NATIONAL FISHERY CONGRESS. 
267 
river and 40 miles below the dam, the average shad yield during the 20 years preceding 
the erection of the obstruction was 9,854 annually; during the 5 years following 1849 
the annual catch averaged 19,490; during the next 10 years it was but 8,364, and for 
the following 6 years, 1864-1870, the annual average was but 4,482 shad, less than 
one-half the former yield. The record of the total catch on the Connecticut from 1853 
to 1896 shows that the yield below the dam decreased from nearly half a million 
annually to an average of less than one-tenth of that number. In a few rivers the 
development of water-power has resulted in completely exterminating the anadromous 
fishes, this being the case in the Thames, the Blackstone, the Merrimac, the Saco, and 
other rivers. However, instead of the employment of a few hundred persons in 
taking fish each spring, the water-power on those streams affords employment to 
thousands of mill operatives. 
Numerous attempts have been made by the erection of fishways to enable shad 
to pass above these obstructions, among the costly contrivances being those in the 
Savannah at Augusta, the Santee at Columbia, the Potomac at Great Falls, the 
Susquehanna at Clarks Ferry, the Housatonic at Birmingham, the Connecticut at 
Holyoke, the Merrimac at Lawrence, and the Kennebec at Augusta. The fishway in 
the dam across the Santee at Columbia, built in 1883, consists of 3£ sections, 36 feet 
long, with a total rise of 9 feet, and is of the type known as the McDonald fishway, 
consisting of two sets of buckets, straight wooden buckets to receive the water in its 
downward flow and curved iron buckets to direct this water back upstream, thus 
affording a comparatively quiet waterway. It is fairly efficient for certain species 
when kept free from trash, but shad do not appear to use it. 
In 1882 an appropriation of $50,000 was made by Congress for the erection of suit- 
able fishways at Great Falls in the Potomac where the river descends almost abruptly 
35 or 40 feet. In 1885 the work of construction was begun, but it was soon abandoned, 
it being decided that “the fishways were not found sufficiently strong to withstand 
the effects of the violent floods of the locality in which they were placed.” 
The fishway over the Holyoke dam on the Connecticut River, one of the largest 
and most expensive in the country, was built in 1873 after the Brackett plan, a modifi- 
cation of the Foster fishway. It is 440 feet in length, so divided into compartments or 
bays, by means of T-shaped partitions extending at right angles to the sides, that the 
water winds through a long, circuitous course, running about 1,500 feet before it 
emerges at the lower end. As the height of the dam is 30 feet, the fall of the water 
averages about 1 foot in 50, with little momentum. But it does not appear that shad 
have ever passed through this fishway in any numbers. 
An account of the construction of fishways in the Columbia dam on the Susque- 
hanna River illustrates the difficulties of making these obstructions passable. This 
dam is only 7 or 8 feet high, and its disastrous effect on the shad fisheries of the 
Susquehanna has attracted very general attention to it. The original charter required 
that a rafting channel should be left in the obstruction. In 1865, in accordance with 
an act of the Pennsylvania legislature, the company removed a 40-foot section of the 
dam, and in that space built a new subdam, the top of which was about level with the 
water below. The lower slope of the subdam was placed at an inclination of 1 in 15, 
and the sides of the aperture in the main dam were dentated, so as to promote the 
formation of eddies in the current. This construction did not appear to answer its 
purposes, and in 1873 the State made an appropriation for another fishway at that 
point after plans modified from numerous designs submitted in competition. That also 
