Size of South Fork Dam and Lake Conemaugh at time of Johnstown Flood of 1889
oougnc , Size and Location. The property consists of between 600 and 700 .acres, and is located about nine miles above Johnstown. " The. great dam was built ia form a reservoir for the old Pennsylvania canal. The dam has a base of 300 feet in thickness at the bottom, gradually narrowing narrowing to a width of about 0 feet at the top, and is 75 feet high, and from 800 to 1,000 feet long. The main portion was formed of the heaviest and most solid stone masonry. The lake formed by the reservoir is actually about 2)4 miles long, but is generally called three miles, and has an irregular width, varying from one-half to three-quarters of a mile. The greatest depth of water is 90 feet, and over a considerable portion the-average depth is CO feet.