The following is transcribed from the New York Times, dated April 21, 1862.

 

Present Defences of New Orleans

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          The Facts as Submitted to the War and Navy Departments. Topography of the City-Ease of Submerging it--The Defences of the Rigolets, Forts Pike and Wood--The Rebel Gunboats on the Lake--Plan of Isolating the City--Defences on the River, Forts Jackson and St, Philip--Rebel Gunboats and Rams on the River--Com. Porter's Plan of Dealing with the Great Rebel Chain--The City at Our Mercy--Probability of its Surrender.

The military situation at the mouth of the Mississippi becomes daily more and more intensely interesting. The City of New-Orleans is virtually besieged by land, lake, and river; and as we hear of the fall of one fort, and the assault upon another, our anxiety increases for the news that the metropolis of the South is once again under the flag of the Union. The defences of the City, natural and artificial, now being assailed by our naval forces, have been described as of vast extent, and very formidable. But we have heretofore had no information of them, at once recent and authentic. The description we gave recently in the TIMES, was mostly taken from rebel newspapers, and it was evident that many of the statements were in the usual style of rebel exaggeration. We are enabled this morning to publish a correct sketch of the city and its defences, from a New-Orleans gentleman, derived from data obtained on the spot after the defences were essentially in the condition in which they will be found by Gen. Butler and Commodore Porter. This evidence was submitted to the War and Navy Departments some time ago, and is now in the hands of our gallant commanders engaged in forcing the passes of the river. No city in the world is so peculiar in its topography as New-Orleans. It is situated on the left bank of the river, one hundred and ten miles from its principal mouth, the South Pass. It stretches or straggles along the bank of the river some six or seven miles, with an average depth of one mile, it only being possible to build on the narrow strip of land lying immediately on the edge of the river, the highest point being in front, and then rapidly sinking in the rear, until lost in interminable swamps. In the rear of New-Orleans, a half mile, perhaps, beyond the suburbs, is the Metarie ridge, a narrow strip of high land two or three feet above high water mark, of an average of a half mile in width; then you come again to the swamp, which continues to the shores of the lake beyond, almost as dense as any in the surrounding valley, gloomy and peculiar and uninhabited, except by alligators and bitterns. The front of New-Orleans is of course on the river, and from the peculiarity of the country, and the levee which serves to protect the city from being overflowed by the Spring rise, our fleet, when it reaches the city, will be above the ground on which the city is built, and command it as from an eminence. This circumstance, with this fact that the breaking of the levee by a cannon-shot, or a few minutes' work with the spade, would submerge the whole place, makes New-Orleans, with its defenceless rear, which we shall describe, the weakest and least protected place of any commercial importance in the world. There is no fortification immediately below the city. Seven or eight miles from the upper line of boundary there are built extensive earthworks on both sides of the river, and at the battle-ground, about an equal distance below the city, are similar low works without casemates, and on the 15th of January last without guns. The rear of New-Orleans may be said to consist of a chain of three lakes; the northern one, the Manshac; the next, Ponchartrain, more immediately in the rear of the city; then Lake Borgne, which is really a well-protected bay on the shores of the Gulf. Now, in approaching New-Orleans from the rear, our ships come out of the Gulf, starting, say, from Ship Island, pass, without obstacle, into Lake Borgne, proceed on to the Rigolets, a narrow entrance, half a mile wide, leading into Pontchartrain. Here, on an island, scarcely visible in the surrounding marsh, is situated Fort Pike; for it must be understood the Rigolets are not passages between high banks as usually suggested; but mere deeper packages in an almost unusual spread of water. Fort Pike is an old-fashioned United States work, mounting twelve casemated guns. The bar at the Rigolets seldom affords more than seven and a half feet of water, and this is really the defensive feature of the place; but each side of the bar the water is of great depth. Fort Wood, another fortification near by, but more inland, is not in the way of an advance to the rear of the city, and requires no description. Our mortar and gunboats once beyond Fort Pike, will find in Lake Pontchartrain, what is termed in New-Orleans, six gunboats -- ordinary lake boats -- mounting from two to six guns each, and two building, but not completed on the 15th of January last. These boats are not formidable, and would make but little resistance to our better-built and more perfect war-craft. The gunboats of the enemy taken, nothing interferes to interrupt the progress of our forces to the lake shore in the rear of the city. This