Hydrologic frequency study and analyses for allerton agricultural watersheds

Abstract

Hydrologic data are basic to the accurate design of hydraulic structures. The design requires an estimate of rainfall and runoff rates that can be ex- pected from watersheds for the design period. For this design, the amounts of water that have to be discharged must be known. If possible, these amounts should be assessed by direct measurements. If not, indirect methods, such as calculation of discharges from rainfall data, will have to be used (Stol, 1973). The most common hydrologic data used for designing hydrologic structures are rainfall and streamflow records. The first step in designing a water con- trol facility is to determine the probable recurrence of storms of different intensity and duration so that the most economical size structure can be pro- A vided (Schwab, 1966).