Seventyfive years ago The Thames Conservancy lived up to its name, that being the conservation of the River Thames and its river banks and towpaths. They were what was the forerunner or that common phrase of "Preventative Maintenance."
When and where it was required the river and its tributary streams were dredged and the banks were repaired.
Where the banks were showing signs of being erroded the watermen would protect that section with a concrete filled sandbag defence, as depicted in the photograph above, with the odd rebar driven through the bags to re-enforce the wall. Many of these structures I am sure still exist today. The burlap sacking would eventually rot off, leaving the concrete block in place.
The hollow behind the wall was filled with gravel and topsoil so that the grass would grow and the repair complete.
Speeds on the river were strictly enforced to ensure that bow waves were keep to a minimum
and the Thames Conservancy had a patrol launch to police the river, especially in the summer time.