Survey definition of natural boundaries
Definition on the plan
A boundary that is formed by a natural feature (bank of stream, mean high water mark, edge of cliff etc) must be surveyed so that each change of course or direction is determined to the appropriate accuracy. This may be achieved by the surveyor adopting a series of bearings and distances that approximates the boundary. These bearings and distances are derived from the end points of a series of radiations taken from one or more field stations to each change in direction of the bank of the stream etc.
In order to ensure the plan of survey remains clear and legible it is common practice to list each bearing and distance in a table of short lines. The actual bank etc is delineated on the plan as an irregular line. See also Clauses 47 and 65 Surveying and Spatial Information Regulation 2012. If the actual position of the natural feature is substantially different to the adopted position of the boundary, both positions must be shown on the survey plan.
Note The previous method of determining the boundary by traverse lines and offsets is no longer acceptable.
Riparian rights of the adjoining land owners must be maintained. To permit the doctrine of accretion and erosion to continue, it is necessary to clearly indicate on the face of the plan that the bank or MHWM remains the boundary of the parcel. Consequently, all new plans that define a riparian or other natural boundary must include an appropriate statement on the face of the plan, e.g:
BANK OF ROCKY CREEK IS THE BOUNDARY
MEAN HIGH WATER MARK IS THE BOUNDARY
Adoption of bank or centreline
Where an existing parcel of land fronts on to a waterway it is necessary for the surveyor to identify whether the prior plan has adopted the high bank, low bank or some other definition of the boundary of the waterway. This will require an inspection of the original Crown Portion Plan to determine the original extent and intention of the parcel. If that plan has been noted as 'high bank', 'top of bank', 'low bank' or indicated in any way, any new deposited plan must also adopt that bank as the boundary and an appropriate notation added to the face of the plan. Where the original plan depicts a traverse along the bank the surveyor must determine whether the original boundary was the traverse or the bank.
Note 1 Standard drawing conventions for Crown Portion Plans is for the boundaries of the portion to be defined by black lines and a pink wash edging, while the traverse is drawn in blue ink.
Note 2 Where the parcel is defined by the high bank, the quantum of land between the high and low banks has not been included in the Grant and remains unalienated Crown Title.
Where the boundary of a parcel extends to the centreline of the stream (either by adopting an existing centreline definition as set out in the base plan or through a successful claim of Ad Medium Filum Aquae) the new plan must define both banks and the centreline of the stream. Two areas must be shown for the parcel (one bounded by the bank and one bounded by the centreline).
Former mean high water mark
The banks of a river or stream, the mean high water mark or any other irregular boundary may be altered by human action either through the channelling of a creek through a canal or pipeline, the construction of a seawall outside the original MHWM or some other means. As these events are man-made, not natural, the boundary of the land parcel may remain in the position of the original riparian boundary even though the bank may no longer be discernible on the ground. In these instances the boundary of the parcel should be shown on the plan as a series of short lines (bearings and distances) that approximate the position of the original riparian boundary.
A suitable notation should be added to the plan, e.g:
FORMER MEAN HIGH WATER MARK (DP...........)
FORMER BANK OF CREEK (DP..........)
Easements with riparian boundaries
The doctrine of accretion and erosion applies to the site of an easement that extends to a riparian boundary. However, if a proposed easement site is intended to be created along the bank of a tidal or non-tidal waterway, and it is intended that the bank constitute the extent of the site, a statement that the boundary of the easement will remain ambulatory should be added to the new plan:
NOTE: THE NORTHERN BOUNDARY OF EASEMENT 'E' WITHIN LOT ... DP....... IS FORMED BY THE MHWM OF .............. AS DETERMINED FROM TIME TO TIME
Alternatively, the extent of the easement site (and its relationship to the bank) should be fully defined by survey.
DP1026436 is an example of a plan with an easement defined along a MHWM boundary.
The usual requirements as to consents and reports apply to deposited plans of easement with riparian boundaries.
For more information see Easements affecting natural boundaries.
Ad Medium Filum Aquae
Title to land with frontage to non-tidal water has not only a conclusive title to the land but also a presumptive title to half of the stream bed. This is known as Ad Medium Filum Aquae - 'to the centre thread of the water'. The presumption can be rebutted but the onus of showing that this has not occurred rests on the person who makes that claim - see Lanyon Pty Ltd v Canberra Washed Sand Pty Ltd (1965-1966) 115 CLR 342.
The grantee of a Crown Grant issued before 3 May 1918 (Eastern and Central Divisions) or 31 May 1935 (Western Division) is regarded as having title ad medium filum aquae if:
- the land was alienated as a Settlement Purchase, or
- the land was the subject of a purchase from the Crown prior to the above dates, or
- the land was formerly held as a Conditional Lease, Homestead Selection, Homestead Farm or Conditional Purchase Lease prior to the above dates, and was subsequently converted, or
- the land is currently held as a Conditional Lease, Homestead Selection, Homestead Farm, Suburban Holding, Week-end Lease, Crown Lease, Settlement Lease, Conditional Purchase Lease, Prickly-Pear Lease, or Returned Soldiers Special Holding which commenced prior to the above dates.
Where the parcel boundary extends to the centre thread of the river (ad medium filum aquae) the survey is required to define both banks and the centreline of the stream - see cl.47(3) Surveying and Spatial Information Regulation 2012. Two areas must be shown for the parcel (one bounded by the bank and one bounded by the centreline of the stream).
A formal claim to the centre line must be made in all cases. Land and Property Information, Legal Branch will make the assessment of all claims.
Where the land is Old System, limited or qualified title
The claim must be based on a Primary Application over land defined in a new deposited plan of survey, defining the claimants adjoining land and the claimed ad-medium-filum land as one lot, together with the relevant evidence in support of the claim.
Where the land is Torrens title
The claim must be based on a Request form 11R (PDF 131 KB) over land defined in a new deposited plan of survey, defining the claimants adjoining land and the claimed ad-medium-filum land as one lot, together with the relevant evidence in support of the claim. The evidence should include:
- a statutory declaration by the person(s) making the claim that he/she or they is/are unaware of any fact or circumstance about claiming title to the land which would mean that the ad medium filum rule should not apply in this case
- a certificate by a qualified person that he/she has:
- inspected all dealings with the land currently held by the claimant (adjoining the land claimed from the bank to the centre line) from the time the existing boundary was established to the present
- found nothing that would rebut the application of the ad medium filum rule
- included a list in the certificate of all instrument inspected.
For further information regarding the ad medium filum aquae rule see Hallmann Paragraphs 13.71-13.83 inclusive.