locations where swell waves are less than 0.5m at breaking
2. The method is often capable of use in South Australia
because much of the coast in settled areas is protected from swells of
Setting out the MHWM contour
overcomes uncertainty involved with breaking waves. However, this method
is only practical for those parts of the coast within levelling distance
of AHD control or a tide gauge. An additional problem with levelling from
AHD control is that the uncertainty of the relationship between the local
MHWM and the AHD increases the further one is from a tide gauge.
Due to the problems inherent
in these methods it is recommended that wherever possible, a
sample point located by one method be checked by the other.
Observing the Water's Edge
1. from Tide Tables
determine the Standard or Secondary Port adjacent to the area of interest.
If not adjacent to a Port some interpolation of predictions at Ports
either side will be required.
2. if Secondary Ports are
used in step 1, determine the Standard Port3
it is related to.
3. obtain the mean of the
high tides4 for the Standard Port. (This has been done in Table
1 by averaging predicted high waters
4. predict from the Tide
Tables the time of day the tide equals this height at the Standard
5. if a Secondary Port is
used apply the time difference of high water at the Standard Port.
6. locate the edge of the
water at this time. Particular note should be taken of the page headed
'Accuracy of Predictions and Weather Effects' in the Tide Tables.
If it is not practical to
observe the tide at the predicted time of MHWM, or if the high water
on a day does not reach the MHWM plane, then a less direct method can
1 - 3 as above.
4. mark the edge of the water
at a convenient time (preferably closer to high water than low water).
5. predict from the tide tables
the tide height at the time of observation
the marks at step 4 by levelling up or down the beach the height difference
between MHWM and the height determined at step 5 (for Secondary Port
predictions this height difference must be adjusted by the
Ratio of Rises quoted in the Tide Tables).
For both of these methods
it is advisable to observe the edge of water on two days, especially
if the first day's weather conditions are abnormal. For verification,
or greater accuracy, actual tide readings at the Standard
Port should be obtained from Flinders Ports and appropriate
adjustments made to the predicted determination
of the tidal plane.
||MHWM above Chart Datum
||AHD above Chart Datum
||MHWM above AHD
Table 1 - MHWM at Standard Ports
Values in this table must be used in accordance with the qualifications
expressed in this section.
datums for Ports may change in subsequent years. Check the current year's
Tide Tables for an indication of such changes. The value for MHWM above
AHD will not be affected by changes to chart datum.
Setting Out The MHWM Contour
Table 1 shows the AHD value
for MHWM for the Standard Ports in South Australia9
This method involves levelling
from AHD control to set out the appropriate contour value for MHWM. The
marking of this contour can then be located in a horizontal direction
for cadastral purposes. The following should be carefully considered:
1. Values of AHD for MHWM
as distance increases from Ports requires intelligent interpolation
(that is, not necessarily linearly) between them to obtain the AHD value
for MHWM at the site of interest. Note that this is not always valid
because of tidal peculiarities in the Gulfs; it may be necessary to
obtain expert advice from Flinders Ports.
2. The Manual of the NSW
Integrated Survey Grid (para. 22.5) has the following comment:
method cannot be used with accuracy in positions within estuaries
and streams unless reliable information on tidal gradients is available.
Tidal gradients vary with the shape of an estuary and distances from
the open sea...
It may be possible for surveyors to determine an AHD value for MHWM
to a greater precision than that shown in Table 1. Chart datum definitions
(height difference to adjacent benchmarks) for Standard Ports are shown
to three decimal places in the Tide Tables. It will be necessary, however,
to connect the datum benchmark to AHD control as these benchmarks do
not necessarily have a published AHD value.
determinations at Secondary Ports (or for the purposes of interpolation
using a Secondary Port) a chart datum value of MHWM can be determined
using the value at the Standard Port, the Ratio of Rises, and the respective
values of MHWS10 . Again
the value becomes more uncertain as distance from these Ports increases.
