Bathing water signage and predictive water quality models in Scotland

Authors

  • Calum D. McPhail Scottish Environment Protection Agency, Redwood Crescent, Peel Park, East Kilbride, G74 5PP, Scotland, UK
  • Ruth T. Stidson Scottish Environment Protection Agency, Clearwater House, Heriot Watt Research Park, Avenue North, Riccarton, Edinburgh, EH14 4AP, Scotland, UK

Keywords:

faecal indicator organisms, bathing waters, prediction, advisory notices, EU Bathing Water Directive 2006

Abstract

The Scottish Environment Protection Agency (SEPA) has developed, and runs, real-time bathing water quality predictions at ten sites throughout Scotland since 2004. Daily bathing water quality predictions are posted on electronic variable message signs at 10 beach locations networked to a central communication centre and updates are simultaneously made on the SEPA website, phone and text message service.

Antecedent rainfall and subsequent river flow can significantly increase the concentrations of faecal indicator organisms in bathing waters. The SEPA signage prediction tool, an Excel spreadsheet based model, was developed and used to set site-specific criteria for rainfall and river flow to predict bathing water quality based on historical data. Real-time predictions against the current EU Bathing Water Directive were correct or precautionary on 99% of days and correct for 82% of compliance samples during 2007, and 81% of compliance samples during the 2008 season.

The revised 2006 Directive sets out more stringent bathing water quality standards which require increased model performance. New predictive models are now being trailed using decision tree statistical software and are intended to replace the existing prediction tool by 2012.

References

Crowther, J., Kay, D. and Wyer, M. D. 2001. Relationships between microbial water quality and environmental conditions in coastal recreational water: the Fylde coast, UK. Water Research, 35: 4029–4038.

Crowther, J., Wyer, M. D., Bradford, M., Kay, D. and Francis, C. A. 2003. Modelling faecal indicator concentrations in large rural catchments using land use and topographic data. Journal of Applied Microbiology, 94: 962–973.

McPhail, C. and Stidson, R. 2004. The Scottish Signage Project. Water and Environment Magazine, 9(4): 12–14.

SEPA. 2001. Technical Paper—A Study Of Bathing Waters Compliance with EC Directive 76/160/EEC:The Relationship Between Exceedence of Standards and Antecedent Rainfall www.sepa.org.uk/data/bathingwaters SEPA website

Scottish Government. 2003. Bathing Water Signage Pilot Project www.scotland.gov.uk/Topics/Environment/Water/bathingwaters/Signage Scottish Government website

Published

2009-05-27

Issue

Section

Research article