Czech University of Life Sciences, Pragueand

PC-Progress, s.r.o., Prague

4th International Conference
HYDRUS Software Applications to Subsurface Flow
and Contaminant Transport Problems
March 21-22 2013
Prague, Czech RepublicCzech University of Life Sciences, Prague
Faculty of Agrobiology, Food and Natural ResourcesKamýcká 129
165 21 Praha 6 – Suchdol
Czech Republic
http://www.af.czu.cz/en/
PC-Progress s.r.o.
Korunní 2569/108a
Prague, 101 00
Czech Republic
http://www.pc-progress.com/en/Default.aspx

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ISBN: 978-80-213-2368-1

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Preliminary Program
Thursday, March 21, Morning session:
Variably-Saturated Water Flow and Transport of ContaminantsTime
9:00-9:05
9:05-9:30

Authors and Title
Jirka Šimůnek and Radka Kodešová: Opening remarks
Keynote Presentation: Rien van Genuchten
General thoughts on modeling flow and transport processes in soils andgroundwater
9:30-9:45 Kalin, J., B Petkovšek, P. Montarnal, A. Genty, E. Deville , and J. Krivic,
Comparison of two numerical modeling codes for hydraulic and transport
calculations in the near field. (Slovenia and France)
9:45-10:00 Pontedeiro, E. M., V. O. Almeida de Sousa, and M. Th. van Genuchten,
HYDRUS-1D modeling applications to waste disposal problems in Brazil.
(Brazil)
10:00-10:15 Xiao, H., J. Böttcher, and J. Šimůnek, Simulation of heavy metal transport inunsaturated soil: Use of scale factors to quantify variable sorption isotherms.
(Germany)
10:15-10:30 Schwen, A., G. Bodner, and W. Loiskandl, Temporal variations of soil
hydraulic properties and its effect on soil water simulations. (Austria)
Coffee Break
11:00-11:15 Grinevskiy, S. O., and S. P. Pozdniakov, The use of HYDRUS-1D forgroundwater recharge estimation in boreal environments. (Russia)
11:15-11:30 Kanzari, S., M. Hachicha, R. Bouhlila, and J. Battle-Sales, Characterization andmodeling of water movement and salts transfer in a semi-arid region of
Tunisia. (Tunisia)
11:30-11:45 Kurinova, N., Sensitivity of recharge evaluation results using HYDRUS toparameters and boundary conditions variations. (Russia)
11:45-12:00 Filipović, V., R. Kodešová, and D. Petošić, Numerical modeling of water flow
and nitrate dynamics on zero tension plate lysimeters using HYDRUS-2D.
(Croatia)
12:00-12:15 Pozdniakov, S., P. Wang, S. Grinevskiy, and J. Yu, Simulation of groundwater
evapotranspiration with HYDRUS-1D in desert environments. (Russia)
12:15-12:30 Elmi, A., Phosphorus leaching potentials from re-constructed soil columns
using HYDRUS-1D model. (Kuwait)
Lunch

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Thursday, March 21, Afternoon Session: Inverse Problems, Nonequilibrium FlowTime
2:00-2:30

2:30-2:45
2:45-3:00

3:00-3:15

3:15-3:30

3:30-3:45

3:45-4:00

Authors and Title
Keynote Presentation: Radka Kodešová
Selected applications of HYDRUS models to evaluate uniform andnonequilibrium flow in structured soils.
Diamantopoulos, E., and W. Durner, Dynamic non-equilibrium water flow invariably saturated porous media. (Germany)
Kébré, M. B., F. Ouédraogo, F. Cherblanc, and F. Zougmoré, Transfer at low
water content: new and simple experimental approach for inverse
determination of van Genuchten transport coefficients. (France, Burkina Faso)
Léger, E., A. Saintenoy, and Y. Coquet, Inverting saturated hydraulicconductivity from surface ground-penetrating radar monitoring of inﬁltration.
(France)Glæsner, N., and H. H. Gerke, Single- and double-porosity modeling of solutetransport in intact soil columns – effects of texture, slurry placement, andintermittent irrigation. (Denmark, Germany)
Turkeltaub, T., O. Dahan, and D. Kurtzman, Investigation of recharge fluxes
under different land-uses with calibrated models to transient deep vadose zone
data. (Israel)
Anlauf, R., and P. Rehrmann, Simulation of water and air distribution in
growing media. (Germany)
Coffee Break

4:30-6:00

Poster Session

6:30 - ….

Mixer, Beer Session, Reception

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Friday, March 22, Morning session: Biogeochemical Transport and Reactions

Time

Authors and Title

9:00-9:30

Keynote Presentation: Günter Langergraber
Langergraber, G., and J. Šimůnek, Reactive transport modeling of subsurface
flow constructed wetlands using the HYDRUS wetland module. (Austria)
9:30-9:45 Morvannou, A., N. Forquet, M. Vanclooster, and P. Molle, Which Hydraulic
Model to Use in Vertical Flow Constructed Wetlands? (France)
9:45-10:00 Karlsson, S. C., H. Jönsson, S. Dalahmeh, and C. Lalander, Hydraulicproperties and reduction of COD, phosphorus and nitrogen in sand filters used
for greywater treatment – simulation and verification. (Sweden)
10:00-10:15 Leterme, B., M. Gedeon, and D. Jacques, Groundwater recharge modelling in
the Nete catchment (Belgium) with HYDRUS-1D – MODFLOW coupling.
(Belgium)
10:15-10:30 Haile, S. S., and B. J. Merkel, Simulation of uranium tailing leaching using
VS2DRT. (Germany)
Coffee Break
11:00-11:30 Keynote Presentation: Diederik Jacques
Jacques, D., J. Šimůnek, D. Mallants, M. Th. van Genuchten, The HPx
reactive transport models: a short overview of development and possibilities.
11:30-11:45 Toride, N., and D. Chen, Fate and transport of nitrogen in soils based on acoupled nitrogen-carbon cycling model using the HP1 code. (Japan)
11:45-12:00 Leterme, B., and D. Jacques, Hg modelling in soil systems using HP1.
(Belgium)
12:00-12:15 Thaysen, E. M., E. Laloy, D. Jacques, CO2 fluxes to aquifers beneath cropland:merging measurements and modeling. (Denmark)12:15-12:30 Sandhu, C., T. Fichtner, I. Hasan, and P.-W. Graeber, Predicting the impact oftreated wastewater on groundwater recharge by simulating reactive transport in
the unsaturated zone. (Germany)
Lunch

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Friday, March 22: Afternoon Session: Irrigation Applications, and Miscellaneous
TopicsTime

Authors and Title

2:00-2:30

Keynote Presentation: Jirka Šimůnek
Šimůnek, J., M. Šejna, D. Jacques, G. Langergraber, S. A. Bradford, and M.
Th. van Genuchten, Development and applications of the HYDRUS software
since the last HYDRUS workshop.
Dabach, S., J. Šimůnek, A. Ben-Gal, J. Shi, and N. Lazarovitch, Optimizationof triggered irrigation using a system dependent boundary condition in
HYDRUS 2D/3D. (Israel)
Phogat, V., M. A. Skewes, M. Mahadevan, J. W. Cox, Seasonal simulation ofwater and salinity dynamics under different irrigation applications of almond inpulsed and continuous mode. (Australia)
El-Nesr, M. N. B., A. Alazba, and J. Šimůnek, Dual-drip subsurface irrigation
system: Can it act as a hydraulic barrier? (Saudi Arabia)
Ramos, T. B., J. Šimůnek, M. C. Gonçalves, J. C. Martins, A. Prazeres, and L.
S. Pereira, Modeling water and nitrogen fate in plots with sweet sorghum
irrigated with fresh and blended saline waters using HYDRUS-2D. (Portugal)

2:30-2:45

2:45-3:00

3:00-3:15
3:15-3:30

Coffee Break
4:00-4:15
4:15-4:30
4:30-4:45
4:45-5:00

Arye, G., and J. Šimůnek, Modeling surface-active solute transport with
HYDRUS. (Israel)
Couvreur, V., F. Meunier, J. Vanderborght, and M. Javaux, The root system as
a hydraulic architecture: principles and applications. (Belgium)Orfánus, T., Slope drainage by logging roads and its contribution to the 2011
flood peak in the Píla village. Simulation with HYDRUS-2D. (Slovakia)
Yurtseven, E., J. Šimůnek, S. Avci, and H. S. Öztürk, Comparison of ion(salt)
movement in the soil profile subject to leaching with the HYDRUS-1D
simulations. (Turkey)
Closing Remarks and Departure6

List of Abstracts
Invited Keynote Presentations:
1. van Genuchten, M. Th., General thoughts on modeling flow and transport processes insoils and groundwater.
2. Šimůnek, J., M. Šejna, D. Jacques, G. Langergraber, S. A. Bradford, and M. Th. van
Genuchten, Development and applications of the HYDRUS software since the last
HYDRUS workshop.
3. Langergraber, G., and J. Šimůnek, Reactive transport modeling of subsurface flow
constructed wetlands using the HYDRUS wetland module.
4. Jacques, D., J. Šimůnek, D. Mallants, M. Th. van Genuchten, The HPx reactive
transport models: a short overview of development and possibilities.
5. Kodešová, R., Selected applications of HYDRUS models to evaluate uniform andnonequilibrium flow in structured soils.

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Volunteered Abstracts:
1. Abramson, A., and N. Lazarovitch, Investigating the impact of irrigation method on
profitability of smallholder gardening: Incorporating HYDRUS-1D into a Decision
Support System. (Israel) (poster)
2. Anlauf, R., and P. Rehrmann, Simulation of water and air distribution in growing
media. (Germany)
3. Antonov, D., D. Mallants, J. Šimůnek, and D. Karastanev, Application of the
HYDRUS (2D/3D) inverse solution module for evaluation of the soil hydraulicparameters of a quaternary complex in Northern Bulgaria. (Bulgaria) (poster)
4. Arye, G., and J. Šimůnek, Modeling surface-active solute transport with HYDRUS.
(Israel)
5. Couvreur, V., F. Meunier, J. Vanderborght, and M. Javaux, The root system as a
hydraulic architecture: principles and applications. (Belgium)
6. Coelho, C. R. B., M. S. Batalha, D. Jacques, M. C. Barbosa, and M. Th. van
Genuchten, Using HYDRUS-HP1 to estimate 226Ra transport in soils following theuse of phosphogypsum in agriculture. (Brazil) (poster)
7. Dabach, S., J. Šimůnek, A. Ben-Gal, J. Shi, and N. Lazarovitch, Optimization of
triggered irrigation using a system dependent boundary condition in HYDRUS
2D/3D. (Israel)
8. Diamantopoulos, E., and W. Durner, Dynamic non-equilibrium water flow in variably
saturated porous media. (Germany)
9. El-Nesr, M. N. B., A. Alazba, and J. Šimůnek, Dual-drip subsurface irrigation system:
Can it act as a hydraulic barrier? (Saudi Arabia)
10. Elmi, A., Phosphorus leaching potentials from re-constructed soil columns using
HYDRUS-1D model. (Kuwait)
11. Fér, M. and R. Kodešová, Using HYDRUS-1D for estimating hydraulic conductivitiesof the soil aggregates and their clay-organic coatings from capillary rise data. (Czech
Republic) (poster)
12. Filipović, V., R. Kodešová, and D. Petošić, Numerical modeling of water flow andnitrate dynamics on zero tension plate lysimeters using HYDRUS-2D. (Croatia)

