Dredging and other human activities resulting in increase in turbidity levels and sedimentation rates may impact coastal ecosystems such as coral reefs and sea grass meadows. The Interactive Dredge Planning Tool (IDPT) is able to perform a rapid assessment of the expected, initial ecological effects caused by interactively defined dredging operations. For this, the IDPT makes use of rapid assessment dredge plume modelling, a database with computed hydrodynamic background conditions and a database with ecological information, i.e. locations, species and species tolerance information. The effect of this increased turbidity and sedimentation on the ecosystems is site and species specific, but has been addressed for certain species in Singapore in different projects within the Building with Nature programme.
Dredging operations can be optimised in terms of environmental impact by assessing these effects before commencement of the work. In particular during the tender phase of a project. However, time hardly allows for a detailed (modelling) study to assess the environmental effects of different work methods already in the tender phase. The Interactive Dredge Planning Tool (IDPT) enables the user to make a rapid quantitative assessment including the newly developed knowledge on ecological response to (dredging-related) sediment stresses. The IDPT is developed based on the Interactive group modelling – MapTable concept.
The Interactive Dredge Planning Tool enables (initial) assessments of the spreading of dredging-induced turbidity plumes and their environmental effects. The results of this assessment are clearly visualised, along with other project-relevant data, on an interactive map which can be used for communication with stakeholders and other interested parties. The tool in its present form has been developed for Singapore, but can serve as an example for applications elsewhere.
In addition, the IDPT can create so-called dredging suitability maps, which indicate the advised maximum turbidity production given a specific maximum allowable ecological effect. Thus it facilitates the transition from the current emission-based practice to a more impact-based approach.
Building with Nature interest
The IDPT consolidates knowledge and tools related to dredging-induced turbidity and ecological effects into a (prototype) rapid-assessment tool for the effects of dredging on ecology. By making BwN knowledge available to practice, it contributes to spreading the Building with Nature philosophy on ecosystem-based norms and rules. The tool is especially useful for projects in ecologically sensitive areas where hydraulic engineering works are planned or executed and where different stakeholders are involved in the project. It can serve as a means to communicate with stakeholders about the effects to be expected and to involve them in the project process.