River Boyne Water Quality Management Plan - EPA

Rivrr Bognr Walrr Quality Alanngrmrnl PlanTables 2.3 and 2.4 summarise the available hydrometric gauging records within the Boynecatchment. These records have significant limitations in terms of :-The coverage of the catch~tzentThe period of recordThe extent of records which are processed m~d available for useA data management system is required by means of which the hydrometric data would be regularlyupdated from the source agencies. Ultimately, this should be in digital fonn suitable for transferbetween the agency and local authority and regular update of the available record. Procedures in thedata management system for calculation of 95 percentile low flow and DWF automatically wouldupdate these key parameters as the dataset is extended.The dry weather flow (DWF) is taken as the minimum flow which might be expected to occur once in50 years. This critical parameter is necessary for consideration of the safe yield for water supplyabstraction and also in considering threshold levels for toxic and dangerous substances. The 95percentile flow is generally used in considering critical pollution thresholds and compliance withwater quelity standards. 95 percentile and DWF flows are presented inTables 2.3 and 2.1, based oncurrently available data.The Boyne arterial drainage scheme results in accelerateQ,rg 'from the catchment with reducedflood stornpe. Therefore, the current run-off regime ;Q v*"-L' bented by post drainage data only.For inspection purposes only.Consent of copyright owner required for any other use.EPA Export 26-07-2013:17:26:59