DESIGN A HYDRAULIC STRUCTURE USING THE RAINFALL INTENSITY- DURATION- FREQUENCY RELATIONSHIP IN IRAQ

A hydrologic analysis is an essential prerequisite for any project, is used to the evaluation of the watershed area for a stream and is used to determine the design discharge or the amount of runoff the culvert should be designed to convey. In this paper the relationship between the intensity- duration- and frequency of rainfall are used to obtain the value of discharge to design a pipe culvert for Najaf station in Iraq, from the relationship be tween Intensity-duration-frequency (IDF) curves, the values of intensity for 10, 100 years return periods with 15, 30, and 60 min. durations are obtained and discharge values are obtained from multiplied the catchment area for Najaf station by the values of intensity for obtaining.