improve these so as to afford extreme low-water navigation would require the expenditure of a sum far beyond the limits of the present appropriation. The plan therefore provides only for the improvement of the worst places, so as to extend the time of navigation as much as possible. The places which have heretofore given the most trouble are Mojave Ford, Six Mile Rapid, and Hatteras Bar, and an improvement of these I am assured by the river men will extend the period of navigation two to three months in the year. The following is a description of these localities: MOJAVE FORD. I was unable to obtain the exact stage of river at this point, and the results of the examination are therefore not considered reliable as to the low-water condition of the river. From all information obtainable the following appears to be the habitual condition of the river at low stages. The river is divided into two branches by a high cobble-ridge. The right branch, which is never used, is crossed at the upper end by a gravel-bar with a few inches of water in a swift rapid over it. The left brauch is crossed by a gravel-bar stretching from the foot of the island diagonally across the stream towards the left bank, giving less than 1 foot of water. The plan for this place contemplates the excavation of a channel 150 feet wide and 3 feet deep through the bar and the construction of a cobble-dam on the crest of the bar, to contract the width of the river. The plan also provides for the construction of a dam to close the right branch, at its upper end. SIX MILE RAPID. The river makes a bend to the left, and is suddenly contracted at the apex by a high projecting rock from the left bank and a ridge or flat of bowlders putting out from the right bank. The ridge extends diagonally down-stream and joins the left bank 1,000 feet below. At the time of my examination the river was about 6 feet above low water, and no bowlders could be seen but the general direction of the ridge was easily traced from the appearance of the surface of the water. At low stage some of the bowlders rise within a few inches of the surface and form the principal obstruction at this point. A second obstruction is formed in the steep slope at the head of the rapid, which, at a stage of 6 feet, was 0.97 feet in a distance of 140 feet, or nearly 37 feet per mile, with a current of 6 miles an hour. To make the crossing here steamboats are compelled to heave over on a strong line secured to the bank above. As the river falls the slope and current are diminished, and on several occasions the boats have been able to effect a crossing without the aid of a line. Unlike most other rapids, which disappear at high stages, this place becomes more of a torrent the higher the river rises. At the time of my examination the width of the river at the narrowest place was 350 feet; at points 800 feet above and below the width was 600 feet. The course of steamboats at medium and low stages is accurately laid down on the map and crosses the ridge nearly perpendicularly where there is a narrow channel between the rocks. On the downward course it is difficult for the boats to make the quick turn required here to cross the ridge, and the place is approached with much uncertainty as to the safety of the passage. It is the most dangerous point between the Needles and El Dorado Cañon. The plan of improvement for this place contemplates the removal of bowlders from the ridge, making a channel 200 feet wide and 3 feet deep. The bowlders vary in size to 5 feet diameter, and are cemented together by a finely divided clayey sediment. The part of the ridge through which the channel is recommended is below the point of greatest contraction and greatest slope, and the effect, it is believed, will be an increase of the slope at low stages without a material reduction in the water-level of the pool above, by which new obstructions, now hidden by an ample sheet of water, might be uncovered. The increased slope will make the place more difficult to heave over, but the danger of the crossing will be removed. HATTERAS BAR. The river at this point is from 1,200 to 1,300 feet wide between banks, contracting below the obstruction to a width of 500 feet from shore to shore. The banks are permanent, that on the right a compacted sand deposit, bordered by high mesa; that on the left a steep sand and gravel deposit overgrown with willows. At the lower end of the reach high hills come down to the left bank. Heretofore at low water a broad bar of cobble has put out from the left bank, leaving a narrow channel 2,400 feet long and 200 feet wide between it and the right bank, 149 ENG barred at both ends by a gravel ridge. This was the condition of the bar at the time of Captain Payson's survey of 1878-79, and, as I am informed, has been its condition since. Present indications, however, point towards a closing of the