[PDF] Feasibility Study Of General Crust Management As A Technique For Increasing Capacity Of Dredged Material Containment Areas eBook

Author : Kenneth Warren Brown
Publisher :
Page : 250 pages
File Size : 16,71 MB
Release : 1977
Category : Dredges
ISBN :

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The influence of meteorological conditions and the physical, chemical, and mineralogical properties of fine-grained dredged material on the formation of crusts resulting from evaporative drying in confinement areas was evaluated. After decantation, the moisture content of the surface layer is equivalent to about 2.5 times the liquid limit. Evaporation of moisture during the first stage of drying is nearly the same as that from an open pan until the moisture content decreases to about 1.8 times the liquid limit. After this, drying proceeds at a rate dependent on the transport of moisture to the surface. As the material desiccates, surface cracks open. The volume shrinkage is equivalent to the volume of water evaporated as the crust forms, and evidence is given that the volume change is irreversible. Rainfall is shed from the crust and drains into the cracks, from which it can run off if channels are provided to the outflow weir. Management practices, including stirring and the removal of a thin layer of crust, produced only small increases in evaporation rate for a few days. Systems were developed to dig drainage trenches in the confinements and to remove the consolidated crust. A small dredge appears to offer the most promise for cutting deep or wide surface drainage ditches.

Author :
Publisher :
Page : 134 pages
File Size : 17,97 MB
Release : 1993
Category : Dredging
ISBN :

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The Craney Island Management Plan was developed to extend the life of the Craney Island Dredged Material Management Area (CIDMMA). The CIDMMA is used to dispose maintenance and new work dredged material from the project area. With current practice, CIDMMA would reach ultimate capacity by the year 2000. If, however, suitable material is barged to the sea and only contaminated material is placed in the facility (Restricted Use Program), then the life of the facility can be extended. Two tasks were addressed in this study: (a) determine service life under Restricted Use and (b) determine contaminant losses and conduct a Comprehensive Analysis of Migration Pathways (CAMP) expected to occur under Restricted Use. The results showed that the service life of the CIDMMA could be extended under Restrictive Use for approximately 140 years under baseline coniditions or 90 years under Worst Case conditions. The CAMP analysis was conducted along three major contaminant migration pathways (effluent, leachate, and volatile). Effluent was the most significant pathway for metal losses and volatilisation and for polynuclear aromatic hydrocarbon (PAH) losses. Leachate losses under a fully dewatered condition would not exceed effluent losses for some metals. PAH losses for a fully dewatered condition would not exceed effluent losses.