2d Session. No. 99. LETTER FROM THE SECRETARY OF WAR, TRANSMITTING Report of Maj. C. R. Suter, Corps of Engineer, of an examination and surrey of Gasconade River, from its mouth to Vienna, in Maries County, Missouri: MARCH 1, 1880.-Referred to the Committee on Commerce and ordered to be printed. WAR DEPARTMENT, Washington City, February 27, 1880. The Secretary of War has the honor to transmit to the United States Senate a letter from the Chief of Engineers dated the 25th instant, and accompanying copy of report of Maj. C. R. Suter, Corps of Engineers, of an examination and survey, made in compliance with the requirements of the river and harbor act of March 3, 1879, of Gasconade River from its mouth to Vienna, in Maries County, Missouri. The PRESIDENT of the United States Senate. ALEX. RAMSEY, Secretary of War. OFFICE OF THE CHIEF OF ENGINEERS, Washington, D. C., February 25, 1880. SIR: I have the honor to submit herewith a copy of a report to this office from Maj. C. R. Suter, Corps of Engineers, of the results of an examination and survey of Gasconade River from its mouth to Vienna, in Maries County, Missouri, made under his direction to comply with the requirements of the river and harbor act of March 3, 1879. Very respectfully, your obedient servant, H. G. WRIGHT, Chief of Engineers, Brig. and Brt. Maj. Gen., U. S. A. Hon. ALEXANDER RAMSEY, Secretary of War. SURVEY OF GASCONADE RIVER, MISSOURI, FROM VIENNA, IN MARIES COUNTY, TO ITS MOUTH. UNITED STATES ENGINEER OFFICE, Saint Louis, Mo., February 11, 1880. GENERAL: I beg leave to submit herewith acopy of a report of my assistant, Thomas T. Johnston, on the Gasconade River, Missouri, from Vienna, in Maries County, to its mouth. The survey of this stream was made under my directions by Assistant Johnston during the past season. From this report it appears that for this portion of the Gasconade, some 78 miles in length, it is a small stream, the low-water discharge being only 450 cubic feet per second. The fall is heavy-108 feet in this distance-and the river is much obstructed by gravel bars, the channels through which are tortuous and shallow. To thoroughly improve a stream of this character is a very costly operation, and before suitable plans could be prepared, more study and observation would be required than the hurried nature of our survey has enabled us to bestow upon the subject. There is not much steamboat navigation on the river, but the rafting interest is important. Under these circumstances it has seemed best to confine our attention for the present to a project for deepening and straightening the low-water channels over the worst shoals by means of low, cheaply-constructed dikes, and for removing the snags which now obstruct the stream in many places. This partial improvement would no doubt be very beneficial to all the interests concerned, and during its progress opportunity would be afforded for a more thorough study of the problem. Assistant Johnston's estimate for this work is $50,000, which could be profitably expended in one season. This estimate is approved by me. Copies of the maps of the survey will be forwarded as soon as they can be traced. I am, general, very respectfully, your obedient servant, CHAS. R. SUTER, Major of Engineers, U. S. A. Brig. Gen. H. G. WRIGHT, Chief of Engineers, U. S. A. REPORT OF MR. THOMAS T. JOHNSTON, ASSISTANT ENGINEER. SAINT LOUIS, MO., January 30, 1880, MAJOR: I have the honor to submit the following, being my report of the survey of and the practicability of improving the Gasconade River from Indian Ford (near Vienna), in Maries County, Missouri to the mouth of the river, and which was done in accordance with instructions received from you dated August 20, 1879, and September 9, 1879. The survey of the river was commenced September 17, 1879, and completed Octo ber 29, 1879. A stadia line was run along the course of the river, from which all other points were located. The length of each change-line was measured from both ends. The directions of the lines were checked by reference to the true meridian about every 20 miles. Topography back from the river bank was sketched as far as time and the amount of the allotment permitted. A line of levels was run to which the water surface was referred at about every 500 feet along the pools, and at shoals sufficient elevations were taken to determine the manner in which the water gets over them with reference to shape and slope. Cadenced soundings were taken in pools on sections averaging about 400 feet between centers; on shoals sufficient soundings were taken to determine its shape and the water depths, the sounder wading and pacing between soundings, thus getting them equidistant. The country along the river was examined as far as possible. The accompanying maps show the results of the work, except that only enough soundings were platted to show the ruling depths on sections. This part of the river crosses from side to side of a crooked valley between bluffs, which are from 1,000 feet to 1 mile (about) apart, the faces of which toward the valley show distinctly northeast and southwest trends; the general direction of the stream is northeasterly. The bluffs are often precipitous, with rock ledges out-cropping; in a few instances they rise vertically from the water's edge, and in a few instances they were observed to rise abruptly from the level and high bottom lands. They are generally, however, footed by a talus which frequently obscures the original bluff face. The country in Maries County and southern Osage County, near the river, is excessively broken, especially on the west side; the ridges are a mass of angular stones, varying in size from small gravel to pieces weighing several hundred pounds; the forests are thin and the underbrush scant; on the hillsides and in the bottoms the land is more or less fertile, and much of it under cultivation; toward the Missouri River and east of the river the country is less jagged; it is thickly settled by Germans, who have placed most of the land (hill-top, side-hill, and bottom