miles back of Narragansett Bay, and immediately north of Narragansett Pier, while the Pettaquamscott River, emptying in the ocean near Narragansett Pier, does the same for the bay slope. The pond itself is quite irregular in its conformation of shore-line, and is interspersed with numerous islands, varying very much in size. The length of the pond is about four miles, the maximum breadth one mile. The southern limit of the pond is a large marsh, interspersed with various creeks. This marsh bounds the entire southern portion of the pond, and is itself limited by a range of sand-hills of some 25 feet in height, fronting on the ocean beach. At the western limits of these hills the present "breach" or opening is. This is a shallow outlet of nearly constant width of 200 feet, and general depth of 14 feet. A prominent feature of the pond is Great Island, lying some 1,200 feet north of the marsh and almost, if not entirely, dividing the pond into two distinct portions for a distance north of quite a mile. The marsh also may be considered an important feature of the pond, in so far as it pertains to the future regimen of the same. From the information gained while on the ground, I should judge that the northern limit of the marsh was gradually encroaching on the limits of the pond, and that a subsidence of the matters in suspension is constantly going on, which has and is increased proportionately to the diminished circulation, caused by the gradual and increasing closing of the "breach.” The changes that have taken place in the pond during the past seventy years are very marked. Previous to 1815 the outlet of the pond to the ocean was on the east side of the pond. This outlet was closed by the "great gale" in September of that same year, and no traces now exist to point out that there ever was an outlet there, except the stony character of the breach near the old outlet. The present breach is about one mile west of the former opening, and its shores being entirely of sand are unstable and drifting. The survey extended along the ocean beach south of the pond, and eastward of the same to within 1,000 or 1,500 feet of Point Judith light-house. The western limit of the survey is some 700 or 800 feet west of the present breach, or outlet of the pond, which is beyond the western limit of the pond proper. It extends north, (up the pond to a point locally known as Beef Island.) The entire survey constitutes an area nearly approximating in form to that of a square, whose sides are about 11,000 feet in ength. The method of conducting the survey consisted in first covering the marsh to the south of the pond, and also the ocean beach, with lines of traverse, closing in an arbitrary starting-point, and forming a polygon of some twenty-three sides, the angular correctness of which was determined by a comparison of the difference of the right and left deflections with 360°. The linear measurements were tested by calculations of the latitudes and departure of the traverse lines, and comparisons of the sums of the same. The linear measurements were also tested by platting. To prevent any gradual accumulation of small and uncertain errors, the eastern portion of the polygon was subdivided into a smaller one, and its correctness determined as before. Upon the acenracy of this latter polygon the position of all the stations on the upper portion of the pond depended. The shores of the pond, together with the northern limit of the marshes, were located entirely by triangulation, it being considered that this would be economical of time, being, in fact, the only practicable way to locate the outlines of the marsh and the numerous creeks therein. Stations for doing this were located on the east and west shores of the pond, and on the same shores of Great Island by a system of triangulation connecting with a side of the smaller polygon just previously mentioned. A tide-guage was established in the pond, which developed the fact that practically there was no oscillation of tide going on in the pond, the maximum difference of readings on the gauge being 0.3 of a foot. A buoy-gauge was also placed in the ocean and read for three consecutive days, and the height of mean low water established by subtracting one-half of the mean rise and fall of the tides, as given by the United States Coast Survey, from the mean sea-level determined from the readings. The two ganges were connected by lines of level, and the difference of height of the zeros of the gauges compared. This comparison showed mean low-water in the ocean to be 4.5. feet below the surface of the pond, at the time of this survey. Soundings were taken inside the pond, on both sides of Great Island, as far north as gave 9 feet and over in the west passage of the pond, 6 feet being the limit of depth obtained on the east side of Great Island. This latter depth was about the maximum to be obtained in the east passage. In the ocean, from Point Judith, west to within 2,500 feet of the present breach, soundings were taken from the shore, to a depth of over 25 feet. The soundings were located by the intersection of known lines of sight