26o
��The Ohio Floods.
��[April,
��In contrast, it may be noted that the St. Lawrence River but slightly varies its flow, above Montreal, because of the restraining power of the Great Lakes, its feeders. The upper Missis- sippi rises not to excess because of the thousands of lakes and lakelets in Wisconsin, Minnesota, and Dakota, its sources. The floods occur in its south- ern portion, chiefly below St. Louis. But for this reservoir system its naviga- tion in the upper portion would be seriously impeded in summer seasons.
Disastrous floods can scarcely occur on the St. John's, St. Croix, Penobscot, Kennebec, Androscoggin, Saco, Piscata- qua, Merrimack, Connecticut, or Hud- son Rivers, except from damming of the ice in winter or springtime (and that cause is of rare occurrence), such is the elaborate system of reservoirs about the headwaters of these streams. This northern country is greatly bene- fited by these excavations occurring from geological causes.
The Merrimack River has a water- shed of about four thousand square mfles — one fiftieth part of that of the Ohio. It has the Winnipiseogee, Squam, and Newfound Lakes, and hun- dreds of ponds to fill, that store a large amount of water, before any consider- able rise can take place in the river, and then they restrain the flow. No excess of water comes through the Winnipiseogee River, though it is the outlet of a water-shed nearly as great as of the Pemigewasset. The freshets of the Merrimack come chiefly from the last-named stream and minor tribu- taries. Without these reservoirs, the manufacturing establishments at Law- rence, Lowell, and Manchester, would cease to be operated by water-power during the summer droughts. The highest flow of water in the Merrimack
��known in forty-six years, as measured at the Lowell dam, was thirteen and seven-twelfths feet. This occurred in 1852, Only a few times have freshets exceeded ten feet rise over that dam.
The greatest fall of water and rise of the freshet, in this valley, known at Concord, New Hampshire, occurred in August, 1826. This storm notably caused the land-slide in the Saco valley, which buried the Willey family. The next was in early October, 1869, which caused the slide of seventy-five acres of land on the western side of Tri- Pyramid Mountain into Mad River, in Waterville.
Messrs. Rand, McNally, and Company, of Chicago, in their Atlas of the World, give data to illustrate the two river sys- tems of the country spoken of. Names of sixty-seven lakes are given in Maine, and beside these are ponds almost in- numerable. By census statistics given, her reservoir and land areas are as i to 13. New Hampshire is accredited with three hundred and sixty-two lakes and ponds, being as i acre to 41 of land. Vermont has forty-one lakes and ponds, including Lake Champlain, being as i acre to 24 of land. Massa- chusetts, forty-seven lakes and ponds ; Rhode Island, forty-seven ; Connecti- cut, eighteen ; New York, two hundred and sixty, beside her great lakes ; New Jersey, ten ; Pennsylvania (chiefly north- eastern portion), fifty-eight; Michigan, ninety-eight lakes, and ponds in great number ; Wisconsin, seventy-two lakes, and a large number of ponds; Minne- sota, one hundred and forty-two lakes, and ponds innumerable ; Dakota, fif- teen lakes, and a great number of ponds ; and Iowa, forty-eight lakes.
In contrast, Virginia has only Lake Drummond — really a part of the Dis- mal Swamp ; West Virginia, Ohio,
�� �
