IADC: Port Expansion Through Land Reclamation
“When you sail into Rotterdam’s Europort and see the new Maasvlakte 2, enter the Khalifa Port and Industrial Zone Project (KPIZ) in Abu Dhabi or visit Hong Kong’s container terminals, it’s hard to imagine that these areas were once simply wide expanses of water,” stated René Kolman, secretary general, International Association of Dredging Companies (IADC) and Jan van’t Hoff, independent consulting engineer.
These port expansion projects are just a few of the many infrastructure developments that owe their existence to the wonders of dredging and land reclamation.
“Land reclamation is land that seemingly appears out of nowhere. And how do dredging contractors create something from nothing? These mega-infrastructures are in fact the domain of engineers specialised in the planning, design and construction of land reclamation using hydraulic fill. And such constructions are only possible because of the dredging industry’s innovative and intensive work, both theoretical and practical, into the characteristics of hydraulic fill. Without suitable hydraulic fill, land reclamation for port expansions would not be possible,” they added.
“Yet, despite its economic importance, a thorough study of hydraulic fill has long been overlooked in the literature of dredging – until now. Only recently, after several years of rigorous research and writing, with contributions from a score of highly respected engineers, is hydraulic fill getting the attention it deserves.”
The recently published book, Hydraulic Fill Manual for Dredging and Land Reclamation Works (2012) was guided into existence under the stewardship of the Construction Industry Research and Information Association (CIRIA) and CUR Building & Infrastructure. Its two editor-experts in the field, Jan van ‘t Hoff and Art Nooy van der Kolff clearly and comprehensively tackle the complexities of hydraulic fill operations.
Hydraulic fill is the process where sediment or rock excavated by dredgers from the seabed or other borrow areas, is transported and ultimately placed into the designated reclamation area. For each of these phases of excavation, transport and placement, a hydraulic filling method is used, meaning that a soil and water mixture is created to facilitate dredging, transport or placement of the fill material. The fill material is then placed as a mixture of the fill (sand) and water into the reclamation site.
But this is the simple mechanics. Before a land reclamation project can commence, months or often years of research are invested in determining the best possible work methods and the availability and suitability of the hydraulic fill.
To begin with, the foundation of constructing a safe reclamation site is collecting a wide range of data. Data collection includes desk studies, field work and laboratory testing. It means gathering bathymetrical and topographical data and geological and geotechnical information in both the borrow and reclamation areas. Add to that hydraulic, meteorological and environmental data and then follow this with reporting on soil and rock classifications and descriptions using various internationally accepted standards.
This data is used during the pre-construction, construction and post-construction stages. Geostatistical methods will be used to develop models of the borrow and reclamation areas. All this information can ultimately be applied to an environmental impact assessment, which in most countries is a requirement in order to get work permits.
Dredging Today Staff, June 17, 2013