Vermilion County, Illinois - Chapter 4: Rainfall, 1879

An interesting topic connected with our rivers is the question of rainfall. The streams of the west, unlike those of mountainous districts, which are fed largely by springs and brooks issuing from the rocks, are supplied mostly from the clouds. It is within the observation of persons who lived long in the valleys of the Wabash and Illinois, or along their tributaries, that these streams apparently carry a less volume of water than formerly. Indeed, the water-courses seem to be gradually drying up, and the whole surface of the country drained by them has undergone the same change. In early days almost every land-owner on the prairies had upon his farm a pond that furnished an unfailing supply of water for his live stock the year around. These never went dry, even in the driest seasons.

Formerly the Wabash afforded reliable steamboat navigation as high up as La Fayette. In 1831, between the 5th of March and the 16th of April, fifty-four steamboats arrived and departed from Vincennes. In the months of February, March and April of the same year, there were sixty arrivals and departures from La Fayette, then a village of only three or four hundred houses ; many of these boats were large side-wheel steamers, built for navigating the Ohio and Mississippi, and known as New Orleans or lower river boats.* The writer has the concurrent evidence of scores of early settlers with whom he has conversed that formerly the Vermilion, at Danville, had to be ferried on an average six months during the year, and the river was considered low when it could be forded at this place without water running into the wagon bed. Now it is fordable at all times, except when swollen with freshets, which now subside in a very few days, and often within as many hours. Doubtless, the same tacts can be affirmed of the many other tributaries of the Illinois and Wabash whose names have been already given.

The early statutes of Illinois and Indiana are replete with special laws, passed between the years 1825 and 1840, when the people of these two states were crazed over the question of internal navigation, providing enactments and charters for the slack-water improvement of hundreds of streams whose insignificance have now only a dry bed, most of the year, to indicate that they were ever dignified with such legislation and invested with the promise of bearing upon their bosoms a portion of the future internal commerce of the country.

It will not do to assume that the seeming decrease of water in the streams is caused by a diminution of rain. The probabilities are that the annual rainfall is greater in Indiana and Illinois than before their settlement with a permanent population. The "settling up" of a country, tilling its soil, planting trees, constructing railroads, and erecting telegraph lines, all tend to induce moisture and produce changes in the electric and atmospheric currents that invite the clouds to precipitate their showers. Such has been the effect produced by the hand of man upon the hitherto arid plains of Kansas and Nebraska. Indeed, at an early day some portions of Illinois were considered as uninhabitable as western Kansas and Nebraska were supposed, a few years ago, to be on account of the prevailing drouths. That part of the state lying between the Illinois and Mississippi Rivers, south of a line running from the Mississippi, between Rock Island and Mercer counties, east to the Illinois, set off for the benefit of the soldiers of the War of 1812, and for that reason called the "Military Tract," except that part of it lying more immediately near the rivers named, was laid under the bane of a drouth-stricken region. Mr. Lewis A. Beck, a shrewd and impartial observer, and a gentleman of great scientific attainments,* was through the " military tract " shortly after it had been run out into sections and townships by the government, and says concerning it, " The northern part of the tract is not so favorable for settlement. The prairies become very extensive and are badly watered. In fact, this last is an objection to the whole tract. In dry seasons it is not unusual to walk through beds of the largest streams without finding a drop of water. It is not surprising that a country so far distant from the sea and drained by such large rivers, which have a course of several thousand miles before they reach the great reservoir, should not be well watered. This, we observe, is the case with all tine-flowing streams of the highlands, whereas those of the Champaign and prairies settle in the form of ponds, which stagnate and putrify. Besides, on the same account there are very few heavy rains in the summer ; and hence during that season water is exceedingly scarce. The Indians, in their journeys, pass by places where they know there are ponds, but generally they are under the necessity of carrying water in bladders. This drouth is not confined to the ' military tract,' but in some seasons is very general. During the summer of 1820 it was truly alarming; travelers, in many instances, were obliged to pass whole days, in the warmest weather, without being able to procure a cupful of water for themselves or their horses, and that which they occasionally did find was almost putrid. It may be remarked, however, that such seasons rarely occur ; but on account of its being washed by rivers of such immense length this section of the country is peculiarly liable to suffer from excessive drouth." The millions of bushels of grain annually raised in, and the vast herds of cattle and other live stock that are fattened on, the rich pastures of Bureau, Henry, Stark, Peoria, Knox, Warren, and other counties lying wholly or partially within the "'military tract," illustrate an increase and uniformity of rainfall since the time Professor Beck recorded his observations. In no part of Illinois are the crops more abundant and certain, and less liable to suffer from excessive drouth, than in the " military tract." The apparent decrease in the volume of water carried by the Wabash and its tributaries is easily reconciled with the theorv of an increased rainfall since the settlement of the country. These streams for the most part have their sources in ponds, marshes and low grounds. These basins, covering a great extent of the surface of the country, served as reservoirs ; the earth was covered with a thick turf that prevented the water penetrating the ground ; tall grasses in the valleys and about the margin of the ponds impeded the flow of water, and fed it out gradually to the rivers. In the timber the marshes were likewise protected from a rapid discharge of their contents by the trunks of fallen trees, limbs and leaves.

Since the lands have been reduced to cultivation, millions of acres of sod have been broken by the plow, a spongy surface has been turned to the heavens and much of the rainfall is at once soaked into the ground. The ponds and low grounds have been drained. The tall grasses with their mat of penetrating roots have disappeared from the swales. The brooks and drains, from causes partially natural, or artificially aided by man, have cut through the ancient turf and made well defined ditches. The rivers themselves have worn a deeper passage in their beds. By these means the water is now soon collected from the earth's surface and carried off with increased velocity. Formerly the streams would sustain their volume continuously for weeks. Hence much of the rainfall is directly taken into the ground, and only a portion of it now finds its way to the rivers, and that which does has a speedier exit. Besides this, settlement of and particularly the growing of trees on the prairies and the clearing out of the excess of forests in the timbered districts, tends to distribute the rainfall more evenly throughout the year, and in a large degree prevents the recurrence of those extremes of drouth and flood with which this country was formerly visited.