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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Flood risk management and adaptation : Daily rainfall disaggregation for flood estimation
Daily rainfall disaggregation for flood estimation
Author : PHUONG CU THI(1) & JAMES E BALL(2)
ABSTRACT
Rainfall is one of the more important factors influencing flows in a river and particularly so for flood flows in a river. Hence
there is a need to adequately model rainfall if flows in rivers are to be predicted with reliability. There are three
components to a rainfall model, namely the rainfall depth, the spatial distribution of rainfall and the temporal distribution of
rainfall. This last aspect of a rainfall model is the focus herein. In many Asian countries, data for assessing the sub-daily
temporal distribution of rainfall is limited by the availability of continuous records. It is far more common for daily rainfall
records to be available. However, these records are rarely suitable for estimation of flood events. There is a need,
therefore to disaggregate these daily rainfall records. One method that has been applied to the problem of disaggregation
of daily rainfall records is the “Method of Fragments”. Presented herein is an application of the “Method of Fragments” to
the disaggregation of daily rainfall records in the Ba River catchment in Vietnam. In this catchment, 14 daily-read gauges
and 12 hourly rainfall stations across the basin were available. The similarity of the these gauges was evaluated using a
Welch Two Sample t-test and the Bartlett test for homogeneity of variances to ensure data transfer did not induce different
characteristics. Following application of the disaggregation model, the estimated rainfall patterns were validated at 3
stations where hourly data was available. Based on the results obtained, application of the “Method of Fragments” to
disaggregate daily rainfalls in a monsoonal region is a suitable method for estimating the temporal pattern of rainfall at a
resolution suitable for flood estimation.
File Size : 429,490 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Flood risk management and adaptation
Date Published : 19/08/2015
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