Chapter 8: Modeling Physical Systems

FIGURES

Figure 8.1. Modeling steady state surface water depth h (shown as 200x exaggerated surface) in terrain with depressions and uniform soil and cover conditions: a) input 10m resolution DEM; b) h as a function of upslope contributing area computed by D8 algorithm: artificial flow pattern on hillslopes, geometrical flow through depressions (r.watershed in GRASS5); c) h as a function of upslope contributing area computed by vector-grid algorithm: depressions act as a sinks, (Mitasova et al. 1996, r.flow in GRASS5); d) 2D kinematic wave solution of continuity equation: water accumulates in depressions to infinity (SIMWE with diffussion->0); e) 2D approximate diffusive wave solution: water fills depressions creating ponds with subsequent outflow (SIMWE); f) 2D approximate diffusive wave solution with a channel with predefined gradient in one of the depressions: water flows rapidly through the depression (SIMWE). The SIMWE model is described by Mitas and Mitasova (1998).: NO COPYRIGHT

BW version of Figure 8.1. :NO COPYRIGHT

Figure 8.2. Path sampling method for solution of partial differential equations.: NO COPYRIGHT

Figure 8.3 Land use and net erosion/deposition pattern computed by USPED (Mitasova and Mitas, 1999) using general GIS (GRASS5). : NO COPYRIGHT

Figure 8.4 Snapshots from a 2D dynamic model of water depth distribution in a relatively flat field (0.8x1.5km) during steady uniform rainfall: a) 3 minutes, b) 15 minutes, c) 1 hour, d) 8 hours after the rainfall. Water depth, represented by color, is draped over exagerrated DEM. Time is approximate, modeling was performed by SIMWE.: NO COPYRIGHT

BW version of Figure 8.4. NO COPYRIGHT

FIGURE 8.5 Modeling of water depth, sediment flow and net erosion/deposition for different land use designs using SIMWE. Land use without conservation measures: a) low water depth due to fast runoff; b) potential for gullies in areas of concentrated water flow. Land use with extended grasss cover including a grassway: c) increased water depth in grass covered areas; d) deposition in grassway with erosion along its edges. Sediment flow is represented as a surface with erosion/deposition draped over it as color. : NO COPYRIGHT

Figure 8.6 Modeling surface water flow on a section of the Mississippi river. Surface-water Modeling System (SMS) was used to predict flow by the finite element two-dimensional hydrodynamic flow simulation program FESWMS http://www.ems-i.com/sms/ , 3D visualization of terrain model, land use and the river was done in GRASS5 using NVIZ tool. Figures courtesy Mingshi Chen, William M. Brown, RiverWeb Museum Consortium http://www.ncsa.uiuc.edu/Cyberia/RiverWeb/Projects/RWMuseum/
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BW version of Figure 8.6. NO COPYRIGHT