5. This Secondary Port value
of MHWM above chart datum can be converted to AHD if Flinders
Ports are able to provide a height difference to an adjacent
benchmark, which the surveyor can then level to AHD control11.
If working close to a tide gauge
(or its datum benchmark) there is an alternative method of setting out
the MHWM contour that does not require AHD connections. With a chart datum
value of MHWM, obtained as described in a3 or b4 above, level direct from
the tide gauge or its datum benchmark. Levelling from the datum benchmark
requires the height difference to chart datum (see Tide Tables
for Standard Ports or Flinders Ports for
The methods described above
are generally adequate for all cadastral surveys. On rare occasions a
more accurate determination of the MHWM plane may be required at a site
than is obtainable by these methods. This can be achieved by establishing
a temporary tide gauge adjacent to the area of interest and recording
and averaging all high water values over an appropriate
Surveyors experienced in determining
MHWM by methods a and b have noticed that a second seaweed line can sometimes
be taken as a useful approximation for MHWM for medium to low energy beaches
(that is where storm waves seldom exceed 1m). This method of determining
MHWM may be suitable as an alternative to graphical methods.
This seaweed line method is
to be avoided if at all possible by surveyors not experienced in determining
MHWM by the more objective methods. While it has been known to sometimes
give good results, it assumes an arbitrary balance between the stage of
the tide, the slope of the beach and the amount of wave set-up and run-up.
These vary greatly and the method has no logical support. Because wave
run-up can be quite large (commonly over a metre in height), this method
can lead to large errors if applied on open coasts.
HEIGHTS OF COASTAL LAND
It is anticipated that there
will be an increased requirement for surveys to determine contours for
land to be subdivided and to establish heights for coastal development.
Developers of coastal land are frequently required by local councils and
the Development Assessment Commission to provide this information; this
is likely to increase as more development is assessed for safety against
extreme tides and the effects of sea level rise.
Where benchmarks are not conveniently
located, sea level or seaweed marks have commonly been used as survey
datum. However this does not always provide sufficient accuracy; the datum
used needs to be sufficiently accurate to enable the development to be
assessed. It would be desirable for surveyors to indicate the likely range
of error when they use these approximate methods, though this has not
been common practice in the past.
Where heights are likely to
be critical, the accuracy needs to be at least within 0.1m. This is normally
only achievable by levelling from AHD benchmarks.
To avoid the cost of levelling
to a distant AHD benchmark this standard may be relaxed where land is
well above the likely effects of extreme tides allowing for sea level
rise (1.5m or more above the extreme wave swash level, which may be discernible
from seaweed or other flotsam, or from local knowledge).
An approximate AHD value for
the site may be derived by either of the two following methods. These
approximate methods should only be used where the subject land or proposed
development is sufficiently elevated to cover the estimated error in the
method. Height accuracy from these methods to within 0.3m would be expected,
and survey should only be carried out when this is attainable.
a. Height Transfer from
the Nearest Tide Gauge
This method is only suitable
in calm conditions, at locations where the swell waves are less than 0.5m
at breaking, and if the site is within 50km of a tide gauge:
1. establish the height of
a new benchmark, at the site, in relation to the sea water level and
note the time of day.
2. make the appropriate adjustment
for tidal travel (refer to Tide Tables) to the site and obtain
from Flinders Ports the actual recorded
tide at the adjusted time.
3. level from the tide gauge
or its datum benchmark12 to
4. deduce the height of the
new benchmark at the site.
5. estimate the accuracy limits,
taking into account the distance from the gauge, wind and sea conditions
and any other factors, and indicate this on the survey drawing, together
with notes on the method used.
b. Simultaneous Levelling
If there are no nearby tide
gauges, but there is AHD control within 20km of the site of interest,
the following method may suffice in some instances. As for the previous
method, it requires calm conditions and an absence of any significant
1. one party levels from sea
water level to AHD control.
2. another party simultaneously
levels from sea water level to a new benchmark at the site of interest.
