Of course not all linear flood defences are just banks of clay soil. For example, yesterday had a short walk along the ‘bank’ at Goxhill Ferry, with very clear views along the Estuary frontage of Hull, here the seaward slope of the bank is reinforced with natural stone blocks laid to fit together then bonded by a layer of some bitumen material. If this reinforcement was created post 1953 floods, as were many along the East Coast, then it has lasted very well (at a different point along the bank between Barton and South Ferriby where an un-bonded stone slope was created the force of the swirling ebb tide has dislodged a couple of facing stones with the result that the clay below is being eroded away and surrounding stones have become unstable, thus a very weak point in the bank is being created).
Most of the Humber Estuary ‘bank’ is blocking the waters from flowing across the lowlands behind as the waters did in prehistoric and geological times. The picture above shows the point on the south bank where there is a natural flood defence Ferriby cliff. Here a 20 feet high boulder clay cliff blocks ingress although it is quite readily undercut by spring tides this leading to cliff retreat (this feature is replicated on the north bank in the parish of North Ferriby). The picture, by the way, is Fig. 4 in the Geology pdf on this website). Beyond the trees begins the lowland coast of the Vale of Ancholme so here the linear man-made flood defence begins again.
So linear man-made flood defences in lowland coastal regions are a challenge by Man to Nature, who is the greater, a struggle that in the era of climate change sees Man on the back-foot. The message in Tidal Lands (s.p.b.s), published 1918, was more positive on the side of Man – it can, and should, be done.