from two transits. The wishes of the people consulted in the matter, relative to the desired improve ment, seem to universally be that the pond should be connected with the ocean in such a manner that vessels drawing from 7 to 8 feet may pass into the pond. The object of the improvement is, however, two-fold: First. To give communication by water to that section of country lying near the head of the pond which comprises quite a number of moderately-sized manufacturing villages, or, in other words, to give that section an opportunity to get their supplies and send off their exports direct by water, which now has first to ship them to Providence, and re-transport by rail by the Providence and Stonington Railroad to the station on that road nearest to the ultimate destination, from which they are brought by teams, for varying distances, to the desired place. Second. To meet the wishes of the fishing interest, as during the winter months, more especially in former years, enormous quantities of bass and perch entered the pond during this season of the year, and the catching of these fish gives employment to numbers of men living near the pond. I have been informed that large quantities of oysters were formerly obtained in the pond, but have now almost entirely disappeared, owing to the impeded circulation in the pond, caused by the gradual closing of the breach. I could not obtain any extended information as to what might be the average magnitude of these fishing interests, but have been informed that it reaches the sum of $20,000 per season. The plan for making a navigable connection with the ocean best adapted to the case is the construction of a canal and lock connecting the pond with the ocean. This method of connection may be considered almost necessary on account of the difference of level between the pond and ocean. This would satisfy the requirements of the first object of the improvement, and, if the second should be considered of sufficient importance to warrant an expenditure, the present breach might be dredged and opened at the mouth to permit the more easy access of fish to the pond. For the choice of location of the canal there offers two places. One line lies on the eastern side of the pond, and presents, in its favor, the fact that the ground is quite level for a distance of at least one-half of its length; for the remaining distance there is a gradual rise to the summit of the beach. The hard and stony character of the beach here is also in favor of this location. This hardness may be of sufficient character and depth to do away almost or entirely with artificial means to preserve the month of the canal from filling up. The other choice for a line of canal is the present opening or breach. The only thing to be said in favor of this location is the level character of the surrounding marsh near it, extending to the mouth of the breach. The breach-creek itself is too crooked to be made use of as a canal by excavation and dredging, and offers the further objection of the extreme unstable and shifting character of its mouth. This unstableness would necessitate the construction of expensive jetties on probably both sides of the opening of the proposed canal as well as causing the building of them some distance inland to prevent the possibility of the sea ever breaking over the beach and sand-hills near the opening. If the fishing interests were alone consulted in the proposed improvement, the present breach might be utilized by dredging to assist the wants of this interests. If this were done it would still be necessary to protect the mouth of the breach by jetties, and it is quite questionable if the opening could be successfully secured against the strong probability of storms closing it during the prosecution of the work. Accompanying this report is a map of that portion of the pond and ocean within the limits of the survey, on a scale of 200 feet to the inch. This map is illustrated with sections of level taken at characteristic portions of the beach, sand hilis, and marsh, on a scale of 100 feet to the inch horizontal and 10 feet vertical distances. I was assisted with commendable energy and earnestness during the entire survey by CHARLES R. MATHER, Civil Engineer, Assistant Engineer in charge of Survey of Point Judith Pond. G. K. WARREN, -EXAMINATION AND SURVEY OF GALENA RIVER TO THE UPPER BRIDGE AT GALENA, ILL. UNITED STATES ENGINEER OFFICE, Saint Paul, Minn., December 29, 1873. GENERAL: I have the honor to make the following report of the result of the examination and survey of the Galena River, from its mouth to the upper bridge at Galena, Ill., made by Assistant J. D. Skinner, under my direction, during the months of August and September, 1873. I herewith submit Assistant Skinner's report to me. The tracings of the river, in four sheets, have this day been forwarded by express to your address. By referring to the tracings it will be seen that there is very little water flowing past the city of Galena during low water, quite insufficient to make any current which would scour out and carry away any deposition of mud made during high