摘要:

The restoration of Vancouver Lake required the dredging of 6.5 × 106m3of material from the Lake, the construction of 17 km of land based retaining dikes to enclose 180 ha of disposal area, and the disposal of nearly 3 × 106m3of material in the lake to form an island. The requirement that all dredge return flow be returned to the lake necessitated careful control of dredging activity and the imposition of several design and operation features to control the quality of the return flow water. Some of the measures used included multiple, or settling basins, extended wier length to reduce crest height, silt curtain enclosures around dredge disposal site outfalls, rapid alteration of dredge disposal sites, and careful monitoring of dredging activity and return flow quality. These measures enabled the project to be completed with minimum delay, ahead of schedule, and with no serious violation of water quality standards. Observations and data on water quality conditions during construction and the efficacy of specific dredging and sediment containment methods will be described.

ISSN:1040-2381    

DOI:10.1080/07438148409354583

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Significant advances have been made in recent years on dredging equipment, operating techniques, and disposal methods for contaminated sediments. Preliminary guidance is available for selecting dredges and operational techniques to minimize resuspension of contaminated sediments during dredging. This is important since research results have indicated that most contaminants are attached to the clay-sized particles and natural organic solids found in lakes. Detailed guidance is available for designing dredged material containment areas based on the settling and physical properties of sediments. A modified elutriate test has been developed to predict levels of both dissolved and particulate associated contaminants in containment area effluents. This test can be used to determine the need for effluent treatment. Guidelines are available for designing treatment systems to clarify the effluent from containment areas. This paper provides information on selecting dredging equipment and operational techniques to minimize sediment resuspension, design of containment facilities, and chemical treatment of containment area effluent to improve suspended solids removal.

ISSN:1040-2381    

DOI:10.1080/07438148409354584

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lake Kasumigaura, the second largest lake in Japan, is an extremely eutrophicated lake, yet is one of the most important water resources around the Tokyo metropolitan area. It is a shallow lake with an average depth of 4 m. Nutrient exchange between the lake water and sediments was found to be the major factor affecting the nutrient balance within the lake. Therefore, it was decided to carry out dredging of sediments along with other measures to control eutrophication of the lake. To dredge fluffy sediments on the top layer effectively and to avoid excessive disturbance of the sediments, a special purpose dredge equipped with the Oozer system was built, and later, a modified version was constructed. The engineering aspects of dredge efficiency are summarized in the paper based on the 5-year experience.

ISSN:1040-2381    

DOI:10.1080/07438148409354585

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Santa Barbara has had a leadership role in the field of environmental concerns for over 50 years and for that reason had a concern of the total environmental considerations involved in the transportation (dredging) of contaminated sediments from their main water supply reservoir, Gibraltar Lake. Silt from the adjacent watershed has been reducing the City's available water supply (equal to 360,000 cu yds) annually with the total of approximately 22,000,000 cu yds of silt currently contained within the reservoir. This R&D Program was sponsored in part by the U.S. Environmental Protection Agency (EPA) to evaluate the removal of mercury contaminated silt using an air pump to a containment area and to assist other responsible agencies in evaluating this method when reviewing other similar projects in the future.

ISSN:1040-2381    

DOI:10.1080/07438148409354586

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor