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<h2>DESCRIPTION</h2>
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-<i>r.sim.water</i> is a landscape scale simulation model
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+<em>r.sim.water</em> is a landscape scale simulation model
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of overland flow designed for spatially variable terrain, soil, cover
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and rainfall excess conditions. A 2D shallow water flow is described by
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the bivariate form of Saint Venant equations. The numerical solution is based
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@@ -8,15 +8,15 @@ on the concept of duality between the field and particle representation of
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the modeled quantity. Green's function Monte Carlo method, used to solve the equation,
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provides robustness necessary for spatially variable conditions and high
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resolutions (Mitas and Mitasova 1998). The key inputs of the model include
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-elevation (<i>elevation</i> raster map), flow gradient vector given by
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-first-order partial derivatives of elevation field (<i>dx</i> and <i>dy</i>
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-raster maps), rainfall excess rate (<i>rain</i> raster map or <i>rain_value</i> single
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+elevation (<b>elevation</b> raster map), flow gradient vector given by
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+first-order partial derivatives of elevation field (<b>dx</b> and <b>dy</b>
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+raster maps), rainfall excess rate (<b>rain</b> raster map or <b>rain_value</b> single
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value) and a surface roughness coefficient given by Manning's n
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-(<i>man</i> raster map or <i>man_value</i> single value). Partial
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+(<b>man</b> raster map or <b>man_value</b> single value). Partial
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derivatives raster maps can be computed along with interpolation of a DEM using
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-the -d option in <a href="v.surf.rst.html">v.surf.rst</a> module. If elevation raster
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+the -d option in <em><a href="v.surf.rst.html">v.surf.rst</a></em> module. If elevation raster
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map is already provided, partial derivatives can be computed using
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-<a href="r.slope.aspect.html">r.slope.aspect</a> module. Partial derivatives are used
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+<em><a href="r.slope.aspect.html">r.slope.aspect</a></em> module. Partial derivatives are used
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to determine the direction and magnitude of water flow velocity. To include a
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predefined direction of flow, map algebra can be used to replace terrain-derived
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partial derivatives with pre-defined partial derivatives in selected grid cells such
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@@ -39,22 +39,22 @@ For saturated soil and steady-state water flow it can be estimated using
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saturated hydraulic conductivity rates based on field measurements or using
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reference values which can be found in literature.
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Optionally, user can provide an overland flow infiltration rate map
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-<i>infil</i> or a single value <i>infil_value</i> in [mm/hr] that control the rate of
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+<b>infil</b> or a single value <b>infil_value</b> in [mm/hr] that control the rate of
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infiltration for the already flowing water, effectively reducing the flow depth and
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discharge.
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Overland flow can be further controlled by permeable check dams or similar type of structures,
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the user can provide a map of these structures and their permeability ratio
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-in the map <i>flow_control</i> that defines the probability of particles to pass
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+in the map <b>flow_control</b> that defines the probability of particles to pass
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through the structure (the values will be 0-1).
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<p>
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-Output includes a water depth raster map <i>depth</i> in [m], and a water discharge
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-raster map <i>discharge</i> in [m3/s]. Error of the numerical solution can be analyzed using
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-the <i>error</i> raster map (the resulting water depth is an average, and err is its RMSE).
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-The output vector points map <i>output_walkers</i> can be used to analyze and visualize
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+Output includes a water depth raster map <b>depth</b> in [m], and a water discharge
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+raster map <b>discharge</b> in [m3/s]. Error of the numerical solution can be analyzed using
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+the <b>error</b> raster map (the resulting water depth is an average, and err is its RMSE).
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+The output vector points map <b>output_walkers</b> can be used to analyze and visualize
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spatial distribution of walkers at different simulation times (note that
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the resulting water depth is based on the density of these walkers).
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-<!--Number of the output walkers is controlled by the <i>density</i> parameter, which controls
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+<!--Number of the output walkers is controlled by the <b>density</b> parameter, which controls
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how many walkers used in simulation should be written into the output. -->
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<!-- from
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http://www.ing.unitn.it/~grass/conferences/GRASS2002/proceedings/proceedings/pdfs/Mitasova_Helena_2.pdf
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@@ -62,13 +62,13 @@ http://www.ing.unitn.it/~grass/conferences/GRASS2002/proceedings/proceedings/pdf
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The spatial distribution of numerical error associated with path sampling solution can be
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analysed using the output error raster file [m]. This error is a function of the number
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of particles used in the simulation and can be reduced by increasing the number of walkers
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-given by parameter <i>nwalkers</i>.
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+given by parameter <b>nwalkers</b>.
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<!--(<font color="#ff0000"> toto treba upresnit/zmenit, lebo nwalk ide prec</font>). -->
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-Duration of simulation is controlled by the <i>niterations</i> parameter. The default value
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+Duration of simulation is controlled by the <b>niterations</b> parameter. The default value
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is 10 minutes, reaching the steady-state may require much longer time,
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depending on the time step, complexity of terrain, land cover and size of the area.