water. Previous to the com pletion of the Illinois Central Railroad to Dunlieth, on the Mississippi River, the river was kept open for navigation during low water by constant dredging. Shortly after the completion of the railroad to the Mississippi River, the dredging was discontinued, and as a consequence the river soon filled up with the washings from the high clay banks. The opening of the cut-off between Harris's Slough and the Galena River undoubtedly backed up the water of the latter river and stopped the current, and much of the matter suspended in the water, before carried into the Mississippi River, is now deposited above the cut-off. The parties who made the cut-off thought, that by doing so, the water in the Galena River would be deepened by one foot, and they were right as to the immediate result, but they do not seem to have considered the result of stopping the current of the river above. At the time of the survey there was no perceptible fall of the river between the city of Galena and the cut-off, a distance of about four miles. From the cut-off to the Mississippi River there was a fall of .937 of a foot. By reference to the map it will be seen that the only way the river can be improved is by dredging, and taking some means to collect the matter brought down by the inflowing streams from the hills before it reaches the rivers. Small dams across the ravines seem to be the most economical method for the latter purpose. The dredging in the river above the cut-off will be expensive, owing to the long towage to dump the dredged material. Owing to the abruptness of the river banks and the great rise of water during the high-water season, none of this material can be deposited in spoil banks, but must all be towed down and deposited into the lower part of Harris's Slough. Were the quantity of water flowing past the city of Galena during low water sufficient for any purpose of scouring the bottom of the river, some good might be done by cleaning the cut-off, but as it is not, it does not seem worth while to make all steamers moving into the Galena River, on their way up and down the Mississippi River, take a long detour by cutting them off from Harris's Slough. Some little dredging is necessary in Harris's Slough, for which Mr. Skinner has made a separate estimate. The filling up of Harris's Slough below the cut-off will throw a large volume of water through the cut-off, and will, no doubt, scour out the bars in the Galena River below it. I would recommend the last plan proposed by Assistant Skinner; that is, to dredge to a depth of 6 feet above the cut-off, and to 4 feet below, to close Harris's Slough below the cut-off, thus throwing the whole volume of water of Harris's Slough through Galena River, and dredging a small amount at the head of Harris's Slough. Small dams of dry masonry backed with earth should be put across the three principal ravines. This would cost not less than $400,000. Half the work could be done in one season and half the next. It is hard to say how much the general commerce of the country would be benefited by the improvement of the Galena River; but there is no doubt that its improvement might greatly stimulate the local commerce. The country about the city of Galena is filled with farms, and when the Southern Wisconsin Railroad is finished this city would be the shipping point for a large quantity of lead and zinc ores and metals. Should Congress deem it advisable to improve the river, the sum of $200,000 could be economically disbursed during one fiscal year. I have the honor to be, very respectfully, your obedient servant, Brig. Gen. A. A. HUMPHREYS, F. U. FARQUHAR, Major United States Engineers. Chief of Engineers, U. S. A., Washington, D. C. UNITED STATES ENGINEER OFFICE, Saint Paul, Minnesota, December 27, 1873. COLONEL: I have the honor to submit the following report of a survey of the Galena River, in the State of Illinois, made by me under your direction, during the months of August and September, A. D. 1873. The main stream is formed by two forks, which have their confluence about three miles above the city of Galena. The Illinois Central Railway follows the valley of the east fork, and the Galena and Southern Wisconsin that of the west fork. This road is graded and bridged, but not yet in operation. Both streams take their rise in Southern Wisconsin. During low water the discharge of these united streams, measured just above Galena, is inconsiderable, amounting, by careful measurement at extreme low water, to 15.89 cubic feet per second, or 1,372,896 cubic feet per 24 hours. This would be altogether insufficient to supply lockage, and, not to speak of other reasons, renders the use of a lock at the cut-off, hereafter referred to, impracticable. At and below Galena there is virtually no current, the stage of the river being entirely the result of the height of water in the Mississippi River, the back-water of which, at its extreme height, extends two miles above the city of Galena. The distance between extreme high and low water marks is 17 feet at the levee, The cut-off, (see map) situated about four