City Mill Lock connected the tidal Waterworks River with the Bow Back Rivers which are a part of the Lea Navigation and thus at a constant level. There is another lock connecting the two systems further north where Carpenters Lock connects the Old River Lea to the start of the Waterworks River close to Carpenters Road. Both locks were built in the 1930s when considerable work was carried out, mainly to reduce flooding but also with the intent of increasing commercial traffic on the Back Rivers, particularly the City Mill River. But I think this never happened and by the 1960s these streams were seldom if ever used.
The River Lea was at least theoretically navigable at the right stage of the tide some way further north – and of course much further by kayaks, though there are legal restrictions on parts of its many streams.
Since the Olympics, the tidal flow on the river has been regulated by a new lock on the Prescott Channel at Three Mills which I photographed in 2010. The original intention of British Waterways that the river above this point should be non-tidal but its level still varies, perhaps simply with the river flow.
The lock gates had clearly seen rather better times and the lock was unusable. These gates were replaced as a part of the makeover of the area for the Olympics.
Just to the west of the lock, behind the lock keepers house, St Thomas’s Creek turns towards the north and becomes the City Mill River. A few boats were moored here, next to Blaker Rd.
Continuing north beside the City Mill River along Blaker Road led to a footpath which went under the Northern Outfall Sewer in a tunnel. It was possible to access the Greenway walkway on the sewer from here.
From where you could look down on the path and the railings beside the river.
This is the view looking back down the City Mill River towards City Mill Lock, now rather different.
The footpath led on past the Northern Outfall Sewer to a rather strangely angled basin taking the river under the main railway lines. From here you could continue walking beside the river and eventually reach the north end of Marshgate Lane and Carpenters Road.
The last time I tried to repeat this walk, in 2019, it was not possible, with work still taking place in the area and fences stopping me. As well as work still taking place after the 2012 Olympics, parts were blocked by work on Crossrail.
All photographs on this and my other sites, unless otherwise stated, are taken by and copyright of Peter Marshall, and are available for reproduction or can be bought as prints.
