River Blackwater – Southern Sections
OSA repair to damaged Essex block revetment
3 sections of seawall along the southern side of the river Blackwater in Essex were identified as requiring maintenance.
Existing damaged revetment
Hesselberg Hydro proposed solutions mainly comprising of LSA & OSA to replace the failed blocks, plus a section of grouted rock and some Elastocoast repairs for two remote patches. These alternatives to the specified design of using Canewdon Blocks were accepted and the works were delivered on time and in Budget with minimal disruption to the existing seawalls.
LSA filter layer
Rather than replace the whole revetment, we only removed the failed blocks, generally in the zone between neap & spring high tide levels. The existing toe was left undisturbed where it was sound and there was minimal risk of undermining (prevented disturbing the important foreshore habitat), and the upper rows of blocks were left in place (prevented disturbing the established vegetation including rare species)