Review of UK Marine Aggregate Extraction Activities

From The Crown Estate and BMAPA showing historic patterns of marine aggregate extraction in metric tonnes for 2000-2005, excluding beach replenishment and fill contracts.

Extraction
Area
2000 2001 2002 2003 2004 2005 Total
Humber 3,122,080 2,933,623 2,710,881 2,928,366 3,031,699 3,392,015 18,118,664
E Coast 9,129,635 9,636,697 9,011,323 8,611,199 8,538,073 7,881,670 52,808,597
Thames 854,483 909,141 1,291,103 838,185 758,257 696,012 5,347,181
S Coast 5,613,538 5,628,008 5,399,080 5,658,262 5,148,959 5,389,346 32,837,193
SW Coast 1,602,394 1,549,431 1,467,122 1,515,241 1,633,383 1,591,610 9,359,181
NW Coast 316,090 421,068 482,270 470,962 558,398 611,983 2,860,771
Rivers
& Misc
46,120 73,047 78,597 85,153 99,079 124,506 506,502
Yearly
Total
20,684,340- 21,151,015- 20,440,376- 20,107,368- 19,767,848- 19,687,142- 121,838,089

According to moisture content and stone to sand ratio, there’s usually between 1.6 and 1.9 metric tonnes weight for each cubic metre of aggregate. That related to uses a dry weight ratio of 1.72:1. Therefore, the six year total take of 121,838,089 tonnes would mean a removal of 70,836,052 cubic metres. The level given is undoubtedly that landed to destination. In practice over twice this would have been extracted as some half is rejected by washing off back to the sea so as to hold the prime coarse cohesive sand and gravel to be used for the best grade concrete.

Such a quantity is difficult to visualise, but can be estimated by theoretically placing it on top of a town or city of a known area. (Don’t try this in practice unless you can chose Westminster) and calculating how high it would reach, or how many times it would fill the Albert Hall.

It is interesting to note that the findings of erosion of each area correlate quite powerfully with the levels taken, as does the lowering of the seabed when related to the cumulative active dredging areas.


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