asked the Minister for Local Government whether he is aware of the concern which the smell from the River Liffey is causing in Dublin city; and what steps will be taken to ascertain and remove the cause of the smell.
88.
Ceisteanna—Questions. Oral Answers. - Dublin Water Pollution.
87.
asked the Minister for Local Government if he will outline the steps his Department have taken to date to deal with the pollution of the River Liffey.
89.
asked the Minister for Local Government the present position regarding the Grand Canal project.
With your permission, a Cheann Comhairle, I propose to take Questions Nos. 87, 88 and 89 together.
I am aware that the condition of the Liffey gives rise at times to unpleasant smells. The present unsatisfactory condition of the river is, I understand, caused by two main sources: the flows from the Camac River, itself heavily polluted, which joins the river at Heuston Bridge and the overflows from the city centre sewers which are at present overtaxed. The Greater Dublin Drainage Scheme or Grand Canal Scheme, the planning of which is being designed as rapidly as possible by Dublin Corporation will, however, take the discharges at present polluting the Camac and will also intercept the flows from the city centre sewers thus eliminating the principal sources of pollution. The whole scheme has been approved in principle and I approved contract documents on the 23rd March last for that section from Mulhuddart via Blanchardstown to the Navan road.
Could the Minister state when the city will be free of these obnoxious smells from the Liffey?
I tried to explain in the reply some of the causes of the pollution and the works which it is proposed to undertake and which will substantially reduce the extent of pollution which is causing these smells at certain times and in certain weathers. It is not possible for me to say when this will be eliminated.
Could the Minister offer any explanation as to why there was this very obnoxious smell over the city of Dublin for approximately three weeks towards the end of June and early July?
There is a rather scientific explanation for some of the odours and I think it would be valuable that the House should know about it. The principal causes of the unsightly conditions and of the odours seem to be the deposits of organic matter and silt which accumulate on the bed along the sides at dead spots, that is, slack water caused by obstructions and by irregularities in the river channel. The organic matter decomposes under anaerobic conditions with the production of hydrogen, sulphide and methane. In warm weather the occluded gases in the sludge mass expand and cause lumps of decaying matter to rise to the surface causing unsightly floating slicks of black sludge. I have asked the city authorities to investigate the feasibility of cleaning the bed of the River Liffey in the city centre area where most of this sludge is deposited in the hope that by removing it we can remove also this evil odour which occurs there at certain times of the year, depending on the temperature and so on. However, I hope that the outcome of the investigation will be that it will be considered feasible to do this work and that in doing it we can eliminate the odour for some time. Naturally this type of stuff will begin to accumulate again after another few years, but I think it is a job worth doing, even if it only has effect for a few years, because it is most unpleasant and is something I would be anxious to have removed as quickly as possible.
I am grateful to the Minister for the explanation.