14 Hrs. Oct 15.13 to 12 Hrs. Oct 28.13
16 Hrs. Nov 3.13 to 16 Hrs. Nov 4.13
16 Hrs. Nov 6.13 to 10 Hrs. Nov 9.13
16 Hrs. Dec 5.13 to 11 Hrs Dec 7.13
11 Hrs. Dec 20.13 to 13 Hrs. Dec 24.13
14 Hrs. Dec 26.13 to 15 Hrs. Jan 2.14
15 Hrs. Jan 2.14 to 15 Hrs. Jan 3.14
Shoeburyness East Beach erosion
Persistent south-west winds and rain have modified the macrotidal upper beach at the Boom in Shoeburyness (Essex, England) in the last half of 2013 and January 2014. Here the rail of the Boom and the onshore concrete 0.4 m square posts above it provide a basis for repeating measurement of sediment and strandline heights after corrections are made at each spot. The exact altitude of the datum line at the inshore end of the rail in 2013 is still unclear, but it is roughly 12 feet O.D. and 6.6 m above the local low water mark at -2.90 m O.D. used for tidal predictions at Southend Pier Head (6 km to W.S.W.). But the tidal range is likely to be less at the Boom where the Estuary is wider than at the Pier. There is a weather station at Shoeburyness which might be used to relate the beach observations to wind speeds and direction in a more exact way.
The Boom extends south-east from the beach at right angles to the general trend of it . Since it was built in its present form in 1950-51, a small peninsular of beach sand and gravel has developed under it, gathering more sediment by long-shore drift and wind saltation of the sand when a S.W. wind reinforces the strong ebb tide in the same direction. When the wind is from the N.E., as it was during the early months of 2013, long-fetch waves from the Netherlands produce erosion and drift in the opposite direction, often day to day. That needs to be considered as the partial explanation for the profile of the beach in early October 2013. The wide sandflats start 2.3 to 2.4 m vertically and 19 to 21 m laterally from my datum points.
But on a time-scale of a few years, there was a persistent ridge (or berm) of gravel built-up and resisting the predictable level of the highest tides (termed spring tides in a very confusing way since they occur every fortnight to some extent and not just in the spring as equinoxial tides). This was finally removed by predicted high tides with an unpredicted surge component to them, that also coincided with rain washing of the beach slope, in the night of November 3/4 and continued through November 5 and 6. These surges were not noticed by the press, unlike the two higher predicted tides with surge components also predicted by the meteorologists on December 6. It was interesting to note that the predicted spring tide of the previous afternoon was actually a neap tide at the boom, while the next one engulfed the grassy sand shelf to a negative distance of 15.54 m along the boom trend. Marked positions of the December 6 strandline wet sand limits were subsequently determined to be respectively 585 and 200 m above my datum vertically. But intermediate engulfed areas and the line of dead Sea Holly (Eryngium maritimum L.) rose to 646 and 696 mm there. The early November surges appeared to be roughly 9 inches (230 mm) above my datum in terms of water level on the boom but they only extended into the grass for a lateral distance of two metres. Judging from the profiles and observations of the actual beach as the transgressive tides in this relatively natural setting produce a sand slope of rather more even gradient.
The St. Jude's Day storm (St. Simon being unimplicated) on October 28 had the highest wind speeds of these events at Shoeburyness. They were coincident with the morning high tide and unlike most of the other events did not involve rain. It was, however, a very low predicted tide at the boom the impressive cliff cut into the lower beach gravel on the east side of Southend Pier was reduced to a slight notch partly obscured by blown sand by the time I measured the profile around noon G.M.T. The storm of January 3 2014 was coincident with the afternoon tide and made one think about the description by Francis Rogers of the same place viewed from H.M.S. Kingfisher during the real hurricane of December 7/8 1703 "all things appearing as dismal as death". The waves arriving at about 45° to the boom and the wind direction rose 400 mm below the boom datum. Each diagram of the upper beach exaggerates the slope by a factor of ten, the horizontal scale showing metres one to 20 from my datum and the vertical one 0.1 m units downwards from the boom rail inshore datum nearly to -2.3 m where the slope of fine sandy gravel flattens out (the fine graph paper squares being 100 and 10 mm respectively). The inshore tidal wet sand limit of the two tides are marked as horizontal lines which in reality would slope down offshore, to the south-east and the left, due to the ability of the sea to climb the slope as the waves broke. Vertical lines draw attention to places where no change in beach level took place between each pair of tides selected to bracket storms or surges. Where net deposition took place the space between the curves are marked with dots and where erosion or little change took place the space is left blank. Adding up the areas between the curves, without any vertical exogeration, one obtains a net area per unit shoreline length added to or lost from this part of East Beach. For the January 3 tides, this sum is 0.25 m2 lost from the retreating cliff, 0.55 m2 lost from the upper beach to the right of the neutral line and 1.59 m2 added to the tower part of the profile inclusive of an extension beyond it to the break of slope at 21.117 m on January 2 and 21.915 m on January 3 (4 pm) at much the same height (-2317mm). Presumably half the sand and gravel added to the lower slope had come from erosion the 0.5 km long open part of East Beach and the other half had just moved downhill.
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