IADC Best Paper Award

Stéphanie Doorn-Groen, and co-author Tom Foster, from the DHI Singapore office, were awarded the IADC Best Paper Award for authors below the age of 35 at the XVlll World Dredging Congress - WODCON recently held in Orlando, USA for their paper on EMMP for reclamation works close to sensitive habitats". IADC - the International Association of Dredging Contractors has instituted the IADC Award to stimulate the promotion of new ideas and to encourage the younger men or women working in the dredging industry and related fields. An amended version of the paper will be published in the international dredging magazine "Terra et Aqua" in September 2007. An abstract of the paper is given below.

Photo by Marsha Cohen, Terra et Aqua
Stéphanie receives the award from Constantijn Dolmans, Secretary General, IADC

The Awarded Paper

"Environmental Monitoring and Management of Reclamation Works close to Sensitive Habitats" by S. M. Doorn-Groen, manager of engineering services and T.M. Foster, managing director of DHI Singapore

Typical Coral Habitats in Singapore

"Environmental Monitoring and Management of Reclamation Works close to Sensitive Habitats" (abstract)

Traditional methods for environmental management of marine reclamation works close to sensitive habitats have generally not provided the level of control necessary to ensure preservation of these habitats. Obtaining the level of control necessary to assure authorities and NGOs of compliance with environmental quality objectives requires quantifiable compliance targets covering multiple temporal and spatial scales. Of equal importance are effective and rapid response mechanisms, to allow feedback of monitoring results into compliance targets and work methods. This paper describes the successful implementation of comprehensive Environmental Monitoring and Management Plans (EMMP), based upon such feedback principles, which allow reclamation activities to proceed in close proximity to Singapore's most important marine habitats under third party scrutiny.

Specific focus is placed on describing the methods utilized to quantify compliance with daily spill budget targets and how such targets and compliances are assessed. To improve reliability, the spill budgets take into account specific habitat tolerance limits for varying magnitudes and durations of sediment loading. Refinements to sediment plume models were undertaken to enhance their ability to hindcast impacts from the contractors' complex reclamation schedules. Methods for segregation of impacts and assessment of cumulative impacts were also integrated into the hindcast procedures. Finally, the paper describes the updating of tolerance limits and confirmation of spill budgets via targeted habitat monitoring.

To date, the EMMPs have been able to document compliance of the works to all pre-project environmental quality objectives at a level of reliability that cannot be refuted by third parties. This has minimized the developers' and contractors' exposure to public complaints and liabilities associated with environmental impacts. The EMMPs have thus allowed the reclamation activities to proceed in an efficient manner, whilst ensuring protection of the environment.

The EMMP techniques presented in the paper have also been successfully adopted for the environmental management of other dredging and reclamation projects in the region, including Bintulu and Kota Kinabalu, Malaysia and Bali, Indonesia. The EMMP techniques are thus becoming accepted best practice methodologies in the SE Asia Region.

Other DHI Papers

Our senior coastal expert and chief engineer Karsten Mangor gave a presentation on "General Guidelines for Good Quality Artificial Beaches and Lagoons, and Case Stories"

"General Guidelines for Good Quality Artificial Beaches and Lagoons, and Case Stories" (abstract)

Artificial beaches behave as natural beaches, i.e. they adjust to the natural and man made conditions at the site. Good quality recreational beaches in the nature occur only when the beach is exposed to a minimum of waves and when the beach sand is of a good quality. The following main requirements shall be fulfilled to obtain a good quality artificial recreational beach:

• Moderate wave exposure in the bathing season
• The beach shall be stable in plan shape and in profile shape
• Stabilizing structures must not generate dangerous rip currents
• Good quality sand fill for construction of the artificial beach
• Good bathing water quality (clear and clean water)

Furthermore, the new beach scheme shall be well adjusted to the existing coastal environment in terms of social activities and urban development and in terms of landscape characteristics. These principles were utilized for the hydraulic design of a new beach park in the Copenhagen area, i.e. the Amager Beach Park. The site is located in an area with a moderate wave exposure; however, the natural shoreface was so shallow that there was hardly any wave exposure of the beach. The old beach was therefore of a very poor quality.

