 The Board replaced the former Trustees of the Lea Navigation, and was responsible for 50 miles of navigable waterways which included the Lea Navigation and, from 1911, the River Stort Navigation.Although police officers appear to have been appointed to keep order in the Hackney Cut as early as 1848, the first reference to a police officer of the Conservancy Board is from 1871, when William Ross, previously a member of the Marine Police Force, was appointed as "Barge Inspector and Police Officer to the Conservancy".Ross made his presence soon felt, when just a few months into the job he arrested and had prosecuted a bargeman for threatening him with violence whilst he was directing traffic on the river.