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13. Glæsner, N., and H. H. Gerke, Single- and double-porosity modeling of solutetransport in intact soil columns – effects of texture, slurry placement, and intermittent
irrigation. (Denmark, Germany)
14. Grinevskiy, S. O., and S. P. Pozdniakov, The use of HYDRUS-1D for groundwater
recharge estimation in boreal environments. (Russia)
15. Haile, S. S., and B. J. Merkel, Simulation of uranium tailing leaching using VS2DRT.
(Germany)
16. Hlaváčiková, H., V. Novák, and M. Rodný, Infiltration into stony soil: modeling of
the process using HYDRUS codes. (Slovakia) (poster)
17. Izadi, F. T., G. A. Fardi, and A. Khodadadi, Investigation the effect of acidic rain pH
on reactive transport of groundwater metal contaminants. (Iran) (poster)
18. Izadi, F. T., A. M. Damuchali, G. A. Fardi, and A. Khodadadi, Simulation of different
rainfall intensities impact on the reactive transport of mine tailing metal contaminants.
(Iran) (poster)
19. Kalin, J., B Petkovšek, P. Montarnal, A. Genty, E. Deville , and J. Krivic, Comparisonof two numerical modeling codes for hydraulic and transport calculations in the nearfield. (Slovenia and France)
20. Kanzari, S., M. Hachicha, R. Bouhlila, and J. Battle-Sales, Characterization andmodeling of water movement and salts transfer in a semi-arid region of Tunisia.
(Tunisia)
21. Kanzari, S., I. Ba, M. Hachicha, and R. Bouhlila, Characterization and modeling ofwater and salt dynamics in a sandy soil under the effect of surface drip irrigation.
(Tunisia) (poster)
22. Karlsson, S. C., H. Jönsson, S. Dalahmeh, and C. Lalander, Hydraulic properties andreduction of COD, phosphorus and nitrogen in sand filters used for greywater
treatment – simulation and verification. (Sweden)
23. Kato, C., T. Nishimura, H. Imoto, and T. Miyazaki, Predicting soil CO2 dynamics inarable land of Andisol in western suburb of Tokyo. (Japan) (poster)
24. Kébré, M. B., F. Ouédraogo, F. Cherblanc, and F. Zougmoré, Transfer at low watercontent: new and simple experimental approach for inverse determination of van
Genuchten transport coefficients. (France, Burkina Faso)
25. Krounbi, L., and N. Lazarovitch, Root water uptake under deficit irrigation: Modelcalibration and comparison. (Israel) (poster)
26. Kurinova, N., Sensitivity of recharge evaluation results using HYDRUS to parameters
and boundary conditions variations. (Russia)
27. Léger, E., A. Saintenoy, and Y. Coquet, Inverting saturated hydraulic conductivity fromsurface ground-penetrating radar monitoring of inﬁltration. (France)
28. Leterme, B., M. Gedeon, and D. Jacques, Groundwater recharge modelling in theNete catchment (Belgium) with HYDRUS-1D – MODFLOW coupling. (Belgium)
29. Leterme, B., and D. Jacques, Hg modelling in soil systems using HP1. (Belgium)
30. Lugli, F., M. Th. van Genuchten, and C. F. Mahler, Modeling phytoextraction andcontaminant transport processes using HYDRUS-1D. (Brazil) (poster)
31. Morvannou, A., N. Forquet, M. Vanclooster, and P. Molle, Which Hydraulic Modelto Use in Vertical Flow Constructed Wetlands? (France)
32. Nakhaei M. and J. Šimůnek, Parameter estimation of soil hydraulic functions andthermal properties for unsaturated porous media using HYDRUS-2D code. (Iran)(poster)
33. Nikodem, A., R. Kodešová, and L. Bubeníčková, Using HYDRUS programs for
simulating Al and SO42- leaching from forest soils. (Czech Republic) (poster)
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34. Nováková, M., J. Takáč, and R. Skalský, Agro-ecological application of soilhydrological data: two local-scale modelling examples. (Slovakia) (poster)
35. Orfánus, T., Slope drainage by logging roads and its contribution to the 2011 flood
peak in the Píla village. Simulation with HYDRUS-2D. (Slovakia)
36. Phogat, V., M. A. Skewes, M. Mahadevan, J. W. Cox, Seasonal simulation of waterand salinity dynamics under different irrigation applications of almond in pulsed andcontinuous mode. (Australia)
37. Pontedeiro, E. M., V. O. Almeida de Sousa, and M. Th. van Genuchten, HYDRUS1D modeling applications to waste disposal problems in Brazil. (Brazil)
38. Pozdniakov, S., P. Wang, S. Grinevskiy, and J. Yu, Simulation of groundwater
evapotranspiration with HYDRUS-1D in desert environments. (Russia)
39. Ramos, T. B., J. Šimůnek, M. C. Gonçalves, J. C. Martins, A. Prazeres, and L. S.
Pereira, Modeling water and nitrogen fate in plots with sweet sorghum irrigated withfresh and blended saline waters using HYDRUS-2D. (Portugal)
40. Rizzo, A., and G. Langergraber, Simulation of peak loads for horizontal flow
constructed wetlands. (Italy) (poster)
41. Ruzicic, S., Z. Kovac, M. Mileusnic, and K. Posavec, Longitudinal dispersivity
determination using conservative tracer in the field. (Croatia) (poster)
42. Sanchez-Ramos, D., and G. Langergraber, Modelling horizontal flow constructedwetlands treating effluents of wastewater treatment plants. (Spain and Austria)(poster)
43. Sandhu, C., T. Fichtner, I. Hasan, and P.-W. Graeber, Predicting the impact of treatedwastewater on groundwater recharge by simulating reactive transport in theunsaturated zone. (Germany)
44. Schwen, A., G. Bodner, and W. Loiskandl, Temporal variations of soil hydraulicproperties and its effect on soil water simulations. (Austria)
45. Šimůnek, J., D. Jacques, and M. Šejna, New developments in the HPx reactive
transport code: Extension to two dimensional flow and transport problems. (USA)(poster)
46. Smethurst, P. J., and G. Langergraber, Hillslope application of the HYDRUS-Wetland
wetland module. (Australia) (poster)
47. Thaysen, E. M., E. Laloy, D. Jacques, CO2 fluxes to aquifers beneath cropland:merging measurements and modeling. (Denmark)48. Toride, N., and D. Chen, Fate and transport of nitrogen in soils based on a couplednitrogen-carbon cycling model using the HP1 code. (Japan)
49. Trakal, L., R. Kodešová, and M. Komárek, Simulation of metal transport in the soil
and into the willows using the HYDRUS program. (Czech Republic) (poster)
50. Turkeltaub, T., O. Dahan, and D. Kurtzman, Investigation of recharge fluxes under
different land-uses with calibrated models to transient deep vadose zone data. (Israel)
51. Tyrrell, S. R., T. Hess, S. F. Tyrrel, and D. Knaggs, Microtopographic enhancementof soil-based wastewater treatment. (United Kingdom) (poster)52. Valdes-Abellan, J., J. Jiménez-Martínez, and L. Candela, Using HYDRUS and HP1
codes to study possible impacts of irrigation with non-conventional water under two
different vadose zone monitoring strategies. (Spain) (poster)
53. Xiao, H., J. Böttcher, and J. Šimůnek, Simulation of heavy metal transport inunsaturated soil: Use of scale factors to quantify variable sorption isotherms.
(Germany)
54. Yurtseven, E., J. Šimůnek, S. Avci, and H. S. Öztürk, Comparison of ion(salt)
movement in the soil profile subject to leaching with the HYDRUS-1D simulations.
(Turkey)
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Please reference the abstracts as follows (adjust highlighted text as needed):
Authors, Title, The 4th International Conference "HYDRUS Software Applications to
Subsurface Flow and Contaminant Transport Problems", Book of Abstracts edited by J.
Šimůnek and R. Kodešová, March 21-22, 2013, Dept. of Soil Science and Geology, Czech
University of Life Sciences, Prague, Czech Republic, ISBN: 978-80-213-2368-1, pp. ??,
2013.