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Output walker, water depth and discharge maps can be saved during simulation using
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-the time series flag <i>-t</i> and <i>output_step</i> parameter
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+the time series flag <b>-t</b> and <b>output_step</b> parameter
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defining the time step in minutes for writing output files.
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Files are saved with a suffix representing time since the start of simulation in minutes
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(e.g. wdepth.05, wdepth.10).
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@@ -82,12 +82,12 @@ In case of invalid water depth data the value -1 is used.
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<p>
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Overland flow is routed based on partial derivatives of elevation
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field or other landscape features influencing water flow. Simulation
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-equations include a diffusion term (<i>diffusion_coeff</i> parameter) which enables
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+equations include a diffusion term (<b>diffusion_coeff</b> parameter) which enables
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water flow to overcome elevation depressions or obstacles when water depth exceeds
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-a threshold water depth value (<i>hmax)</i>, given in [m]. When it is reached,
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-diffusion term increases as given by <i>halpha</i> and advection term
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+a threshold water depth value (<b>hmax)</b>, given in [m]. When it is reached,
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+diffusion term increases as given by <b>halpha</b> and advection term
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(direction of flow) is given as "prevailing" direction of flow computed
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-as average of flow directions from the previous <i>hbeta</i> number of grid cells.
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+as average of flow directions from the previous <b>hbeta</b> number of grid cells.
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<h2>NOTES</h2>
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@@ -149,15 +149,13 @@ r.mapcalc "manning = if(elevation.10m, 0.05, null())"
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r.mapcalc "infilt = if(elevation.10m, 0.0, null())"
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# simulate
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-r.sim.water elevation=elevation.10m dx=elev_dx dy=elev_dy \
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- rain=rain man=manning infil=infilt \
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- nwalkers=5000000 depth=depth
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+r.sim.water elevation=elevation.10m dx=elev_dx dy=elev_dy rain=rain man=manning infil=infilt nwalkers=5000000 depth=depth
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</pre></div>
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<p>
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<center>
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<img src="r_sim_water.png" alt="r.sim.water generated depth map"><br>
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-<i>Water depth map in the Spearfish (SD) area</i>
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+<i>Figure: Water depth map in the Spearfish (SD) area</i>
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</center>
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@@ -169,31 +167,7 @@ If the module fails with
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ERROR: nwalk (7000001) > maxw (7000000)!
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</pre></div>
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-then a lower <em>nwalkers</em> parameter value has to be selected.
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-
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-<h2>SEE ALSO</h2>
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-
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-<em>
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-<a href="v.surf.rst.html">v.surf.rst</a>,
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-<a href="r.slope.aspect.html">r.slope.aspect</a>,
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-<a href="r.sim.sediment.html">r.sim.sediment</a>
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-</em>
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-
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-<h2>AUTHORS</h2>
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-
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-Helena Mitasova, Lubos Mitas<br>
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-North Carolina State University<br>
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-<i><a href="mailto:hmitaso@unity.ncsu.edu">hmitaso@unity.ncsu.edu</a></i>
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-
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-<p>
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-Jaroslav Hofierka<br>
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-GeoModel, s.r.o. Bratislava, Slovakia<br>
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-<i><a href="mailto:hofi@geomodel.sk">hofierka@geomodel.sk</a></i>
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-
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-<p>
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-Chris Thaxton<br>
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-North Carolina State University<br>
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-<i><a href="mailto:csthaxto@unity.ncsu.edu">csthaxto@unity.ncsu.edu</a></i>
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+then a lower <b>nwalkers</b> parameter value has to be selected.
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<h2>REFERENCES</h2>
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@@ -237,4 +211,28 @@ April 2015
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The International Series in Engineering and Computer Science: Volume 773. Springer New York Inc, p. 406.
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</ul>
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+<h2>SEE ALSO</h2>
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+
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+<em>
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+<a href="v.surf.rst.html">v.surf.rst</a>,
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+<a href="r.slope.aspect.html">r.slope.aspect</a>,
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+<a href="r.sim.sediment.html">r.sim.sediment</a>
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+</em>
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+
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+<h2>AUTHORS</h2>
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+
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+Helena Mitasova, Lubos Mitas<br>
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+North Carolina State University<br>
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+<i><a href="mailto:hmitaso@unity.ncsu.edu">hmitaso@unity.ncsu.edu</a></i>
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+
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+<p>
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+Jaroslav Hofierka<br>
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+GeoModel, s.r.o. Bratislava, Slovakia<br>
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+<i><a href="mailto:hofi@geomodel.sk">hofierka@geomodel.sk</a></i>
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+
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+<p>
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+Chris Thaxton<br>
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+North Carolina State University<br>
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+<i><a href="mailto:csthaxto@unity.ncsu.edu">csthaxto@unity.ncsu.edu</a></i>
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+
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<p><i>Last changed: $Date$</i>
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