The locks at Buckby were all built with side ponds, to conserve water. These are maintained at an intermediate level between the upper and lower pound. When a lock is emptying, water from the top of the lock fills the side pond, and the rest is then discharged to the lower pound. When a lock is filling, the bottom of the lock is filled from the pond, and the rest is drawn from the upper pound. Typically, this system uses 40 per cent less water, but the ponds have been disused for a long time, and an electric pump is now used to pump water from the bottom of the flight to the top. The Grand Junction Canal experimented with side ponds from the early 1800s. The locks at Bourne End had several radial ponds, but use of the ponds was abandoned because it took too long to use the lock. Those at Buckby had two rectangular side ponds per lock, at different levels, and this design was eventually installed at most locks between Buckby and lock 45 at Bulbourne, the junction with the Wendover Arm.