Damming the Thames.

Taranaki Daily News, Volume XLVI, Issue 140, 17 June 1904, Page 4

Damming the Thames.

FKOFOSAL TO CONSTRUCT A

BARRAGE. For sonic time past considerable dissatisfaction has existed in those shipping oirclca whose traffic is concerned with the Vort of London, because of the insntliciont depth of water in the river. Owing to the increasing size and tonnage of steam- I ships it is often necessary to await a favourable tide at Gravescnd.which delays are detrimental to the commercial interests of the port of London. Then again the navigation channel up the river is so narrow and so crowded that traffic is seriously impeded. Many plans have been advocated for the surmounting of these dbbtacles, says the Scientific American. One of the most ambitious of these is to emulate the engineering achievements on the River Nile in the Aswan and Asyut barrages, by the construction of a great dam 'across the river between Tilbury and Gravcsend, and convert the 46 miles of the river between Teddington Lock and Gravcsend into one huge basin or lock.

Pho projectors of this scheme, of which complete plans and specifications have been prepared, contend that as the river level can be regulated by the erection of such a barrage -as this,, it will be possible to objtain a navigable depth of water varying from 65ft at Gravcsend to !12ft at London Bridge, without dredging, together with a fairway to allow ships drawing 30ft. of water to proceed to London Bridge at any time, irrespective of the tide. The barrage would be constructed on the same lines as those at Aswan and Asyut on the River Nile. It would be built of mass concrete, faced with granite on all exposed faces. The foundations of the barrage would be in the underlying chalk, and they would bo built by means of large cofferdams, inclosing an area sufficient for tho walls and locks. The latter, when completed, would fc« opened for the up and down traffic of the river, while the construction of the weirs and sluices was proceeded with. Tie sluices would bo left open for the free passage of the tides until the closing of the barrage, which would take place at high water of a spring tide. The locks would be worked electrically from a power house built upon the central pier of tho locks, the necessary electric energy for which would be generated by dynamos operated by the fall of part of the water flowing over the dam. The river traffic would bo signalled and regulated' from a pilot house, from which all the locks, movalbJej bridges, etc., would be controlled. Four locks are proposed, each provided with internal gates in addition to the outer ones, in order that they may be worked in long or short lengths to suit the traffic. The lengths provided in this way would fbe 300 ft., 500 ft., 700 ft., and 1000 ft, and the widths 80ft. and ]ooft. It is not likely that these dimensions will ever be exceeded by steamships. There would bo a roadway across the barrage, for pedestrian and vehicular traffic.

A tunnel 28ft. wide by 25ft. in height is a'so proposed in- the base of the barrage to afford a means of communication between the trunk railroads on either side of the river. The cost of this project is estimated at 18.290,000 dollars, and it is proposed to meet this expenditure by levying a toll of lj cents per ion upon all vessels passing up and down the river.