No. 3.
WATER-SHED.
The courses of our streams show at a glance that a water-shed crosses the State from north-east to south-west. This water-shed forms a range of highlands that slope by long and easy descent to the Ohio in the south, more rapidly to the lake in the north. This water-shed in its relief is almost insignificant, its average altitude being only 500 feet above the lake, its highest point rising perhaps 1,000 feet above the bottom valley of the Ohio. Our topographical features may therefore be described of a plain, slightly raised along a line traversing it from north-east to south-west.
The following altitudes will show the topography of the northern divide. The levels are all above Lake Erie:
| SURVEY OF DAYTON AND MICHIGAN R.R. | MIAMI CANAL. | ||
| FEET. | FEET. | ||
| Cincinnati—below lake, | 67 | Junction, Paulding County, | 147.25 |
| Lock 27. | 182.25 | ||
| Hamilton, | 29 | Delphos, Lock 23. Allen County, | 211. |
| Dayton, | 180 | ||
| Dayton Canal, | 166 | Spencerville, Lock 15. Allen County, | 274. |
| Troy, | 270 | ||
| Piqua, | 360 | Lock 13. St. Marys, Auglaize County, | 291.25 |
| Sidney, | 428 | Lock 10.“ “ | 313. |
| Principal Summit, | 430 | Lock 9. “ “ | 319. |
| Wapakoneta, | 318 | Lock 4. “ “ | 361. |
| Lima, | 302 | Lock 3. “ “ | 367.50 |
| Cairo, | 241 | Lock 1. Bremen Summit, Auglaize Co., | 386.30 |
| Weston, | 103 | Near Sidney, | 376.00 |
| — | Troy, | 257.00 | |
| Perrysburgh, | 64 | D. & M. R.R. crossing Dayton, | 166.00 |
| Toledo, | 12 | Basin at Hamilton, | 37.00 |
| — | Upper level of canal at Cincinnati, | 23.00 | |
| — | Low water in Ohio River, below lake, | 133. | |
The actual crest of the divide forms a singularly tortuous line with remarkable variations of altitude. The water-sheds, with which we are particularly interested, are found in the counties of Shelby, Mercer, and Auglaize, where we have the water-gap of the head-waters of the St. Marys and Auglaize, as feeders of the Maumee River with the Wabash and Big Beaver Rivers on one side, and the Great Miami on this side; with another gap, between the Miami and Mad Rivers, and the Scioto River, found in Logan and Hardin Counties, in which the highest points of the State are found viz., 1,000 feet above low water in the Ohio River. These streams descend very rapidly to the level plateau (500 feet above the Ohio River) passing over lime and magnesia rocks, through swampy lands and “cat-head prairies,” the latter composed largely of vegetable accumulations. The population, through which the Great Miami and Mad rivers flow, is approximately 360,000.
The available resources of the Big Beaver, Wabash, and St. Mary’s water-sheds are collected in St. Mary’s Reservoir, a lake of 47,000 acres, for feeding the Miami Canal north; while Lake Laramie in Shelby County, and Lewistown Reservoir in Logan County gather the waters of the Miami, and being at the summit level, feed the canal both north and south. This level is 519 feet above low water in Ohio River, St. Mary’s 424 feet, Eden Park Reservoir at Cincinnati 235 feet, and Third Street Reservoir 173 feet. The distance in air line from Cincinnati to St. Mary’s is about 95 miles, to Lewistown over 100 miles.
The waters of all the streams named present those features that experience considers most objectionable for a gravity supply, namely:
“1st. In the calcareous nature of the soil, producing hardness of water.
“2d. In the low and level plateau of water-sheds from which a minimum surface flow can be realized, requiring storage reservoirs of large surface area, that are objectionable, because; 1. The loss of water by evaporation: and 2. The liability to stagnation of water and propagation of vegetation.
“3d. The streams are fed by the drainage from richly manured farms, and the water polluted by vegetation of the swampy lands, and the sewage of a large and growing population. This condition is intensified, when we consider the proportional size of the streams to the amount of pollution, and the fact that the most perfect means of filtration would not suffice to make the water wholesome.