A NEW DREDGING INFORMATION SYSTEM (DIS) FOR ASSESSMENT OF ENVIRONMENTAL EFFECTS OF TURBIDITY

摘要

This paper addresses the development of a new method for synoptic monitoring of turbidity represented by Total Suspended Solids (TSS). The method aims at optimising information from operational dredging data, earth observation data, modelling of currents and sediment transport and in-situ data by means of new data-model integration (DMI) techniques.As a test case, Penny's Bay in the Hong Kong Special Administrative Region was selected. Background TSS levels are determined by using model simulations, archived optical earth observation (SeaWiFS, MODIS, Landsat and IKONOS) and in-situ data. The transport and concentration of dredging / disposal plumes is modelled using the water quality model Delft3D-WAQ. A new flexible input editor is presented to translate the relevant operational dredging data into consistent model information. An outline is given as to how earth observation imagery and in-situ data can be integrated into modelling results such that short period forecasting of the plume behaviour by the model is optimised. The results show that the Penny's Bay feasibility experiment was a realistic test case to assess the suspended sediment information that can be derived from in-situ data, earth observation imagery and plume modelling. At present the DIS is well-suited for use in project preparation and post-project evaluation. With increasing coverage of high resolution satellites and further reduction of the time between imaging and delivery of the satellite product, the potential for operational use will increase.