Extreme value theory applied to the definition of bathing water quality discounting limits

Haggarty, R. A., Ferguson, C. A., Scott, E. M. , Iroegbu, C. and Stidson, R. (2010) Extreme value theory applied to the definition of bathing water quality discounting limits. Water Research, 44(3), pp. 719-728. (doi: 10.1016/j.watres.2009.10.007)

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Publisher's URL: http://dx.doi.org/10.1016/j.watres.2009.10.007


The European Community Bathing Water Directive (European Parliament, 2006) set compliance standards for bathing waters across Europe, with minimum standards for microbiological indicators to be attained at all locations by 2015. The Directive allows up to 15% of samples affected by short-term pollution episodes to be disregarded from the figures used to classify bathing waters, provided certain management criteria have been met, including informing the public of short-term water pollution episodes. Therefore, a scientifically justifiable discounting limit is required which could be used as a management tool to determine the samples that should be removed. This paper investigates different methods of obtaining discounting limits, focusing in particular on extreme value methodology applied to data from Scottish bathing waters. Return level based limits derived from threshold models applied at a site-specific level improved the percentage of sites which met at least the minimum required standard. This approach provides a method of obtaining limits which identify the samples that should be removed from compliance calculations, although care has to be taken in terms of the quantity of data which is removed. (c) 2009 Elsevier Ltd. All rights reserved

Item Type:Articles
Keywords:Bathing water quality CRITERIA Discounting limits EC Directive Europe Extreme value modelling MANAGEMENT Methods MODEL MODELS
Glasgow Author(s) Enlighten ID:Scott, Professor Marian and O'Donnell, Dr Ruth and Miller, Professor Claire
Authors: Haggarty, R. A., Ferguson, C. A., Scott, E. M., Iroegbu, C., and Stidson, R.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Statistics
Journal Name:Water Research

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