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Jeff Sadler

 Recent activity

ABSTRACT:

An extension of the WBMplus (WBM/WTM) model. Introduce a riverine sediment flux component based on the BQART and Psi models.

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ABSTRACT:

Gridded water balance model using climate input forcings that calculate surface and subsurface runoff and ground water recharge for each grid cell. The surface and subsurface runoff is propagated horizontally along a prescribed gridded network using Musking type horizontal transport.

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ABSTRACT:

The VIC model is a large-scale, semi-distributed hydrologic model. As such, it shares several basic features with the other land surface models (LSMs) that are commonly coupled to global circulation models (GCMs):
The land surface is modelled as a grid of large (>1km), flat, uniform cells
Sub-grid heterogeneity (e.g. elevation, land cover) is handled via statistical distributions.
Inputs are time series of daily or sub-daily meteorological drivers (e.g. precipitation, air temperature, wind speed).
Land-atmosphere fluxes, and the water and energy balances at the land surface, are simulated at a daily or sub-daily time step
Water can only enter a grid cell via the atmosphere
Non-channel flow between grid cells is ignored
The portions of surface and subsurface runoff that reach the local channel network within a grid cell are assumed to be >> the portions that cross grid cell boundaries into neighboring cells
Once water reaches the channel network, it is assumed to stay in the channel (it cannot flow back into the soil)
This last point has several consequences for VIC model implementation:
Grid cells are simulated independently of each other
Entire simulation is run for each grid cell separately, 1 grid cell at a time, rather than, for each time step, looping over all grid cells
Meteorological input data for each grid cell (for the entire simulation period) are read from a file specific to that grid cell
Time series of output variables for each grid cell (for the entire simulation period) are stored in files specific to that grid cell
Routing of stream flow is performed separately from the land surface simulation, using a separate model (typically the routing model of Lohmann et al., 1996 and 1998)

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ABSTRACT:

A multi-dimensional numerical model for sediment transport based on the two-phase
flow formulation is developed. With closures of particle stresses and fluid-particle interaction,
the model is able to resolve processes in the concentrated region of sediment
transport and hence does not require conventional bedload/suspended load assumptions.
The numerical model is developed in three spatial dimensions. However, in this version,
the model is only validated for Reynolds-averaged two-dimensional vertical (2DV) formulation
(with the k − epsilon closure for carrier flow turbulence) for sheet flow in steady and
oscillatory flows. This numerical model is developed via the open-source CFD library of
solvers, OpenFOAM and the new solver is called twoPhaseEulerSedFoam.

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ABSTRACT:

This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model.

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Model Program Resource Model Program Resource
Anuga
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Habili, Nariman

ABSTRACT:

ANUGA is a hydrodynamic modelling tool that allows users to model realistic flow problems in complex 2D geometries. Examples include dam breaks or the effects of natural hazards such as riverine flooding, storm surges and tsunami. The user must specify a study area represented by a mesh of triangular cells, the topography and bathymetry, frictional resistance, initial values for water level (called stage within ANUGA), boundary conditions and forces such as rainfall, stream flows, windstress or pressure gradients if applicable.
ANUGA tracks the evolution of water depth and horizontal momentum within each cell over time by solving the shallow water wave governing equation using a finite-volume method.
ANUGA also incorporates a mesh generator that allows the user to set up the geometry of the problem interactively as well as tools for interpolation and surface fitting, and a number of auxiliary tools for visualising and interrogating the model output.
Most ANUGA components are written in the object-oriented programming language Python and most users will interact with ANUGA by writing small Python scripts based on the ANUGA library functions. Computationally intensive components are written for efficiency in C routines working directly with Python numpy structures.

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Model Program Resource Model Program Resource
Avulsion
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Hutton, Eric

ABSTRACT:

Model stream avulsion as random walk

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Model Program Resource Model Program Resource
CREST
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Wang, Jiahu

ABSTRACT:

The Coupled Routing and Excess STorage (CREST) distributed hydrological model is a hybrid modeling strategy that was recently developed by the University of Oklahoma (http://hydro.ou.edu) and NASA SERVIR Project Team. CREST simulates the spatiotemporal variation of water and energy fluxes and storages on a regular grid with the grid cell resolution being user-defined, thereby enabling global- and regional-scale applications. The scalability of CREST simulations is accomplished through sub-grid scale representation of soil moisture storage capacity (using a variable infiltration curve) and runoff generation processes (using linear reservoirs). The CREST model was initially developed to provide online global flood predictions with relatively coarse resolution, but it is also applicable at small scales, such as single basins. This README file and the accompanying code concentrates on and tests the model at the small scale. The CREST Model can be forced by gridded potential evapotranspiration and precipitation datasets such as, satellite-based precipitation estimates, gridded rain gauge observations, remote sensing platforms such as weather radar, and quantitative precipitation forecasts from numerical weather prediction models. The representation of the primary water fluxes such as infiltration and routing are closely related to the spatially variable land surface characteristics (i.e., vegetation, soil type, and topography). The runoff generation component and routing scheme are coupled, thus providing realistic interactions between atmospheric, land surface, and subsurface water.