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Some General Thoughts about Modeling Flow and Transport
Processes in Soils and GroundwaterMartinus Th. van Genuchten
Department of Mechanical Engineering, Federal University of Rio de Janeiro, UFRJ
Rio de Janeiro, Brazil

Numerical models have become indispensable tools in both research and engineering toobtain a better understanding and prediction of subsurface water flow and solute transport
processes. The HYDRUS codes in particular have seen many applications as evidence by thebroad range of topics being discussed at this conference. The increased use of HYDRUS andrelated models is spurred by the introduction of increasingly powerful computers, advanced
numerical methods, improved descriptions of the basic flow and transport processes involved,
and simultaneous progress in the development of improved technologies for estimatingmuch-needed model parameters. These advancements cannot be fast enough in view of thetremendous environmental challenges facing this planet, including water, food and energy
security issues. At the same time it is important also for us to appreciate the limitations ofeven the most advanced numerical models. For example, we continue to struggle with suchvery basic issues as how best to capture observed flow and transport processes in usable
equations for modeling purposes, how to characterize subsurface heterogeneity (including
preferential flow) at a range of scales, and how best to integrate all pertinent physical andbiogeochemical information into predictive tools for management and engineering
applications. The main message of this introductory presentation is to keep pressing further
development and testing of our simulation and measurement technologies. This must include
further improvements in the conceptual basis of our models, and developing better methods
to integrate or fuse modeling expertise and hard and soft data into practical protocols to more
effectively address our environmental problems. Some of the opportunities and challenges areillustrated by three different HYDRUS applications: (1) estimating subsurface radionuclidetransport from a uranium mining site, (2) phytoremediation processes, and (3) the subsurface
transport of selected radionuclides in phosphogypsum when applied as an amendment inagricultural operations.

11New Features and Developments in HYDRUS Software
Packages
Jirka Šimůnek1, Miroslav Šejna2, Diederik Jacques3, Günter Langergraber4, Scott A.
Bradford5, and M. Th. van Genuchten61Department of Environmental Sciences, University of California Riverside, CA, USA, jiri.simunek@ucr.edu
2
PC-Progress, Ltd., Prague 2, Czech Republic, m.sejna@pc-progress.cz
3
Performance Assessments, Belgian Nuclear Research Institute, Mol, Belgium, djacques@sckcen.be4
Institute for Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life
Sciences, Vienna (BOKU University), Austria, guenter.langergraber@boku.ac.at
5
US Salinity Laboratory, USDA, ARS, Riverside, CA, USA, Scott.Bradford@ars.usda.gov
6
Department of Mechanical Engineering, Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, RJ,
Brazil, rvangenuchten@hotmail.com