old and the formation of a new channel through the cobble plat located about midway between the banks. At the time of my examination the river was divided by two cobble ridges about 2,500 feet long into three branches carrying about the same amount of water. The left branch is deep at the lower end and barred at the upper end by a cobble ridge, which at low stage rises nearly to the surface and converts the branch into a deepwater slough, open at the lower end. The right branch is deep at the upper end and barred at the lower end by a wide cobble ridge or flat, giving less than one foot for a distance of 1,000 feet. The middle branch, which is now used by the steamboat, is barred at the upper end by a cobble ridge, giving less than 2 feet over a distance of 600 feet. This channel was cut out during this summer's flood, and I think it may be safely asserted will be the low-water channel the coming season. The plan suggested for this place is the excavation of the cobble or gravel ridge to a depth of 3 feet and the construction of stone dams, closing the right and left branches at the upper ends. The bars to be excavated are of gravel and cobble of varying sizes firmly cemented together by a fine clay sediment. A method which has been used to deepen the gravel bars on the upper Mississippi, it is believed, could be successfully applied here. This method is to loosen the material by charges of dynamite and then to drag the bar by a rake or drag of suitable construction, drawing the material into the deep pool below. The swift current over the bars will aid in moving the loosened material. The dams will be exposed to violent tests from the summer floods, and are therefore designed as outworks of timber filled with stone, and of square or triangular crosssection, as they are opposed obliquely or squarely with the current. The timbers will have to be obtained from the Needles; stone can be found in abundance where the dams are to be built. The months of November, December, January, and February are most favorable for the work, the river being at its lowest. During the time of the execution of the work this portion of the river is closed to the steamboats, and all supplies will have to be brought from the Needles in skiffs for a distance of from 50 to 90 miles. Under the circumstances, and the impossibility to foresee the many contingencies that might arise, involving expensive delays, it is easy to conceive that nothing like a reliable estimate can be made as to the cost of the work. No estimate is therefore submitted. For the same reasons it is not believed that the work can be economically done by contract if a contractor could be found at all willing to undertake the work. Similar improvements on the Upper Mississippi and Upper Missouri are made by hire of labor and purchase of material, no contractor being found willing to undertake them. The method recommended, therefore, is the purchase of the necessary plant, and the execution of the work by labor and purchase of material. A plant suitable for this work is estimated at a cost of $6,000, consisting of a derrickboat, with crab capstan and engine, a quarter-boat and bateau. Details for their construction have not yet been prepared. I have the honor to be, very respectfully, your obedient servant, Capt. A. H. PAYSON, Corps of Engineers, U. S. A. S. W. ROESSLER, First Lieut. of Engineers REPORT OF MR. W. P. SMITH, ASSISTANT ENGINEER. SIR: I have the honor to submit the following report upon the improvement of the Colorado River, made under your directions from November 1, 1884, to April 1, 185: After considerable inquiry, discussion, and thought as to what might be the best plant to put on the river, that would be the most suitable for the work required to be done; that would combine quarters for the men employed, and could be used for raising and moving large bowlders, carrying material for dams, &c., it was decided to construct one boat only that would serve all purposes. In November a barge was commenced, to be 100 feet in length, 26 feet beam, and of very light draught. It was supplied with a derrick capable of raising 12 tons and a steam capstan for moving the barge and handling the derrick. The frame was set up in San Francisco, then taken down, and, with the material for completing, shipped by rail to the Needles, a station on the Atlantic and Pacific Railroad, on the Colorado, 245 miles above Yuma. A force of carpenters and calkers left San Francisco December 7, and built the barge near the railroad bridge, 2 miles from the station. On January 8 the barge was ready to start up-river. Arrangements had been made with the railroad company owning the steamers on the river to tow the barge as far up-stream as the stage of water at the time would permit, and it was understood that the steamer would leave Yuma on January 1. From some misunderstanding the