N 2. OFFICE OF THE CHIEF OF ENGINEERS, Washington, D. C., February 8, 1871. SIR: The communication from the Committee on Commerce of the Senate, referred to this office, inclosing a resolution of the Senate of the 14th December last, instructing that committee to inquire into the expediency of constructing a canal from the Mississippi River, near Fort St. Philip, to a point near Bréton Island, in the Gulf of Mexico, is herewith respectfully returned, and I also transmit a report from Captain C. W. Howell, Corps of Engineers, in charge of the improvement of the mouth of the Mississippi, to whom the subject of this resolution was referred. The information in the possession of this office in regard to this project indicates the practicability of constructing and maintaining such a canal, but it does not admit of the preparation of a project with estimate of cost. It has had for years past many advocates and opponents. In 1837, Major Chase, Corps of Engineers, prepared a careful estimate of its cost, upon a plan originating with Major Buisson, of New Orleans. He concluded that a canal 100 feet at surface and 30 feet deep would cost, all accessory works included, $10,000,000. Colonel Crozet, about the same time, advised a reduction of the depth to 20 feet, and believed that the cost would not then much exceed five million. Mr. Montaign, in a memoir upon the subject, printed in New Orleans in 1869, puts down the cost at $2,600,000, a sum beyond question entirely too low. Assuming the whole cost at $10,000,000-and it will probably not fall short of that sum-the yearly interest of this would be more than double the cost of maintaining two such dredge-boats as the one now successfully operating at the Southwest Pass, in constant work during the year, and insure a continued depth of 20 feet over the bar. Still, the project of a canal is one which deserves careful examination. I would, therefore, suggest an appropriation of $10,000 for the purpose of making careful investigation of all questions bearing upon its location and construction and estimates of its probable cost. Very respectfully, your obedient servant, Hon. W. W. BELKNAP, A. A. HUMPHREYS, Brigadier General and Chief of Engineers. Secretary of War. N 3. UNITED STATES ENGINEER OFFICE, GENERAL: In obedience to telegraphic orders of February 3, Í have to render this preliminary report of an examination made from the mouth of Bayou St. John, Louisiana, through Lake Pontchartrain and the Rigolets, to Ship Island. The line along which examination was directed is that proposed by the New Orleans and Ship Island Canal Company for the location of a ship-canal. The examination was made with a view to ascertaining the feasibility of this canal project. It was only considered necessary to determine the following, viz: 1st. The depth of water along the route indicated; 2d. The nature of the bottom and sub-strata where excavation would be required; and 3d. The probable action, on the bottom, of winds, tides, and storms. 1st. The first was ascertained by verifying the soundings exhibited on existing charts of the line, as well as it could be done while passing over the line in a steamer and employing an ordinary sounding-lead. The results are shown on a tracing submitted herewith. 2d. From the mouth of Bayou St. John to the head of the Rigolets the bottom was found to be composed of a very soft mud, that over the middle ground being of the lightest quality of alluvial deposit. The great depth of the Rigolet made it unnecessary to determine the nature of its bottom. The middle ground at the mouth of the Rigolet, (oppo. site the mouth of Pearl River,) extending to the tide-bore at St. Joseph's Island, is of the same material as the upper middle ground. The bottom of the tide-bore named is of stiff clay and sand. Passing St. Joseph's Island, there is found a large shoal produced by the tidecurrents through Mississippi Sound, Cat Island Pass, the St. Joseph tide-bore, and the entrance to Lake Borgne; its surface material is varied in character, being of light sand, and a deposit similar to that observed on the middle grounds, but more sticky and compact. The sand is found fringing the northern, eastern, and southern edges of the shoal, forming a hard bottom about 18 inches in thickness, resting on soft mud, the same as is found in the center of the shoal. This fringe was found of but slight width at the points examined. Passing this, through Cat Island Pass, there was found sticky clay bottom, and the same was observed on the bar at the entrance to Cat Island Pass. Along the whole line, at depths varying from 16 to 18 feet, was observed a stratum of clay and sand mixed, sticky and compact. The thickness of this stratum was not determined. As it underlies the deepest parts of the channels examined, it is shown to be at least from 12 to 14 feet thick. 