44 BULLETIN 71, U. S. DEPARTMENT OF AGEICULTUEE. 



reduced to about 3 feet below the surface. The water was lowered very 

 slowly in the canals, beginning about tbe 1st of September, 1911. No large 

 slides occurred until about the end of December. At that time the water was 

 lowered to the bottom of the canal and the banks became very soft, due to 

 heavy and continued rains. In the immediate vicinity of the pumping plant, 

 where the water was the lowest, and where an old muck-filled bayou was 

 crossed, both sides of the main canal caved in for a length of about 200 feet. 

 The surrounding ground surface for a distance of 100 feet was lowered by this 

 action. The foregoing is a good illustration of the way this material will flow 

 when conditions are favorable. The capacity of the reservoir system when 

 it is brought back to its original size will be about 0.5 inch between the sur- 

 face and a 4-foot level. This should bring the water to the pumps in sufficient 

 quantities to keep both of them in operation until the water in the canal is 

 lowered to at least a 4-foot level. 



Ditches. 



The spacing of ditches on this tract probably will be about 200 feet. It is 

 likely that on the higher and more solid portions the ditches will not require 

 such close spacing as this, at least for the present. The ditches were being 

 cut with a ditcher similar to those usually employed on land of this character 

 and will be of the usual size. They will discharge into the small canals and 

 none of them will connect directly with the main reservoir canal. The idea is 

 to cause the silt to deposit In the small canals and thus leave the large canal 

 free from mud. Owing, to the regular shape of the district and the regular 

 arrangement of the canals the ditches will all be of about the same length and 

 the whole tract should receive about the same degree of drainage. The length 

 of ditch will be nearly 2,000 feet. With the good outlet that the canals will 

 afford, when compared with collecting ditches, this length should not prove to 

 be too long to afford good drainage. If the ditches are placed at the usual 

 spacing of about 200 feet the proportion of land in ditches and canals will 

 be 3.6 per cent. 



Pumping Plant. 



The pumping plant is located about 300 feet back from the bayou front, on a 

 leveed outfall canal. The plant was thus located in order that advantage might 

 be taken of a firm ridge of silt as a foundation for the machinery. The arrange- 

 ment and character of the foundation are shown in figure 13 and are very similar 

 to those of the foundation under the plant on area No. 4. In this plant there are 

 two units, which are duplicates. The pumps are cast-iron centrifugal with a 24- 

 inch diameter of discharge. Plate I, figure 2, shows this plant under construction 

 and gives an idea of the arrangement of boilers and machinery. The discharge 

 and Intake pipes are both enlarged and tapered the full length. The area of 

 the intake pii^e is about four and one-half times and the area of the end of the 

 discharge pipe is nearly three times that of the discharge opening on the pump. 

 This enlargeu)ent saves a loss of velocity head of nearly 4 feet, which is about 

 equal to the ordinary actual lift of the pumps. The intake pipes have but the 

 one elbow where they enter the pump and the discharge pipes are both straight. 

 These pumps .should operate very efficiently, as everything possible has been 

 done to cut out unnecessary losses. To each pump a 12 by 12 inch simple 

 vertical engine is direct connected with a flexible connection. Steam is fur- 

 nished by two return-tube boilers burning coal. Oil burners are now being 

 installed. This plant has been in operation since September, 1912, and is run- 

 ning very smoothly. Both of the units have been run continuously for a period 