land) under cultivation, growing grapes, wheat, and corn in large quantities. The bottom lands are quite level, being at the river banks generally about 20 feet above the low-water level of the river; in such places as the river is shifting about, or is influenced by the tributaries or by original valley topography, there are lower lands subject to frequent overflow. They are for the greater part very fertile, though in many places too sandy to be of much value. Where the river banks are being eroded the material below the alluvial crust is shown to be a mixture of sand and gravel in varying proportions; tributaries cutting through the bottom lands, show the same formation. No evidence of bed-rock was observed within at least 10 feet of the lowwater level of the river. While the regular trend and the age of the bluff rocks indicate the pre-glacial existence of the valley, the limited area the river could ever have drained and the character of the valley formations indicate the flow of a large amount of water, such as could have been produced by the melting of glaciers. The river is a series of pools and shoals, the low-water width of the channel varying from 60 to 500 feet, but being generally about 200 feet wide; as shown on the maps the depth of the former varies from 20 feet to 3 or 4 feet, but for the most part showing a depth of 8 or 9 feet; the current in these is almost imperceptible at lowwater. The maximum depths of water on the shoals varies from 2.5 to 1.3 feet, but for the most part being about 2 feet; the depth varies with the shape of the shoal to some extent. These shoals appear to be banks of gravel, acting as dams athwart the course of the stream; sand in the river bed is absent except near the mouth. The fall of the river from Indian Ford, as shown by the levels, is 107.895 feet, the Missouri River being low. The length of the river surveyed is 781 miles. The pools (as a rule) lie adjacent to the bluff's, while the shoals (as a rule) occur where the river crosses from bluff to bluff'; they occur also (as a rule) very close to where the river commences a crossing and rarely at the end of a crossing; frequently there are shoals between these points. There are a class of shoals which appear to be the consequence of some tributary, doubtless the latter bringing in material that the river is incapable of moving, thus forming a nucleus for a shoal. Two or three shoals along the bluffs are doubtless the consequence of some obstacle, as, for instance, a bed of snags. Undoubtedly snags have exerted a large influence over the formation of shoals. The river has an oscillation between high and low water of 22 feet, as given by a high-water mark at Pay Down. (Sheet 4.) The slope of the country that the river drains is such that the water passes off rарidly, the river rising very rapidly and staying high but a short time. The prevalence of low-water is indicated by the growth of vegetation close to the low-water line. Persons living along the river were a unit in representing the river to have been unnsually low during the past season. It was noticed that scarcely any water was brought in by the numerous small tributaries below Indian Ford. IMPROVEMENT. The quantity of water passing through the stream at extreme low-water does not vary much from 450 cubic feet per second. The shoals in the river, acting as dams, hold a depth of water behind them sufficient for all needs of navigation; while the water spreads over the dams in a more or less thin layer. The question turns on a method of passing these dams. Locks would answer the purpose but are unnecessary and expensive. The present needs of navigation do not require a channel of more than 2.5 feet depth by about 30 feet botton width and 60 feet or more surface width. The sectional area of the stream on the shoals shows that this can easily be had. It is believed that this can be had by using wing-dams and dikes of various construction. A considerable care must be used on placing them, particularly to make them sufficiently low. They should be no higher than sufficient to maintain the required channel. Some years ago Powell's dam (sheet 25) was built, which has caused changes in the river especially detrimental to navigation. It had, probably, a fall of 4 feet; as a consequence, the river below has a large fall and numerous shoals; exactly what its effect has been is difficult to decide, but an examination of the map will show it in a measure. Using a shoal in the capacity of a dam involves the consideration of its stability; the apparent relations between the positions of shoals and the features of the river indicates their permanency, though, doubtless, slow changes may exist; the material of which they consist is somewhat difficult of transportation, though the case of Powell's dam shows that it is moved in not small quantities; the way gravel has banked up below the dam shows what may be expected at any other dam; an artificial obstruction at Stake Shoal (sheet 29) indicates the same thing; likewise the shoal-forming capacity of snags. A low dam or immovable ridge on the crest of a bar shoal will prevent any undesirable changes, being coupled with needed protections at the river banks. Being assured of the permanency of the shoals, the works on any shoal may be considered. Primarily, these should not damage the river elsewhere; to satisfy this condition the dams should be as low as possible, and not much alter the elevation of or fall over a shoal. It is partly on this account that it would be unadvisable to scrape a channel through the gravel shoals, thus reducing the level of the pool above, and maybe developing new shoals; moreover, this process would be equivalent to making wingdams of loose gravel, which material (from personal observation) is easily moved when the regimen of the stream is molested. While satisfying this primary condition it must be considered how and where the channel over the shoal is to be. Its width will be governed by the fall over the shoal and the variation from the depth of channel