Hydrus-1D Projects - The effects of water content transients on colloid transport
Consideration of the effects of water content transients on colloid transport and attachment/detachment to/from the air-water interface are not standard features of the HYDRUS-1D code. However, since we have been working with Scott Bradford on this option in the past year and thus have a version of the H1D code, which can take these processes into account, we have decided to share this code (and selected demonstrative examples) with the HYDRUS users.
Figure 4: An example of observed [Wang et al., 2014] and simulated D21g release with repeated cycles of water drainage and imbibition. Phases 1 and 2 were conducted under saturated conditions, and then the sand was repeatedly drained and imbibed during Phase 3 by adjusting the boundary conditions at the bottom and top of the column. In Figure on the left, similar amounts of drainage and imbibition occurred with each cycle, whereas in Figure on the right, the column was successively drained to lower water saturations of 0.57, 0.36, and 0.27. D# and I# denote the drainage and imbibition number (#), respectively.
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Project
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Description
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Figure 2
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Figure 2, Initial unsaturated, two imbibition, Phase 3, theta_ra
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Figure 4
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Figure 4a, Cycles of drainage and imbibition - continuous fit
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Figure 4a1
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Figure 4a, Cycles of drainage and imbibition - fit of D2+I3
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Figure 4a2
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Figure 4a, Cycles of drainage and imbibition - fit of D3+I5
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Figure 4a3
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Figure 4a, Cycles of drainage and imbibition - fit of D4+I7
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Figure 4b
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Figure 4b, Cycles of drainage and imbibition - continuous fit
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fr_0
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Figure 5a, f_awi=0.5, f_r=0.0
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fr_25
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Figure 5a, f_awi=0.5, f_r=0.25
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fr_50
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Figure 5a, f_awi=0.5, f_r=0.50
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fr_75
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Figure 5a, f_awi=0.5, f_r=0.75
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fr_1
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Figure 5a, f_awi=0.5, f_r=1.0
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Fawi_0
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Figure 5b, f_awi=0.00, f_r=1.00
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Fawi_25
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Figure 5b, f_awi=0.25, f_r=1.00
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Fawi_50
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Figure 5b, f_awi=0.50, f_r=1.00
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Fawi_75
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Figure 5b, f_awi=0.75, f_r=1.00
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Fawi_1
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Figure 5b, f_awi=1.00, f_r=1.00
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BC_25
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Figure 6a, Drainage time = 25 min
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BC_50
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Figure 6a, Drainage time = 50 min
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BC_75
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Figure 6a, Drainage time = 75 min
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BC_100
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Figure 6a, Drainage time = 100 min
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BC_150
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Figure 6a, Drainage time = 150 min
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Flux_0.1
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Figure 6b, Imbibition Flux 0.10 mL/min
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Flux_0.25
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Figure 6b, Imbibition Flux 0.25 mL/min
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Flux_0.50
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Figure 6b, Imbibition Flux 0.50 mL/min
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Flux_0.75
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Figure 6b, Imbibition Flux 0.75 mL/min
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Flux_1.0
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Figure 6b, Imbibition Flux 1.00 mL/min
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Download computational modules (both direct and inverse) (1.2 MB)
Download demonstrative examples (2.1 MB)
To use the code, you can simply replace the h1d_calc.exe (direct code) and h1d_clci.exe (inverse code) files in the HYDRUS installation folder (make a backup of the original file first, so that you can return to it for other than these applications), or you can place it anywhere else and run it outside of the GUI (see FAQ4).
A brief note on the implementation can be downloaded here (pdf)
The theory behind this program and the demonstrative examples (listed below) are described in Bradford et al. (2015):
Bradford, S. A., Y. Wang, S. Torkzaban, and J. Šimůnek, Modeling the release of E. coli D21g with transients in water content, Water Resources Research, 51(5), 3303-3316, doi:10.1002/2014WR016566, 2015.
Data used in selected examples are from Wang et al. (2014):
Wang, Y., S. A. Bradford, and J. Šimůnek, Release of E. coli D21g with transients in water content, Environmental Science & Technology, 48(16), 9349-9357, doi: 10.1021/es501956k, 2014.