Beneficial use of dredged sediment
Lymington Estuary (Hampshire)
This was undertaken by the Lymington Harbour Commission (LHC) to counteract the ongoing marsh erosion and as mitigation for habitat damage installing a rock amour breakwater in the estuary. An estimated 2,000m3 of maintenance dredged silt material was placed on site over two campaigns in February 2012 and February 2013. A discharge pipe pumped the dredged sediment directly from a suction head within the adjacent Yacht Haven Marina onto the adjacent marsh. The sediment was retained in situ using willow and straw fences built across the main (eroded) drainage channel in the marsh and through six subsidiary drainage channels. During sediment pumping it was evident that the structure across the main drainage channel was allowing too much drainage from the site. This was remedied by placing temporary corrugated plastic sheeting which resulted in better retention of pumped sediment on site. A square bale area was also used to retain sediment near the discharge point.