Review of methods for deriving areal reduction factors

Svensson, C.; Jones, D.A.. 2010 Review of methods for deriving areal reduction factors. Journal of Flood Risk Management, 3. 232-245.

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The design of hydraulic structures requires knowledge of how much rain is likely to fall within a certain amount of time, and over a specific area. Point rainfalls are only representative for a very limited area, and for larger areas the areal average rainfall depth is likely to be much smaller than at the point of maximum observed depth. The estimation of areal reduction factors is concerned with the relationship between the point and areal rainfalls. This relationship has been found to vary with, for example, predominant weather type, season and return period. Methods for estimation of areal reduction factors include empirical and analytical methods. The current design guidelines in the United Kingdom are based on an empirical method, but since they were issued in 1975, several new analytical methods have been proposed. These methods are discussed, and recommendations for an update suitable for United Kingdom conditions are made.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: CEH Topics & Objectives 2009 - 2012 > Water > WA Topic 3 - Science for Water Management > WA - 3.1 - Develop next generation methods for river flow frequency estimation and forecasting
UKCEH and CEH Sections/Science Areas: Boorman (to September 2014)
ISSN: 1753-318X
Additional Information. Not used in RCUK Gateway to Research.: The definitive version is available at The Journal of Flood Risk Management, Chartered Institution of Water and Environmental Management, and John wiley & Sons are acknowledged.
Additional Keywords: areal rainfall, areal reduction factor, design rainfall, methodology, rainfall
NORA Subject Terms: Meteorology and Climatology
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Date made live: 29 Sep 2010 13:35 +0 (UTC)

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