N 8. UNITED STATES ENGINEER OFFICE, GENERAL: I have to submit the report of Lieutenant H. M. Adams, Corps of Engineers, United States Army, on a survey made at Brazos Santiago, Texas, in February, 1871. The work is located in the collection district of Brownsville, Texas, near the port of Brazos Santiago, and the light-house on Brazos Island, Texas. Commercial statistics will be forwarded when received. Very respectfully, your obedient servant, C. W. HOWELL, Brigadier General A. A. HUMPHREYS, UNITED STATES ENGINEER OFFICE, SIR: You are assigned to the duty of making an examination and survey of the harbor and pass of Brazos Santiago, Texas, for the purpose of collecting `all information needed to form plans and estimates for such work of improvement as you may recommend be undertaken by the General Government to deepen a channel across the par at the entrance to the pass, and to protect the harbor. You will be guided by verbal instructions received and by your own judgment as to the nature of examination to be made, as to extent and character of survey required. Very respectfully, your obedient servant, First Lieutenant H. M. ADAMS, C. W. HOWELL, Captain of Engineers, U. S. A. Corps of Engineers, U. S. A., New Orleans, Louisiana. NEW ORLEANS, LOUISIANA, March 13, 1871. SIR: I have the honor to submit the following report in compliance with the above letter of instructions. I left New Orleans on the 28th January, arrived at Brazos Santiago and commenced examination February 1. We were enabled to finish the field-work in time to return to New Orleans by the first steamer arriving here on 25th of February. The harbor of Brazos Santiago is situated about ten miles from the mouth of the Rio Grande. Nearly all freight brought to this point is immediately shipped on the river steamers, which run up the Rio Grande to Brownsville and Matamoras. The depth of water on the bar at the mouth of the river is 4 feet. This makes it necessary to "lighter" everything destined for Brownsville. The harbor at Brazos affords a good position for shifting freight from vessels which cannot cross the Brazos bar or to the river steamers which can cross the bar at the mouth of the river. All merchandise to be shipped from Brownsville is brought down the river and around through the Gulf to Brazos and then reshipped. The harbor at Brazos affords a secure anchorage and good point for reshipping freight in transitu to and from Brownsville. The entrance to the harbor, like the entrance to all harbors on the coast of Texas, is obstructed by a bar not extending directly across the mouth of the pass, but from points of the shore above and below, in a curved form, out to sea. The bar is situated so as to be entirely exposed to the action of heavy storms; it is composed of a quicksand formation, acted upon with extraordinary facility by water. The channel across the bar is constantly shifting and cannot be depended on from day to day. The depth of water at the time of the examination was 7 feet at high tide. The greatest depth of water in the harbor is 27 feet. The channel from Brazos to Point Isabel is 5 feet deep to within 100 yards of the old wharf at the point. I submit with this report a sketch showing the present condition of the bar, the pass, and the harbor. The improvement desired is a deeper channel across the bar. The harbor is ample for the commerce of the port and needs no protection. The small pass south of Brazos, called Boca Chica, was closed up in 1868, with the hope of increasing the amount of water flowing through the Brazos Pass, and the depth of water on the Brazos Bar by increasing the scouring effect of the ebb tide. Boca Chica remains completely closed, but the Brazos Bar has not been improved. From the best information which I have been able to collect, I am satisfied that the views submitted to the Chief of Engineers by Captain McClellan, in 1853, in regard to this bar, were undoubtedly correct. The examination which I have just made convinces me that his report is a concise and exact statement of the case. The main features of the harbor and bar have not in any particular changed, and I therefore submit the same opinion: "I regard it as impossible to improve the bar by dredging, scraping, or any similar means; for, supposing that means may be formed to overcome the difficulty of working on the bar so exposed, and that the channel were actually deepened to the required extent, it is certain that the same causes which now operate in so constantly shifting the position of the channel would almost immediately fill up any new one made by artificial means." The bar as it stands is the result of the joint action of the ebb current from the bay and the wind current and sea along the shore. The latter are constantly working to diminish the depth, while the former is striving to increase it. The present depth is the result of an equilibrium between the opposing forces. Dredge the bar to a greater depth, the equilibrium will be destroyed, and the outside current referred to will restore it. The present depth is all that the ebb current needs, and all it can get and hold from the opposing forces. Deepen the bar by dredging to-day, and it will fill up again to-morrow or a week hence. Such an improvement, if possible, would be of the most transitory character, as is clearly proved both by reason and experience. This must not be considered as applying to such bars as those at the delta of the Mississippi, where the current is always outward, and where the bars are formed by deposits from the current, totally different laws applying to such bars as these. The depth of water on the Brazos Bar is