3. assuming sea water level
adjacent to the AHD control and the site of interest at the same time
is on the same plane, deduce the height of the new benchmark.
4. estimate the accuracy limits
and indicate on the survey drawing as in step 5 of method a.
NON TIDAL BOUNDARY DEFINITIONS AND PRINCIPLES
describes the extent of riparian ownership:
the river is non-tidal and runs through the centre of adjoining land,
in the absence of statutory provisions, the boundaries are determined
according to the common law rule of ad medium filum aquae,
which literally means 'to the centre line of the water'. Under this
rule, ownership of a non-tidal river, lake or pool is presumed to be
divided between the riparian owners down the middle line of the stream.
The middle line is determined according to the usual position of the
banks of the river rather than extraordinary periods where flooding
or deluge has occurred. The entire area between the banks, including
areas that are left uncovered when the water levels are low, represents
the relevant alveus 19in
Halsbury's then clarifies the
conditions under which the riverbed is excluded from riparian ownership:
express description of land as 'abutting' a non-tidal river within a
certificate of title or plan, without mention of the ad medium filum
rule, will not prevent the application of the rule unless clear and
express words indicate that the rule is inapplicable. The ad medium
filum aquae rule is presumptive and may be rebutted by proof that
title to the centre line of the alveus was not intended to pass pursuant
to a Crown grant or a subsequent conveyance of title. However, such
proof must be unequivocal in nature and either be:
expressly incorporated into the grantor conveyance of land; or
implied where the circumstances indicate that the transferor of the
land intended to retain the relevant area for a particular purpose.
implied intention to rebut the presumption of land ownership ad
medium filum aquae will not arise in the absence of strong supporting
the cases cited by Halsbury's is Lanyon Pty Ltd. v Canberra Washed
Sand Pty Ltd wherein the judgement says:
law holds that it is the exclusion of that land which must be evidenced
by the terms of the grant and not its inclusion, and that if not
so evidenced that land will be deemed to have been included in
the grant ... no description in words or by plan or by estimation of
area is sufficient to rebut the presumption that land abutting on a
... stream carries with it the land ad medium filum merely because the
verbal or graphic description describes only the land that abuts on
the ... stream without indicating in any way that it includes land underneath
that ... stream. [italics added].
where the riverbed is excluded from riparian ownership, what is the limit
of the riverbed? One definition comes from the case Kingdon v Hutt
has defined banks, but the flow of water between such
banks is irregular. During the dry months, and for the greater part
of the year, it flows in a small channel considerably to the east of
the claimant's land. In wet weather the flow is greatly increased, and
seven or eight times in a year during such wet weather the water flows
from bank to bank, and this flow of water is called by the witnesses
"ordinary freshes." In very wet weather the river is "in
flood," and then it overflows its banks.
a river has defined banks, but the flow of water between the banks is
irregular, being confined to a small channel during the dry months and
for the greater part of the year, but greatly increasing during wet
weather and extending occasionally, in each year, from bank to bank,
whilst in exceptional instances, happening once in every two or three
years, when the rainfall has been long continued and of great severity,
it overflows the banks, the "bed" of the river (in law) extends
from bank to bank. It is not confined to the channel in which the water
is for the time being flowing in dry weather, nor does it extend beyond
the banks to land over which the water flows in time of flood.
definition comes from The State of Alabama v The State of Georgia:
bed of the river is that portion of its soil which is alternately covered
and left bare, as there may be an increase or diminution in the supply
of water, and which is adequate to contain it at its average and mean
stage during the entire year, without reference to the extraordinary
freshets of the winter or spring, or the extreme droughts of the summer
in such places on the river where the western bank is not defined, it
must be continued up the river on the line of its bed, as that is made
by the average and mean stage of the water...
While Alabama refers
to the limit of the bed being adequate to contain the river at its mean
height, Kingdon's definition of the bed appears to be higher.
