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|Title:||Guidelines for designing, operating and managing dredged material containment areas|
|Authors:||Dredged Material Research Program (U.S.)|
Palermo, Michael R.
Montgomery, Raymond L. (Raymond Lowree)
Poindexter-Rollings, Marian E.
Dredged material disposal
|Publisher:||U.S. Army Engineer Waterways Experiment Station.|
Engineer Research and Development Center (U.S.)
Abstract: Guidelines are presented for designing, operating, and managing dredged material containment areas to meet required effluent solids standards and to provide adequate storage volume. The guidelines are equally applicable to design of new containment areas and to evaluation of existing sites. Field investigations necessary to provide data for containment area design are described to include channel sediment investigations and foundation investigations at the containment area. Sample type and location, sampling equipment, and sample preservation techniques are included. Laboratory testing procedures required to obtain data for sediment characterization, containment area design, and estimates of long-term storage capacity are given. Sediment characterization tests include salinity determination of near- bottom water and natural water content, Atterberg limits, organic content, specific gravity, and grain size analysis of the sediments. Sedimentation tests performed in an 8- in.-diam. column are used to define settling behavior within the dredged material containment area . Procedures for both flocculent settling tests, generally applicable to freshwater sediments, and zone settling tests, generally applicable to saltwater sediments, are described. Results of conventional consolidation tests are used to estimate settlements due to self-weight consolidation of newly placed dredged material and consolidation of compressible foundation soils. Procedures are given for containment area design for retention of suspended solids based on solids removal through gravity sedimentation. Separate design procedures for freshwater and saltwater sediments provide for determination of the respective surface area or detention time required to accommodate continuous dredged material disposal. Procedures are also given for estimation of the storage volume required for a single disposal activity and the corresponding pending depths, freeboard requirements, and dike heights. Factors influencing containment area hydraulic efficiency are evaluated to include effects of short-circuiting, pending depth, spur dikes, weir placement, and containment area shape. Guidelines for estimation of gains in long-term storage capacity due to settlements within the containment area are presented. The guidelines are based on conventional consolidation theory modified to consider self-weight consolidation behavior of newly placed dredged material. The effects of foundation consolidation, time-rate of consolidation, and placement of sequential lifts of dredged material are also described. Design and operational procedures for weirs are presented based on providing the capability of selective withdrawal of the clarified upper layer of ponded water. Weir design guidelines allow evaluation of the trade-off involved between the two most important weir design parameters, pending depth and effective weir length . Operational procedures for weirs are outlined to include weir boarding, maintenance of adequate pending depth, use of static head and depth of flow over the weir as operating parameters, and weir operation for undersized basins and for decanting surface water. Containment area management activities are described which may be considered as possibilities for improving efficiency and prolonging the service life of containment areas. Separate activities may be performed before, during, and following the dredging operation and include site preparation, removal of existing dredged material for construction programs, surface water management, suspended solids monitoring, inlet and weir management, thin-lift placement, separation of coarse material, dredged material dewatering, and disposal area reuse management. Summaries of research pertinent to designing, operating, and managing dredged material containment areas and example calculations are included in appendices to the main text.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|
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|TR-DS-78-10.pdf||24.91 MB||Adobe PDF|