PART III EFFECT OF DIVERSION GREAT LAKES It had long been denied by the sanitary district that the diversion of Lake Michigan water through the drainage canal to the Illinois Valley had any appreciable effect upon the levels of the Great Lakes. Of recent years their attitude has changed so that they accept the principle that the levels are materially lowered, the only point of disagreement remaining as far as this is concerned being the degree of damage inflicted upon navigation and power interests as a result of this lowering. In the suit for injunction on the part of the United States to restrain the sanitary district from diverting more than 4,167 cubic feet per second it was proven to the satisfaction of the court that there was an actual lowering of the levels of the lakes. Accordingly it is not considered necessary to prove the fact of lowering or go into any details concerning it except in a descriptive way. The effect of the Chicago diversion upon the lake levels has been investigated a number of times by officers of the Corps of Engineers, the most recent investigation being that of Col. J. G. Warren, in compliance with Resolution No. 8, Sixty-fifth Congress. A brief quotation from pages 372 and 373 of that report will serve to illustrate fully the principal effect of this diversion. Diversions of waters from Lake Michigan into the Mississippi Valley result in a lowering of all water levels of the Great Lakes from the lower sill of the locks at Sault Ste. Marie down to tidewater in the St. Lawrence River. The amount of lowering on each lake as derived from discharge formula adopted by the Lake Survey office is shown in Table No. 46 for various amounts of diversions up to 14,000 cubic feet per second. The effect on the lower sills of locks at Sault Ste. Marie and in the lower St. Mary's River is practically the same as for Lakes Michigan and Huron. The lowering at points along the St. Clair and the Detroit Rivers is somewhat less than for either Lake Huron or Lake Erie. Effects in the upper Niagara River decrease from Lake Erie to the Falls, amounting at Niagara Falls to about 60 per cent of the Lake Erie effect. In the St. Lawrence River the lowering effect varies considerably on account of the variety of cross sections and slopes. The maximum above Cornwall is on the lower sill of Lock 25 of the Canadian canals, and this effect is given in the table. It is claimed that the effect of a diversion of 10,000 cubic feet per second at Chicago on the level of the water at Montreal is somewhat more than eight-tenths of a foot, but this has not been verified. 26 TABLE NO. 46.-Lowering of lake levels in feet by diversion of water from Lake Michigan through the Chicago drainage canal Elevations of the lakes above mean tide level at New York for the stages referred to in this table are as follows: Colonel Warren finds, among other things, that the present diversion at Chicago of 8,000 cubic feet per second decreases the mean depths in the harbors of the lakes as follows: It goes without saying that navigation in the open lakes will not be affected by any such diminishing of available depths. With the exception of well-defined shoals which are studiously avoided by mariners, depths are so great as to leave plenty of margin for safe navigation including the lowering produced by the Chicago diversion. But the ships have to enter harbors to take on or discharge cargo. 98203-24- -3 Very few of the lake harbors are natural ones with sufficient depth throughout to permit a lowering without reducing the margin below the point of safety or economy. Most of the harbors have been improved by dredging at considerable expense, the more modern ones so as to provide a safe entrance and anchorage for vessels drawing 21 feet of water. It has been the practice for the Government to provide a foot of overdepth, i. e., the channels have been dredged to a depth of 22 feet, the extra foot of depth being provided so that vessels could load to a full 21 feet without dragging on the bottom In some rock cuts an additional foot of material is removed for the sake of safety. On page 392 of his report to Congress on the diversion of water from the Great Lakes, previously referred to, Colonel Warren places the economic navigation loss due to the diversion at Chicago at $2,866,000 per year. The same report places this loss at $326 per cubic foot of diversion. The total loss increases with the diversion and with the volume of commerce. The result is that this navigation loss will assume considerable proportions in the future if the amount of diversion continues to increase. NAVIGATION OF CHICAGO RIVER-HISTORY OF DEVELOPMENT OF CHICAGO RIVER The Chicago River, so far as navigable parts are concerned, is wholly within the limits of the city of Chicago and the county of Cook, State of Illinois. Originally it was a sluggish bayou or creek, nearly stagnant for the greater part of the year, but in rainy seasons, when discharging not only water from its own watershed, but also a large quantity from the Des Plaines River passing over the low divide between the two streams, it was a rapid stream. At such times the large discharge kept scoured a natural channel varying from 8 feet or less to 14 feet or more in depth as far as its mouth, where it was obstructed by a bar over which the depth of water varied from 4 feet or less to 9 or 10 feet. The stream is bifurcated, the North Branch joining the South Branch somewhat over a mile above its mouth. The North Branch is of greater natural length and has a large drainage basin. The South Branch is likewise bifurcated, being formed from the confluence of the West Fork and the South Fork at about 5.5 miles from the mouth of the river. It was by way of the West Branch and a marsh to its west that the flood waters of the Des Plaines sometimes passed from the Mississippi watershed to that of the Great Lakes, and it was over this route that the early traders are supposed to have conducted their traffic which caused the Des Plaines River to be considered navigable. The work of improvement at Chicago Harbor was undertaken by the United States Government in 1833. Previous to this the Chicago River made a sharp bend southward at a short distance from the lake and had its outlet into the lake fully half a mile from the bend. The work of improvement was commenced by giving the river a straight outlet by cutting through the bar and by constructing a pier on the north bank. Somewhat later the construction of a pier was begun in prolongation of the south bank. As sands accumulated and vessels increased in draft the piers and jetties were extended, from time to time, further into the lake, and as commerce by water increased greater facilities for entering the river were provided. Up to the year 1892 the United States Government confined its work of improvement to the entrance to the river, but the rivers and harbors act of July 13, 1892, in making appropriation for improving the harbor at Chicago stated" and the engineer in charge of the harbor is directed in his next report to submit what, if any, improvement should be made by the Government in Chicago River, and the cost of same." Within the original shore line of Lake Michigan the stream had been partly improved by the city of Chicago and partly by private interests, the work of improvement being dredging to remove accumulations of sewage deposits and the material washed into the streams. by rains and the construction of bulkheads, slips, and docks. There was no coordination of the work, with the natural result that there were obstructive angles, curves, and bridges, besides three tunnels under the river, which limited the usefulness of the stream from the point of view of navigation. Since in its natural state the river was far from straight and regular it was not satisfactory as a highway for vessels capable of navigating the Great Lakes. The district engineer in his annual report for the fiscal year 1892 recommended the adoption of a project for a 16-foot-draft channel extending from the mouth to Belmont Avenue on the North Branch and to the stockyards on the South Branch, but in view of the use of the river by the city of Chicago as a means of disposing of its sewage he recommended that the expense of maintaining the channel be borne by the city. The project thus recommended was formally adopted by Congress in the rivers and harbors act of June 3, 1896. The dredging work authorized by that act, i. e., deepening the river to provide for vessels of 16-foot draft, was completed the latter part of 1899. While this dredging was going on a project was drawn up, approved, and appropriated for by Congress in the sundry civil act of July 1, 1898, providing for the acquisition by the United States of lands adjoining the river so as to permit widening of the stream at certain critical points. The widening was undertaken as rapidly as acquisition of the lands would permit and was completed in 1903. |