steamer did not leave Yuma until January 10, and then the river had fallen so low that it took her until the 25th to reach the Needles. On the morning of the 26th we left the Needles in tow of the steamer and ran that day to Fort Mojave, where we stopped to deliver freight. The next day continued up and ran until dark, stopping for the night near Bull's Head Cañon. The next day, the 28th, we made Mojave Ford or Crossing, over which the steamer could not go. There was less than 2 feet of water on the bar. Our barge, with stores and material for the season's work, drew less than 9 inches. We got up steam in the boiler and pulled ourselves over. The steamer returned to Yuma. The intention, and which was carried out, was to go as high up as El Dorado Cañon, 85 miles above the Needles-make examinations on the way up, and work as we dropped down-stream, at such places as we thought we might benefit during the short season before us. The distance from where the steamer left us to El Dorado Cañon is 34 miles. This was made in a few hours less than seven days, and nearly one whole day was lost from the anchor catching in a snag in mid-stream and stopping to clear it. This was our method of moving up-stream: We had two skiffs. Into one of them a line was coiled from a few hundred feet to 2,000 feet long, and the Indians rowed or towed this skiff as far up stream as the nature of the river would permit, and then, fastening the end of the line to a tree or rock or burying an anchor in the sand, would come down with the current, paying out the line astern. Coming to the barge the line was taken to the capstan, and when there was no special rapid, pulled the barge up stream at the rate of 2 miles per hour. The second skiff was working itself up-stream in the mean time with another line. So one skiff was always working upstream and one alongside receiving the line from the capstan. The capstan was rigged with a fast and a slow purchase. In the swift rapids a 44-inch line was well tried, but the capstan never failed to pull us steadily over. On February 4 we arrived at El Dorado Cañon, 7 days from Mojave Ford and 10 days from the Needles. One of the points where improvements were needed was at Hatteras Bar, 1 mile below El Dorado Cañon. The condition of the bar was the same as described in Lieutenant Roessler's report of October 4, 1884, making the allowance for the fall in the river, which was 2.5 feet since the time of his survey. As predicted by Lieutenant Roessler, the middle channel was the low-water channel of this season. The left channel was nearly closed by the cobble bar at the head and the right-hand channel by a gravel bar at the foot. Over the bar at the head of the left channel the river flowed only a few inches deep, and after crossing the bar, some 200 feet wide, made a deep and narrow channel, which kept the left bank and widened as we went down. The right-hand channel soon after leaving the head of the gravel island shoaled to 2 feet and escaped in many small outlets at the foot of the island. There were two ways suggested to me to improve this place: one to close the left and right channel, confining the river to the middle one; and the second to close the right and middle channels and open the left-hand one by cutting through the gravel bar at the head. The first of these, after making a survey, I concluded would not succeed for the reason that not sufficient increased velocity in the current would be obtained to start the gravel on the bar, and the shoal was too long (some 2,000 feet) to think of dredging or scraping. The water would be raised some in the channel, but unless the dam closing the left channel was very long the water would escape over the left-hand cobble island into the left channel and be lost to the middle channel. The second plan, closing the right and middle channel, seemed the one promising the best results, but when I ascertained that the dam must be 600 to 700 feet long, concluded, with the short season left us, and the more urgent work below, it would not be advisable to commence it. We accordingly moved down-stream 4 miles to Six Mile Bar, where it was necessary that something should be done this season. Steamboat men claim that Six Mile Rapid is the most dangerous point on the river below El Dorado Cañon. The numerous bowlders directly in the channel made it dangerous at or near low water, and after the river raised 8 or 10 feet the grade of the rapid became so great that it was very difficult to haul over. The reef of bowlders obstructing low-water navigation crosses the river diagonally, and was nearly 200 feet wide. When we arrived the river was 1.5 feet above low water. Two of the bowlders were just awash and some thirty more had less than 2 feet over them, and they were scattered entirely across the river, so that it looked impossible for a boat running the rapid to escape