It includes the banks up to a height beyond which the stream is considered
to have overflowed in flood. This height would appear to be the top of
the bank that contains the stream in its normal flow
Hallmann concludes (para 13.64,
13.65) that while NSW legislated a definition for the limit
of the bed of a river (adapting the definition in Alabama) the
Kingdon definition would be applicable for cases not falling within
Apparently there was a definable
top of bank in Kingdon's case. It may be that Alabama
is applicable in the absence of a definable top of bank as it included
consideration of stretches of river with low and flat banks where during
freshets water spread as far as half a mile beyond the river.
The precedent established by
Yeomans v Peter is relevant where a lake bed is excluded
from riparian parcels alienated after construction of a dam. Hallmann
(para 13.50) summarised the judgement:
was held that the boundaries of an artificial lake, as contained by
a dam wall, would, in absence of evidence to the contrary, be fixed
by the line representing the level of the water when the lake was full
to the top of the dam wall.
Two issues in particular should
be considered with respect to exclusion of all or part of the bed of the
River Murray from its riparian parcels:
The Control of Waters Act
1919-1975 stated at Section 5:
any watercourse to which this Act applies forms the boundary, or part
of the boundary, of any land which after the date of the passing of
this Act is alienated by the Crown, the bed and banks of such
watercourse shall, notwithstanding such alienation, remain the
property of the Crown and shall not pass with the land so alienated,
unless the alienation is made pursuance of some agreement existing
at the date of such passing and inconsistent with this Section. [italics
The Act specifically included
application to the River Murray in Section 3 (1) by stating "This
Act shall apply to - (a) that portion of the River Murray which is situated
between Mannum and the eastern boundary of this State... ." The
Control of Waters Act was repealed by the Water Resources
Act 1976; the later not having provisions similar to Section 5.
Regulation 13 of the Harbors
and Navigation Regulations 1994 specifies that the River Murray
upstream of the sea mouth does not vest in the
Any riparian land alienated
(from the Crown) prior to 1940 as far upstream as Blanchetown may be
limited to MHWM (see Table 2 and section
12.3b). See section
12.7a for comment on innundation of MHWM.
||Date of Completion
|Lock 1 Blanchetown
|Lock 2 Waikerie
|Lock 3 Overland Corner
|Lock 4 Bookpurnong
|Lock 5 Renmark
|Lock 6 Murtho
2 - River Murray
The situation for land between
the barrages and Blanchetown alienated after
1940 is less certain as damming of a tidal river cuts it off from the
ebb and flow of tides.
upstream of Blanchetown, alienated after construction
of river locks and weirs, raising the water level should not logically
affect the presumption of ad medium filum aquae. Where, however,
the river bed has been excluded from riparian parcels:
- if the pool level is above the historic banks, the
pool level, being the normal river level in the absence of banks,
would be the appropriate extent for the limit of the stream bed in
accordance with Alabama's case (see section
12.6). This contour may be set out in accordance with Table
- if the historic banks are not inundated the extent
of ownership of riparian parcels would be unaffected by the timing
of alienation relative to weir construction.
ACCRETION & EROSION
For the doctrine of accretion
(or erosion) to apply two factors must be present:
- an ambulatory boundary, and
- a gradual and imperceptible change caused naturally.
When redefining natural boundaries
surveyors must assess the evidence collected to determine whether the
doctrine of accretion is applicable.
At common law where movement
of a natural boundary is not gradual, natural
and imperceptible the boundary becomes fixed in the position immediately
prior to such movement. The surveyor must compile whatever information
is available to ascertain the boundary position at that time.