miles below Galena, is a connection with Harris's Slough, (a portion of the Mississippi River at a point where it approaches within feet of Galena River.) Here a small ditch was cut by some steamboat-men about three years ago, and the water at that point, being a foot higher than that of the latter, soon forced a deep and permanent water-way, and through that opening a large amount of Mississippi water finds its way to the mouth of Galena River, changing the character of the water, and creating a strong current below the cut-off. The necessary effect was to raise the water of the latter stream, above the connection, at least one foot, which gain, as the latter is wholly dependent on the Mississippi for Its stage of water, is permanent. Another result has been to fill up the lower portions of Harris's Slough, and at low water almost no water passes through it, as will be seen by reference to the map. This can be permanently closed so as to entirely divert the water of Harris's and Key's Sloughs (see map) until it has reached a height of 10 feet above low water, (the height of the adjacent islands,) and this will greatly tend to cut out and deepen the channel, the bed of which, below the cut-off, is mostly of sand, and will render dredging in that part of the river mostly, if not wholly, unneccessary. The embankments closing this can be made from the material dredged from the upper river, which will seek a place of deposit, and will save three or four miles of towage for that portion which composes it. Its face can be thoroughly protected with riprap, an abundance of which is at hand, and its upper surface paved to an extent sufficient to protect the necessary portion from wash at high water. The upper river is entirely different in character; the water is sluggish, muddy, and fetid; large amounts of deposits are annually swept down by storms, &c., from the steep hillsides, which form its banks, and out of the valleys, or coulées, which at intervals extend back into the country. The natural result has been that the river has been filled by the deposits from these sources to such an extent that in low water even the smallest steamboats cannot approach nearer than two miles to Galena. Thirty years ago, from the most reliable information to be obtained, there was a depth of water in the basin (see map) of 10 feet; now it is a mass of mud virtually dry at low water, and the deposits have reached in places a height of 5 feet above low water. The remedy for this after the necessary dredging has been done would be, first, a dam at Meeker street bridge to collect the silt from the upper river; second, similar dams across the mouths of the coulées discharging into the river, the deposits to be removed at proper periods; this would be gladly done by the proprietors of the adjacent vineyards and farms. With these precautions a number of years would elapse before a repetition of dredging would become necessary. This, however, when required is the only way in which navigation can be mantained to the city of Galena. I herewith submit an estimate of the amount of dredging to be done to put the river in a navigable condition. This is based upon a width of 100 feet for a distance of 8,500 feet below the basin; at this point a sharp bend in the river necessitates a change of the channel. This can be made by cutting through the point (see map) and the material deposited in the present channel. Here a width of 200 feet has been given, and in all cases a slope of two upon one has been allowed for. Below this point a width of 150 feet has been given. The estimate is based upon, 1st, a depth of 6 feet; this would be desirable in the upper river to allow for the unavoidable deposit; 2d, a depth of 4 feet throughout; 3d, a depth of 6 feet above cut-off and 4 feet below the same. Below the cut-off the river would in all probability make for itself a sufficient channel after the preliminary dredging had been done. A depth of 4 feet below the cut-off would be likely to meet the requirements of all boats that ply on the Upper Mississippi. Owing to the character of the banks of the river and the causes which have filled it at present, all material dredged must either be deposited in the embankment closing Harris's Slough, at the cut-off, or towed below the mouth of the river and dumped into the Mississippi at a suitable point. The amount of excavation estimated above Green street bridge (see map) is believed to be unnecessary, as no boats have ever passed above that structure. The estimates above referred to are as follows, forty per cent. having in all cases been added to actual quantities: Estimate of amount of dredging to be done in Galena River in order to give a channel-way from 100 to 150 feet wide, and 6 feet depth of water, as above described. Should river be dredged between Green and Meeker street bridges there will be added 93,540 The same for 6 feet of water above and 4 feet below the cut-off. Riprap for face of embankment closing Harris's Slough at cut-off.. 750 HARRIS'S Slough. Amount of dredging necessary to render Harris's Slough navigable for boats plying to Galena, |