The photographs below show unacceptable pollution of the River Clare (Lough Corrib candidate Special Area of Conservation) at Miltown Co Galway during the construction of the Miltown Sewerage Scheme. These photographs were taken by ECOFACT staff who passed this construction site on the 31st May 2013. Water is being pumped out of excavated areas and discharged without treatment into a candidate Special Area of Conservation. This is considered to be unnecessary and damaging pollution of this important salmon river.
Inland Fisheries Ireland often recommend that water be pumped over ground to allow suspended solids to settle out before water discharges into a watercourse. It is appreciated that the contractor may be trying to follow this approach. However, as the photographs show this an unsuitable mitigation for this site, and is clearly not working. From our experience of construction sites this approach never really works and ECOFACT never recommends this approach any more.
What should have been used here?
At this site portable silt traps, such as the silt buster system should have been employed and operated to the manufacturer’s guidelines. There are other suppliers of these traps as well as Siltbuster.
Operating to the manufacturers guidelines is of ultimate importance here, which includes using an appropriate number of silt buster units for the discharge to be treated, and also maintaining and emptying the silt from the traps when they are more than 50% full of silt. The silt removed from the traps then has to be disposed of appropriately.
Suspended solids in a river the River Clare can be particularly damaging. Brook lampreys Lampetra planeri are a key conservation interest of this SAC and are currently spawning in the River Clare. Silt discharged from these works has the potential to silt up the gravel areas and kill the ova of lampreys. Likewise juvenile salmon and trout have just emerged and are also vulnerable to suspended solid pollution. It is also likely that toxic substances such as cement washings and oils could be discharges into the river here due to the absence of treatment.
Although it is hoped that the Milltown Sewerage scheme will eventually improve water quality in the River Clare, it is unacceptable that these impacts on a water dependant Special Area of Conservation are occurring during the construction phase. The contractor here could be prosecuted under the water pollution legislation.
ECOFACT are the experts in Ireland in water quality protection mitigation. We have designed successful water quality mitigation for building sites in the most sensitive of catchments in Ireland. If you are planning to work near an SAC contact us to ensure the environmental compliance of your construction site.