SSFATE (Suspended Sediment FATE), a Model of Sediment Movement From Dredging Operations

摘要

SSFATE is designed to assist project managers defining temporal windows for dredging operations. Operational windows are intended to protect biological resources or their habitats, as requested during interagency coordination processes for dredging projects. SSFATE employs a shell-based approach consisting of a color graphics based, menu-driven user interface, GIS, environmental data management tools, gridding software, and interfaces to supply inputs and display outputs from the model. SSFATE runs on a personal computer. Data input/output is interactive and mainly graphics based. SSFATE can be set up to operate at any dredging operation site and includes a series of mapping/analysis tools to facilitate applications. Initial setup for new locations of dredging operations can normally be accomplished in a few hours, unless numerical hydrodynamic models are run to provide flow fields. A computational model predicts the transport, dispersion, and settling of suspended dredged material released to the water column as a result of dredging operations. User inputs enable definition of sediment source strength and the vertical distribution of sediments generated by the dredging operation. SSFATE requires a flow field for execution of the particle tracking computations. The flow field can be sketched in, using limited field data, or can be imported as output from a hydrodynamic model. The processes modeled are primarily far field processes in which the mean transport and turbulence associated with ambient currents dominate. A random walk particle model predicts transport and dispersion of suspended material. Animated model output includes both horizontal and vertical concentration contours of each or all sediment classes, time-series of suspended sediment concentrations at a particular point, spatial distribution of sediment deposited on the sea bottom, and tabular summaries of sediment in suspension, and deposited. The user interacts with the contoured data to obtain pertinent information such as a cross-sectional view along a transect, the distance to features from the sediment source, and the area covered by material that has been deposited on the bottom.