shore is hard, and so continues for a short distance inland, when, as in the case of the land on the river front, it gradually sinks until it is lost in the surrounding swamp. If any defence is attempted by the Confederates, it must be made on the causeways -- the "shell-roads" -- that lead from New-Orleans out to the lakes, or by soldiers stationed along the ditches dug to drain the swamps; but our gunboats can easily and with precision shell out these named places, rendering every point untenable. But another important point can here be gained. Our gunboats can proceed up Pntochartrain 35 miles, when they will reach Pass Manshac, a narrow entrance that leads into the lake of that name. Here upon piles crosses the great. Northern railway; that is the only land connection New-Orleans has with the country lying on the Mississippi River. This connection destroyed, all communication with the city is cut off except by the river -- a catastrophe of itself almost fatal to a long successful defence. The second and most important approach to New-Orleans is, of course, up the Mississippi River. Here the defences are more multifarious, but are really, if we except one fortification, not formidable. Fort Jackson, the strongest work, is one of our old United States fortifications, situated sixty miles below the city, possessing sixteen casemated guns and some forty en barbette. Two of the guns are rifled 32s; several of the others are 58s; the remainder the old armament. Fort St. Philip, also a United States work, is directly opposite, (the river at this point is a trifle less than a half mile wide -- the Mississippi grows narrower as you approach its mouth;) is built of low earth walls, mounting forty guns, with no casemates built up to the middle of January last. These two forts are so situated that they command the river three miles below them. From shore to shore between these fortifications is stretched a chain, composed of cables stolen from the ships in the harbor of New-Orleans at the time of the breaking out of the rebellion. The chain is suspended within a few feet of the surface of the river by rafts, which are, in turn, held in their places by guys, running up stream, and fastened to the neighboring trees. This chain is formidable in this, that our boats must approach it from below, and will have, in striking it, to push it up stream, having both the strength of the chain and the force of the current to contend with. In addition to these forts or chains there were, on the 15th of January, eight gunboats afloat and four more building, now probably completed, mounting from two to four guns, but with no iron protection except to save the machinery from being damaged. The floating battery, made from the dry-docks, mounted twenty guns en barbette, having in the centre of the deck an iron casing, to protect the engine used in pumping the hull from intruding water. (This is probably the battery now at Island No. 10.) The people of New-Orleans on the 15th of January, were also building two large [???], cased with railroad iron, which were probably launched between the 1st and 15th of February; how formidable they are is not known. The Confederates, at the time just named, had also purchased (!) twenty towboats used on the Mississippi, their machinery [???] on deck, which they were to encase in iron, and, we believe, claim to have made very formidable, but the iron could only be applied to the machines, as New-Orleans could not supply the amount of material for a more complete armament. The gentleman from whom we have gleaned the facts regarding the Confederate defences up to the middle of January, says that there has never been in New-Orleans more than six or eight thousand regularly-organized troops; that the reported strength of fifty thousand includes the militia, which in turn takes in all the supposed able-bodied men in the city, who drill in the afternoons -- the large majority of whom do not wish or expect to meet the enemy in the shape of our Union forces. The facts we have stated were given to the War and Navy Departments on the 1st of February and Commodore PORTER and his brave compatriots have gone to New-Orleans with a clear idea of the work they have to accomplish. The gallant Commodore, at the description of the chain across the river, became excited, and promptly said, "I will run by steam two or three heavily-loaded boats on it, and let them sink the thing in the depths below," which, by the way, is near 200 feet to the bottom. Forts Jackson and Philip once taken by our troops, those who should know New-Orleans we [???] believe that the city will surrender. The mass of the permanent population is composed of intelligent men, and the commercial interests have always had a more clear idea of the folly of this rebellion than the people in the interior. At all events, after the forts alluded to fall, and the gunboats, which are not really formidable, are taken, New-Orleans is helpless -- more helpless indeed than any other city can be; and we look upon its speedy reduction, once the work is undertaken, as certain -- and with its fall snaps the backbone of this most formidable rebellion.

 

Present Defences of New Orleans. April 21, 1862. The New York Times Complete Civil War. CD-ROM. Black Dog & Leventhal, Inc. 2010