3d. From the character of the bottom observed, the slight depth of water over the shoals, their exposed position, and the strong currents at times passing over them, it is inferred that their surfaces must be continually shifting. The sand-fringes observed on the outer shoal give evidence of a backward and forward movement of material across the shoal, and of a sorting of that material by the currents. The action of the tidecurrents alone may be slight, but when aided by storms or high winds, particularly over the outer shoal, which is exposed from every quarter, the movement over the surface of the shoals must be very considerable. I did not have an opportunity to observe this on the line examined, but judge from having observed the effect of a strong northwest wind on a bottom of like material similarly exposed, (Poza Bay,) depth of water from 7 to 8 feet. The deposit was stirred up in such quantity as to discolor the water of the bay. It is not to be inferred that other than comparatively slight and temporary changes may be effected in the form or location of the shoals or in the depth of water over them, for I have good evidence that for a very long period no appreciable permanent changes have taken place, particularly in the depth of water. What I infer is that but little first deposit is being added, and that the tendency of the tide-currents is to simply level the deposit on the shoals by moving it back and forth, (not. to carry it away,) maintaining a constant cross-section of water-way. However much storms, muds, or the hand of man may change this, the tides will act continuously and effectively to restore the normal condition; in other words, if excavation is made, it will be filled; if ridges are formed, they will be leveled.' I have styled this a preliminary report, because, although I consider the results of my first examination conclusive, I yet wish to multiply the number of borings along the line examined, and make more exact observations as to the thickness of the several strata found. When a second examination is made, I will forward the information gained as an addendum to this report. I take pleasure in acknowledging the courtesy of Captain Davis, of the United States revenue-cutter Wilderness, who afforded me many facilities for making this examination. In conclusion, I have the honor to be, very respectfully, your obedient servant, Brigadier General A. A. HUMPHREYS, C. W. HOWELL, Captain of Engineers. Chief of Engineers, U. S. A., Washington, D. C. N 4. UNITED STATES ENGINEER OFFICE, New Orleans, Louisiana, May 2, 1871. GENERAL: I have the honor to forward herewith a report made by First Lieutenant E. A. Woodruff, Corps of Engineers, United States Army, after a careful survey and examination at Corpus Christi and Aransas Passes, opening from Corpus Christi Bay and Harbor, Texas, and at Pass Cavallo, the entrance to Indianola Harbor, Texas. These surveys were made in compliance with instructions dated Office of the Chief of Engineers, Washington, D. C., July 23, 1870. Lieutenant Woodruff presents plans for improving the entrance to Corpus Christi Harbor through Aransas Pass, and estimates the cost of carrying them out, but does not recommend that the work be undertaken. No attempt to improve the two other passes is recommended. I coincide with Lieutenant Woodruff in the opinion that all the plans suggested and discussed by him offer no certainty of producing good results, and that the expense which will be incurred by testing them will be out of all proportion to the benefits derivable from success. Very respectfully, your obedient servant, C. W. HOWELL, Brigadier General A. A. HUMPHREYS, UNITED STATES ENGINEER OFFICE, New Orleans, Louisiana, April 1, 1871. SIR: I have the honor to report that I have complied with your instructions, dated at this office, February 7, 1871, directing me "to make examination and surveys of the bars at the entrance to Pass Cavallo, Aransas Pass, and Corpus Christi Pass, on the coast of Texas, for the purpose of collecting all information needed to form plans and estimates for such works of improvement as I may recommend be undertaken by the General Government to deepen the channel across the bars at the entrance of these passes." I submit the following report concerning each of the harbors