Avoca River ranks high on coun­try’s pol­luted list

Bray People - - Kilmacanoguediary - Myles BUCHANAN

DE­SPITE show­ing some in­fre­quent signs of im­prove­ment, the Avoca River is still one of the most se­ri­ously pol­luted rivers the coun­try.

Sil­ver Strand and Brit­tas Bay beaches meet the strictest of EU stan­dards, while Bray and Grey­stones can’t quite meet those stan­dards, and the Up­per Glendalough Lake and its feeder streams are amongst the most acid­sen­si­tive you could find.

Th­ese are just some of the re­sults con­tained in a re­port re­leased by the EPA de­tail­ing the state of the na­tions en­vi­ron­ment.

‘Ire­land’s En­vi­ron­ment 2008’ is the fourth such re­port car­ried out and sums up the state of the en­vi­ron­ment across themes such as cli­mate change, air qual­ity and emis­sions, waste, chem­i­cals, land and soil.

But per­haps the most re­veal­ing statis­tics can be found in the wa­ter qual­ity sec­tion, in­clud­ing the wa­ter qual­ity of lakes, rivers and es­tu­ar­ies and coastal ar­eas.

LAKES

Wick­low has the most acid-sen­si­tive lake sys­tems in Ire­land, with only the west­ern seaboard any kind of match. This oc­curs in ar­eas with slowly weath­er­ing bedrock for­ma­tions such as gran­ite, shale, gneiss, sand­stone and other as­so­ci­ated soils.

It means that sur­face wa­ters have very low alkan­lin­ity lev­els and as a re­sult have a poor ca­pac­ity to neu­tralise acid in­puts. The Up­per Glendalough Lake would be one of the largest acid-sen­si­tive lakes in Ire­land, which would also af­fect any feeder streams.

This can re­sult in el­e­vated lev­els of phos­pho­rus and ni­tro­gen, which can given rise to over en­rich­ment. This is a form of pol­lu­tion which re­sults in in­creased phy­to­plank­ton growth and in­ten­sive al­gal bloom and a de­cline in wa­ter trans­parency

Tests car­ried out be­tween 2004 and 2006 showed the Lug­duff River, which flows into the Glendalough Lake Up­per, is ac­tu­ally show­ing signs of im­prove­ment. It was re­garded as se­verely im­pacted each time it was sam­pled from 1985 to 2003, to moderate on two sam­pling oc­ca­sions, to no im­pact the one time it was sam­pled dur­ing the cur­rent pe­riod.

How­ever, the forestry sur­round­ing the Lug­duff does cause acid in­puts and will con­tinue to do so.

Over­all a slight im­prove­ment is no­tice­able both at Lug­duff and Glendalough.

RIVER QUAL­I­TIES

Ini­tially tests car­ried out brought about some good news with re­gards to the Avoca River, but un­for­tu­nately it wasn’t to last long.

It had been re­moved from the list of se­ri­ously pol­luted lo­ca­tions af­ter tests in 2006 noted a marked im­prove­ment, but that proved tem­po­rary.

Tests in 2007 showed that a 11.5 km stretch of the river was once again classified as se­ri­ously pol­luted. Its prox­im­ity to acid mine leachate since the 1850s has al­ways left it very vul­ner­a­ble.

Only 0.5 per cent of the to­tal river length tested na­tion­ally proved se­ri­ously pol­luted.

A num­ber of fish kills were also doc­u­mented in the Avoca River due to mine wastes. It seems the river re­cov­ers from time to time, al­low­ing fish to re­turn. But this re­cov­ery is al­ways brief, and toxic con­di­tions re­oc­cur when there is a low flow or high dis­charge from the old mines, re­sult­ing in fur­ther fish kills.

The fu­ture is also omi­nous for Brown’s Beck Brook in the Donard area where 0.5 of the river has been caused by agri­cul­ture, first noted in 2004.

ES­TU­AR­INE

An­nual mon­i­tor­ing of bathing wa­ters was car­ried out at 131 des­ig­nated ar­eas through­out the coun­try, in­clud­ing Bray, Grey­stones, Sil­ver Strand and Brit­tas Bay beaches. The pro­por­tion of sea­wa­ter bathing ar­eas com­ply­ing with strin­gent EU guide­line stan­dards fell from 92 per cent in 2005 to 81 per cent in 2007.

But Brit­tas Bay, both up­per and lower sec­tions of the beach, and Sil­ver Strand still meet those strict EU re­quire­ments. Bray and Grey­stones don’t meet the EU Guide Val­ues, but are con­sid­ered com­pli­ant with the less strin­gent EU Manda­tory Val­ues. This means they don’t match the good qual­ity of Brit­tas Bay or Sil­ver Strand but are still deemed ac­cept­able qual­ity.

Brit­tas Bay is the only beach in the county deemed of high enough qual­ity to re­ceive Blue Flag recog­ni­tion. In or­der to re­ceive such sta­tus, a beach must main­tain a high stan­dard of wa­ter qual­ity, and meet spe­cific en­vi­ron­men­tal and safety ser­vices re­quire­ments.

While oxy­gen con­di­tions in the ma­jor­ity of Ir­ish es­tu­ar­ies and coastal wa­ters re­main high, by far the low­est lev­els in the coun­try were recorded in the up­per reaches of the Avoca es­tu­ary.

Some of the most eu­trophic wa­ter con­di­tions in the whole coun­try were recorded in the Slaney. This pol­lu­tion man­i­fests it­self in the form of nu­tri­ent en­rich­ment.

The scene that greets tourists at the pic­turesque Glendalough Lake.

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