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is not faced by an impervious blanket and does not have a 25-foot-wide crown-or it is otherwise slightly deficient in cross section; for the remaining half, the levee is slightly below grade.

The levees of the Yazoo Basin have been strengthened by the addition of about 90 miles of seepage berms designed to guard against danger from sand boils.

After leaving Vicksburg, there are no levees on the east bank of the river above Baton Rouge.

Passing now to the west bank, protection of the great Tensas Basin whose area is 5,370 square miles is accomplished by a levee 378 miles long and about 26 feet in average height. In order to tie into high land, this levee has to originate at Pine Bluff on the south bank of the Arkansas River about 117 miles above its mouth. It is the longest continuous levee line on the river.

The portion which follows the south bank of the Arkansas River is 66 miles long. It is not as high as the Mississippi River portion of the line but will average about 20 feet in height when completed. About 28 miles are already completed or under contract to present approved grade; of the remaining 38 miles, which require grade increases of from 1 to 6 feet, some 26 miles embracing the lowest stretches are to be cared for this coming fiscal year, leaving 12 miles for future years. About 8 miles of seepage berms have been built or are under contract. The arbitrary dividing line between the Arkansas River levee and the Mississippi River levee is at Yancopin. Between that point and the lower end of the levee near Old River at Point Breeze-312 leveemiles the embankement will average 28 feet in height. About 172 miles have been brought to grade or are under construction to grade. This includes 15 miles at the extreme lower end which are to remain at 1914 grade. Some 60 miles-between Willow Point and Lakeportshown on the chart as needing treatment are already above grade, but are to be given an impervious facing at some future time. Of the remaining 79 miles which require raising, 35 miles are to be raised during the coming fiscal year and the remainder in subsequent years. About 17 miles of seepage berms have been completed or are under construction. In general, the west-bank soils are less permeable than those of the east bank.

In the general vicinity of Old River, the project flood flow of 3,000,000 cubic feet per second is to divide equally between the Mississippi and the Atchafalaya Basin. The east bank of the Mississippi is not leveed between Vicksburg and Baton Rouge because the overflow basins are too narrow to warrant the cost of the high embankments that would be required for their protection. The highlands end at Baton Rouge, however, and the Pontchartrain and Lake Borgine Basins aggregating some 2,000 square miles require protection. The levee begins at Baton Rouge and is continuous for 172 miles to Pointea-la-Hache. Its average height is about 161⁄2 feet. At Bonnet Carre, some 33 river-miles above New Orleans, it is interrupted by the Bonnet Carre spillway, a needle dam structure some 7,700 feet in length whose function is to pass enough water from the river via a leveed floodway into Lake Pontchartrain to prevent the Carrollton (New Orleans) gage from reading higher than 20 feet. With 1,500,000 cubic feet per second in the river below Morganza, the withdrawal necessary to peg the Carrollton gage at 20 feet is estimated at 250,000 cubic feet per

second. The spillway has operated twice-1937 and 1945-and has performed its necessary function adequately both times.

On the west bank of the river, the levee is continuous from the head of the Atchafalaya River to the Jump (271 miles). Its height averages 1612 feet. Both the east bank and the west bank levees below Öld River are in general at or above approved grade. The exceptions are relatively short, isolated stretches, which are slightly deficient in grade or cross section or both. These deficiencies are being corrected as maintenance set-backs are made. The tightness of the soils below Old River makes the need for seepage berms infrequent. There are, however, about 111⁄2 miles of them.

As noted above, the east bank levee, insofar as the adopted project is concerned, ends at the Pointe-a-la-Hache gap. The levee line originally extended as far toward the Gulf as the west bank levee, and was included in the programs of the Mississippi River Commission to its end. In 1926, however, local interests, with the consent, but not at the instigation, of the commission created a relief outlet for floodwaters by degrading about 11 miles of levee southward from Bohemia, La. No further work was performed by the commission on the 22 miles of levee south of the outlet and it was not specifically mentioned in the project adopted in 1928. The territory behind it has, however, now developed into a great oyster and fur producing area with some cattle industry. The bank for some distance inland along the degraded reach has built up a great deal from repeated overflows, and diversions from the river are now largely concentrated in a few breaches in these natural levees. The land behind the levee southward of the gap has not built up and a crevasse in the levee would permit damaging flows to invade the area. During the flood of last winter assistance in preventing crevasses was rendered under section 6 of the 1928 Flood Control Act and there is small doubt that requests for aid will continue. The estimated expense involved is $400,000 to $600,000 required in the main for wave-wash protection.

