Property:Describe processes
From CSDMS
This is a property of type Text.
V
Land Cover and Soil Snow Model
Meteorology (Inputs, Distributed Precip, and Snow/Elevation Bands)
Frozen Soil (including Permafrost)
Dynamic Lake/Wetland Model (new to 4.1.1)
Flow Routing +
C
Linearized RANS
Aeolian sediment transport
Shear stress reduction by vegetation
Plant growth (exponential relaxation) +
M
MARSSIM is a grid based, iterative framework that incorporates selectable modules, including: 1) flow routing, optionally including event-driven flow and evaporation from lakes in depression as a function of relative aridity (Matsubara et al., 2011). Runoff can be spatially uniform or variably distributed. Stream channel morphology (width and depth) is parameterized as a function of effective discharge; 2) bedrock weathering, following Equation 1; 3) spatially variable bedrock resistance to weathering and fluvial erosion, including 3-D stratigraphy and surficial coherent crusts; 4) erosion of bedrock channels using either a stream power relationship (Howard, 1994) or sediment load scour (Sklar and Dietrich, 2004; Chatanantavet and Parker, 2009); 5) sediment routing in alluvial channels including suspended/wash load and a single size of bedload. An optional sediment transport model simulates transport of multiple grain sizes of bedload with sorting and abrasion (Howard et al., 2016); 6) geometric impact cratering modeling optionally using a database of martian fresh crater morphology; 7) vapor sublimation from or condensation on the land surface, with options for rate control by the interaction between incident radiation, reflected light, and local topography; 8) mass wasting utilizing either the Howard (1994) or the Roering et al. (1999, 2001a) rate law. Bedrock can be optionally weathered and mass wasted assuming a critical slope angle steeper than the critical gradient for regolith-mantled slopes. Mass wasted debris is instantaneously routed across exposed bedrock, and the debris flux can be specified to erode the bedrock; 9) groundwater flow using the assumption of hydrostatic pressures and shallow flow relative to cell dimensions. Both recharge and seepage to the surface are modeled. Seepage discharge can be modeled to transport sediment (seepage erosion) or to weather exposed bedrock (groundwater sapping); 10) deep-seated mass flows using either Glen's law or Bingham rheology using a hydrostatic stress assumption; 11) eolian deposition and erosion in which the rate is determined by local topography; 12) lava flow and deposition from one or multiple vents. These model components vary in degree to which they are based on established theory or utilize heuristic
MODFLOW 6 presently contains two types of hydrologic models, the Groundwater Flow (GWF) Model and the Groundwater Transport (GWT) Model. The GWF Model for MODFLOW 6 is based on a generalized control-volume finite-difference (CVFD) approach in which a cell can be hydraulically connected to any number of surrounding cells. Users can define the model grid using
1. a regular MODFLOW grid consisting of layers, rows, and columns,
2. a layered grid defined by (x, y) vertex pairs, or
3. a general unstructured grid based on concepts developed for MODFLOW-USG.
For complex problems involving water-table conditions, an optional Newton-Raphson formulation, based on the formulations in MODFLOW-NWT and MODFLOW-USG, can be activated. The GWF Model is divided into "packages," as was done in previous MODFLOW versions. A package is the part of the model that deals with a single aspect of simulation. Packages included with the GWF Model include
- those related to internal calculations of groundwater flow (discretization, initial conditions, hydraulic conductance, and storage),
- stress packages (constant heads, wells, recharge, rivers, general head boundaries, drains, and evapotranspiration), and
- advanced stress packages (streamflow routing, lakes, multi-aquifer wells, and unsaturated zone flow).
An additional package is also available for moving water available in one package into the individual features of the advanced stress packages. The GWF Model also has packages for obtaining and controlling output from the model.
The GWT model for MODFLOW 6 simulates three-dimensional transport of a single solute species in flowing groundwater. The GWT Model solves the solute transport equation using numerical methods and a generalized CVFD approach, which can be used with regular MODFLOW grids or with unstructured grids. The GWT Model is designed to work with most of the new capabilities released with the GWF Model, including the Newton flow formulation, unstructured grids, advanced packages, and the movement of water between packages. The GWF and GWT Models operate simultaneously during a MODFLOW 6 simulation to represent coupled groundwater flow and solute transport. The GWT Model can also run separately from a GWF Model by reading the heads and flows saved by a previously run GWF Model. The GWT model is also capable of working with the flows from another groundwater flow model, as long as the flows from that model can be written in the correct form to flow and head files.
G
Main purpose of the model is to calculate subsurface temperature profile, active layer depth and freeze-up day. +
S
Many 2D flow situation with simple boundary conditions (ie no inflow or outflow). suitable for lock/exchange simulation of gravity/turbidity currents or to study stability properties of stratified flow. +
W
Marsh boundary erosion by waves
Marsh boundary progradation by accumulating sediments
Mudflat sediment erosion/deposition by wind waves
Sediment exchange between mudflat and open ocean
Sediment exchange between mudflat and marsh platform
Organogenic sediment production on marsh platform +
B
Mass flux per unit width, dry mass of grains moving over the unit bed area, calculates the suspendable amount present in the moving bed +
T
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) +
S
G
Natural, agricultural, atmospheric, and direct human (sewage and P detergents) inputs; effect of hydrological functioning; generalized loss of nutrients in soils and groundwater; loss in rivers, reservoirs, and through consumptive water withdrawals (irrigation). +
N
NearCoM predicts surface waves and wave-induced nearshore processes such as nearshore circulation, sediment transport and morphological changes. +
S
O
None, the module analyses strata produced by all depositional processes +
None. Code tests for the presence of order in strata that could arise from allocyclic or autocyclic processes +
G
Note: See also the GEOMBEST++Seagrass Users Guide, section 4
Seagrass wave attenuation and bay depth effects
Equilibrium profile & barrier transgression
Sea level rise
Back-barrier deposition
Marsh expansion/contraction
Marsh wave erosion +
M
Organic accretion
Inorganic accretion (function of elevation and distance from channels)
Pond formation
Pond expansion
Pond deepening
Pond drainage
Bank slumping (soil diffusion)
Subsidence due to ditches +
1
Overall, the module simulates a particle-based model of hillslope evolution in 1D.
The module contains several scripts and functions, the most important of which are the following.
(1) zrp.m is the script wherein the parameters are set and from which the following functions are called.
(2) init_x.m is the function which generates an initial profile for the hillslope.
(3) make_moves.m is the function which samples the probabilistic dynamics.
(4) calc_rates.m is the function which determines the rates at which the particles are moving.
In addition to these, there are the following.
(5) perturb.m is the function which implements the hillslope perturbation and is called by the main script.
(6) calc_flux.m and calc_fluxes.m are the functions which infer fluxes along the hillslope. +
O