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Model Program Resource Model Program Resource
DHSVM
Created: Jan. 19, 2017, 4:31 a.m.
Authors:

ABSTRACT:

DHSVM is a distributed hydrology model that was developed at the University of Washington more than ten years ago. It has been applied both operationally, for streamflow prediction, and in a research capacity, to examine the effects of forest management on peak streamflow, among other things.

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Model Program Resource Model Program Resource
DR3M
Created: Jan. 19, 2017, 4:31 a.m.
Authors:

ABSTRACT:

DR3M is a watershed model for routing storm runoff through a Branched system of pipes and (or) natural channels using rainfall as input. DR3M provides detailed simulation of storm-runoff periods selected by the user. There is daily soil-moisture accounting between storms. A drainage basin is represented as a set of overland-flow, channel, and reservoir segments, which jointly describe the drainage features of the basin. This model is usually used to simulate small urban basins. Interflow and base flow are not simulated. Snow accumulation and snowmelt are not simulated.

Input Parameters:
aily precipitation, daily evapotranspiration, and short-interval precipitation are required. Short-interval discharge is required for the optimization option and to calibrate the model. These time series are read from a WDM file. Roughness and hydraulics parameters and sub-catchment areas are required to define the basin. Six parameters are required to calculate infiltration and soil-moisture accounting. Up to three rainfall stations may be used. Two soil types may be defined. A total of 99 flow planes, channels, pipes, reservoirs, and junctions may be used to define the basin.

Output Parameters:
The computed outflow from any flow plane, pipe, or channel segment for each storm period may be written to the output file or to the WDM file. A summary of the measured and simulated rainfall, runoff, and peak flows is written to the output file. A flat file containing the storm rainfall, measured flow (if available), and simulated flow at user selected sites can be generated. A flat file for each storm containing the total rainfall, the measured peak flow (if available), and the simulated peak flow for user-selected sites can be generated.

Process:
The rainfall-excess components include soil-moisture accounting, pervious-area rainfall excess, impervious-area rainfall excess, and parameter optimization. The Green-Ampt equation is used in the calculations of infiltration and pervious area rainfall excess. A Rosenbrock optimization procedure may be used to aid in calibrating several of the infiltration and soil-moisture accounting parameters. Kinematic wave theory is used for both overland-flow and channel routing. There are three solution techniques available: method of characteristics, implicit finite difference method, and explicit finite difference method. Two soil types may be defined. Overland flow may be defined as turbulent or laminar. Detention reservoirs may be simulated as linear storage or using a modified-Puls method. Channel segments may be defined as gutter, pipe, triangular cross section, or by explicitly specifying the kinematic channel parameters alpha and m.

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Model Program Resource Model Program Resource
FLDTA
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Slingerland, Rudy

ABSTRACT:

Calculates the flow velocity and depth based on the gradually varied flow equation of an open channel.

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Model Program Resource Model Program Resource
GEOtop
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Rigon, Riccardo · Endrizzi, Stefano · Dall'Amico, Matteo

ABSTRACT:

GEOtop accommodates very complex topography and, besides the water balance integrates all the terms in the surface energy balance equation. For saturated and unsaturated subsurface flow, it uses the 3D Richards’ equation. An accurate treatment of radiation inputs is implemented in order to be able to return surface temperature.
The model GEOtop simulates the complete hydrological balance in a continuous way, during a whole year, inside a basin and combines the main features of the modern land surfaces models with the distributed rainfall-runoff models.
The new 0.875 version of GEOtop introduces the snow accumulation and melt module and describes sub-surface flows in an unsaturated media more accurately. With respect to the version 0.750 the updates are fundamental: the codex is completely eviewed, the energy and mass parametrizations are rewritten, the input/output file set is redifined.
GEOtop makes it possible to know the outgoing discharge at the basin's closing section, to estimate the local values at the ground of humidity, of soil temperature, of sensible and latent heat fluxes, of heat flux in the soil and of net radiation, together with other hydrometeorlogical distributed variables. Furthermore it describes the distributed snow water equivalent and surface snow temperature.
GEOtop is a model based on the use of Digital Elevation Models (DEMs). It makes also use of meteorological measurements obtained thought traditional instruments on the ground. Yet, it can also assimilate distributed data like those coming from radar measurements, from satellite terrain sensing or from micrometeorological models.

