How much rock armour is there at mapleton
450m
How much coast is lost per year on the holderness coast
3m
what effect have groynes had and where
groynes have caused there to be less erosion where they have been installed but further down the coast in the direction of the prevailing wind there has been an increase in erosion as the sand from further down coast has been stopped by the groynes. This is at Great Cowden Farm