In the final part of chapter VIII (Tidal Land Reclamation – Works) the authors of Tidal Lands (s.p.b.s) go into some technical detail about concrete flood defences as being trialled in the Netherlands in the early 20th century (published 1918).
Considerable stretches of the Humber flood bank are concrete barriers to tidal water ingress. All the tidal barrier on the north bank from the ex-drying fields of St. Andrew’s Dock site east to Queen Elizabeth Dock and Saltend works has been built as a concrete wall and promenade. Furthermore the Tidal barrier at the mouth of the River Hull is capable of blocking very high Estuary waters from surging up the River and spilling over its banks into the town. Both have served Hull well, so far!, but the surge of 5th December 2013 overtopped the concrete wall and was within a few inches of overtopping the Tidal Barrier.
On the south bank a concrete promenade exists from the mouth of East Halton Beck east into Grimsby with much of Immingham Dock also being flooded on 5/12/’13. However, here much of the lower slope of the tidal barrier is bonded rocks sloping into the foreshore.
The picture above shows a section of reinforced flood bank on the western side of Barton parish, just west of the once Ness Brick Works and Adamant Cement works, now part of the Far Ings national nature reserve. Here the lower part of the seaward slope is concrete laid at a fairly gentle gradient whereas the upper part of the slope is bonded rocks set at a steeper angle topped by a concrete promenade with low parapet. Thus the lower, gentler slope experiences all spring tides with the gentle slope defusing (to an extent) the force of the tidal waters – the upper slope will only have to resist the tidal waters in more extreme circumstances. In this particular area the rocks have been bonded by mastic in places and by cement in others, the loose rocks lying below the tidal barrier may have been left after repairs to the bank or may have been left when the bank was reinforced after the 1953 floods.
Clearly then, linear tidal flood defences can take many forms, their composition varying according to local coastal factors and the level of funding available when created, repaired or reinforced. The Humber Estuary affords a good example of the variety of builds.