1r.sim.sediment(1) Grass User's Manual r.sim.sediment(1)
2
6 r.sim.sediment - Sediment transport and erosion/deposition simulation
7 using path sampling method (SIMWE).
8
10 raster, hydrology, soil, sediment flow, erosion, deposition, model
11
13 r.sim.sediment
14 r.sim.sediment --help
15 r.sim.sediment [-s] elevation=name water_depth=name dx=name dy=name
16 detachment_coeff=name transport_coeff=name shear_stress=name
17 [man=name] [man_value=float] [observation=name] [transport_capac‐
18 ity=name] [tlimit_erosion_deposition=name] [sediment_concentra‐
19 tion=name] [sediment_flux=name] [erosion_deposition=name] [log‐
20 file=name] [walkers_output=name] [nwalkers=integer] [nitera‐
21 tions=integer] [output_step=integer] [diffusion_coeff=float]
22 [random_seed=integer] [nprocs=integer] [--overwrite] [--help]
23 [--verbose] [--quiet] [--ui]
24 Flags:
26 -s
27 Generate random seed
28 Automatically generates random seed for random number generator
29 (use when you don’t want to provide the seed option)
30 --overwrite
32 Allow output files to overwrite existing files
33 --help
35 Print usage summary
36 --verbose
38 Verbose module output
39 --quiet
41 Quiet module output
42 --ui
44 Force launching GUI dialog
45 Parameters:
47 elevation=name [required]
48 Name of input elevation raster map
49 water_depth=name [required]
51 Name of water depth raster map [m]
52 dx=name [required]
54 Name of x-derivatives raster map [m/m]
55 dy=name [required]
57 Name of y-derivatives raster map [m/m]
58 detachment_coeff=name [required]
60 Name of detachment capacity coefficient raster map [s/m]
61 transport_coeff=name [required]
63 Name of transport capacity coefficient raster map [s]
64 shear_stress=name [required]
66 Name of critical shear stress raster map [Pa]
67 man=name
69 Name of Manning’s n raster map
70 man_value=float
72 Manning’s n unique value
73 Default: 0.1
74 observation=name
76 Name of sampling locations vector points map
77 Or data source for direct OGR access
78 transport_capacity=name
80 Name for output transport capacity raster map [kg/ms]
81 tlimit_erosion_deposition=name
83 Name for output transport limited erosion-deposition raster map
84 [kg/m2s]
85 sediment_concentration=name
87 Name for output sediment concentration raster map [particle/m3]
88 sediment_flux=name
90 Name for output sediment flux raster map [kg/ms]
91 erosion_deposition=name
93 Name for output erosion-deposition raster map [kg/m2s]
94 logfile=name
96 Name for sampling points output text file. For each observation
97 vector point the time series of sediment transport is stored.
98 walkers_output=name
100 Base name of the output walkers vector points map
101 nwalkers=integer
103 Number of walkers
104 niterations=integer
106 Time used for iterations [minutes]
107 Default: 10
108 output_step=integer
110 Time interval for creating output maps [minutes]
111 Default: 2
112 diffusion_coeff=float
114 Water diffusion constant
115 Default: 0.8
116 random_seed=integer
118 Seed for random number generator
119 The same seed can be used to obtain same results or random seed can
120 be generated by other means.
121 nprocs=integer
123 Number of threads which will be used for parallel compute
124 Default: 1
125
127 r.sim.sediment is a landscape scale, simulation model of soil erosion,
128 sediment transport and deposition caused by flowing water designed for
129 spatially variable terrain, soil, cover and rainfall excess conditions.
130 The soil erosion model is based on the theory used in the USDA WEPP
131 hillslope erosion model, but it has been generalized to 2D flow. The
132 solution is based on the concept of duality between fields and parti‐
133 cles and the underlying equations are solved by Green’s function Monte
134 Carlo method, to provide robustness necessary for spatially variable
135 conditions and high resolutions (Mitas and Mitasova 1998). Key inputs
136 of the model include the following raster maps: elevation (elevation
137 [m]), flow gradient given by the first-order partial derivatives of
138 elevation field ( dx and dy), overland flow water depth (water_depth
139 [m]), detachment capacity coefficient (detachment_coeff [s/m]), trans‐
140 port capacity coefficient (transport_coeff [s]), critical shear stress
141 (shear_stress [Pa]) and surface roughness coefficient called Manning’s
142 n (man raster map). Partial derivatives can be computed by v.surf.rst
143 or r.slope.aspect module. The data are automatically converted from
144 feet to metric system using database/projection information, so the
145 elevation always should be in meters. The water depth file can be com‐
146 puted using r.sim.water module. Other parameters must be determined
147 using field measurements or reference literature (see suggested values
148 in Notes and References).
149 Output includes transport capacity raster map transport_capacity in
151 [kg/ms], transport capacity limited erosion/deposition raster map
152 tlimit_erosion_deposition [kg/m2s]i that are output almost immediately
153 and can be viewed while the simulation continues. Sediment flow rate
154 raster map sediment_flux [kg/ms], and net erosion/deposition raster map
155 [kg/m2s] can take longer time depending on time step and simulation
156 time. Simulation time is controlled by niterations [minutes] parame‐
157 ter. If the resulting erosion/deposition map is noisy, higher number
158 of walkers, given by nwalkers should be used.
159
161 v.surf.rst, r.slope.aspect, r.sim.water
162
164 Helena Mitasova, Lubos Mitas
165 North Carolina State University
166 hmitaso@unity.ncsu.edu
167 Jaroslav Hofierka
168 GeoModel, s.r.o. Bratislava, Slovakia
169 hofierka@geomodel.sk
170 Chris Thaxton
171 North Carolina State University
172 csthaxto@unity.ncsu.edu
173 csthaxto@unity.ncsu.edu
174
176 Mitasova, H., Thaxton, C., Hofierka, J., McLaughlin, R., Moore, A.,
177 Mitas L., 2004, Path sampling method for modeling overland water flow,
178 sediment transport and short term terrain evolution in Open Source GIS.
179 In: C.T. Miller, M.W. Farthing, V.G. Gray, G.F. Pinder eds., Proceed‐
180 ings of the XVth International Conference on Computational Methods in
181 Water Resources (CMWR XV), June 13-17 2004, Chapel Hill, NC, USA, Else‐
182 vier, pp. 1479-1490.
183 Mitasova H, Mitas, L., 2000, Modeling spatial processes in multiscale
185 framework: exploring duality between particles and fields, plenary talk
186 at GIScience2000 conference, Savannah, GA.
187 Mitas, L., and Mitasova, H., 1998, Distributed soil erosion simulation
189 for effective erosion prevention. Water Resources Research, 34(3),
190 505-516.
191 Mitasova, H., Mitas, L., 2001, Multiscale soil erosion simulations for
193 land use management, In: Landscape erosion and landscape evolution mod‐
194 eling, Harmon R. and Doe W. eds., Kluwer Academic/Plenum Publishers,
195 pp. 321-347.
196 Neteler, M. and Mitasova, H., 2008, Open Source GIS: A GRASS GIS
198 Approach. Third Edition. The International Series in Engineering and
199 Computer Science: Volume 773. Springer New York Inc, p. 406.
200 Last changed: $Date: 2018-06-12 02:43:40 +0200 (Tue, 12 Jun 2018) $
202
204 Available at: r.sim.sediment source code (history)
205 Main index | Raster index | Topics index | Keywords index | Graphical
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208 © 2003-2019 GRASS Development Team, GRASS GIS 7.6.0 Reference Manual
210GRASS 7.6.0 r.sim.sediment(1)