The natural and imperceptible
criteria require particular qualification. Discussion of this and other
consequences of accretion and erosion follow.
with the tidal flow led to the case Brighton and Hove General Gas Co
v Hove Bungalows Ltd:
general law of accretion applies to a gradual and imperceptible accretion
to land abutting upon the foreshore brought about by the operations
of nature, even though it has been unintentionally assisted by,
or would not have taken place without, the erection of groynes for the
purpose of protecting the shore from erosion.
general law of accretion also applies where the natural accretion, gradual
and imperceptible, abuts upon land of which the former boundary was
well known and readily ascertainable. [italics added]
case Verrall v Nott even though the process of accretion had been
facilitated by the erection of a rubble wall by Verrall it was held:
Verrall was entitled to the benefit of any accretion to his land from
the sea, although the original boundary of his land was ascertainable.
Verrall was not prevented from taking the benefit of accretions because
of the erection of the rubble wall.
(para 13.45) also refers to the above two precedents dealing with actions
leading to unintentional accretion and then confirms that:
other cases, however, where the landowner's acts can be shown to have
been intended to cause accretion, the doctrine does not apply: A-G
v Chambers (1854); A-G of Southern Nigeria
v John Holt & Co. (Liverpool) Ltd (1915).
Centre of Theosophy Inc v State of South Australia confirmed that
the doctrine of accretion is applicable to non tidal lakes, and that '...accretion
may also occur where the deposits are carried by the wind, if they become
settled and extend the boundary of the land into the water...' (Hallmann
This judgement considered the
criteria of imperceptibility in some detail. The
court accepted that in certain conditions of wind and weather, movement
of sand was detectable, however:
of parts of the dunes, or of drifts of sand upon the dunes, is not the
same thing as movement of the land boundary out into the sea. The one
may be observable but does not, of its nature, constitute the other.
The real question is how long it takes for a consolidation to take place
bringing about a stable advance of the land.
to accretion where the boundary was surveyed as right (straight) lines,
also shown as medium high water and a fixed area given, was investigated
in 1980 at North Haven. The accretion was due to the Outer Harbor Breakwater.
Two international cases supported the claim:
Hallmann advises (para 13.38):
land in a Crown grant is described as bounded by "measured lines
along" the margin of a coastal "lake" (really an inlet)
which is tidal, the legal opinion is that the high-water mark is intended
to be the boundary, the "measured lines" merely indicating
the approximate position of the high-water mark as it was at the date
of grant. Such a construction would not apply, however, if the land
is described as bounded by " measured lines near" the margin
or bank. Presumably, the above constructions would apply to similar
descriptions relating to the seashore or to the bank of a tidal stream.
The legal principles involved where
a right line, fixed boundary, inland from the coast becomes gradually
submerged are somewhat obscure. See Horlin (1994) for discussion of this
(1974, p.14) proposes that the method for apportioning accreted lands
to abutting owners depends on the facts of the case. Three methods referred
1. prolonging the side boundaries,
2. joining the previous terminus
of the side boundary to the new riparian boundary such that it intersects
the new riparian boundary at a right angle, or
3. give to each owner a share
of the new shore line in proportion to what was held in the old shore
Refer to Willis for a fuller
explanation and examples.
Murray - Effect of the Locks and Barrages
The construction of the locks
and barrages along the River Murray has complicated boundary redefinitions
in the area. The barrages have had a significant effect in the low lying
areas around Lakes Alexandrina and Albert. In many instances the intentionally
raised river level is above the old limit of the lake or river bed meaning
the doctrine of accretion is not applicable and
the now fixed boundary is lost. That is, the extent of tidal influence
is no longer evident and the historic bank of the river is permanently
The locks and weirs have caused
only minor inundation upstream and may not have
raised the river level above the original river bank. If so, the riparian
boundary probably remains ambulatory and locatable.
of inundation there are various methods for determining the position of
the historical limit of the river bed, either to enable delineation of
a lost boundary or to determine if the historic bank is still above water.
Some of these methods are outlined below:
1. By Survey
Many of the original surveys
of the river located the edge by line and offset. This position may
be re-established from a combination of the original surveyors field
work and physical evidence of the boundaries.
