Typical Projects

Strategic Assessment and Site Selection Study for Contaminated Mud Disposal , Hong Kong

DRL supported ERM-Hong Kong Ltd in a study for the Civil Engineering Department which identified potential options for the disposal of contaminated dredged materials when the capacity of the existing confined aquatic disposal site at East Sha Chau is exhausted. This work represented a continuation of DRL's long involvement in the management of contaminated sediments in Hong Kong which commenced in 1990 with the Contaminated Spoil Management Study for the Environmental Protection Department and laid the foundations for the present strategy of confined aquatic disposal.

Since then, DRL have assisted with the development of refined operational procedures for the placement of contaminated mud in the specially-dredged disposal pits at East Sha Chau, have measured sediment losses during placement and have supported main consultants on three of the major Environmental Monitoring and Audit contracts.

TASS System for the prediction of Sediment Release from Dredging Plant

DRL are working with HR Wallingford to develop a computer-based system for the prediction of sediment release from dredging plant and during open-water disposal of dredged material. The work is being undertaken for VBKO of The Netherlands, a trade organisation that includes most of the Dutch dredging contractors. The core of the system is a series of dredging process models that are designed to predict sediment release rates at various points in the dredging process. The process models take into account the type of dredger, its method of operation and the site and soil characteristics.

The process models are linked to a dynamic plume model being developed by HR that will simulate the initial very rapid decay of the sediment plumes during which sediment is moved rapidly to the bed. This, in turn, will be linked to a passive plume model that will simulate the longer-term passive development of the plume.

Hulhumale, Republic of the Maldives

Dredging Research Ltd was part of a team that carried out an environmental assessment of proposed dredging and reclamation works for the Ministry of Public Works. The work consisted of identifying potential sources of material for reclamation, simulating the dredging operations and assessing the sediment re-suspension from these. The potential effect of suspended sediment on the coral reefs was then evaluated. Current reclamation activities on Hulhumale were also examined and recommendations made for improvements in operational efficiency and environmental protection.

Hulhumale

 

Kings Pond, Alton

When Alton Town Council decided to remove accumulated silt from the environmentally important Kings Pond in the town centre, Dredging Research Ltd were approached to provide dredging expertise. Details of the proposed works were described by DRL to the local Working Party set up for the project and, after approval, the Contract Documents were produced and Tenders were received and evaluated. The dredged material was used to re-build islands, improve the littoral shallows and was spread over the adjacent green areas to improve soil quality. The works were carried out in the autumn to meet ecological concerns and by the following spring the whole site was greening up nicely. The accompanying pictures show one of the islands and the dredged material spread over adjacent areas.

Kings Pond beneficial use	Kings Pond Island

Navigability Study, River Trent

As part of Inland Waters Consultants, DRL participated in a major navigability study of the locked portion of the navigable Trent between Gainsborough and Nottingham. In particular, the study focused on navigational marking, dredging and surveying of the shallow reaches. Recommendations included the setting up a river marking group, formed from the main river users, a maintenance dredging strategy and proposals for regular surveying to monitor channel movement and shoal formation.

Trent Bucket dredge