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The data files of rainfall including the weather stations of
CentralWeather Bureau, Taiwan Provincial Water Conservancy
Bureau, and Taiwan Electric Power Company were collected and
analysed in order todevelop the relations among rainfall
intensity , duration and frequency for Taiwan area. The annual
maximum serious is used for selection of rainfall in frequency
analysis. The criteria for selection of weather stations is
those have record length longer than ten years. In this
research, 167 stations were chosen, which include 21 stations
from Central Weather Bureau, 96 stations from Taiwan Provincial
Water Conservancy Bureau, and 50 stations from Taiwan Eletric
Power Company. Frequency analysis was done for a total of 167
stations based on Pearson Type of III distribution . The
results from frequency analysis is used as the source data for
developing rainfall intensity , duration and frequency
relations. Then, multiple regression is applied to estimate the
coefficients of Rainfall Intensity - Duraion - Frequency
formula. The regression is based on the source data from
frequency analysis corresponding return period and duration. In
order to improve the accuracy of Rainfall Intensity - Duration
- Frequency formula, The rainfall duration was divided into
long duration and short duration. The long duration is five to
seventy - two hours, and the short duration is ten minutes to
five hours. The established regional Rainall Intensity -
Duration - Frequency relationship for Taiwan has been
preliminarily verified and shown applicable in planning and
design of hydraulic works.
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