[7] A NEW SYSTEM OF FISHWAY-BUILDING. 49 



panded so as to take the entire discharge of a river. Constructed 

 roughly of boards it furnishes at a nominal cost the means of re-estab- 

 lishing in our innumerable trout streams the natnral conditions of re- 

 production. These fish ways maybe made so light as to be readily jiort- 

 able, so that, in the season when the fish are not running, they may be 

 stored away under shelter and thus protected from decay or destruc- 

 tion by ice or floods. In public parks and trout preserves, where con- 

 siderations of cost are not controlling, the fish way may be built of iron 

 in ornamental designs, and while serving its essential purpose, made to 

 contribute to the picturesqueness of the landscape. S-olidly built of 

 stone and iron, and of dimensions proportioned to the volume of the 

 stream, it may be made strong enough to resist the utmost force of 

 floods and ice, and by furnishing an easy passage for shad, salmon, and 

 other anadromous species of fish, make possible the restoration and 

 maintenance of our valuable river fisheries, in spite of the obstructions 

 which are the inevitable and necessary adjuncts of civilization, 



6. Mode of construction. 



As an example of construction we have given in Fig. 6a the elevation, 

 and in Fig. 6b the plan of a double fishway built of timbers. It consists 

 of an inclined sluiceway of boards, the sides and bottom of which are 

 supported by suitable framing. The sluice has in this case an inclina- 

 tion of 1 foot in 3. The upper end is let into the dam so that its upper 

 line is flush with the crest line of the dam. The lower end descends to 

 the water below the dam and is firmly anchored by being secured by 

 bolts either to the rocky bed of the stream or to piles suitably placed, 

 or by other suitable means. Intermediate supports may be provided 

 by trestling, as shown in the figure, by log cribs or by rubble masonry. 

 The inclined flume or sluice thus established furnishes the foundation 

 for the structure of the fishway proper, which is placed within it. De- 

 tails of construction are given in Figs. 7, 8, and 9, which are on a 

 scale one quarter inch to the foot. 



The substructure having been established, we begin by setting up 

 along the center line of the trough or sluice the bulkheads i i i, &(i., 

 at intervals of 12 or 15 inches. These are made of planks 1^ inches 

 thick, 2 feet long, and 15 inches wide, which are firmly attached to the 

 flooring of the sluice either by spikes or bolts. Posts h h, &c., of 

 1^ inch stuff, 9 to 12 inches wide, and extending from the floor to the 

 upper edge of the inclined trough, are now set up at similar intervals 

 of 12 to 15 inches and firmly secured to the sides and bottom of the 

 trough. To the posts h h, and bulkheads i i, the fifteen-inch joists 

 are securely nailed or bolted. The floor d (Fig. 8), of 1^-inch plank, is 

 next laid and nailed to the inclined joists, as shown in Figs. 7 and 

 8. Upon the floor d next set up the short return buckets, in m, &c. 

 (Figs. 8 and 9), securing the same to the parts h h and to the floor 

 by nailing or other suitable means. The cap e e (Fig. 8), made of a 

 S. Mis. 40 4 



