50 BULLETIN 71, U. S. DEPARTMENT OF AGRICULTURE. 



was secured to build a levee with a height of 5 feet and a top width of about 

 the same. Owing to the solid nature of the subsoil, the levee as a whole sub- 

 sides very little except for the usual shrinkage of the material itself. The 

 slight depth of muck also contributes to this favorable condition. In a few 

 places, however, some old muck-filled bayous have been encountered and the levee 

 remaining after one trip over with the dredge is only about 2 feet high. It 

 will be necessary to go over these spots several times to get the required 

 height. The berms left by the dredges doing the work are not much over 8 

 feet. No muck ditch is being used under this levee. Taking into considera- 

 tion the facts that the base of this levee is from 3 to 4 feet above mean tide, 

 that the storm tide in this vicinity is not more than 2 feet, that the subsoil is 

 very solid, and that the muck is only about 1 foot deep, it would seem in this 

 case to be the best practice to place the levee canals on the inside of the district 

 and thus to have use of them for drainage canals. 



The levee should be certain protection from storm tides that occur in this 

 section and should also cut off practically all seepage into the district. On the 

 other hand, as all the canals are on the inside of the district their usefulness 

 as navigation canals will be impaired. In the development of a district of this 

 size the advantage of having navigable canals all around it is considerable. On 

 newly reclaimed lands the question of water transportation is one of impor- 

 tance, as roads are very hard to construct when the land is first drained. It 

 is the intention to use the levee as a road for most of its length. 



Reservoir Canals. 



In addition to the canals that border this district a collecting canal has 

 been cut every half mile throughout. These collecting canals are about 7 feet 

 deep and the reservoir is of about the same depth at the upper end and 10 feet 

 deep at the lower end. In this soil these canals should maintain their original 

 depth and there should be no trouble from the flow of the earth when the canals 

 are first pumped out. The canals are of ample cross section to insure a small 

 loss of head when the pumps are in operation. When the water is lowered to a 

 level 4 feet below the surface the storage capacity will be 0.75 inch. 



A lock has been built at the end of the main reservoir so that barges can be 

 floated into the district. The depth of 10 feet in the main reservoir will 

 allow navigation even when the water is low enough to give drainage to the 

 entire tract. This district has one of the largest excavated reservoir capacities 

 of any of the districts so far attempted. The frequent and regular lateral 

 canals make it an easy matter to install an efficient ditch system. Plate III, 

 figure 1, shows a dipper dredge cutting reservoir canal and building levee on 

 this district. 



Ditches. 



Lateral ditches were cut on this district with an apron traction ditcher at a 

 uniform spacing of 330 feet. (See PI. Ill, fig. 2.) These machines worked on 

 this district in from 1 to 3 feet of water. Owing to the solid nature of the soil 

 the apron wheel did not sink into the ground to any great extent. Unlike the 

 districts that are being reclaimed in the vicinity of New Orleans, the soil will 

 not need to be drained for about two years before it becomes solid enough to 

 cultivate in the ordinary manner, and this district should come under cultiva- 

 tion quite soon after the system is installed. However, the old muck-filled 

 bayous will be soft for perhaps two years after the rest of the land is under 

 cultivation. In these bayous the muck is about 5 feet deep. The area of this 

 district that is in canals and ditches is about 3.2 per cent of the whole. 



