THE 1MI>ROV1:MJ-;.\1 OF RIVERS. 



CURTAIN DAMS. 



General. The Came>6 curtain is the invention of the French engineer M. Ca- 

 mertf. It consists of narrow horizontal strips of wood, hinged together, and capable 

 of being rolled up by a chain, which passes round them, each curtain reaching from 

 the surface of the water to the sill. (See illustration on page 243.) 



This type is in use at Suresnes, Villez, Poses, and other important dams in France, 

 where it has given excellent satisfaction. 



Maneuvers. -The curtains are supjxnted by trestles, of design similar to those for 

 Bould gates, and similarly raised and lowered, or by frames suspended from an over- 

 head bridge and resting against shoes. When the dam is to be closed the curtains, 

 each of which is attached to a frame, are brought out on a truck, and set in place 

 between the trestles by a special winch and unrolled by releasing the chain. The pool 

 is regulated by rolling them up from the bottom as much as may be desired. Wlien 

 the dam is to be opened they are rolled up entirely, and the frames with the curtains 

 attached arc lifted off and placed on the truck, and taken to the storehouse. 



Remarks. The Cam6r6 curtain possesses an advantage over the Boulc gate in 



that it does away with the 

 sliding friction of the latter, 

 and hence can be used for 

 higher lifts, that of the Poses 

 dam being 13.7 feet, with 16.4 

 feet of water on the sill of the 

 deepest pass. On the other 

 hand, the curtain is more ex- 

 pensive than the gate, and 

 more liable to get out of order, 

 owing to its more complicated 



METHOD OP HANDLING CURTAINS WITH A SERVICE TRUCK AND CRAB. 



parts. It permits, however, 



of a very exact and easy regulation of the pool. 



The Suresnes Dam. The Suresnes dam, located just below Paris, was built by 

 M.- Boulc in 1885. It is one of the largest as well as one of the most recent works on the 

 Seine, and one of the best examples of movable dams in the world. It is composed of 

 alternate bays of Boul6 gates and Camerd curtains. The trestles of the pass arc i<)J 

 feet high, and the gates 17 feet in total height and 4.1 feet wide, supporting a head 

 of 10.6 feet. The dam is divided into three parts by two islands. The navigable pass 

 is 238 feet wide, and is located in the left arm of the river, while in the right arm there 

 is an elevated pass 206 feet wide. Between the two islands there is a weir 206 feet wide. 

 The sills of these three passes are 17.9, 16.25, an d I2 - J 3 feet, respectively, below the 

 level of the upper pool. 



The gates and curtains are supported by Pojrec trestles 19.5, 17.9, and 13.44 feet 



