No. CCCI.
JAMNA RIVER SUSPENSION BRIDGE, CHAKRATA ROAD.
[Vide Plates I.-III.]
The papers regarding the design, execution and testing of the above noteil bridge have been sent for the Papers by the Inspector General, Military Works, at the kind suggestion of Sir Andrew Clarke. They are somewhat voluminous, but the following selections from the case will it is hoped prove interesting. No attempt to show detail has been maile, only to give a general idea of the work.
The estimate for the bridge was made out by Major Brownė, R.E., and submitted for sanction by Colonel A. Taylor, C.B., R.E., in Decem- ber 1873, with the following Note.
Note by Colonel A. Taylor, C.B., R.E., Chief Engineer, Military Works, on the design for a suspension bridge over the Jamna River near Kalsie on the Saharanpur and Chakrata Road.
The cart-road from Saharanpur to Chakrata crosses the Jamna in the 51st mile.
Area of catchment basin.—At this point the area of the catchment basin is 895 square miles (Surveyor General's letter No. 948 of 10th June 1872).
The bed of the river is composed of boulders, some of which are of very large size, measuring upwards of 200 cubic feet, and has a longi- tudinal slope at the rate of 35.9 feet per mile.
Surface velocity in floods.--The greatest actually measured surface velocity, of which we have information, is 15 feet per second, but it may be accepted that it occasionally is more than this.
Rise in floods.—The flood level shown is about 11 feet above the
highest of which we have reliable knowledge, but the discharge when
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