The capabilities of the HYDRUS (2D/3D) software package have been substantiallyexpanded by new modules accounting for processes not available in the standard HYDRUS
version. These new modules include the DualPerm, C-Ride, HP2, Wetland, andUnsatChem. All these modules simulate flow and transport processes in two-dimensionaltransport domains and are fully supported by the HYDRUS graphical user interface.
Additionally, the DualPerm module implements the dual-permeability modeling approach of
Gerke and van Genuchten (1993) simulating preferential flow and transport. The C- Ride
module implements colloid transport and colloid-facilitated solute transport (Šimůnek et al.,2006), the latter often observed for many contaminants, such as heavy metals, radionuclides,
pharmaceuticals, pesticides, and explosives. HP2 is a two-dimensional alternative of the HP1
module (Jacques and Šimůnek, 2005), currently available with HYDRUS-1D, that couples
HYDRUS flow and transport routines with the PHREEQC geochemical model of Parkhurst
and Appelo (1999). The Wetland module includes two alternative approaches (CW2D of
Langergraber and Šimůnek (2005) and CWM1 of Langergraber et al. (2009)) for modelingaerobic, anaerobic, and anoxic biogeochemical processes in natural and constructed wetlands.
Finally, the UnsatChem module simulates the transport and reactions of major ions in a soil
profile. A brief description and several demonstrative applications of each module will bepresented. Many processes included into these specialized modules of HYDRUS (2D/3D) arecurrently also available as part of HYDRUS-1D. Further development of these modules, aswell as of several other new modules (such as Overland Flow, Slope Stability, and Meteo), isstill envisioned. Continued feedback from the research community is encouraged.
References
Gerke, H. H., M. Th. van Genuchten, A dual-porosity model for simulating the preferential movement of waterand solutes in structured porous media, Water Resources Research, 29, 305-319, 1993.
Jacques, D., and J. Šimůnek, User Manual of the Multicomponent Variably-Saturated Flow and Transport
Model HP1, Description, Verification and Examples, Version 1.0, SCK•CEN-BLG-998, Waste andDisposal, SCK•CEN, Mol, Belgium, 79 pp., 2005.
Langergraber, G., and J. Šimůnek, Modeling variably-saturated water flow and multi-component reactive
transport in constructed wetlands, Vadose Zone Journal, 4(4), 924-938, 2005.
Langergraber, G., D. Rousseau, J. García, and J. Mena, CWM1 - A general model to describe biokinetic
processes in subsurface flow constructed wetlands, Water Sci. Technol., 59(9), 1687-1697, 2009.
Parkhurst D. L., and C. A. J. Appelo, User’s guide to PHREEQ C (Version 2) – A computer program forspeciation, batch-reaction, one-dimensional transport and inverse geochemical calculations, WaterResources Investigations, Report 99–4259, Denver, Co, USA, 312 pp., 1999.
Šimůnek, J., Changming He, J. L. Pang, and S. A. Bradford, Colloid-facilitated transport in variably-saturated
porous media: Numerical model and experimental verification, Vadose Zone Journal, 5(3), 1035-1047,
2006.

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Reactive Transport Modeling of Subsurface Flow ConstructedWetlands using the HYDRUS Wetland Module
Günter Langergraber1, and Jirka Šimůnek2
1

Institute for Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life
Sciences, Vienna (BOKU University), Austria, guenter.langergraber@boku.ac.at2
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA,jiri.simunek@ucr.edu

Constructed wetlands (CWs) are engineered water treatment systems designed to remove
various types of contaminants. A large number of processes simultaneously contribute towater quality improvement in CWs. During the last decade, there has been a wide interest in
the understanding of complex "constructed wetland" systems, including the development of
numerical process-based models describing these systems. A number of process-based
numerical models for subsurface flow (SSF) CWs have been developed during the last few
years. However, most of them are either in a rather early stage of development or areavailable only in-house. The HYDRUS wetland module is the only implementation of a CW
model that is currently publicly available. Version 2 of the HYDRUS wetland module
includes two biokinetic model formulations simulating reactive transport in CWs: CW2D and
CWM1. In CW2D, aerobic and anoxic transformation and degradation processes for organic
matter, nitrogen and phosphorus are considered, whereas in CWM1, aerobic, anoxic andanaerobic processes for organic matter, nitrogen and sulphur are taken into account. In thispaper, we describe the HYDRUS wetland module, as well as its two biokinetic models. We
further present simulation results for horizontal flow CWs obtained using both biokinetic
models. Compared with the CWM1 implementation in the RETRASO code, the HYDRUS
implementation is able to simulate fixed biomass, which is of high importance for obtaining
realistic predictions of the treatment efficiency of CWs. We also compare simulation resultsfor horizontal flow CWs obtained using both CW2D and CWM1 modules that show thatCWM1 produces more reasonable results since it also considers anaerobic degradation
processes. The influence of wetland plants on the simulation results is also demonstrated.
Simulated biomass profiles in the filter are completely different when considering oxygen
release from roots, thus indicating the importance of considering plant effects.
Reference