always increased by a strong north or northwest wind, but it takes only a few days of calm weather to restore the original depth. The depth of water on the bar in 1853 was reported as varying between 6 and 8 feet. It is about the same now, being greatest during the winter and spring, when the prevailing winds are from the north, and least in summer, when there are fewer storms and more southerly winds. It remains to be considered whether it is possible to improve the bar by contracting or changing the channel by means of dikes, jettees, &c. The only possible application of dikes, in this case, would be to prolong the walls of the outlet until they reached a point very near the present position of the bar, in order to concentrate upon one spot the whole action of whatever outward current there might be. The immediate effect of this might be favorable. The ultimate effect would undoubtedly be the formation of a new bar outside the present one, and that at no distant period. The foundation of the dike would be in quicksand, and the difficulties of construction would be very great. I have estimated the cost of a single concrete jettee of this kind, to be built out from the shore on the line A B, (see accompanying sketch,) the foundation to be constructed by covering the bottom with a layer of gunny sacks filled with hydraulic concrete. The sacks, being made of a loose coarse material, will retain the concrete in position, while a small portion will ooze through the pores of the cloth, and in a measure unité the bags. The bottom should also be covered on both sides in this way, for a distance of 15 feet. In view of the character of the bottom and distance the jettee will probably settle, the average cross-section is taken at 22 feet in width by 15 feet in height, the width being, at every point, 50 per cent. greater than the height. The jettee head should be circular, and 50 feet in diameter. Above the foundation the jettee may be built of blocks of hydraulic concrete. The concrete blocks are proposed to be laid without mortar, in courses, and to be lowered into position by means of cranes. If necessary, piles on each side of the jettee, with string-pieces and cross-pieces, may be used as guides in laying the blocks, and to bind them together as proposed by General McAllister in his plan for improving Galveston harbor, 1868. This kind of construction adopted for the purpose of estimate is the most economical consistent with any assurance of stability practicable on the Texas coast.. The method proposed for securing a foundation for the jettee has, I am told, been used with success. The jettee constructed in 1870 of piles by the city of Galveston, in the same kind of quicksand as that of the Brazos Bar, was undermined at the outher end, and about 100 feet carried away soon after it was finished. ESTIMATE. 1,752 palmetto piles, 25 feet long, at 30 cents per running foot.. cross-ties, at $50 per M.... 148,197 feet, board measure, 8 by 8-inch timber, for capping-pieces and $13, 140 00 3,506 bolts, 1 by 18 inches, (13,961 pounds,) at 12 cents.. 7,409 85 For driving 1,752 piles, at $2. For cutting and fitting capping and cross-ties, at 75 cents per pile. 1,675 32 1,314 00 30,610 sacks, at 20 cents... 3,504 00 49,431 cubic yards concrete, at $15, laid in jettee.. 6,122 00 741,465 00 Total cost of jettee..... 774,630 17 If, after constructing a jettee of this kind, it is found that the bar has only moved farther out into the Gulf, which will probably be the case, it will then be necessary to prolong the jettee to the new position of the bar. The object of submitting this estimate is to show the cost of what is believed to be the best plan for improvement. The necessities of the case do not seem to call for such an expenditure. Appended, and marked A, is a statement showing the number of clearances of vessels from Brazos, for the years 1869 and 1870. Application was made, February 2, to Mr. A. M. Burney, collector at Brownsville, for a detailed statement showing the kind and amount of merchandise imported and exported by way of Brazos. The answer to this request is appended, and marked B. Application has also been made to the agent of the Morgan Line steamers, and to the agent of King & Kennedy line of river steamers, for statistics showing the amount of freight carried in and out of this port. Very respectfully, your obedient servant, Captain C. W. HOWELL, H. M. ADAMS, First Lieutenant Engineers. Corps of Engineers, U. S. A., New Orleans, Louisiana. A.-Abstract of tonnage, &c., of vessels which have entered at the port of Brazos Santiago Texas, in the year ending December 31, 1869 Abstract of tonnage, &c., of vessels which have entered at the port of Brazos Santiago, Texas, in the year ending December 31, 1870. CUSTOM-HOUSE, Brownsville, Texas, April 13, 1871. SIR: In response to your request for statistics as to the quantity and description of merchandise passing through the port of Brazos de Santiago during the year 1869, 1870, I have to state that the imports amount to the sum of $1,668,663; that the exports amount to the sum of $2,624,794; total, $4,293,457; and consist of the following principal articles: Hides, wool, goat-skins, coffee, sugar, cigars, cocoa, dry-goods, machinery, tobacco, wines, liquors, &c. It will be a work of considerable magnitude to furnish the actual quantities and values of each specific article, and with the present force in this office it will be impracticable for me to make a full and complete report at once. Should it be deemed necessary for your purposes, however, I can give you such a report, but must take time for it, as I cannot omit my regular