them all. Our improvement here made was a removal of the bowlders, clearing a channel 150 feet wide and to 3 feet of water at that stage. The bars on the river below would prevent steamers coming up when the river was lower, therefore 3 feet of water was considered all that was necessary for the present. Besides the removal of the bowlders, an attempt was made to relieve the rapid at the head by widening the river, and, if possible, lessen the grade. At Johnson's Rock the river at low water is only 175 feet wide. The bowlders and cobble from the point of the bar opposite the rock were removed 60 feet from the water's edge and the bar lowered 3 feet, giving the river that additional cross-section at this point. The rest of the bar, which was here 400 feet wide, was covered with bowlders of all sizes up to 10 tons' weight and many of them rising several feet above the general level of the bar, obstructing the flow of high water. The largest and most prominent of these were drilled and blasted into small pieces. The bowlders taken from the dry bar were placed in the form of a wing-dam from the left bank below the rapid. to confine the water at the foot of the rapid and assist in lessening the grade. We remained at Six Mile Rapid for twenty-five days, and in that time removed from the channel 36 bowlders from 1 to 12 tons' weight each. Eight were over 5 tons and 1 of 12 tons. Three hundred and eight tons of bowlders and cobbles were removed from the dry bar in widening out the head of the rapid and with which a wing-dam 150 feet in length was built at the foot of the rapid. One hundred and fourteen of the largest bowlders on the bar between low and high-water lines were drilled and broken up. The derrick and capstan on the barge handled stone of 12 tons with ease and safety. On March 3 we left Six Mile Bar and dropped down to Mojave Ford or Crossing, 28 miles. An examination was made, and the practical thing to do this year seemed to be to close the west channel around Northwest Island by a dam of stone. About one-third of the river was going down this channel with the river 2.6 feet above low water. Southwest Island is about 3,000 feet long and the ford or crossing is at the lower end of the island, the bar crossing obliquely to the left bank of the river. Bowlders and cobbles were found on the right bank at a convenient distance above the site of proposed dam, and the barge was loaded, dropped down to the dam, and built it in eleven days, taking 900 tons of stone. The dam connected the right bank with the head of the island, and was 464 feet long, 20 feet wide at base, and 200 feet of it was 5 feet high, the rest from 2 to 5 feet high. The immediate effect of the dam was to raise the water in the open channel six-tenths of a foot and lower the west channel 500 feet below the dam, 2.4 feet, the fall at the dam 3.2 feet. I do not expect that the best effect of the dam will be seen until another low water, when it is expected that the west channel will not open at all, but that the island will then be the west bank proper of the river. If this does not make a sufficient-water on the crossing, a dam must be run from the lower end of the island towards the east shore, contracting the river directly on the bar. It was now March 18, and the river was at the 3-foot mark and rising steadily. The only place where it was thought an improvement could be made that would warrant the expense was at Bowlder Rapid, 14 miles up-stream; so on that day we moved up and began widening the throat of the rapid, which is formed by a gravel, cobble, and bowlder bar on both sides, confining the river at low water to 120 feet in width. The left-hand bar was shelving, and permitted the river to flow smoothly over it. The right-hand bar was formed in ridges running at right angles to the current, producing at high water a succession of rapids, where the force and body of the current seemed to be. We spent eight days at this place, and in that time moved 550 tons of stone from the point of the right-hand bar back into a recess of the right bank, which widened the channel-way 100 feet and lowered the bar 2 feet. On removing the large bowlders and cobble from the surface we found a large proportion of sand mixed with those underneath, which the next high water will wash away, and another layer of cobble 2 feet deep can be removed the next low water. To facilitate this scour two ditches were cut, 4 feet wide and from 3 to 4 feet deep, parallel with the current and across the bar to give the high water a face to cut against. The river was now up to the 4-foot mark, and I knew of nothing more that could be done to advantage this season. On March 26 we dropped down to Hardyville, the safest place to leave the barge during the high water, and, after giving it a thorough cleaning up, left her in charge of a keeper. Two days later, on March 28, we