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Model Program Resource Model Program Resource
Glimmer-CISM
Created: Jan. 19, 2017, 4:31 a.m.
Authors: Hagdorn, Magnus · Johnson, Jesse · Lipscomb, William · Payne, Tony · Price, Stephen · Rutt, Ian

ABSTRACT:

Glimmer is an open source (GPL) three-dimensional thermomechanical ice sheet model, designed to be interfaced to a range of global climate models. It can also be run in stand-alone mode. Glimmer was developed as part of the NERC GENIE project (www.genie.ac.uk). It's development follows the theoretical basis found in Payne (1999) and Payne (2001). Glimmer's structure contains numerous software design strategies that make it maintainable, extensible, and well documented.

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Model Program Resource Model Program Resource
IceFlow
Created: Jan. 19, 2017, 4:32 a.m.
Authors: Wickert, Andy · Colgan, William

ABSTRACT:

IceFlow simulates ice dynamics by solving equations for internal deformation and simplified basal sliding in glacial systems. It is designed for computational efficiency by using the shallow ice approximation for driving stress, which it solves alongside basal sliding using a semi-implicit direct solver. IceFlow is integrated with GRASS GIS to automatically generate input grids from a geospatial database.

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Model Program Resource Model Program Resource
MODFLOW-2000
Created: Jan. 19, 2017, 4:32 a.m.
Authors: Barlow, Paul · Harbaugh, Arlen · Banta, Edward · Hill, Mary · Winston, Richard

ABSTRACT:

MODFLOW is a three-dimensional finite-difference ground-water model that was first published in 1984. It has a modular structure that allows it to be easily modified to adapt the code for a particular application. Many new capabilities have been added to the original model. OFR 00-92 (complete reference below) documents a general update to MODFLOW, which is called MODFLOW-2000 in order to distinguish it from earlier versions.
MODFLOW-2000 simulates steady and nonsteady flow in an irregularly shaped flow system in which aquifer layers can be confined, unconfined, or a combination of confined and unconfined. Flow from external stresses, such as flow to wells, areal recharge, evapotranspiration, flow to drains, and flow through river beds, can be simulated. Hydraulic conductivities or transmissivities for any layer may differ spatially and be anisotropic (restricted to having the principal directions aligned with the grid axes), and the storage coefficient may be heterogeneous. Specified head and specified flux boundaries can be simulated as can a head dependent flux across the model's outer boundary that allows water to be supplied to a boundary block in the modeled area at a rate proportional to the current head difference between a "source" of water outside the modeled area and the boundary block. MODFLOW is currently the most used numerical model in the U.S. Geological Survey for ground-water flow problems.
In addition to simulating ground-water flow, the scope of MODFLOW-2000 has been expanded to incorporate related capabilities such as solute transport and parameter estimation.

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Model Program Resource Model Program Resource
ParFlow
Created: Jan. 19, 2017, 4:32 a.m.
Authors: Maxwell, Reed · Smith, Steven · Kollet, Stefan

ABSTRACT:

ParFlow is an open-source, object-oriented, parallel watershed flow model. It includes fully-integrated overland flow, the ability to simulate complex topography, geology and heterogeneity and coupled land-surface processes including the land-energy budget, biogeochemistry and snow (via CLM). It is multi-platform and runs with a common I/O structure from laptop to supercomputer. ParFlow is the result of a long, multi-institutional development history and is now a collaborative effort between CSM, LLNL, UniBonn and UCB. ParFlow has been coupled to the mesoscale, meteorological code ARPS and the NCAR code WRF.

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Model Program Resource Model Program Resource
Pllcart3d
Created: Jan. 19, 2017, 4:32 a.m.
Authors: Oliviera, Rafael

ABSTRACT:

Nonlinear three dimensional simulations of miscible Hele-Shaw flows using DNS of incompressible Navier-Stokes and transport equations.
The code models the evolution of a diffusive interface and the instabilities that arises when a less viscous fluid pushes a more viscous one in a confined rectangular geometry. Incompressible Navier-Stokes equations coupled to a convective-diffusive equation to describe the concentration field of the particles. In its current state, the code is restricted to low Reynolds number and Peclet number of order 1000.