reports and returns to the Department. I attempted to give you a full report, but found that it would require so much labor and time that I deemed it best to give you the total values now, hoping that it may be sufficient for your purposes. Yours, &c., HENRY M. ADAMS, A. M. BARNEY, Collector. First Lieutenant Engineers, Box No. 950, New Orleans, Louisiana The above amounts do not include articles the growth, produce, and manufacture of the United States, but foreign merchandise, or bonded goods. A. M. B. N 9. UNITED STATES ENGINEER OFFICE, New Orleans, Louisiana, July 24, 1871. GENERAL: In compliance with instructions dated Office of the Chief of Engineers, Washington, D. C., March 15, 1871, I have caused to be made an examination at Mississippi City, State of Mississippi, for a harbor at that place connecting with Ship Island Harbor. The report of First Lieutenant H. M. Adams, Corps of Engineers, United States Army, who conducted the examination, is submitted herewith. The report of Lieutenant Adams deals simply with the question of construction and cost of a channel to connect an artificial harbor at Mississippi City with Ship Island Harbor. No estimate is considered necessary for the construction of the harbor itself, the cost of the connection being considered sufficient to condemn the project, not as impracticable, but as not warranted by the interests to be subserved. If this artificial harbor and canal should ever be constructed, it is quite certain that the tide-bore created between the head of the canal and Cat Island will effect the formation of a bar across the deep water toward Ship Island, which bar would require constant dredging to give a channel across it. Respectfully submitted. C. W. HOWELL, Brigadier General A. A. HUMPHREYS, NEW ORLEANS, LOUISIANA, June 20, 1871. SIR: In compliance with your instructions of the 11th instant, I have to make the following report on the examination which I have just completed at Mississippi City. Mississippi City is situated on Mississippi Sound, in the collection district of Bay St. Louis, about nine miles from the light-house at Biloxi, Mississippi, and twelve miles from Ship Island light. It is neither a port of entry nor delivery, and has no commerce. This so-called city was chartered some years ago, but has never been built. At present it consists of a few houses scattered along the beach, the whole population being less than one hundred. The city is without any natural advantages except those of a summer watering-place. There is no harbor, the place being situated directly on the open beach, which forms almost a straight line from Bay St. Louis to the Bay of Biloxi, Mississippi City being midway between the two bays. (See accompanying chart.) There is no reason to expect that Mississippi City will ever become anything more than a comfortable retreat for the citizens of Mobile and New Orleans during the warm weather and sickly season. The object of the survey and examination may be inferred from an act of the legislature of the State of Mississippi, which is appended to this report, and marked A. Ship Island Harbor is situated just opposite Mississippi City, and distant eight miles. It is proposed in the sixth section of the act referred to to connect Mississippi City with Ship Island Harbor by a ship-canal, starting from a point (marked A on the accompanying chart) where the water is 20 feet deep. The distance to the bank at Mississippi City is seven miles. The water shoals very gradually for the whole distance, being only 12 feet deep five miles from shore, and 8 feet deep two miles from shore. The bottom consists of a very soft blue mud. I have made borings to the depth of 29 feet below the surface of the water, and have ascertained that the bottom is of the same nature and same consistency for the entire depth, being so soft that a 3-inch pipe can be pushed down 18 feet into the mud by the weight of one man. It is not probable that a channel excavated through this material will remain open, even supposing it possible to excavate it without first inclosing it on both sides by some kind of cribwork. The amount of excavation necessary to open a channel 200 feet wide and 20 feet deep, (as proposed by the harbor company,) to within one mile of the shore, would be 1,591,431 cubic yards. At 30 cents per cubic yard, this would cost $477,429 30. The cost of protecting such a canal on both sides for a distance of six miles would be enormous. The cheapest kind of pier, which will at the same time have sufficient solidity to resist the action of the waves at this locality, is a crib-work filled with stone. The cribs may be built of palmetto logs or of the cabbage tree, these being the best to withstand the action of the ship-worms, which are very destructive in this locality. Yellow pine would be the cheapest, but it could not last more than two years, while the palmetto will stand fifteen or twenty years. The mean depth of water for the whole length where the canal must be excavated is 13 feet. (See line A B on chart.) It is probable that a crib loaded with stone will sink at least 7 feet into the soft mud of which the bottom is composed. Allowing the crib to project 2 feet above the surface of high water, the average height of the line of cribs will be 24 feet. The width of the crib ought at least to be equal to the height. The cribs should be built of 12-inch logs, with close ends and sides, the latter projecting two feet beyond the former. The bottom may be a heavy grillage of yellow pine logs. The ends and cross-ties must be dove-tailed into the side timbers, and all parts firmly united by bolts 14 inches diameter. |