The pitch at the ground measures approximately long by wide, with a few metres of run-off space on each side. The centre of the pitch is about nine inches higher than the edges, allowing surface water to run off more easily. As at many modern grounds, under the pitch is an underground heating system, composed of of plastic pipes. Former club manager Alex Ferguson often requested that the pitch be relaid, most notably half-way through the 1998–99 season, when the team won the Treble, at a cost of about £250,000 each time. The grass at Old Trafford is watered regularly, though less on wet days, and mowed three times a week between April and November, and once a week from November to March.