Input Parameters:
Geometrical parameters: Nx, Ny, Nz, X1, X2, Y1, Y2, Z1, Z2 (ASCII);
Flow parameters: Reynolds, Peclet, Viscosity Ratio; Flags: resume simulation, add wave perturbation.

Output Parameters (Binary):
Velocities and concentration fields of the particles are stored to binary files at given time steps.

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Model Program Resource Model Program Resource
STVENANT
Created: Jan. 19, 2017, 4:32 a.m.
Authors: Slingerland, Rudy

ABSTRACT:

Predicts 1D, unsteady, nonlinear, gradually varied flow

Input parameters (ASCII):
Number of cross sections, Time (s) and space (m) descretisation steps, Chezy friction coefficient (m**1/2 s**-1), Period (s) and amplitude (m) of incoming waves, Number of time steps desired, Channel width at the Ith cross section (m), Still water depth (m)

Output parameters (ASCII):
water depths (m), water discharges (m3/s), free surface elevation with respect to the SWL (m)

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Model Program Resource Model Program Resource
TopoFlow
Created: Jan. 19, 2017, 4:33 a.m.
Authors: Matell, Nora · Overeem, Irina

ABSTRACT:

TopoFlow is a powerful, spatially-distributed hydrologic model with a user-friendly point-and-click interface. Its main purpose is to model many different physical processes in a watershed with the goal of accurately predicting how various hydrologic variables will evolve in time in response to climatic forcings.
Modeled processes include:
Channelized flow (kinematic, diffusive or dynamic wave, all 1D and D8-based)
Overland flow
Snowmelt (degree-day or energy balance)
Icemelt (from valley glaciers using GC2D)
Meteorology (including precipitation, air temperature, shortwave and longwave radiation, etc.)
Evaporation (Priestley-Taylor or energy balance)
Infiltration (Green-Ampt, Smith-Parlange or Richards' 1D, multi-layer), *Shallow subsurface flow (Darcy, up to 6 layers)
Flow diversions (sinks, sources or canals)

Each process can have its own timestep. Typical timesteps are:
Channel flow (seconds)
Infiltration (seconds to minutes)
Snowmelt (hours to days)
Subsurface flow (hours to days), etc.
Model can be run for a full year or longer, if necessary.

Overland flow is currently modeled in a nonstandard way. Diffusive wave and dynamic wave routing routines need more testing. The linkage between the unsaturated zone (infiltration component) and saturated zone (subsurface flow component and water table) is not robust.

Available test datat sets:
Treynor watershed, in the Nishnabotna River basin, Iowa, USA. (Two large rainfall events.)
Small basin in Kentucky.
Inclined plane for testing.
Arctic watershed data from Larry Hinzman (UAF).
See /data/progs/topoflow/3.0/data on CSDMS cluster.

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Model Program Resource Model Program Resource
Landlab
Created: Jan. 20, 2017, 4 a.m.
Authors: Tucker, Greg · Gasparini, Nicole · Istanbulluoglu, Erkan · Hutton, Eric

ABSTRACT:

Landlab is a Python software package for creating, assembling, and/or running 2D numerical models. Landlab was created to facilitate modeling in earth-surface dynamics, but it is general enough to support a wide range of applications. Landlab provides three different capabilities:
(1) A DEVELOPER'S TOOLKIT for efficiently building 2D models from scratch. The toolkit includes a powerful GRIDDING ENGINE for creating, managing, and iterative updating data on 2D structured or unstructured grids. The toolkit also includes helpful utilities to handle model input and output.

(2) A set of pre-built COMPONENTS, each of which models a particular process. Components can be combined together to create coupled models.

(3) A library of pre-built MODELS that have been created by combining components together.

To learn more, please visit http://landlab.github.io

Input Parameters:
Because this is a toolkit for model building, there are no set input parameters. Rather, developers use the code to create their own models, with their own unique inputs.
The ModelParameterDictionary tool provides formatted ASCII input for model parameters. The I/O component also handles input of digital elevation models (DEMs) in standard ArcInfo ASCII format.

Output Parameters:
Gridding component provides ASCII and/or netCDF output of grid geometry.

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Model Program Resource Model Program Resource
GISS GCM ModelE
Created: Jan. 20, 2017, 3:38 a.m.
Authors: Schmidt, Gavin

ABSTRACT:

ModelE is the GISS series of coupled atmosphere-ocean models, which provides the ability to simulate many different configurations of Earth System Models - including interactive atmospheric chemsitry, aerosols, carbon cycle and other tracers, as well as the standard atmosphere, ocean, sea ice and land surface components.

