title: Merits of partial shielding in dumping sediment spoils.
abstract: The commonly adopted method of dumping dredge spoil at sea using split-hull barges leads to considerable sediment loss to the water column and a subsequent dispersion of fine material that can pose a risk to sensitive "downstream" habitats such as coral reefs. Containing sediment loads using stitched closed geotextile bags is practiced for minimizing loss of contaminated sediment, but is expensive in terms of operational efficiency. Following promising observations from initial laboratory trials, the plunging of partially shielded sediment loads, released on open sea, was studied. The partial shielding was achieved with rigid, open containers as well as flexible, open bags. The loss of sediment from these modes of shielding was measured, and it was observed that even limited and unstitched shielding can be effective in debilitating the entrainment of water into the descending load. In particular, long-sleeved flexible bags practically self-eliminated the exposure of the load and thus losses.
authors.affiliation: DHI Water & Environment (MY), 3A01-02, Block G, Pusat Dagangan Phileo Damansara 1, 46350 Petaling Jaya, Selangor, Malaysia. Electronic address: jhj@dhigroup.com.
authors.forename: Jacob Hjelmager
authors.initials: JH
authors.lastname: Jensen
authors.affiliation: DHI Water & Environment (DK), Agern Allé 11, 2970 Hørsholm, Denmark. Electronic address: sis@dhigroup.com.
authors.forename: Sina
authors.initials: S
authors.lastname: Saremi
authors.affiliation: Energy, Environment and Water Research Centre of The Cyprus Institute, Cyprus; Enalia Physis Environmental Research Centre, Nicosia, Cyprus. Electronic address: c.jimenez@cyi.ac.cy.
authors.forename: Carlos
authors.initials: C
authors.lastname: Jimenez
authors.affiliation: Enalia Physis Environmental Research Centre, Nicosia, Cyprus. Electronic address: l.hadjioannou@enaliaphysis.org.cy.
authors.forename: Louis
authors.initials: L
authors.lastname: Hadjioannou
mesh_terms: D003247:Conservation of Natural Resources / Q000379:methods*; D057894:Coral Reefs; D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry*; D008962:Models, Theoretical; D009792:Oceans and Seas; D012037:Refuse Disposal / Q000379:methods*; D012767:Ships; D014872:Water Movements; D014876:Water Pollution / Q000517:prevention & control*
keywords: Dredge spoils; Environmental dumping method; Environmental impacts; Hopper; Shielding; Split-hull barge