Regionalization of heavy rainfall to improve climatic design values for infrastructure: case study in Southern Ontario,Canada |
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| Authors: | Edson Paixao Heather Auld M Monirul Qader Mirza Joan Klaassen Mark W Shephard |
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| Institution: | 1. Adaptation and Impacts Research Section (AIRS), Environment Canada , Toronto, Ontario, M3H 5T4, Canada edson.paixao@ec.gc.ca;3. Adaptation and Impacts Research Section (AIRS), Environment Canada , Toronto, Ontario, M3H 5T4, Canada |
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| Abstract: | Abstract Southern Ontario, Canada, has been impacted in recent years by many heavy rainfall and flooding events that have exceeded existing historical estimates of infrastructure design rainfall intensity–duration–frequency (IDF) values. These recent events and the limited number of short-duration recording raingauges have prompted the need to research the climatology of heavy rainfall events within the study area, review the existing design IDF methodologies, and evaluate alternative approaches to traditional point-based heavy rainfall IDF curves, such as regional IDF design values. The use of additional data and the regional frequency analysis methodology were explored for the study area, with the objective of validating identified clusters or homogeneous regions of extreme rainfall amounts through Ward's method. As the results illustrate, nine homogeneous regions were identified in Southern Ontario using the annual maximum series (AMS) for daily and 24-h rainfall data from climate and rate-of-rainfall or tipping bucket raingauge (TBRG) stations, respectively. In most cases, the generalized extreme value and logistic distributions were identified as the statistical distributions that provide the best fit for the 24-h and sub-daily rainfall data in the study area. A connection was observed between extreme rainfall variability, temporal scale of heavy rainfall events and location of each homogeneous region. Moreover, the analysis indicated that scaling factors cannot be used reliably to estimate sub-daily and sub-hourly values from 24- and 1-h data in Southern Ontario. Citation Paixao, E., Auld, H., Mirza, M.M.Q., Klaassen, J. & Shephard, M.W. (2011) Regionalization of heavy rainfall to improve climatic design values for infrastructure: case study in Southern Ontario, Canada. Hydrol. Sci. J. 56(7), 1067–1089. |
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| Keywords: | heavy rainfall events flooding intensity-duration-frequency regional frequency analysis infrastructure design |
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