Since 1989, the NCCHE has been supported by USDA Agricultural Research Service by means of funds appropriated by the U.S. Congress, with a mandate to develop state-of-the-art numerical models for simulating flow and sedimentation processes in the natural environment. Since then a suite of 1D, 2D and 3D computer models have been developed, verified, refined, validated, documented and applied to simulate a variety of free surface flow and sediment transport related phenomena.

CCHE1D is available for general release and CCHE2D is currently in beta testing. They are available for testing/use free of charge from our download page.

Other NCCHE models, such as CCHE3D and CCHE-FLOOD, or extensions of CCHE1D or CCHE2D, such as CCHE-WQ, CCHE-TIDE, CCHE-COAST, etc., can also be used free of charge, by collaborating with NCCHE researchers.

CCHE1D Package

CCHE1D is a software package for the simulation of one-dimensional unsteady flows and sediment transport in dendritic channel networks. The software package has been designed to facilitate the combined modeling of watershed and channel processes.

CCHE1D’s hydrodynamic model includes special procedures for the computation of flow across hydraulic structures like culverts, low and high-drop structures, bridge crossings, and measuring flumes.

The sediment transport module computes non-equilibrium transport of non-uniform sediment mixtures. It has been designed for long-term predictions of channel morphological changes, and it can be used to evaluate the effectiveness of in-channel remedial and control structures on the sediment yield.

The CCHE1D water quality module simulates the transport and fate of nutrients and other pollutants in channel networks, including the biogeochemical reactions that take place in the streams.

An ArcView GIS graphical interface facilitates the data management and the integration of the channel model with watershed models and other tools. It also includes a landscape analysis module that delineates the drainage network and corresponding subcatchments based on digital elevation data. 

Free Software (Download)
Find more about CCHE1D here

CCHE2D Package

CCHE2D is an integrated package for two-dimensional simulation and analysis of river flows, non-uniform sediment transport, morphologic processes, coastal processes, pollutant transport and water quality. These processes are solved with the depth integrated Reynolds equations, transport equations, sediment sorting equation, bed load and bed deformation equations. This model is based on Efficient Element Method, a collocation approach of the Weighted Residual Method. Internal hydraulic structures, such as dams, gates and weirs, can be formulated and simulated synchronously with the flow. Dry and wet capability enables one to simulate flows with complex topography with ease. Three turbulence closure schemes, depth-averaged parabolic, mixing length eddy viscosity models and k- e model, and available. The numerical scheme can handle subcritical, supercritical flows and their transition.

A comprehensive and user-friendly mesh generator is available for generating structured quadrilateral mesh on the background of bed topography and the bed elevation data. A Graphic User Interface (GUI) is also available with detailed manual and documentation. Starting with a computational mesh, the GUI helps users to setup parameters, boundary conditions and to run the simulations and visualize the computational results. 

Free Software (Download)
Find more about CCHE2D here

CCHE3D Package

CCHE 3D is a three-dimensional computational simulation model developed at the National Center for Computational Hydroscience and Engineering, The University of Mississippi. It is for simulating unsteady, free surface turbulent flows and associated sediment transport, pollutant transport and water quality problems.

This model is based on Efficient Element Method, a collocation approach of the Weighted Residual Method. The computational domain is discretized into a collection of hexahedrons with quadrilateral elements in horizontal space connected with vertical mesh lines. Free surface is solved with the kinematic equation, the discretization of 3D elements varies with the motion of the surface.

A variety of turbulence closure schemes, including parabolic, mixing length, k-ε, RNG k-ε, k-ω, and non-linear k-ε mode, are available. For most applications in hydraulic engineering study, the hydrostatic pressure assumption is valid, however, one often needs dynamic pressure solution for near field problems around hydraulic structures. CCHE3D provides both options. This model has been verified using analytic approach, physical model data and field data; it has been applied to many problems of river flow, sedimentation, coastal processes, thermal stratification, wind driving flow, pollutant transport, and water quality analyses.

CCHE3D is not a free package.
Find more about CCHE3D here

Graphical User Interface (GUI)

Interactive, graphical user interfaces (GUIs) are being developed for the NCCHE flow, sediment transport, and water quality models. Each GUI provides a convenient environment for input datapreparation and model operation. They also provide advanced visualization capabilities and tools to facilitate the application of the NCCHE models toreal-life engineering problems.

Each graphical interface program has been designed to provide the most convenient set of tools for the model user. The CCHE1D interface program is integrated into ArcView GIS to facilitate the use of GIS data and to simplify integration with watershed models. The CCHE2D and CCHE3D GUIs are implemented using OpenGL to provide fast, high quality computer graphics, including the production of video animations.

Graphical interfaces for the CCHE1D and CCHE2D models are part of free software packages, and are distributed with the respective models. For more information on the research related to graphical interface programs, click here.

Mesh Generator (2D & 3D)

NCCHE has developed a complete, interactive mesh generation program to support both the CCHE2D and CCHE3D models. The program includes several techniques for the generation and optimization of structured meshes.

This graphical program allows the rapid creation of complex mesh systems. Several algebraic and numerical methods are available for the generation of boundary-fitted meshes. A novel multi-blockapproach facilitates mesh generation for complex geometries.

The NCCHE Mesh Generator is distributed as free software, and it is part of the CCHE2D modeling package. Find out more here. 

Free Software (Download)

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CCHE1D-Flood

The CCHE FLOOD is a finite volume model based on the solution of the full dynamic shallow water equations in conservative form. CCHE-FLOOD exists in both one-dimensional and two-dimensional versions. The model is particularly adapted for simulating real flood propagation over complex topography. It can be used to determine arrival/receding times of flood waves, to delineate the inundated area and to plot flow-depth contours as a function of time, to carry out operational flood-risk analysis and mapping, etc. 

The 2D version of CCHE-FLOOD can be efficiently used for studying flood propagation due to dam-break, and embankment or levee breaching.

CCHE-Flood is not a free package.
Find more about CCHE-Flood here

CCHE1D-WQ

CCHE-WQ is a physical and bio-chemical process-based module which simulates the water quality variables and pollutant transport dynamically. It is based on the mass transport equation and can be coupled with CCHE2D and CCHE3D hydrodynamic and sediment transport models.
 
CCHE-Flood is not a free package.
Find more about CCHE-Flood here

CCHE2D-Coast

The CCHE2D-COAST is an extension to CCHE2D, which allows the simulation of various coastal processes such as irregular wave deformation from offshore to onshore, near-shore currents induced by radiation stresses, sediment transport, and seabed morphological changes.

CCHE2D-Coast is not a free package.
Find more about CCHE2D-Coast here

CCHE2D-Tide

The CCHE-TIDE is an add-in module for CCHE2D to add the capability of simulation tidal flows in estuaries and coastal areas. CCHE-TIDE extends the use of CCHE2D for simulating tidal waves, tidal currents, and residual currents under the conditions of incident tidal waves (non-reflective), tributary flows, non-uniform wind force, and Coriolis force.

CCHE-Tide is not a free package.
Find more about CCHE-Tide here