mentioned, beginning with that of Corpus Christi: Corpus Christi Pass or Inlet is an entrance from the Gulf of Mexico to Corpus Christi Bay, between Mustang Island on the north and Padre Island on the south, in the collection district of Corpus Christi. The channel from the pass to Corpus Christi Bay is narrow, and bears in general direction nearly due north about six miles before reaching the deep water of the bay. Entering the pass from the Gulf, we find the water on the bar from 5 to 7 feet deep, varying with wind and tide. In the middle of the channel, at its mouth, are two sand islands, the lower of which extends at low tide to the coast line. These islands form a sand ridge, dividing the channel nearly equally for about two miles up from the coast line, where on the left we find a series of mud flats and low islands obstructing the entrance to Laguna del Madre. The south and deeper channel through the bar continues along the shore of Padre Island, gradually shoaling till lost in these mud flats, while the north and shallower channel is found near the shore of Mustang Island, till its entrance into Corpus Christi Bay. No passage deeper than 6 feet was found between the north and south channels above the island at the mouth, but from a short distance above these islands the channel near Mustang Island has from 10 to 20 feet of water to within about a mile from the deep water of Corpus Christi Bay. Here the channel divides, the part near Mustang Island carrying 3 or 4 feet into the bay, while the part which continues north has deep water, (10 to 18 feet,) till it is closed by a sand flat called "the bulkhead." The end of this channel in the bulkhead is called "the pocket," in ascending which the water suddenly shoals from 18 feet to 8 feet, gradually shoaling thence to 24 feet at low tide on the top of the bulkhead, whence it deepens gradually to the depth of the bay of Corpus Christi, 15 to 18 feet. The distance across the bulkhead from 8 feet in the pocket to 8 feet in Corpus Christi Bay at low tide is 2,400 feet, and the flat on the top of the bulkhead, where the water is 24 feet deep, is about 900 feet. This channel is evidently the natural outlet of Corpus Christi Bay, but the gradual accumulation of shell, mud, and sand washed from Flour Bluff on the west and Mustang Island on the east, has closed it at the bulkhead, and the bar. at the Gulf entrance prevents the safe entrance of vessels drawing over 5 feet. The length of the channel, six miles, from the bulkhead to Corpus Christi Pass, lessens the probability that a free passage of water from the bay would sufficiently deepen the pass through the bar, but the direction of the channel, the position and volume of Corpus Christi Bay, and the direction of prevailing winds, make it very probable that such passage would have a favorable influence in the improvement of the pass. At best, however, although the shore lines show a pretty straight passage from the bulkhead to the bar, the deep-water channel is narrow and crooked, precluding the possibility of vessels of ordinary size, in the Gulf trade, beating between the Gulf and Corpus Christi Bay. The commerce which seeks Corpus Christi, owing to the facilities for inland communication with Mexico and the region between the Nueces River and the Rio Grande, is of considerable and increasing importance; and as Corpus Christi Bay is in every way the best on the coast, it seems very desirable to open a good channel between it and the Gulf. Aransas Pass, fifteen miles north of Corpus Christi Pass, seems as susceptible of improvement as any on this coast, and it is my opinion that a channel to allow the free passage of water from Corpus Christi Bay to Aransas Pass would improve that entrance and afford at the same time a permanent way for vessels to Corpus Christi Bay. The superiority of Aransas Pass to Corpus Christi Pass as an entrance from the Gulf is evident from an inspection of the maps accompanying this report. At present the commerce of Corpus Christi passes through Corpus Christi Bayon, a narrow and crooked passage, through mud flats north of Harbor Island, which separates Aransas from Corpus Christi Bay. This passage gives only four or five feet of water, and requires the use of lighters to transport freight from Aransas Pass to Corpus Christi. The following statement, compiled by Dr. Thomas Kearney, collector of customs for the port of Corpus Christi, gives authentic information from which its importance may be judged: Total amount of duties collected, from organization of the district February 1, 1867, to May 1, 