2. By Vegetation
In a number of areas, particularly
in the lower reaches, considerable inundation of lands adjacent to the
river has been caused by the construction of the barrages. In some of
these areas a line of trees are found at the edge of the historical
3. From Records Held by
In the years around 1907,
the old EWS Department undertook a detailed topographic survey of the
River Murray; numerous cross sections were taken. These records contain
some information regarding the position of the bank and river both horizontally
and vertically and could provide assistance in redefinition of the river
banks in some areas. Contact the Dams & Civil Unit of the Engineering
Group of SA Water.
4. By Scale and Plot
In cases where no other evidence
exists the historic edge of river can be fixed by scaling from the original
THE WATERFRONT RESERVE / ROAD BOUNDARY
In 1835, prior to his departure
for South Australia, Colonel Light was instructed in all surveys to reserve
as public roads all land within a minimum width of the coast, each side
of navigable rivers, and around lakes.
Initially most waterfront roads
were fixed during survey of abutting Sections with the landward boundary
parallel to and 150 (or 100) links from the waterfront. Colonel Light's
instructions were not always uniformly applied and many grants were made
with waterfrontages, provision of the roads not continuing to the same
extent after about 1845.
Whenever the first opportunity
arose after 1898 to dispose of parcels by grant or offer for lease, provision
was made for a reserve along the coast and River Murray. In most cases
the landward boundary of this reserve was not surveyed, but was merely
delineated on existing survey records as a broken line. Very few were
dedicated as public roads, and eventually became known as the 150 link
reserve. They were not reserves in the sense of having been reserved or
dedicated under the Crown Lands Act, but were simply areas of Crown land.
In the 1970s concern by the
Surveyor-General about the status of the boundary between the 150 link
reserve and adjacent land led to a legal opinion that it was necessary
in each case to consider the terms of the land grant, or certificate of
title, as to the nature of the boundaries so granted
In the majority
of cases the reservation of waterfront land operated as an exception
to the land granted. Even though the term '150 link reserve' implied an
ambulatory inland boundary it was opined that this would be an unusual
step, the usual course being the immediate and permanent fixing
of boundaries at the date of the exception. Due to the complexity
of the matter the Surveyor-General was advised against the issue of a
general direction to surveyors.
of the reservation by exception is given in the case McGrath v Williams:
plaintiff claimed to be the owner in fee simple of a piece of land fronting
on the north of Shoalhaven River, which is tidal. The land in question
was granted by the Crown in 1843 to plaintiff's predecessors in title.
The grant was subject to certain reservations, including a reservation
of "all land within one hundred feet of high-water mark on the
sea coast, and on every creek, harbour and inlet of the sea." The
plaintiff sought to bring the land down to high- water mark on the Shoalhaven
River, under the Real Property Act, claiming that the hundred feet reservation
had been eroded away. The Crown objected to the plaintiff's application
on the ground that the reservation in the grant enabled the Crown at
any time to take possession of a hundred feet from the existing high-water
mark at the time of such taking of possession. Held, that the
reservation operated by way of exception from the grant, and that consequently
the hundred feet must be measured from high-water mark as at the date
of the grant.
Similar relevant cases on reservation
by exception are found in Smith v Renwick and A-G v Dixon.
of Allen Taylor & Co Ltd v Croll confirmed that the same
principle applies with respect to waterfront roads excluded from land
grants. The landward boundary is fixed at the time of grant so the road
benefits from any accretion.
Accurate determination of the
MHWM or river edge is essential to determining the landward boundary of
the reserve. This landward boundary was not directly fixed by survey,
it was not marked on the ground so that it could be fenced, and it generally
cannot be relocated by directly retracing the surveyors measurements,
as there are none.
The date of creation of the
150 link reserve may be obtained from withdrawn Hundred Plans located
at the Public Search Counter of the LTRO. The date the land was leased
from the Crown can be found in the Crown Lease books held by the Registrar-General.
