DRAINAGE OP WET LANDS OP SOUTHERN" LOUISIATSTA. 77 



items will vary greatly according to local conditions. An accompanying dia- 

 gram (fig. IS) shows comparative approximate costs of single-unit centrifugal 

 pumping plants erected complete, inclusive of foundations, but exclusive of 

 buildings, intake, discharge canals, or flume. These costs are based on esti- 

 mates for work in Louisiana and Texas, and the diagram is published by 

 courtesy of Mr. H. L. Hutson, of A. M. Lockett & Co. (Ltd.), New Orleans, La. 

 These figures are approximate, but are on the safe side, i. e., they take into 

 consideration construction under unusual difficulties. In making up these 

 costs it was assumed that the effects of the three items which are mentioned 

 as varying according to local conditions would be a constant percentage of the 

 cost of the plant. It is obvious that this diagram should not be used for 

 accurately obtaining the cost of a drainage plant, but that its chief usefulness 

 is in showing the relative cost of the various types of machinery, for deciding 

 upon the most economical size of unit to be used in large plants, and for making 

 approximate estimates of the total cost of plants. 



In making the diagram the cost of the plant has been divided into the cost 

 of the " water end," being pump, pump foundation, and piping ; and the cost of 

 the " steam end," which includes the engines, boilers, and their foundations 

 and auxiliaries. The cost of the water end is given in terms of gallons per 

 minute of rated capacity, and that of the steam end in terms of indicated horse- 

 power. Owing to the variation in costs, it is necessary to use zones instead of 

 lines to indicate them. 



The zone marked " Steam end, compound condensing Corliss or 4-valve en- 

 gines," includes the cost of this type of engine and water-tube boilers. The 

 zone marked " Compound condensing slide valve " includes the cost of this type 

 of engine and either water-tube or return tubular boilers, according to the size 

 of plant. The zone marked " Simple slide-valve noncondensing " includes the 

 cost of this type of engine and horizontal return tubular boilers. It will be 

 noted that for the higher class engines the cost is not indicated below about 10) 

 horsepower, as engines of this class can not be purchased in smaller sizes than 

 75 or 100 horsepower. 



In estimating the cost of a plant the following steps are necessary. With a 

 given capacity of plant in gallons per minute, estimate the cost of the water end 

 by use of the water-end zone. In order to get the cost of the steam end the 

 indicated horsepower must first be calculated. The water horsepower is first 

 determined, knowing the capacity and lift of the plant ; this is then divided by 

 the combined efficiency of the engine, transmission, pump, and piping, which 

 will give the indicated horsepower. By using the various zones of cost of 

 different types of engines, the cost of the steam end can be determined. Then 

 by combining the cost of water end and steam end the total cost of plant will 

 be determined. 



Cost of Operation. 



Full and complete records of pumping operations have not been kept on any 

 district in this section until the present investigation was started in June, 

 1909. The records of cost of operation are therefore incomplete, and those that 

 have been given are useful in illustrating the need for more efficient machinery 

 rather than as serving as a guide for estimating the cost of operation of drain- 

 age plants in this section. On page 78 is a statement showing the comparative 

 fuel costs of several types of pumping plants when removing 12 inches of water 

 from a tract of 1,000 acres at the rate of approximately 1 inch per 24 hours 

 against a total head on pump of 8 feet. This table and the one on page 80 have 

 been prepared by A. M. Lockett & Co. as being applicable to local conditions 

 and are published by their courtesy. 