proposed; this latter, to be accurate, will have to be determined by actual experi ment; with the proposed channel-depth sufficient width (and more) can be had and the variation therefrom may have to be governed, but to what extent remains to be determined; however, it is believed that sufficient is known concerning the probable variation upon which to base estimates. The location of the channel over the shoals involves the consideration of its ease of navigation; the cost of forming it; its chances of maintenance; the conditions above prescribed; and the consideration of erosion of banks. Experience has shown that boats can move up-stream over the steepest shoals with no difficulty. Ease of naviga tion requires, then, only that the channel should be reasonably straight. The cost of forming the channel will depend on the nature of the shoal; the chances of maintenance depend on the same thing, together with the high-water action of the river. The discussion of these properties will not be undertaken here, but will, if desired, form the subject of a supplemental report. at The nature of the bottom-lands is such as to render them capable of easy erosion. Along the straighter pools, and where the concave side is a bluff, this action is absent on account of absence of current except high-water and the protection of vegetation; at other pools, bending sharply, this action exists, though progressing slowly and only at the occasional high-waters. At shoals evidence of past erosion exists, and is at present progressing, and must be prevented from interfering with the improvements on any shoal. PLAN. It is proposed, in order to bring about an improvement, to use some device for concentrating and governing the flow of water through a channel, the location of which has been determined, in consideration of conditions before mentioned. These devices will have to be constructed, with few exceptions, where the water (at its lowest) is about 2.5 feet deep, or less, and in such a manner that the resistance of the device demanded will never be very great, which resistance is lessened as much as possible by the design of the devices; it is not believed that water-tight dams and dike will be demanded, at least only in rare instances. Having once fixed a section for the channel, the concentrating capacity and quality demanded will depend upon the shape of and fall over the shoal and the governing capacity on the same thing to a greater or less extent; the impossibility of calculating the intensity of these requirements makes actual experiment necessary to determine them. It is believed that the changes intended on any shoal will take place so rapidly that the effect of the works can be observed approximately at once, and thus govern their extent. The estimates below are based upon the effect of the works anticipated, and it is believed they will not vary much from what will be needed. Where a wing-dam or dike is needed over 2 feet high, brush and stone will be used (depending, of course, on the resistance demanded); where a less height is needed, poles and planks driven into the gravel in single or double rows (depending on the case), somewhat after the nature of sheet piles, either alone or backed by stone, or gravel will answer for dams and dikes. These will be driven 2 or 3 feet into the gravel, or until they take a firm hold and are out of the limit of scour; when used to deflect the current, poles alone will answer, driven several inches apart; none of these works are intended to reach above low-water; in many cases even this height will be unnecessary (besides the previously mentioned conditions, the desirability of maintaining the point of maximum scour at or near lowwater will govern the height of the works). Similar works will be used to prevent the bars from giving openings for other channels and for governing undesirable scour in the channel. The parts of this class of work that may be subject to hard knocks, as from rafts or boats, will be of the same construction, but stronger than elsewhere. It is believed that the spaces behind the works will fill up with sand and gravel, and that these sediment banks and the works will afford mutual protection. The greatest danger to this plan is the possibility, though remote, of the channel filling up at highwater in a manner to prevent it being opened again at low-water. This objection is common to all wing-dam and dike systems, and can be obviated only by work in the nature of maintenance and repairs. The survey of the river develops 76 places needing improvement, as shown on the maps and in the following table. The estimates are based upon the condition of the river when surveyed, and will vary with any variation in the shoal prior to improvement. No changes are anticipated which will much alter the amounts. Dike and dam work has been placed at an average cost of 25 cents per running foot, as determined by averaging the amount of work on a number of shoals. These estimates refer to the actual cost of construction. Ten per cent. has been added on account of possible error in estimates, and the same amount on account of such scraping and governing of the channel as may be needed to develop the intended effect of the work. There are localities along the river favorable for the location of snags; and at those places they are sometimes so thick that a boat or raft cannot pass without coming in contact with them. These localities are at such places as the banks are being eroded, either along pools or at shoals; also at the heads of islands. They occur also, as a rule, in groups, an isolated one being rare. There are long stretches of the river where none will be found. They seldom locate in the channel on shoals, except where erosion of banks exists. There are, then, a number of localities, more or less full of snags, enumerated below. They are easily accessible from the shores, and can be removed by apparatus located thereon, and by blasting. The localities are as follows: Loggybend, sheet 3 of maps. One mile above Pay Down, sheet 4 of maps. |