In order to provide maximum possible wave exposure the new beach was moved seawards on an artificial island located off the shallow shoreface, whereby sufficient wave exposure was established. The new beach was divided into two sections separated by a headland. The two sections are orientated against the prevailing wave directions NE and SE, respectively, whereby both sections are made stable. The shallow area behind the new beaches was excavated to form a lagoon and the excavated material was used to form the body of the island.

The beach park has been very successful and has received several distinctions.

Besides giving examples of designs that work, optimised by the use of DHI's numerical models, Karsten also stressed the importance of getting planners and developers to understand the key principles in order to ensure that these are taken into consideration at an early stage of any waterfront development project.

WODA Environmental Commission Panel

>A session entitled "Addressing Environmental Issues is Key to Dredging Project Success Stories" where each panel member was asked to present a statement or rule regarding environmental control of dredging and dredge material placement activities for discussion with the panel and floor. Our dredging expert and chief engineer Anders Jensen, member of CEDA Board, raised the following:

Rule 7: Monitoring and control programs shall be ecologically motivated, economically reasonable, technical feasible

Dredging projects worldwide are facing increasingly stricter environmental constraints and requirements from authorities, project owners and banks. The resulting monitoring and control programs are becoming increasingly complex and costly, but do they do any good?

It is not a simple task to design an environmental monitoring and control program for dredging projects which at the same time is ecologically motivated, technically feasible and economical reasonable. Too often dredging projects become subject to requirements, which fulfils neither of these objectives and which at best are waste of resources and some times are working contrary to protecting the environment.

Monitoring and control programs must be focused on variables which will be (or can be) directly affected by the dredging project. The parameters (parameter can be e.g. turbidity, sea grass coverage, mussel biomass etc.) chosen for monitoring must fulfil the following criteria:

• The parameter must be measurable at a reasonable cost
• The results must be reliable
• The results must be statistically significant
• The results must be predictable (cause and effect must be established)
• The variable must have a short response time
• The limits of impact must be reasonable and established for the benefit of the environment

Fixed threshold values on monitoring variables are not necessarily for the benefit of the environment. For example laying down a fixed spill % or a fixed maximum level of turbidity is not necessarily beneficial for the environment because:

• It does not allow maximum activity during less sensitive seasons and or conditions
• The flux (= dose to the environment) is not considered
• Spatial distribution of spill across the work area is not considered
• Relation between the limitation and the effect on the environmental response is only indirect

Threshold values should be established based on proven and locally established relations between the dose and the effect on the environment.

IADC/CEDA presentation of new book

Anna Csiti, manager of CEDA, gave, on behalf of the Editorial Board, a presentation of what one can expect to find and not to find in the coming revised and restructured series of guides on environmental aspects of dredging, which will be published in one book. The guides have been produced by IADC and CEDA to promote a responsible dialogue about dredging and the environment. Owing to the great success of the series these have been updated and will be available in August this year. Anders Jensen and Bo Mogensen from DHI are authors of some of the chapters. The book can be ordered from IADC and CEDA web sites or directly from the publisher, Taylor and Francis.

DHI's Exhibition booth

Top - The rear side of our booth as seen from the entrance to the exhibition area

Below - our murial poster highlighting some of our services relevant for the dredging community

Many of the 500+ participants (200 international and 300+ from the US) visited our booth, which served as a good meeting point for new and old friends of DHI. For those not familiar with DHI technology examples of model applications (animations) served as a good platform for a dialogue. Besides the DHI Software products and associated support, special interest was shown in DHI ' s water forecast services and to a n on - going coral relocation study in Singapore with an underwater video documentary. Our services in relation to offshore wind parks were acknowledged by many visitors and extended in general to Denmark as a key producer of wind mills.