For new or widened reserve requirements
Determining the landward boundary
of the coastal reserve can be a difficult task, where there has been natural
and imperceptible movement of the MHWM. Often the original survey was
carried out some time before delineation of the reserve, which in turn
may have been some time prior to alienation/exception. Consequently there
is no record of the position of the MHWM at the time of exception of the
One method of determining this
landward boundary is as follows:
1. plot the high water mark
located by the original survey.
2. using one of the methods
in section 12.4, determine
and plot the position of the present MHWM.
3. from records held in the
LTRO, determine the date the land adjacent to the coastal reserve was
4. determine the position
of the MHWM at the time of alienation by proportioning between the original
and present determination of the MHWM.
5. set out a line 150 links
back from the position derived for the MHWM at step
Surveys adjacent to the River
Murray commenced in the 1840s, initially around Lake Alexandrina. By 1870
most of the Hundreds up to Morgan had been surveyed. Surveys between Morgan
and the State border were completed by 1920. The definition of the landward
boundary of the 150 link reserve is the main problem facing surveyors
re-establishing boundaries adjacent to the River Murray due to the affect
on the river of the construction of the weirs and barrages:
- In some cases the historic edge of the river (see sections
12.6 and 12.6b2)
will have been inundated. Parcels alienated prior to
the construction should be located 150 links from a point as determined
by one of the methods described in section
- On the other hand, inundation of the historic
edge of the river where alienation occurred after
construction would be treated differently. Consistent with the principles
in Yeomans v Peter (section
12.6a), the landward boundary of the reserve is considered
to be 150 links from pool level. This can be measured from a contour
set out in accordance with Table 2.
- The timing of alienation in relation to construction would be irrelevant
where the historic edge was the bank 18
and it has not been inundated; the 150 links
should be measured from the bank at the time of alienation/exception.
The following list contains
information relevant to natural boundary law. While far from exhaustive
it does provide a range of reference material. Not all will be specifically
relevant to the South Australian system.
Books & Articles
Butt (1995), The
Laws of Australia, The Law Book Co.
Brown (1980), Law
Relating to Land Boundaries and Surveying, Association
of Consulting Surveyors, Queensland.
Hallmann (2nd edition, 1994),
Legal Aspects of Boundary Surveying as apply in New South
Wales, The Institution of Surveyors, Australia,
New South Wales Division.
Halsbury (1998), Laws
Horlin (1994), Submerged
Boundaries, The Australian Surveyor, Vol.39 pp40-
Manual of the NSW
Integrated Survey Grid (1976), NSW Department of Lands.
Moore (1968), Land
by the Water, The Australian Law Journal, Vol.41
Weidener (1979), Surveying
the Tidal Boundary, Surveying and Mapping, Vol.39
Willis (1974), Notes
on Survey Examination, NSW Registrar-General's Department.
Allen Taylor & Co Ltd
v Croll (1923) LVR 87
A-G v Chambers (1854) 43 ER
A-G v Dixon (1904) 273 AC
A-G of Southern Nigeria v
John Holt & Co (Liverpool) Ltd (1915) AC 599
Brighton and Hove General
Gas Co v Hove Bungalows Ltd (1924) 1 Ch 372
Frost v Palmerston North -
Kairan a River Board (1916) NZLR 643
Kingdon v Hutt River Board
(1905) 25 NZLR 145
Lanyon Pty Ltd v Canberra
Washed Sand Pty Ltd (1966) 115 CLR 342
McGrath v Williams (1912)
12 SR (NSW) 447
Raven v Keane (1920) GLR 168
Smith v Renwick (1882) 3 LR
Southern Centre of Theosophy
Inc v State of South Australia (1982) AC 706
State of Alabama v State of
Georgia (1859) 64 US 515
State of Penang v Ben Hon
Oon (1971) 3 A11 ER 1163
Verral v Nott (1939) 39 SR
Yeomans v Peter (1895) 16
NSWR (Eq) 197
Case Reference Abbreviations
English Law Reports, Appeal Cases
Commonwealth Law Reports
Gazette Law Reports (NZ)
LVR (NSW) Land &
NSW Reports 1960-1970
New Zealand Law Reports
United States Supreme Court Reports Lawyers Edition 1754-1956
also has predictions for current week.
