24 BULLETIN 304, TJ. S. DEPABTMENT OP AGBICULTTJBE. 



mine whether the plant is operating economically or wastefully — 

 records which would be of great value to the district immediately 

 Concerned as well as to others. 



As indirect evidence it may be stated that for many years in 

 central Illinois the one-fourth-inch coefficient has been used in 

 designing ditches for the drainage by gravity of flat lands and has 

 been found adequate and satisfactory. For a much longer time in 

 Holland and in the fens of England the coefficient of one-fourth inch 

 or a little more has been the basis used in the designing of pumping 

 plants. Although their total annual rainfall is about the same as in 

 Illinois, their climate is otherwise quite different. In England and 

 Holland there are many more rainy days, so that the rainfall is 

 much more evenly distributed than in this country. In these coun- 

 tries, too, there is much less sunshine and hot weather in summer, 

 and therefore less rapid evaporation. On the other hand, they do 

 not have such violent and excessive rains falling during brief periods 

 as we have. 



Valuable data were obtained from the Coal Creek, Pekin-La Marsh, 

 and East Peoria Districts on the Illinois River and from the Louisa- 

 Des Moines District on the Mississippi River. While the records at 

 the plants were carefully kept, unfortunately the periods covered by 

 the most accurate portions of the records do not include any very 

 heavy precipitation. The data obtained from each plant will be 

 discussed in the order the plants are mentioned. 



The Coal Creek Levee and Drainage District, near Beardstown, 111., 

 has been securing drainage by pumping since about 1898, though 

 entire success had not been attained previous to 1909. Up until the 

 end of 1913 the equipment of this plant was as follows: One 24-inch 

 centrifugal pump with a nominal rated capacity of 33.5 cubic feet 

 per second; and two 15-inch pumps, each rated at 15.5 cubic feet per 

 second, or a total capacity of 64.5 cubic feet per second. Since the 

 area of the watershed of the district is 7,425 acres, this would make 

 the approximate capacity of the plant 0.21 inch in depth in 24 hours. 



Since July, 1909, accurate and detailed daily records of the opera- 

 tion of this plant have been kept by the owners. With the knowledge 

 gained from these records of the stages of the water in the ditches, 

 the hours of pumping, the rainfall, and the capacities of the ditches 

 at the various ditch stages, the capacity of the plant as operated was 

 estimated. It was found to be a little over 0.14 inch per 24 hours. 

 The rainfall is measured at the pumping station by means of a rain 

 gauge of the Weather Bureau pattern. Between July 1, 1909, and 

 May, 1910, two very heavy periods of precipitation occurred. On 

 July 7, 8, and 9, 1909, the total rainfall was 2.8 inches, necessitating 

 that all the piimps be run continuously for 57 hours, after which one 

 of the smaller pumps was stopped and the other two were operated 



