Study on extraction of storm rainfall events in a small urban watershed considering non-rainfall duration

Abstract

Recently, storm rainfall is very short time. So, it is necessary to consider the method of extracting the storm rainfall events. This paper studies on extraction method of storm rainfall events considering non-rainfall duration using the 1-minute ground observation rainfall data in a small urban watershed. A target observation point was Ikebukuro-bashi in the upper basin of Kanda river, Tokyo. Rainfall event is defined as another event by greater than the value of the period of non-rainfall duration. By changing the period of non-rainfall duration, it was possible to investigate the deference of rainfall duration and total amount of rainfall of storm rainfall events. The results showed that, using 1-minute data, it is desirable to define the storm rainfall event as another event when the period of non-rainfall duration continues for more than one hour.