Storm Water Trigger Levels

A common provision of EPA issued IPC and Industrial Emissions licences is a requirement to monitor storm water emissions and set trigger levels for these emissions.

The methodology for setting Stormwater Trigger Levels is based upon the EPA ‘Guidance Note on the Setting of Trigger Values for Storm-water Discharges to off-site Surface Waters at EPA IPPC & Waste Licenced Facilities’ published in 2012.

Stormwater Trigger Levels are not a licenced emission limit value (ELV), rather, trigger levels are intended to give an indication of the normal levels of a given parameter in natural, unpolluted stormwater leaving a site. A deviation from this trigger level may indicate unintended contamination of stormwater, triggering a requirement to carry out an investigation of the potential sources of the deviation.

Trigger level is defined in the licence as a parameter value, the achievement or exceedance of which requires certain actions to be taken by the licensee.

Storm-water Trigger Levels are determined through a statistical assessment of the historic storm-water monitoring analysis at a site in order to establish site-specific storm-water “warning” and “action” trigger levels.

Panther Environmental Solutions Ltd can provide a quotation upon request for the preparation of a Stormwater Trigger Level Assessment report.

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