River Boyne Water Quality Management Plan - EPA

River Bovnc Wnlrr Oualihl Manrecmcnt Plan5. Current Water Quality5. J IntroductionWater quality in the River Boyne catchment has been assessed as follows:-* Biological monitoring; biological assessment expressed as a biotic index which combinesdiversity on the basis of certain taxonomic groups, with the pollution indication of individualspecies or groups, into a single index or score. The water resources branch of the EPAformerly ERlJ has developed a biotic index suitable for the procedures used in theevaluation of Irish Water Bodies. The basis of the index is summarised in Table 5.1. Itprovides a relatioitship behveen water qualip and typical rr@e fauna rangingfrom Q1 (bad)to Q5 (good). These ratings cart be further interpreted to four basic classifications of"~i~~poNuted", "slight pollution" "moderate pollulion " and "serious pollzition " at times.Physico-cliemical assessment ; physical and chemical paranteters which can determine thecharacteristics of the water column based on laboratory analysis. These parameters can bereferenced to specified standards such as those previozrs!~ summarised in E. U Directives andassociated Natioi~al Regulatio~ts (dissolved oxygen. BOD. suspended solids, phosphates.nilrates, ammonia, etc.).,.cMicro6iulogical nssessment ; generully zrsed t3~s.g te pzrblic health issues associatedwith water qzialip. Typical microbiological p&f"'/ers ore fora1 coliforms, faecal colifor~ns.faecal streptocacci, salmonella and enter&;&lses. These parameters are particularly+' .U:significurit in the context of the bathii~g~w~hyat~d dri~tkirig water standards (see 4.9).,+ ,G.ab -c"*X \VTruphic status ; based oil assessr$I?it+pf plant and algal production associated with ntrtrientloads. This is an important parb&er in the cantex/ of lakes and slow moving rivers where-Cnutrient enrichriient can result &I very serious water qualify impacts such as severe algalblooms with associated sev&' changes in oxygen concen@ation, water qualip and tasteproblems due to subseqzier&igal decay5.2 Biological Quality AssessmentFor inspection purposes only.Consent of copyright owner required for any other use.The EPA carry out regular biological assessment of Irish rivers which provide a basis for determiningcurrent water quality status and trends over time. Biological assessment has important advantagesover chemical-data in the following respects:-Biological organisms integrate pollution effects over time, whereas chemical data representsa once oflrepresentation of conditions in the water column at a test locationBiological communities integrate the effects of azrltiple stresses and clemonstrate ctrmulativeimpactsBiological conimunities can serve as early warning by detecting iitternlittent poNzrtion andsubtle changes, missed by occasional chemical szirveys (e.g. the ir~ipact of storm sewerover$'ows)EPA Export 26-07-2013:17:27:00