SMS:Cascade

This article is for Cascade model. The Cascade model has been replaced by the GenCade model in current editions of SMS.

Cascade is a regional model for calculating coastal sediment transport, morphology change, and sand bypassing at inlets and engineered structures. Cascade is developed by the U.S. Army Engineer Research and Development Center (USACE-ERDC), Coastal and Hydraulics Laboratory (CHL).

Functionality

Cascade simulates shoreline change relative to regional morphologic constraints upon which these processes take place. The evolution of multiple interacting coastal projects and morphologic features and pathways, such as those associated with inlets and adjacent beaches may also be simulated. Cascade, Version 1 calculates wave-induced longshore sediment transport rates, shoreline change, tidal inlet shoal volume evolution, natural bypassing, and the fate of coastal restoration and stabilization projects. It is intended for regional applications, engineering decision support, and long-term morphology response to physical and anthropogenic forcing.

Versions of the Model

The USACE-ERDC team continues to develop the Cascade model using a Spiral Development paradigm. This means that multiple features are being developed as independent capabilities and will be incorporated into a release version of the model when functional and verified.

The current version is version 1. Version 2 and 3 are under construction.

Version Descriptions

Version	Functionality
1	Longshore processes
2	Addition of some cross-shore processes.
3	Ecological component (habitat and population dynamics)

Using the Model / Practical Notes

A Cascade grid is created in SMS and initial shoreline and regional shoreline trend may be created in SMS or imported from survey data. Model parameters and spatial and temporal boundary conditions are assigned within the SMS interface. These may include dredge and fill projects, construction of coastal structures, opening of new inlets, shoal and morphologic feature development or equilibrium volumes, wave information forcing, and sediment coefficients and parameters.

Cascade output solutions consist of shoreline change, sediment transport rates through time and space, average sediment transport rates, and inlet shoal evolution calculated by the inlet reservoir sub-model.

Graphical Interface

Cascade Menu

• Attributes
• Film Loop...
• Set Active Coastline
• View Coastline Data
• View Solution Plots
• Create Grid
• Model Control...
• Run Cascade...

Cascade Module Toolbar

• Select Coastline Point
• Create Coastline Point
• Select Dredge/Fill
• Create Dredge/Fill
• Select Grid Cell (also add wave information)
• Edit 1-D Grid
• Select Inlet
• Create Inlet

Rates of Sediment Input or Loss

Similar to other time-varying parameters in Cascade, the time listed represents the time at which the condition change. The condition shown at that time is the condition that is valid up to that time from the previous change. In this example, the source has a constant rate of 0.0000666 m2/sec from time step 185640 to 187031 and again from 264480 to 265871.

Example of the Rates of Sediment Input or Loss dialog

The user may also redefine the sediment source or sink region by changing the starting and ending cell indices in the top section of the window, in this case cell 83 to 91.

Case Studies / Sample Problems

• Cape Henlopen to Chincoteague Inlet, Delmarva Peninsula, DE/MD/VA
• Fire Island to Montauk Point (FIMP), Long Island, NY

External Links:

• Cascade User Guide: [1]
• Cascade Theory and Model Formulation: [2]
• Inlet Reservoir Model (sub-model within Cascade): [3]

Related Topics

• 1D Grid Module
• GENESIS