The 1,500,000 cubic feet per second of the project flood flow which is to be carried through the Atchafalaya Basin has three distinct routes of travel down to the end of the Atchafalaya River levees where all three merge into a single broad leveed floodway about 15 miles wide with two outlets-one, the natural channel of Berwick Bay at Morgan City, the other, an artificial dredged and leveed channel near Calument, La., called the Wax Lake outlet. The separate routes followed in the upper part of the floodway are the Atchafalaya River, which is leveed for 55 miles below its head, which carried the flow of Red River plus flows of varying amounts from the Mississippi at practically all stages, and which, in the project flood, will probably carry from 600,000 to 700,000 cubic feet per second; the Morganza floodway, about 5 miles wide, which leaves the Mississippi just north of Morganza, La., and in a project flood will probably carry 600,000 to 650,000 cubic feet per second; and the west Atchafalaya floodway, some 10 miles wide which will come into action last and will carry the difference between the combined capacities of the Atchafalaya River_and the Morganza floodway, and the 1,500,000 cubic feet per second required to be diverted. If the Atchafalaya River and Morganza floodway perform as planned this difference will be but 150,000 to 300,000 cubic feet per second. The capacity of the west floodway is estimated

at about 600,000 cubic feet per second, so the margin of safety appears ample.

Except between the latitudes of Simmesport and Melville where the levee on the east bank protects the upper part of the Pointe Coupee Parish and has been raised to confining grade; the Atchafalaya River levees are maintained at existing height, which is below the grade of the floodway guide levees. This permits interchange of flow between the two floodways, and the river, in the event that either should become overloaded.

Water is to enter the west Atchafalaya floodway by overtopping and crevassing the so-called fuse-plug levee at its head. This levee is to be maintained at 1914 grade and 1928 cross section. It is already practically to that grade, and it is planned to bring it to full crosssectional dimensions this coming year.

It is planned to construct a control structure similar to that at Bonnet Carre at the head of the Morganza floodway, supplemented perhaps with a fuse-plug section to be breached in case the control structure proves unable to admit flow to the floodway's full capacity. The frequency of operation will depend upon a number of factors, including the amount of silting evidenced in its first operationwhich is still to be experienced. If silting is slight it will probably be used to reduce operation of Bonnet Carre where sedimentation has proved to be heavy.

The floodway guide levees above Berwick and Morgan City are completed except for closure of various gaps left for convenience of navigation, roads, and railroads, and for adjustment of grades involving increases of about 1 foot between Viva and Ramah, 26 miles on the east levee and between Courtableau and Catahoula, 49 miles on the west levee; levee enlargement by placement of second and third lifts on levees where soft foundation and poor material have necessitated this method of construction between Ramah and Morgan City (60 miles) on the east, and Catahoula and Berwick floodgate (58 miles) on the west. These levees range from about 1 foot to 5 feet below grade. About 2311⁄2 miles of grade raising and second-lift work are already under contract and it is planned to complete all of this work next year, insofar as foundations and physical limitations of the material will permit.

The east guide levee crosses the Plaquemine-Morgan City route of the Intracoastal Canal. A lock is planned at Bayou Sorrel. It has been offered to bidders and should be under construction very shortly. In the meantime, traffic has used a gap in the east guide levee at Bayou Sorrel, which has been a source of much trouble. When the Atchafalaya River overflows its banks, water enters the basin east of the guide levee through the gap and pressure is exerted by those living there to have it closed. Navigation on the other hand is interested in having it remain open because after it is closed vessels have to go about 150 miles farther (via Harvey lock and New Orleans) to reach ports north of Plaquemine, and have to contend with the swift Mississippi River currents all the way from New Orleans.

The traffic over the Plaquemine-Morgan City route amounted last calendar year to about 1,161,000 tons even with the route closed for about 5 months, and the year before to some 2,358,000 tons. The cost of moving that much commerce 150 miles farther, with 110 miles of

the added distance against a Mississippi River current, is considerable, and while one's sympathies may be with the small farmers and merchants whose way of life is disrupted by the water, and the natural inclination is to close the gap when even moderate flooding is in prospect, it has to be recognized that the navigation interests have equal rights. The problem is further complicated by the fact, not appreciated by many of the people affected, that below the latitude of Napoleonville or Pierre Part, the flooding is due in the main to backwater occasioned by high stages at Morgan City, induced or increased oftentimes by high wind tides and heavy rainfall. Closure of the gap for ordinary floods such as that of this year would not greatly affect stages in this area, where the bulk of the damage and discomfort occurs, as was evidenced last year, when closure (in the face of much higher predicted stages than have been in prospect this year) failed to afford relief below Pierre Part.