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Model Program Resource Model Program Resource
GreenAmptInfiltrationModel
Created: Jan. 20, 2017, 3:50 a.m.
Authors: Jiang, Peishi

ABSTRACT:

The Green-Ampt method of infiltration estimation.

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Model Program Resource Model Program Resource
RHESSys
Created: Jan. 20, 2017, 4:21 a.m.
Authors: Tague, Christina · Choate, Janet

ABSTRACT:

RHESSys is a GIS-based, hydro-ecological modelling framework designed to simulate carbon, water, and nutrient fluxes. By combining a set of physically-based process models and a methodology for partitioning and parameterizing the landscape, RHESSys is capable of modelling the spatial distribution and spatio-temporal interactions between different processes at the watershed scale.

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Model Program Resource Model Program Resource
TopoFlow-Channels-Diffusive Wave
Created: Jan. 19, 2017, 4:33 a.m.
Authors: Peckham, Scott

ABSTRACT:

This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model. It uses the "diffusive wave" method to compute flow velocities for all of the channels in a D8-based river network. This method includes a pressure gradient term that is induced by a water-depth gradient in the downstream direction. This means that instead of using bed slope in Manning's equation or the law of the wall, the water-surface slope is used.

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Model Program Resource Model Program Resource
TopoFlow-Snowmelt-Energy Balance
Created: April 11, 2017, 1:25 a.m.
Authors: Scott Peckham

ABSTRACT:

This process component is part of a spatially-distributed hydrologic model called TopoFlow, but it can now be used as a stand-alone model.

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Model Program Resource Model Program Resource
TwoPhaseEulerSedFoam
Created: April 11, 2017, 1:25 a.m.
Authors: Zhen Cheng · Tian-Jian Hsu

ABSTRACT:

A multi-dimensional numerical model for sediment transport based on the two-phase
flow formulation is developed. With closures of particle stresses and fluid-particle interaction,
the model is able to resolve processes in the concentrated region of sediment
transport and hence does not require conventional bedload/suspended load assumptions.
The numerical model is developed in three spatial dimensions. However, in this version,
the model is only validated for Reynolds-averaged two-dimensional vertical (2DV) formulation
(with the k − epsilon closure for carrier flow turbulence) for sheet flow in steady and
oscillatory flows. This numerical model is developed via the open-source CFD library of
solvers, OpenFOAM and the new solver is called twoPhaseEulerSedFoam.

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Model Program Resource Model Program Resource
VIC
Created: April 11, 2017, 1:39 a.m.
Authors: Dennis Lettenmaier

ABSTRACT:

The VIC model is a large-scale, semi-distributed hydrologic model. As such, it shares several basic features with the other land surface models (LSMs) that are commonly coupled to global circulation models (GCMs):
The land surface is modelled as a grid of large (>1km), flat, uniform cells
Sub-grid heterogeneity (e.g. elevation, land cover) is handled via statistical distributions.
Inputs are time series of daily or sub-daily meteorological drivers (e.g. precipitation, air temperature, wind speed).
Land-atmosphere fluxes, and the water and energy balances at the land surface, are simulated at a daily or sub-daily time step
Water can only enter a grid cell via the atmosphere
Non-channel flow between grid cells is ignored
The portions of surface and subsurface runoff that reach the local channel network within a grid cell are assumed to be >> the portions that cross grid cell boundaries into neighboring cells
Once water reaches the channel network, it is assumed to stay in the channel (it cannot flow back into the soil)
This last point has several consequences for VIC model implementation:
Grid cells are simulated independently of each other
Entire simulation is run for each grid cell separately, 1 grid cell at a time, rather than, for each time step, looping over all grid cells
Meteorological input data for each grid cell (for the entire simulation period) are read from a file specific to that grid cell
Time series of output variables for each grid cell (for the entire simulation period) are stored in files specific to that grid cell
Routing of stream flow is performed separately from the land surface simulation, using a separate model (typically the routing model of Lohmann et al., 1996 and 1998)

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Model Program Resource Model Program Resource
WBM-WTM
Created: April 11, 2017, 1:39 a.m.
Authors: Balazs Fekete · Charles Vorosmarty · Dominik Wisser

ABSTRACT:

Gridded water balance model using climate input forcings that calculate surface and subsurface runoff and ground water recharge for each grid cell. The surface and subsurface runoff is propagated horizontally along a prescribed gridded network using Musking type horizontal transport.

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Model Program Resource Model Program Resource
WBMsed
Created: April 11, 2017, 1:39 a.m.
Authors: Sagy Cohen

ABSTRACT:

An extension of the WBMplus (WBM/WTM) model. Introduce a riverine sediment flux component based on the BQART and Psi models.

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