WET LANDS OF SOUTHERN LOUISIANA. 43 



machinery. Where a large body of laud is to be ditched rapidly a more rapid 

 means than handwork is desirable, even where the cost by machinery is about 

 the same or even greater. Wheel excavators mounted on apron traction and 

 driven by gasoline engines have been very successful. They cut a very satis- 

 factory ditch .and place the excavated material farther back from the ditch 

 than is possible by hand. Where there is much timber or stumps these ma- 

 chines can not be used. Machines can not be used on the softer prairies until 

 the iand has been surface drained for some months and become somewhat 

 solid. A common practice has been to cut ditches at a spacing of about 1,000 

 feet by hand, the resulting drainage making it possible to use the machine 

 soon afterwards to cut the remaining ditches. Hundreds of miles of ditch have 

 been cut with excavators at from 3 to 6 cents per cubic yard. In one case 

 ditches were cut with a heavy wooden-framed plow, especially built for the 

 purpose, drawn across the strips of land between the reservoir canals by cables 

 and pulling engines mounted on barges. These ditches were cut as soon as 

 the pumps were started and the water drawn off the surface, which was many 

 months before the land would have supported the ordinary wheel excavator. 

 Ditches in this class of land require much attention for the first year or two 

 after cutting. A soft mud from the banks collects in the bottom, and rapidly 

 growing weeds and grasses impede the flow of the water and aid in the silting 

 process. The soil shrinks considerably after it is drained and cultivated, and 

 the effective depth is soon reduced below that required. This clean-out work is 

 done best by hand, but even that is an unsatisfactory process, the mud being 

 too thick to run out of the ditch, but also too thin to pick up with a shovel. By 

 selecting a time of scant rainfall, when the bottom of the ditch is nearly dry, 

 it can be cleaned the most effectively. It is necessary to cut the grass and 

 weeds in these ditches about twice a year, and for the first few years after 

 first cutting they will have to be cleared of soft mud at least once a year, 

 taking out about a cubic foot of material per linear foot. After perhaps four 

 years, cleaning will be necessary only once in two years. The cost of main- 

 taining these open field ditches would more than pay the interest on the extra 

 investment necessary to tile-drain the land. In addition there would be a 

 large saving in land and a greater convenience in farming operations. While a 

 shallow open ditch would still be necessary to carry away the run-off from 

 heavy rainfalls, the action of a well-laid tile drain would be much more uni- 

 form in taking away the ground water than would an open ditch, which is in 

 good condition only for a few weeks after it is cleared of grass and weeds. 

 It would not be possible to lay tile drains in the newly reclaimed lands, but 

 after they have become firm a large percentage of the open ditches should be 

 replaced by tile drains. 



Reservoir Canals. 



The primary requisite of the reservoir canals is that they give sufficient outlet 

 to the field ditches. To do this they must be spaced not much more than a 

 half mile apart and preferably should be located in parallel lines. Without 

 too much sacrifice of regularity they should be located in the lowest ground, 

 so that the flow of the water from the field ditch will be facilitated as much as 

 possible. The arrangement of canals also should be such that the water in 

 flowing from the farthest corner of the district to the pumping plant travels as 

 short a distance as practicable. 



The reservoir canal serves a two-fold purpose: (1) To take the water from 

 the small field ditches and carry it to the pumping plant, and (2) to store up the 

 dry-weather flow of the ditches so that the pumping plant will not need to be 

 operated so frequently. When some of the districts examined were first 



