The authors of the recently acquired book Tidal Lands (see blogs of 6th and 9th of May), published 1918, devoted one chapter, entitled Tidal Land Reclamation, to clay bank technology around the North Sea at that time. This is of particular interest to me as I have a long-term objective to research and publish on the topic of tidal defences, land reclamation and current thinking related to habitat sustainability and rising sea levels.
On lowland coasts the simply device of digging a trench and creating a linear mound to hold back tidal waters has been used certainly since Roman times. Historically such a scheme were only relevant to lowland, gently shelving coastlines, and then relatively near the furthest extent of spring tides to reduce to a minimum the impact of the wash on the base of the clay bank.
Clay banks are just one example of how back in time large volumes of earth were moved by man-power using simple hand tools to create an artificial local landscape for a variety of purposes. The picture above shows the site of the Norman motte-and-bailey castle at Barrow on Humber. The earthworks here, although hard to dis-cipher, were created to provide a defensive network around the site of the castle keep which, in this instance, was almost certainly only ever built of wood and never up-dated to a stone keep as, for example, in the case of Lincoln, Conisburgh, London and Norwich. Interestingly at Barrow the earthen mounds may also have acted as tidal defences as the castle site stands near the head of the Lincolnshire (coastal) Marsh.
As at Conisburgh the curving earthen mounds at Barrow may have defined an inner and outer bailey, so adding further security to the newly installed alien landowner.
(To be continued).