have EA sanctioned modifications made to them for such use. Reaches The locks and weirs, in effect, break the river up into 44 lakes or lock reaches. Each lock controls the reach above it and thus identifies it. Each reach has its own character and points of interest. Many reaches host regattas and other events and these are coordinated through a River User’s Group for the reach. The Environment Agency may close all or part of a reach for an event, but most regattas only require one side of the river which may then be closed off. When the boats were horse drawn, a towpath was needed on the bank side. This towpath has formed the basis for the Thames Path which runs between the source and mouth of the river. The path runs between locks and is therefore often the main means of access on land. Where the towpath changes from one side of the river to the other ferries were once provided. These have now almost all disappeared and the Thames Path has to be diverted to the nearest bridge, often a considerable distance, to cope with this. Foot crossings All of the Thames locks have walkways on top of the lock gates, so except at Whitchurch Lock one can cross to the lock island from the adjacent bank. Upstream of Wallingford, many locks also have walkways on top of the weir to cross the whole river. Downstream of Wallingford, Caversham Lock and Boulters Lock have footbridges nearby, and Hambleden Lock has a walkway on top of the weir, but the other locks below Wallingford do not allow river crossing on foot. List of locks and weirs The list of locks, weirs and ferries is given in upstream to downstream order, from source to sea. Most of the older flash locks have disappeared and there are only three ferries still operating (Weybridge, Hampton and Hammerton's). Nearly all of the older weirs and most of the current ones once had associated mills, fifteen of which are mentioned in the Domesday book, but very few of these survive. A few weirs had bucks for catching eels. Additionally, Blake's Lock is located on a reach of the River Kennet that is administered by the Environment Agency as part of the River Thames, and is often counted as a Thames Lock. It is the only manual Thames lock below Oxford. The tide