 From the 1960s there was a major clearing and rebuilding operation, culminating in a visit by Queen Elizabeth II in 1990 to open the new locks officially, although the flight had been navigable for a number of years before then.Because a large volume of water is needed for the locks to operate, a back pump was installed at Foxhangers in 1996 capable of returning of water per day to the top of the flight, which is equivalent to one lockful every eleven minutes.In 2010 British Waterways planned to install sixteen new locks gates in twelve weeks as part of its winter maintenance programme, in an attempt to reduce the amount of water lost.