THE SIDE CHAMBERS

AT DIGBY BRIDGE, CO. KILDARE

In 1838, some 34 years after the Grand Canal was completed to the River Shannon, trade had increased to such an extent that there was now a water shortage problem during the summer months. To help alleviate this the Grand Canal Company constructed side chambers (sometimes called side ponds) at three locks along the Grand Canal. The first was at the 20th lock, Ticknevin and later at the 17th lock, Landenstown and at the 16th lock, at Digby Bridge near Sallins.

The three side chambers were of differing stiles. The side chambers at Digby Bridge consisted of three chambers, two of which were parallel to the canal lock chamber and a third chamber to the rear of these.

These two chambers were linked to the lock chamber by a sluice. The side chambers are not as deep as the lock chamber. When a boat wished to descend in the lock, it was first necessary to open the sluices leading into the side chambers, before opening the sluices on the tail gates. This meant that some of the water in the lock chamber would flow into the side chambers, until the two levelled out. The sluices were then closed to retain the water in the side chamber. The sluices on the tail gates could then be opened to let the remaining water out of the lock and into the level below. The water in the side chamber could then be reused to partly refill the lock chamber. This meant that only toping up water was needed to fill the lock chamber.

This side chamber remained in use until 1947 when it was filled in. In the same year the Electricity Supply Board (ESB) took over responsibility for maintaining the water level in the canal. To this purpose they took over the pumps which the Grand Canal Company had installed to pump water up from the River Liffey at the Leinster Aqueduct. It was these pumps that had made the side chambers redundant. This was part of an agreement which allowed the ESB use canal water for cooling, at the Alanwood power station. The side chambers then went through a period of degeneration.

In 1996 the IWAI commenced restoration work on the side chambers at Digby Bridge. The side chambers were in a very bad state and a number of trees had caused extensive damage to the masonry, much of which was compleetly destroyed during nearly fifty years of dereliction. When completed this will be the only example of a working side chamber in this country.