32 BULLETIN 6;")2, U. S. DEPARTMENT OF AGBICtrLTTJEE. 



feet from the levee. The foundation :ii this point was of solid silly clay, but 

 examination showed thai the ground had been honeycombed to a depth of 

 several feet by muskrats or alligators. A trench aboul M feel deep was dug 

 immediately along the inside of the levee by means of an orange-peel bucket 



dredge which Heated in the outside canal. The material excavatod from the 



trench was then dropped back into it from a height of about 2f> feet by the 



same dredge, and the seepage was stopped entirely. No further seepage has 



been noticed. 



Ki.si i;voii: Canals. 



As shown in figure 7, the reservoir canals were all cut in the interior of 

 the district rather than along the levee. By extending the canals to all parts of 

 the tract the necessity of small collecting ditches was eliminated. A small 

 canal gives a much better outlet to the ditches than does the collecting ditch 

 aud is easier to maintain in good condition. Such canals can be of sufficient 

 depth to have from 1 to 2 feet of water in them to discourage the growth of 

 grass. These canals were cut with a small dipper dredge, aud the material was 

 deposited rather too close to the sides of the canal. This resulted in a certain 

 amount of shrinkage in the size of the canals, and by February. 1912, there 

 was from 2 to 4 feet of soft mud in them. A small hydraulic dredge was tried 

 at cleaniug out this mud, but was not successful owing to faults of coust ruc- 

 tion in the dredge. A large orange-peel dredge was used to clear the main 

 canal of silt in the latter part of 1913, but the lateral canals were still in 

 poor coudition. From that time until the summer of 191C the capacity of 

 the canals was not sufficient to bring the water to the pump rapidly enough 

 to secure operation at full capacity, except when the stage of the water was very 

 high. When the canal was empty at the pumping plant the water was still 

 relatively high in the farthest corner of the district. In 1916 these canals were 

 cleared of soft mud and enlarged somewhat by the use of a 1-yard dipper 

 dredge mounted on an IS-foot hull and swinging a 35-foot boom. The width of 

 the main canal now is about 42 feet and that of the small canals about 20 feet. 

 The average depth was increased from about 5 to !) feel. With this increased 

 depth and width good drainage is insured for the entire district, and the pump- 

 ing plant can be operated continuously until the water at the far end of the 

 district is lowered enough to give good drainage. Trior to (his clean-out work 

 it was necessary to run the pump a- few hours and then wait for the water to 

 come in slowly to the plant. 



The canals originally were smaller on this district (ban has become g 1 



practice, but if they had been cleared of silt early in 1913 there would have been 

 little interference with drainage. Such clearing out of the canals should be done 

 after they have been cut two or three years and the district drained for a year 

 or two. The material along these canals is now quite solid, and a second clear- 

 ing of the canals should not be necessary for a long term of years. 



Ditches. 



The spacing of the ditches on this tract is 210 feet. They are of about the 

 usual size. 3 to 4 feet deep with a 4-foot top and a 1-foot bottom width. All 

 discharge into the smaller lateral canals. Thus any silt which is carried along 

 in the ditches is deposited in the small canals and does not choke up the large 

 • anals. Due to the regular shape of the district and to the good layout of 

 canals, the ditches are all of about the same length, 2,000 feet, which has proved 

 to be satisfactory where ditches are kept in good condition. However, in the 

 portion of the district between the railroad and the nearest lateral canal the 

 problem of getting the water from the far end of the small ditch into the caual 



