A “Serious fish kill” in County Limerick this summer started in County Cork.
Cork County Council confirmed there was a silage effluent discharge to the River Deel in May.
“The silage effluent discharge occurred on a farm near Milford in County Cork. Inland Fisheries Ireland officers indicated that they observed almost 600 dead fish of various species in the 6km river stretch downstream of the silage effluent discharge location.
“The incident occurred close to the Cork-Limerick border and the majority of the dead fish were found in County Limerick,” said a spokesperson for Cork County Council.
Action is being taken against the responsible farmer, they stated.
“The farm in question has good silage storage facilities with effluent collection channels and a slatted tank for storing effluent. A pit of silage was made in late May on the farm.
“The silage was wet, the pit split, causing the silage to slip out past the effluent collection channels. Due to this slippage effluent escaped to a nearby drain and flowed to the river,” said the spokesperson.
The farmer co-operated fully with the authorities - Inland Fisheries Ireland, Limerick City and County Council, and Cork County Council - in controlling the spillage once it was brought to his attention.
“This was an accidental silage effluent spillage which occurred on a farmyard with good silage storage facilities. It demonstrates that even with good facilities it is essential that management is good and that farmers need to be very vigilant in dealing with silage effluent,” said the spokesperson.
Aidan Leonard, agricultural scientist, Limerick City and County Council, said: “It is essential to regularly check that there is no silage effluent escaping from the facilities. All drains and watercourses downstream of the farmyard should also be checked regularly to ensure they are free from contamination.”
He said that silage effluent is over 200 times more polluting than raw sewage.
“Its impact on waters can be devastating. Every year, despite widespread awareness across the industry of the threat from silage effluent leakages, there are incidents of leakage which can cause immense damage to rivers and streams.
“2019 has been a particularly bad year in this regard. During June 2019, eight cases of pollution resulting from silage effluent came to the attention of the Limerick City and Council.
“One of these cases resulted in a serious fish kill [the River Deel incident], another caused serious pollution of a neighbouring well. Other cases gave rise to significant damage to the biology of the rivers and streams,” said Mr Leonard.
Among the reasons identified for these spillages, Mr Leonard said, was wet silage / over-filling of the silage pit, effluent conduits damaged by machinery, inappropriate storage of baled silage and silage bases with cracks in them due to joints not being properly sealed.