intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 




Sub groups
D-Flow Flexible Mesh
Cohesive sediments & muddy systems



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BLOOM algae sedimentation velocities

Anonymous Anonymous, modified 5 Years ago.

BLOOM algae sedimentation velocities

Jedi Master Posts: 333 Join Date: 7/30/20 Recent Posts
For anyone interested, here are some guidelines from Hans Los regarding the sedimentation velocities of algae in BLOOM:

In BLOOM.SPE the default sedimentation rates for BLOOM.SPE for fresh water phytoplankton are 0, while for marine phytoplankton they are in the order of 0.5 to 1.0 m per day. This is not because there is a fundamental difference between fresh water and marine algae, but because the net sedimentation rates are also depending on the depth. Since many shallow lakes exist in which sedimentation rates are low, we have therefore decided not to put a positive default into the bloom.spe. Instead the user who wants to include sedimentation of (fresh) water algae in a model application is advised to include the appropriate values as constants in the model input (either via the GUI or directly into the input file, whatever the user prefers).

With respect to the species groups, sedimentation rates should be highest for diatoms, moderate for green algae and flagellates and very small or zero for blue green algae. Nutrient limited types are less healthy compared to energy types so their sedimentation rates as a rule should be higher.

Typical values for a deep lake would be Diatoms-E = 1.0 m per day, Diatoms-P 1.5 m per day, Green-E = 0.5 per day, Greens-P/N = 1.0 per day, BlueGRN-E = 0, BluegrnN/P = 0 or perhaps 0.5