A class of Step Change events, generally improvements that mark a step change water quality such that it is no longer appropriate to include samples taken prior to the step change in on-going annual compliance assessments
Article 5 of the EC Bathing Water Directive (76/160/EEC) allows the Environment Agency to disregard results that exceed the bathing water standards if they were affected by floods, other natural disasters or abnormal weather conditions.
This applies to both the mandatory and guideline bathing water quality standards.
Our monitoring policy requires us to take bathing water samples according to a pre-determined timetable. We don't avoid taking samples because there is a forecast of wet weather. If it subsequently happens that there is a mandatory exceedence and the sample was affected by abnormally wet weather, flooding or natural disaster, we will make an application for a waiver. If the application is successful the sample result will be disregarded when we assess compliance but it will not be removed from our public register.
Our policy for waiving bathing water results as a result of abnormal weather conditions has been agreed with Defra.
Abnormal weather for the purposes of the Bathing Water Directive is defined as a storm event with return period of at least 1 in 5 years. A storm event will usually have occurred between 1 to 48 hours before the sample was taken (exceptionally upto 72 hours for larger catchments). We use rainfall data from rain-gauges that are representative of the bathing water catchment and approved by the Met Office. We then use this data to make an assessment based on the 1 in 5 year criteria.
The sample results displayed in the 'What's in your Backyard' section of our website only hold the results used to assess Bathing Water Directive compliance. When a waiver is granted the result is removed from this site but is still available to the public through our public register.