Iken Cliff, near the Snape Maltings, in the Alde Ore estuary, is an area backed by sandy cliffs, fronted by reed beds and salting’s and boat moorings. One noticeable feature is the presence of breached flood defences. One cause of breaches in flood defences is a process known as desiccated cracking, which involves flood water seeping in through existing cracks, causing weakness and breaches in the landward side of flood defences. Cracking can occur right across the width of the flood defence.
Eddies in the water, show levels to be quite high against the tops of old, breached flood defences, as the high tide retreats. The peak of the high tide on 9th April 2021, was at 12:47, and this photo was taken about 50 minutes later.
Figures gathered from tidetimes.org.uk show approximate daily tide times and levels. On the 9th of April 2021, the high tide was 2.76 metres, which was the highest for the 9th of the month for 2021. But in comparison to figures from the 9th of the month going back to 2019, the tide on the 9th April 2021, was the lowest. In 2019 the high tide at 16:39 was 2.77 metres, and in 2020 the tide at 15:02 was 3.08 metres. Interestingly, the low tide on 9th April 2021, was highest measurements for a low tide for 2019 and 2020. In 2019, the low tide at 23.02 was 0.75 metres. On 9th April 2020, the low tide at 21.32 was 0.62 metres. However, the low tide on 9th April 2021 at 19.18 was 0.98 metres.
Water partially covering the path by the side of the estuary indicates a high tide can reach right to the edge of the estuary space. Sections of path fronted by reed beds and salting’s, showed much less surface water, which suggests vegetation can act to limit the reach of tidal waters.
The composition of Iken Cliffs is very sandy, though there is overgrowth and large tree roots which can add structure. But the ever-present erosion risk is indicated by warning signs to passers-by.
There are long-standing flood defences at the bottom of one part of Iken Cliffs and it looks possible that these defences and the trees in the flood defence and the grass may resist any rising tide. Though the top of the flood defence and bottom of the embankment could be vulnerable to scouring by flood waters as well as desiccated cracking, as a rising tide does not necessarily have to overtop to weaken a flood defence to cause it to breach.
One of the special features of the Alde Ore estuary are the seals, and this photo shows a seal in the foreground resting on an island, with another seal swimming behind. It is a nice peaceful estuary image to conclude on, aside from the turbulence of tidal erosion, past and present.
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