1870, $95,245; total expenses for same time, $40,670; total profit to United States, (gold,) $54,575. Table showing the different ports in the customs district from which duty has been collected, during the term of the present collector, up to May 1, 1870, (eleven months and thirteen days,) and the amount collected from each. Table showing value of merchandise, in bond, exported to Mexico from district of Corpus Christi, from 1st of January, 1868, to 24th of May, 1870; also value of merchandise which passed through respective ports. Value of bonded goods which entered warehouse in customs district of Corpus Christi, from June 17, 1867, to May 24, 1870, $135,890. Number and tonnage of vessels entered and cleared in customs district of Corpus Christi, from July 1, 1868, to May 1, 1870. Entered: Number, 253; tonnage, 45,803.90. Amount of produce and merchandise received and shipped at Corpus Christi, from 1st of January, 1869, to May 20, 1870, compiled from books of wharf agents. Merchandise received: 69,500 pounds assorted; 2,081,447 feet of lumber; 1,585,475 shingles. Produce shipped: Wool, 1,908,829 pounds; dry hides and skins, 2,220,953 pounds; tallow, 846,278 pounds; salt beef, 100,159 pounds; lard, 21,514 pounds; bones, 75,000 pounds; pig-lead, 340,651 pounds; rags, 2,381 pounds; horns, 5,198 pounds. ARANSAS PASS. By a comparison of the Coast Survey maps of 1853, 1868, and the map herewith submitted, February, 1871, it is seen that the channel is constantly encroaching on Mustang Island, (on the south,) while St. Joseph Island is accumulating, and making out with a low sand flat, with shoal water at considerable distance from the shore-line. In 1853 the channel through the bar was parallel to its present position, but farther north. In 1868 it was about perpendicular to its present position. In 1869 a work was begun by private enterprise, to improve the channel through the bar by running out lines of jettees from the St. Joseph Island shore, to cut off a secondary channel near this shore. These jettees, crates, or caissons, as they are variously called by the builders, were made of live-oak poles, spiked together in the general form of a triangular prism, and placed longitudinally. Each crate was about 8 or 10 feet long, 6 feet high, and 6 feet wide at the base, resembling, when in position, the roof of a house, with only rafters in place. These crates were ballasted with a few hundred-weight of stone, filled with brush, and sunk in two or three parallel rows, in the position described. They were expected to act as a nucleus, about which sand would settle, and close up the secondary channel, thus directing the flow of the water directly through the channel in the bar. From the fact that the secondary channel has shoaled about 2 feet, and the main channel deepened about 2 feet since placing the crates, it may be supposed that they have contributed to produce this result, but one of the oldest pilots holds that the change is due to storms, and would have taken place without any work. Owing to the constant erosion of Mustang Island, and consequent shifting of the pass to the sonth, in a few years the jettees mentioned will have no effect on the current, being left on St. Joseph's Island, which follows the channel in its progress south. It seems probable that the channel must continue to shoal, unless the erosion of Mustang Island, and consequent shifting and widening of the channel, can be prevented. The scour is at least 36 feet deep; hence any attempt to protect Mustang Island by a revetment would be expensive, requiring piles at least 45 feet in length, if a pile revetment were attempted. As any plan for deepening the channel through the bar by the action of the current must require the protection of Mustang Island against the encroachment of the channel, before attempting jettees or piers from the Gulf-shore line toward the bar, the means of affording such protection is the first question for consideration. Turtle Cove affords no passage over a foot in depth to Corpus Christi Bay; hence there is no current of importance at its mouth. The present entrance to Corpus Christi Bay is through Corpus Christi Bayou, a crooked channel of scant 5 feet of water, which enters Aransas Bay about ten miles from Aransas Pass. A canal 150 feet wide and 12 feet deep, from the mouth of Turtle Cove due west to Corpus Christi Bay, would allow sailing-vessels to pass in either direction at almost all times with the prevailing winds, thus opening the best bay on the Gulf as a harbor for vessels which could enter Aransas Pass. It is |