Madam, – As one of those responsible for the supply of drinking-water in the Dublin region, I would like to address some issues.
As to why it may take four months to fully rectify the situation, you first have to understand the “normal” water supply situation in the area.
The Dublin region, consisting of the four Dublin county councils, Kildare, northern Wicklow and a small part of Co Meath, is supplied with drinking-water from one common network. Four main water-treatment plants provide the bulk of drinking water to this network.
Three of these plants are operated by Dublin City Council, and one by Fingal County Council.
The combined maximum output of these plants is 540-550 million litres per day. Under normal circumstances, the average demand in the region is 530-540 million litres per day. So, on an average day, we would have 2-4 per cent spare capacity.
This means we have to operate our plants at 96 per cent capacity, or more, almost every day of the year.
Compare this to Paris, where water is supplied by three major treatment plants, each operating at about 50 per cent capacity.
To address the lack of spare treatment capacity, Dublin City Council is expanding its plant at Ballymore Eustace (which will provide extra water later this year) and Fingal County Council is about to go to tender for an expansion of its plant at Leixlip (which will provide extra water in about two years).
However, the region will still need further extra capacity to cater for situations like this – and to cater for a long hot summer, if we ever get one.
Dublin City Council is in the early stages of planning a new major water source for the region, but the earliest this would be operational is five to 10 years’ time, due to the procurement hurdles it will have to cross.
No matter how much rain falls and finds its way into the lakes and rivers, these water-treatment plants have a maximum capacity. Like any food factory, they can only produce a certain amount of product every day, no matter how much raw material is available.
In the days leading up to the weekend of January 9th-10th, demand on the system increased to about 570 million litres per day. Over that weekend, demand continued to rise, hitting a record 628 million litres per day on the Sunday.
This was due to a combination of extra leaks in the pipe network (caused by frost heave), and the fact that some people left their taps running in an effort to prevent frozen pipes.
This resulted in very low levels at the treated-water reservoirs, with demand far outstripping capacity.
As a consequence, we were left with no option but to restrict supplies to allow reservoirs to recover.
This restriction will have to continue until (a) we recover water in the treated-water reservoirs; and (b) find and fix enough leaks to bring the demand down to the “normal” level.
As the thaw has now come, we expect that people will not feel the need to run taps any more, so this element of demand should correct itself.
Fixing leaks is not a problem for Fingal and the other councils. However, contrary to popular belief, finding the leaks is the major problem.
Many leaks occur and flow away for days, weeks and even months without announcing their presence, ie where water is showing above ground. Those that do are quickly spotted and fixed, usually within 24 hours.
Finding the backlog of leaks may take up to four months. However, we expect to have found and fixed enough of them to stabilise the situation and restore normal supplies to the region within a few weeks.
I hope that this aids people’s understanding of the situation.
Separately, the letter from Mr Kehoe (January 16th) regarding dishwashers is quite correct: proper use of dishwashers and washing-machines can help save water.
That is why, at Fingal council, we suggest only putting on dishwashers and washing-machines when you have a full load. – Yours, etc,
Madam, – In addition to turning off the tap while brushing one’s teeth (WeekendReview, January 16th), another simple way of conserving water is to place a plastic bottle filled with water (say 500ml) in the toilet cistern.
The amount of water saved at each flush will equal this bottle’s volume without affecting the operation or performance of the toilet. Over time, a lot of water can be saved. – Yours, etc,
Madam, – Once again there are massive water shortages, especially in urban areas. A long dry summer will exacerbate the many underlying problems.
Household water meters must now be made an urgent priority! – Yours, etc,