Langergraber, G., and J. Šimůnek, Reactive transport modeling of subsurface flow constructedwetlands using the HYDRUS Wetland module, Vadose Zone Journal, 11(2), Special Issue"Reactive Transport Modeling", doi:10.2136/vzj2011.0104, 14 p. 2012.

13

The HPx Reactive Transport Models: A short Overview ofDevelopment and Possibilities
Diederik Jacques1, Jirka Šimůnek2, Dirk Mallants3, and Martinus Th. van Genuchten41Belgian Nuclear Research Centre, Belgium, djacques@sckcen.be
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
3Land and Water, CSIRO, Adelaide, Australia
4
Department of Mechanical Engineering, Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, RJ,
Brazil2

The HPx reactive transport codes are developed to consider coupled flow and transport
processes in variable-saturated porous media with a variety of low-temperature geochemical
processes. They consist of the HYDRUS models for water flow and solute transport(HYDRUS-1D, version 4.16 and HYDRUS (2D/3D), version 2.02) with the generic
thermodynamic and kinetic model PHREEQC-2.17. As such, HPx, now available for one(HP1) and two-dimensional (HP2) flow and transport problems, expand significantly thecapabilities of the individual codes.
Recent developments and applications are:• Gas diffusion. One important application of this process is CO2 sequestration in soils.
HPx gives a large flexibility in defining different kinetic networks with rate
coefficients depending on temperature, water content, or any other variable. Such
implementation is illustrated using parts of the model of Porporato et al. (2003).
• Extension to two-dimensional flow problems.
• Inverse optimization of geochemical parameters. An example is given, in which soil
hydraulic, solute transport, and cation exchange parameters are optimized using datafrom water and solute absorption experiments (Jacques et al., 2012).
• Feedback between changes in geochemical variables and transport properties. As an
example, leaching of a cementitious material and the progression of pH and porosity
fronts is discussed.
• Benchmarking of several of these new developments with other reactive transport
codes.
HPx is a flexible tool which can handle complex flow and transport problems combined withrather complex geochemistry models. A typical example is geochemistry of mercury, which
is present in a (contaminated) soil in different forms and phases.
References
Jacques, D., C. Smith, J. Šimůnek, and D. Smiles, Inverse optimization of hydraulic, solute transport,
and cation exchange parameters using HP1 and UCODE to simulate cation exchange, Journal ofContaminant Hydrology, 142-143, 109–125, 2012.
Porporato, A., P. D’Odorico, F. Laoi, and I. Rodriguez-Iturbe, Hydrological controls on soil carbon
and nitrogen cycles: I. Modeling scheme, Advances in Water Resource, 26, 45-58, 2003.

14

Selected Applications of HYDRUS Models to Evaluate Uniform
and Nonequilibrium Flow in Structured Soils.
Radka Kodešová
Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Dept. of Soil
Science and Soil Protection, Kamýcká 129, CZ-16521 Prague 6, Czech Republic. kodesova@af.czu.cz

