314 Revieivs—T. W. Barber— The Thames Barrage. 

 E, E "V I E "W S. 



I. — The Port of Lonbon and the Thames Barrage, a series of expert 

 studies and reports, by T. W. Barber, M.Inst. C.E., and others. 

 Issued by the Thames Barrage Committee. 8vo ; pp. 193, with 

 maps and other illustrations. London : Swan Sonnenschein & Co., 

 1907. Price 12s. M. net. 



ONE of the difficulties which hampers the Port of London is the 

 insufficient depth of water in the river for the increasing size and 

 tonnage of ships, and the deepening of the river by dredging has been 

 recommended as a remedy. Another and effective plan, if it could be 

 carried out, is the one discussed in the very interesting work before us. 

 As stated in the Introduction, " The Committee formed in 1903 to 

 promote a public enquiry into the proposed Barrage across the Thames 

 in the neighbourhood of Gravesend — thus converting the whole of the 

 lower river into a freshwater lake — having so far failed to attain its 

 main object, has instituted a series of expert enquiries and studies into 

 the various (Questions which have arisen and are involved in the 

 Barrage proposal." 



The chief purpose of the volume is to deal with the objections that 

 have been raised to the above scheme; and the most important are the 

 questions of drainage and percolation. 



The proposed barrage or dam would be made between Gravesend 

 and Tilbury, and consist " of a straight monolith wall of Portland 

 cement concrete, faced with granite, founded on the Chalk and carried 

 up to six feet above the highest known tide." Further, the upper 

 surface of roadway and foot-pavements would be 100 feet wide, 

 flanked with granite parapets, and the base or foundation width would 

 be 175 feet, with tunnels for road and rail traffic. 



The proposed level at which the Thames would be maintained is 

 Trinity High AVater or 12 ft. 6 in. above Ordnance Datum. The area 

 ■Upheld would be between Gravesend and Teddington, a distance of 

 46A^ miles. 



The main factor of geological import, and the most serious one for 

 the inhabitants along the valley bordering this long portion of the 

 river, is the infiltration and uprise of water that would take place in 

 the adjacent porous strata. 



This subject is dealt with in an able and candid manner by 

 Mr. Clayton Beadle, who points out that large volumes of water would 

 pass in from the river at different points, into the Chalk and Gravels, 

 and, in. addition, much flood- water from direct rainfall on the marsh 

 lands would have to be dealt with. In another report Mr. T. Hennell 

 estimates that more than one and a quarter million pounds would be 

 required for pumping Avorks and walls, and £33,000 per annum for 

 the maintenance and working of pumps. 