It cannot, of course, be alleged that it is desirable to have an opening in the levee, nor that closing it is not desirable. I am merely trying to point out that in the present instance the relief (with stages in prospect this year) would be entirely incommensurate with the expense and inconvenience occasioned navigation, and it became my unwelcome obligation to recommend accordingly.

We have advertised the Bayou Sorrel lock for contract but it will take at least 2 years to build it and the Bayou Pigeon Gap cannot be closed without disrupting navigation until the lock is ready, unless an alternate route to the east of the guide levee is made available. It fortunately appears that in connection with our plans for work below Morgan City the provision of such an alternate route can be justified. The manner of extending the Atchafalaya floodway levees below Morgan City and Barwick has been under study for a long time. A number of alternatives were investigated, each having its own advantages and draw-backs. It has finally been determined that the east levee should cross Bayou Boeuf just east of Morgan City, follow down the western shore of Avoca Island, cross Bayou Penchant, and continue to the lower end of Sweet Bay Lake. This obviously will require either a lock in Bayou Boeuf at Morgan City or a rerouting of the Intracoastal Canal. The latter appears to be preferable, hence it is planned to continue the route south from the present route beginning at mile 70 west of Harvey lock by a new cut reaching the Atchafalaya at the end of the proposed east Atchafalaya Basin levee. An added feature is a cut from the end of the proposed levee to Bayou Chene and improvement of Bayou Chene to compensate for the interruption of southward-flowing drainage entailed in closing Bayou Boeuf and Penchant by the east levee. The cut will incidentally provide a protected route to Morgan City from the modified Gulf-Intracoastal Waterway.

It is tentatively planned to place a floodgate in Bayou Boeuf at Morgan City. It is also planned to provide an alternate, slackwater route, for the Plaquemine-Morgan City sector of the canal by dredging a channel along the shore of Lake Palourde and performing such operations in Bayou Milhomme and other streams as are necessary to secure a workable alinement and 12-foot depths in the natural water courses above the lake. The cost of providing the

alternate route is about $950,000. It will obviate at high stages the difficult and somewhat dangerous trip up the lower Atchafalaya River and through the Morgan City railroad bridge-and will permit the closure of the Bayou Pigeon gap without forcing commerce to go materially out of its way. It is not planned to alter the highway and railroad bridges over Bayou Boeuf although their horizontal clearances-66.0 and 54.5 feet, respectively-are less than standard for the main Intracoastal. The plan as now conceived should adequately protect not only the Morgan City area and the lands below Pierre Part, now inundated by backwater, but the territory to the east near Houma as well.

On the west side it is planned to carry the levee line to the present Intracoastal Canal and along it to the spoil bank levee of the Wax Lake outlet, with a drainage canal running to the vicinity of Patterson for the evacuation of drainage from the leveed area between Berwick and Wax Lake outlet. The lowlands between the canal levee and the Teche Ridge should, it is believed, provide adequate sump storage facilities. If further study shows that they will not, it may be found desirable to extend the levees southward, closing the present Intracoastal Canal, or to provide pumping facilities. To provide adequately for navigation to Patterson which is a large shrimp-packing center, the plan includes the provision of a lock in the lower Atchafalaya River north of Berwick. This will furnish access to the shrimping fleet and other commerce at all times.

Considerable flooding has occurred between the Wax Lake outlet and the Bayou Sale Ridge and navigation has had trouble crossing the Wax Lake outlet when it was discharging floodwaters from the Atchafalaya Basin. For these reasons, and to avoid a difficult upstream trip against rapid currents in the lower Atchafalaya River for vessels traveling west on the Intracoastal Canal after it has been relocated east of the Atchafalaya River as proposed, it is planned to close the present canal at its intersection with the west spoil bank of the Wax Lake outlet and reroute it from Bayou Sale Ridge to Wax Lake Pass a wide body of water which should permit tows to traverse the outlet without danger-and from Wax Lake Pass to the lower end of Sweet Bay Lake.

The estimated cost of the treatment below Morgan City and Berwick, including the conversion to a lock of the floodgate in the lower Atchafalaya River north of Berwick on which construction had been started prior to the war and including the necessary rerouting of the Intracoastal Canal and the provision of an alternate route for high water use landward of the east guide levee is approximately $8,000,000. It constitutes a rather major modification of the existing project which originally contemplated termination at Morgan City in the form of a ring levee. It is conceived to be within the scope of the authority over engineering aspects of the project vested in the Chief of Engineers. In describing the state of completion of the floodway guide levees a little earlier it was mentioned that a number of gaps for roads and railroads remain. The 1936 Flood Control Act authorized the provision, at Federal expense, of three railroads and two highway crossings of the Morganza floodway and of one highway crossing, and of. one railroad crossing with suitable physical connections thereto, of the west floodway.

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