after averaging out the water level fluctuations, breaking waves induce
a higher still water level inside the breaker zone. This higher still
water level will vary with the slope and nature of the coast, but is generally
about a tenth of the offshore wave height. On exposed coasts the tide
heights at the beach will nearly always be between 0.1m to 0.6m higher
than those deduced from nearby tide gauges depending on the prevailing
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See ANTT for additional Secondary Ports. Those possibly useful
include Arno Bay, Elliston, Port Neill and Port Stanvac.
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Note MHWM is not the same as the average of mean high water springs
(MHWS) and mean high water neaps (MHWN) (see section
12.3a). The average of MHWS and MHWN can be significantly different
to averaging all the high tides (for example, at Port Adelaide the former
is 0.18m lower than the later).
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In averaging the predicted high waters for a full year, it is
noticed that the average of the high waters for the months closest to
the equinoxes (March or September) gives a close approximation to the
full year average. Similarly, the average of all the high waters in both
of the months closest to the solstices (June and
December) is a close approximation.
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interpolation between high and low waters is sinusoidal, not linear. This
interpolation can be determined from the Table for Finding the Height
of Tide at Times between High and Low Water in the Tide Tables or
the following formula (derived from ANTT):
- t is the time at which tide is at height h.
- t1 and h1 denote the time
and height of the tide (high or low) immediately preceding the tide
- t2 and h2 denote the time
and height of the tide (high or low) immediately following tide height
- the arc cos function is solved in degrees.
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This interpolation can be determined from the Table for
Finding the Height of Tide at Times between High and Low Water in
the Tide Tables or the following formula (derived from ANTT):
- h is the tide height at time t.
- t1 and h1 denote the time
and height of the tide (high or low) immediately preceding time t.
- t2 and h2 denote the time
and height of the tide (high or low) immediately following time t.
- the argument for the cos function is in degrees.
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In Table 1 MHWM above chart datum has been determined by Land
Boundaries Branch from Tide Tables. This was done by averaging all the
predicted high waters for the months of March, June, September and December.
Cape Jervis's value was determined from 2008 predictions
(when chart datum lowered 0.30m), Wallaroo's
value was determined from 2005 predictions (chart datum lowered 0.10m).
Port Lincoln values were determined from 2004 predictions (chart datum
raised 0.20m). Port Adelaide's (Outer Harbor) value was determined
from 2001 predictions (chart datum raised 0.27m), Victor Harbor's from
1999, Port Giles's from 1998, and the remainder from 1997.
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The values for AHD above chart datum in Table 1 are taken from
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= MHWSSecondary - RR(MHWSStandard - MHWMStandard)
- RR = Ratio of Rises (from Tidal Data and Levels table in
- MHWMStandard = MHWM above Chart Datum from Table
- MHWS from Tidal Data and Levels table in Tide Tables.
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some Secondary Ports tide gauges no longer exist, however the chart datum
benchmark may still be extant.
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the height difference from chart datum to the datum benchmark from Tide
Tables for Standard Ports or Flinders Ports
for Secondary Ports.
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In a minority of cases the reservation operates as a defeasance,
expressing the grant as being subject to a public right of way 150 links
wide adjoining the coast. The grant retains contingency with the sea/river
and the right of way is an ambulatory ribbon 150 links wide.
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example of this process is seen on DBP 52, Hundred of Carribie.
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is assumed historic edges determined as MHWM, above the barrages, have
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is defined as "the land forming the bed and channel through which
a stream ordinarily flows".
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May not be applicable to areas such as South Australia that have
mixed tides, that is, two high tides per day having marked inequalities
in height. A tidal datum based on the higher of these two daily high waters
is referred to as mean higher high water.
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