Minutes of Proceedings of the Institution of Civil Engineers Volume 67, PT. 1 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1882 edition. Excerpt: ... a bridge, and not only obstructed the waterway itself, but formed a nucleus for other rubbish, so that the channel had become almost entirely blocked up. At several mills, the millers were unwilling to open the sluice-gates to their full extent in flood time, for fear of reducing too much the head of water for driving their mills, owing to the rising of the tail water below, so that water was retained on the lands that might have easily been discharged. It was sufficiently evident from these facts how entirely the river channels were neglected, and how a moderate amount of inspection, care, and control would suffice to ensure a more rapid discharge of the flood-waters in the upper parts of rivers. He, however, quite agreed with Mr. Wheeler in thinking that the whole river should be dealt with; otherwise, relief of the upper parts would entail Mr-Vernongreater floods in the lower portions, and for this reason all works of improvement should be commenced at the lower end. These works would entail the reconstruction of all weirs on navigable rivers; and he was of opinion that, as stated in his Paper on "Fixed and Movable Weirs,"1 the introduction of movable weirs would be of the greatest benefit for the control of floods. Those weirs would enable a river to be held up at any desired height in dry weather, for navigation or irrigation, and would leave the channel entirely unimpeded in flood time. It had been pointed out by Mr. Jacob that the inclination of the Eiver Irwell decreased towards its mouth. This was the case with all rivers; but the rate of the change of slope varied considerably, depending upon the inclination of the surface of their valleys. Thus rivers like the Thames and the Seine had a small fall throughout; whilst...