Scottish Court of Session Decisions

In this case the following interlocutor was pronounced;—“Find that the boundary between the property belonging to the pursuer and that belonging to the defenders, so far as the said properties consist of shore-ground between high-water mark as now existing and low-water mark, has never been fixed or ascertained in anyway; find that the said boundary-line must be now settled and fixed, upon the principle of ascertaining the average line of the centre of the river Clyde at low water opposite the said properties, and dropping a perpendicular from the said average line on the land boundary between the said properties at high-water mark as that existed before any part of the shore-ground was embanked or gained from the sea by either party; therefore remit to Professor Macquorn Rankine, of the University of Glasgow, to lay down on a copy of the Ordnance Survey map a straight line representing the average direction of the middle line of the river Clyde at low water, commencing at that part of the river which is opposite the point of the hill of Ardmore on the north, and Cappielow on the south, and extending thence eastward for two and a-half miles, and from the said straight line to lay down a perpendicular at right angles to the said straight line, falling upon the point representing the original land boundary between the said properties, being the point represented by the letter E on the plan No. 13 of process.”

Professor Rankine having laid down a line as in accordance with this remit, it was objected for the pursuer that the reporter had not taken the average direction of the middle line of the river, as between the low-water line on the south and the low-water line on the north side of the river respectively, but had disregarded the low-water line of the north shore.

The Court accordingly, after hearing parties, made a second remit to Professor Rankine, to make

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any additional report he might think desirable, in regard to the objection.

Professor Rankine accordingly made a second report, in which he stated that in considering, the state of the Clyde at low water it was necessary to distinguish between the boundaries of the main stream and the boundaries of the whole expanse of water in the estuary. At low water the main stream is bounded on the south by the low-water mark. On the north it is bounded by a chain of sandbanks, beyond which at low water lies a body of water forming no part of the main stream, and receiving at low water no part of the waters of the Clyde.

The question arose whether the true medium filum was to be taken as the middle line of the main stream, or as the middle line of the whole expanse of water covered at low tide.

The Court were of opinion that, looking to the character of the Clyde at Port Glasgow, which was that of a river in its estuary, and also looking to the nature of the question—the division of a piece of shore ground, valuable just because it adjoined a navigable river—the true medium filum was the centre of the whole expanse covered by water at low tide.