 In addition to the Knight and Bessborough reservoirs there were four smaller rectangular reservoirs (each 750 ft by 550 ft, 229 m by 167 m) located east of the intake channel.In the 1920s a water treatment works was constructed to the north of the reservoirs.By 1933 this comprised six slow sand filters (each 220 ft by 170 ft, 67 m by 52 m) located west of the intake channel.