reached the Needles, where the Indians were paid off and discharged, and the white men of the party returned to San Francisco. The force employed during the two months the barge was actually in commission was: 1 assistant engineer, 1 foreman and pilot, 1 mate, 1 steam engineer and blacksmith, 1 carpenter, 1 rodman, 1 cook, and a crew of Indians varying from 12 to 34. The laboring work and handling the barge was done by Indians, for which service 75 cents per day with board was paid. For water work, such as moving the barge, handling small boats and lines in all ways, the Indians are as serviceable, perhaps more so, than any white labor we could hire for the same service. For labor with shovel or barrow they were worth the price paid and no more. The greatest trouble with them was to keep the same ones contented for more than three or four weeks. It would be advisable to change them once a month if possible. SUGGESTIONS for future OPERATIONS. The river was examined for 12 miles above El Dorado Cañon or to the head of Roaring Rapid. As the steamers make occasional trips during high water for 75 miles above El Dorado Cañon, chiefly for salt used in the reduction of ores, I would suggest the removal of three rocks within the distance examined. In Roaring Rapid is a very dangerous rock directly in the channel and in the swiftest portion of the rapid. A sketch is shown in my note-book. When I was there the river was 2 feet above low water and the rock at the water-surface was 12 by 7 feet and the highest point 7 feet above water. It can be blasted out, but the barge must be taken there, as it is not safe to work from a small boat, the current is so swift. This is the most dangerous obstruction in the portion of the river navigated above El Dorado Cañon. In Papoose Rapid, 5 miles above El Dorado Cañon, is a large bowlder with top 2 feet above low water. This can be removed by drilling and blasting. Explorer's Rock, 4 miles above El Dorado Cañon, is the one which sunk the steamer of Lieutenant Ives's expedition. It is just awash at low water and can be removed or enough blasted off to make it harmless. Below El Dorado Cañon we have many places that can be improved with the time and funds. First comes Hatteras Bar, 1 mile below the cañon, where a dam will probably be needed closing the middle and right-hand channels. At Six Mile Rapid, if the river should go to its low-water mark, more of the bowlders can be taken from the channel and more from the dry bar on right-hand shore. I would suggest that a channel be opened east of Johnson's Rock by blasting down the high points of cement and cobble. This will relieve the rapid at the head, where most of the difficulty is experienced. The bars at head of Round Island and at head of Cottonwood Island were both good this year, but may need attention another year. At Bowlder Rapid the river was 4 feet high when work was done there this year. At or near low water, more of the cobbles and bowlders should be taken from righthand bar to widen the rapid at the head. At Mojave Ford or Crossing, the dam from the lower end of Southwest Island will probably be needed. Deep Rapid, 2 miles below Mojave Ford. Bowlders could be taken from each point, which would widen the channel and improve it. Pest House Rapid was good this year; had 3 feet of water. It looks as if the channel would be down the east bank another year. Greek Rock, 8 miles above Hardyville, is much in the way; top 1.2 feet above low water and directly in the channel. It can be easily blasted down. The above are the points where it appeared to me work would be the most needed next year. The effect of the present high water cannot however be foreseen. I notice that where the bars adjacent to all rapids slope evenly down to the water, we have a swift even current, but not a very troublesome rapid. When bowlders are left in ridges at considerable angle with the current, a bad rapid is formed, steep, troubled, and swift, especially at the upper end. This applies to sand in some degree as well as cobble and bowlders. I wish to give to Capt. J. A. Mellon, who acted as foreman and pilot, much of the credit of what we were able to do in the short season available. His long experience in navigating this river and in working Indians made his services invaluable. There are sent to accompany this report two note-books and four maps: Hatteras Bar, Six Mile Rapid, Bowlder Rapid, and Mojave Ford or Crossing, each on a scale of 1 inch to 200 feet. Respectfully submitted. W. P. SMITH, Capt. A. H. PAYSON, Corps of Engineers, U. S. A. R R 6. PRELIMINARY EXAMINATION OF YUBA RIVER, CALIFORNIA. San Francisco, Cal., October 24, 1884. GENERAL: Referring to the examination or survey of the Yuba River, California, provided for in the act of July 5, 1884, and which I was di rected to make by paragraph 9, Special Order No. 118, dated headquar |