LONDON'S WATER TUBE.

Evening Star, Issue 11725, 7 April 1902, Page 3

LONDON'S WATER TUBE.

The population of " Water London" is upwards of six millions, of whom abonfc a million and a-balf live outside the strictly metropolitan area. The consumption of water bv them amounts in round figures to 200,000,'000gal per day. But London, especially Outer liOndon, is rapidly growing, and there is every probability that in another thirty years no less than twelve million people will look for their modest 35 to 40gal per day. The Thames is an accommodating river, with an average daiiv flow of over 1,000,000,000ga1. but can i't be safely expected to yield, during a prolonged drouglit, more than double its present quantity, and still leave plenty for the penny steamboats and the newly-intro-duced salmon? Hie water companies say " Yes," and thaL if necessarv. no less than 400.000.000 gal of water fit "for use can be obtained daily from the Thames without reducing the fiow at Tecklington Weir below the neeessarv 200,000.000, and another 225,000,000 gal from the Lea and other sources. It is simply, in fact, a question of storage, of taking water in times of plenty and reserving it for times of drought. They are, accordingly, constructing enormous reservoirs near Staines and elsewhere, from which an additional 35,000,000 gallons daily may be drawn, or, in times of emergency, 45,000,000ga15. The Staines reservoirs will be capable of holding 3.500,000,000,000ga15. The London County Council, on the other hand, contend that not more than 300,500,0Q0gal can be safely drawn from the Thames and Lea Valleys, and that though the present supply is sufficient, at least 447,000,000 gal a day will be required by 1931. Consequently, the deficiency must be made up from some other source, and there is no adequate watershed available nearer than Central Wales. Sir Alexander Binnie's scheme propose* to bring, by the simple action af gravitation, an additiouaj 200,000,000 gal a day all the way from Wales to London. This will ensure a total supply of 500,000,000 gal a day, but if at some distant date even this enormous quantity should prove insufficient, the scheme provides for a second line of aqueduct to bring yet another 200,000,000 gallons. The project involves the formation of a reservoir in three districts. The great Yrfon Reservoir Avould form a magnificent lake of some 3,000 acres, as nearly as jmssible the size of Windermere. The total capacity of this lake would be about 39,000,000,000ga1, the capacity available 35,750,000,000 gat. The top-water level would be 610 ft above the sea. It would be formed by damming up the Yrfon River on the eastward side with a great dam 166 ft in height. The reservoir on the Upper Wye would be about 900 acres, and the Towy Reservoir of smaller size. Both would be connected by tunnels with the great Yrfon Reservoir," which they would help to feed. The gigantic conduit would extend from Llangorse Lake, in Radnorshire, right across the counties of Hereford, Gloucester, Oxford, Bucks, and Hertford, to the Klstree Hills, twelve miles north-west of Charing Cross, where it would discharge into an enormous reservoir, 300 ft above sea level, capable of holding 3,200,000,000ga1, or sixteen days' supply. The aqueduct would be 150 miles in length, and would bo formed of masonry and concrete, except at valley crossings, where parallel iron and steel pipes would bi used. The masonry portions would be about 16ft in width, and the water would flow to a depth of about lift. Thus the conduit would bo practically an underground " Tube," conveying water instead of people. And just as," in the construction of electric railways, full advantage is taken of inclines to lessen the amount of propulsive force required, so the couduit would have a gentle fall the whole distance in order that the water might run by simple gravitation, pumping, needless to say, bein" a verv expensive performance. The wateished "consists of 312,400 acres, or 488 square miles, in the heart of W T ales. Over this area the rainfall is at least twice as heavy as in the Thames Valley, and it is estimated that 415,000,000gai a day can be drawn, after making every allowance for dry sasons and evaporation, without dep'ctinf the local rivers. The cost is put at £17,500,000, bnt the London water companies contend that is far too low. Should the second aqueduct (which it is proposed should serve the south of London from a reservoir at Banstead) be required, the cost would be more than doubled. The work would take from ten to fifteen years to complete.—H. Goldinff in the 'Windsor.'