Natural water boundaries

This guidance covers natural water features and their effect on property boundaries.

Natural water features, such as rivers, often form boundaries of properties. The positions of such water features aren’t necessarily fixed: they can shift over time. If the water feature moves, the associated legal boundary can move with it.

Warranty is statutorily excluded from boundary changes due to the movement of natural water features.

Owners of adjacent plots can agree in a Section 66 agreement to exclude a common natural water boundary from such shifts, provided both plots are already registered in the land register.

Water boundary movement

Natural water features often form the boundaries of properties. As a naturally occurring feature, such boundaries, whether fresh or salt water, do not necessarily remain fixed for all time. Natural water features are liable to movement over time, so that where the feature forms the boundary of a property, that boundary is liable to movement too.

For example, a boundary might be the centre line of a river, but the riverbanks may in fact be gradually moving, with the eastern bank being eroded, and the western bank increasing by deposits of silt, in which vegetation establishes itself. This increase is known as alluvion and is classified as a form of accession. If a boundary feature moves by alluvion the legal boundary moves with it. In this scenario, the boundary remains the centre line of the river in its new position.

Effect on warranty

Section 73(2)(i) of the 2012 Act, states that the Keeper does not warrant that alluvion has not had an effect on a boundary. Warranty is therefore statutorily excluded from natural water boundaries in respect of alluvial change. Unlike the practice adopted under the 1979 Act, the Keeper no longer requires to specify in the title sheet that the water boundary is excluded from warranty, and no reference requires to be added to the cadastral map to identify a water boundary that may be affected by alluvion.

Alluvion is not displaced by registration of title. Where the land register depicts a natural water boundary on the map, this is simply a snap shot in time, defining the boundary as at the date of registration. Where a title boundary is changed by alluvion, the effect in registration terms is to make the cadastral map inaccurate, as it wrongly depicts what the position is in law or fact, in terms of section 65. However, upon request to the Keeper, such an inaccuracy may be corrected by rectification.

Excluding a boundary

Section 66 of the 2012 Act permits registered proprietors of adjacent registered plots of land, separated by a natural water feature, to agree that their common boundary (or part of it) may be excluded from the effect of subsequent alluvial changes. The effect of such an agreement is to fix the line of the title boundary. Such agreements are only registrable in the land register.

In terms of registration, a consequence of an agreement under section 66 is that the cadastral map and title sheet do not become inaccurate as a result of alluvion affecting the fixed boundary.

The Keeper’s policy is that such agreements should be dual registered against both registered titles. A boundary agreement under section 66 cannot be dis-applied or discharged; any subsequent change to the boundary would require formal conveyancing.

The affected boundary will be annotated on the cadastral map. A note will be added to the title sheets of the affected plots of land to advise that a boundary agreement is in place, and as such said boundary will fall within the Keeper’s general warranty policy.