The tidal régime of the river Mersey, as affected by the recent dredgings at the bar in Liverpool Bay

Liverpool, the premier port of the world after our metropolis, with the annual total of in-and-out tonnage, in 1904, of 32 millions of tons, had suffered, in the approach thereto, up to about 15 years ago, from a sand-bar, situate at the outer or seaward entrance into Liverpool Bay, which afforded a depth of water over it, at low water of equinoctial springs, of only ten feet. When it is borne in mind that some of the large Atlantic liners have a draft of close upon 30 feet, it is easy to conceive the amount of inconvenience, chiefly by loss of time in enforced waiting outside the Bar, which this caused —a period of waiting, which affected more or less, according to their individual tonnage, all vessels visiting the port. Attempts were made as far back as 1838 by the then Marine Surveyor of the Port of Liverpool, Lieutenant (afterwards Admiral Sir) H. T. M. Denham, to diminish the height of the Bar, by first harrowing the sand and then removing the loosened material by means of bucket-dredgers. After some years, however, it was found advisable to abandon these operations, since the effect thereof upon the Bar was so slight that a single storm from the Irish Channel often more than counteracted any deepening at the Bar, which had been effected by months of dredging. It was not, however, till shortly before 1890, that the late Mr. G. F. Lyster, then Engineer to the Mersey Docks and Harbour Board, was able to resume the attempt to remove any material at the Bar, by calling to his aid the newly invented form of sand-pump dredger, which by means of exhaust suction displaced the material in a semi-liquid state with such rapidity as to cause very sensible progress to be made in the removal of the material.