| Popis: |
The Bureau of Agricultural Engineering has, since 1910, been studying the problem of runoff from small areas of land. Early studies would be considered crude today but the technique has been gradually improved until now we feel that the studies cover fairly adequately the purposes for which they are made. The first studies undertaken were made for the purpose of determining the amount of runoff that should be provided for drainage-ditches that were to provide artificial drainage for cultivated land. When I joined the staff of Drainage Investigations, Office of Experiment Stations, in 1907, one of the moot points in the design of drainage-ditches was the amount of runoff it was necessary to provide for in order to secure adequate drainage ditches was the amount of runoff it was necessary to provide for in order to secure adequate drainage. About the only data available were the records of the United States Geological Survey in regard to the discharge of streams and every engineer engaged in this work—and there were not so many of us in those days—had his opinion as to the proper amount of runoff to provide for, but very little information with which to back his judgment. Consequently, the arguments were numerous and at times heated. |
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