| At | 3-foot stage, | by Water-Works mark, | the velocity was | .97 | miles per hour. |
| “ | 6 “ “ | “ “ “ “ | “ “ “ | 1.125 | “ “ “ |
| “ | 18 “ “ | “ “ “ “ | “ “ “ | 3.51 | “ “ “ |
| “ | 21 “ “ | “ “ “ “ | “ “ “ | 3.20 | “ “ “ |
| “ | 27 “ “ | “ “ “ “ | “ “ “ | 4.70 | “ “ “ |
| “ | 31 “ “ | “ “ “ “ | “ “ “ | 4.30 | “ “ “ |
| “ | 41 “ “ | “ “ “ “ | “ “ “ | 5.002 | “ “ “ |
The slope of water surface, from water-works to bridge, was .367 of a foot for low stage; for average stage, .403 of a foot; and .415 of a foot per mile for high stage. The approximate flow of water in cubic feet per second at the Southern Railway Bridge is 5,000 feet for minimum stage, 100,000 feet for mean stage, and 400,000 for maximum stage. The minimum flow of the Schuylkill is 378 cubic feet per second; the Delaware, 2,000 cubic feet; the Merrimack, 2,100 cubic feet; and the Thames River, 700 cubic feet.
Investigations of the influence on our climate, by the removal of the forests, develop the fact that streams, utilized for water-power, have become less constant in their flow than formerly. The Ohio River has of late years exhibited greater fluctuations of levels than ever known, and has lost its prestige as a reliable channel of navigation. Prof. Newburg, in Vol. I of the Geological Survey of Ohio, records an instant where a large rock, at Smith’s Ferry, has recently become so fully exposed that on its surface inscriptions were found, that are ascribed to a race which once populated this country anterior to the nomadic Indians.
There are about 78 villages and towns and 13 cities on the Ohio River between Cincinnati and Pittsburgh, a distance of 460 miles. The population on this portion of the river, and its contributing streams, is over 3½ millions. The average population, per square mile of drainage area, on the Ohio River is 47; above Cincinnati, 35; on the Great Miami, 109; on the Delaware, 176; on the Hudson, 172; on the Merrimack, 92½; on the Susquehanna, 62; on the Connecticut, 78; on the Potomac, 54; on the Schuylkill, 45; on the Thames, above water-works, 300.
Considerable space has been devoted to River Pollution, to which attention is directed. The following remarks, however, afford comparative results for the Ohio River.
The comparative merits of river waters, as expressed in analytic results of pounds of sewage in each million gallons, are, for the Ohio water at Dayton sand-beach, .82; at Markley Farm, 1.00; at the pumping works, 1.81; at Eden reservoir, 1.78; at Eggleston Avenue sewer, 4.41; the Croton water, New York, .98; Glasgow, Scotland, water, .65; Thames River, 4.91; London supply, 1.33; Fresh pond, Cambridge, Massachusetts, 1.50; Mystic River, Boston, 1.87; Schuylkill River, Philadelphia, 1.58; Merrimack, above Lowell, .93; above Lawrence, .90; below Lawrence, 1.03.
The Thames and Lea Rivers have been condemned by the Rivers Pollution Commission because, as they say, there is no hope of remedying their disgusting condition, notwithstanding the parliamentary laws for their protection against pollution.
The Schuylkill River is the principal source of supply for Philadelphia, but its water is very suspicious. Above Reading, it is unfit for manufacturing and culinary purposes, owing to the large amount of sulphuric acid. This acid is, however, neutralized and considerably reduced before the water reaches Philadelphia. The Fairmount pool is polluted by cess-pool and slaughter-house drainage. The following means to restore and maintain the purity of the Schuylkill water has been suggested by Dr. Cresson:
1. The diversion of all sewage, now flowing into the pool of Fairmount dam, into another channel.
2. The diversion of all sewage, containing fœcal and animal matter, flowing into the river below Flat Rock.