Water flow and contaminant transport in structured soils are frequently influenced either bywater and solute temporal immobilization inside soil structure elements (e.g. concept ofmobile and immobile water) or by bypassing the soil matrix due to enhanced water flow andcontaminant transport in macropores (e.g. preferential flow). Such nonequilibrium flow may
occur and can be visualized at macro- and microscales using a dye tracer (Kodešová et al.,2012). Both phenomena may be simulated using either the dual-porosity or dual-permeability
models implemented in HYDRUS programs, which assume two continuums (domains)
within a simulated flow region. Using these models require assessing fractions and hydraulicproperties of both domains and characteristics describing mass exchange between these
domains. Equilibrium and nonequilibrium water flow and herbicide transport within the soil
profile (3 different soil types) under field conditions and in the undisturbed soil samples(taken from all diagnostic horizons of 3 soil types) under laboratory conditions was simulatedusing single-porosity model and both dual domains modules in HYDRUS-1D (Kodešová etal., 2008, 2009). Fractions of domains were in these studies evaluated using
micromorphological images. Other properties were partly measured and partly optimized
using the program. Great impact of parameters describing mass exchange between matrix andmacropore domains on preferential flow character was documented using the radiallysymmetric dual-permeability model in HYDRUS 2D/3D (Kodešová et al., 2010). Interaction
between domains is frequentaly influenced by clay and organic matter coatings, which
slowdown water and solute transport between domains (Kodešová et al., 2012; Fér andKodešová, 2012), and enhance preferential flow in structural soils (Kodešová et al., 2010).
ReferenceFér, M., and R. Kodešová, Estimating Hydraulic Conductivities of the Soil Aggregates and their Clayorganic Coatings using Numerical Inversion of Capillary Rise Data, Journal of Hydrology, 468469, 229-240, 2012.
Kodešová, R., M. Kočárek, V. Kodeš, J. Šimůnek, and J. Kozák, Impact of soil micromorphology
features on water flow and herbicide transport in soils, Vadose Zone Journal, 7(2), 798-809, 2008.
Kodešová, R., K. Němeček, V. Kodeš, and A. Žigová, Using dye tracer for visualization ofpreferential flow at macro- and microscales, Vadose Zone Journal, 11, vzj2011.0088,
doi:10.2136/vzj2011.0088, 2012.
Kodešová, R., J. Šimůnek, A. Nikodem, and V. Jirků, Estimation of parameters of the radiallysymmetric dual-permeability model using tension disc infiltrometer and Guelph permeameter
experiments, Vadose Zone Journal, 9, 213-225, 2010.
Kodešová, R., N. Vignozzi, M. Rohošková, T. Hájková, M. Kočárek, M. Pagliai, J. Kozák, and J.
Šimůnek, Impact of varying soil structure on transport processes in different diagnostic horizonsof three soil types, Journal of Contaminant Hydrology, 104, 107-125, 2009.

15

Investigating the impact of irrigation method on profitability ofsmallholder gardening:
Incorporating HYDRUS-1D into a Decision Support System
Adam Abramson1 and Naftali Lazarovitch2
1

Dept of Environmental Hydrology and Microbiology,
Zuckerberg Institute for Water Research, adamab@bgu.ac.il
2
Wyler Department of Dryland Agriculture, French Associates,
Institute for Agriculture and Biotechnology of Drylands
The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev,
Sede Boqer Campus, Midreshet Ben-Gurion, Israel.

Dry-season irrigation in remote areas of tropical developing regions provides many
households with both nutritional and monetary supplements. Often, smallholders depend on
traditional (unimproved) water sources for meeting their irrigation needs, which are highly
seasonal and many times unreliable throughout the length of the season: dams, natural ponds
in ephemeral streams, or hand-dug shallow wells. Optimizing profits from these small-scalegardens is complicated by the unpredictability of water amounts available through the season
as well as the time, labor and capital constraints common to subsistence livelihoods. Millions
of smallholder farmers face these challenges daily.
The HYDRUS-1D numerical model was incorporated into a Decision Support System (DSS)
for investigating these dynamics of smallholder irrigation. In this case, revenue from fieldgrown tomato was modeled. Transpiration levels for a range of irrigation rates and watersalinity levels were obtained using the HYDRUS-1D code. These transpiration results werethen translated into actual crop yields according to the yield-transpiration relationship forfield-grown tomato. In addition, various measures of time availability in the garden were
input into the DSS, in order to introduce labor constraints into the decision process. For eachirrigation and salinity level, total agricultural costs, comprised of capital and operation costs,
were output alongside yields and benefits. This was done for both hand watering and drip
irrigation in order to provide a comparative measure of the two irrigation approaches inrelation to smallholder economies.
Results of this investigation suggest that, due to the tradeoff between capital costs and timesavings, drip irrigation does not always result in optimal net revenue as compared to handwatering. We identified a linear relationship between the rate of revenue earned and the ratio
between water and time availability for both irrigation methods. While these relationships arenearly identical, they reach a unique threshold value after which water becomes a limiting
factor. The value of this threshold is lower for hand watering because the amount of water
applied per unit of time working is less, thus labor becomes a limiting constraint at lower
water supply levels. Drip irrigation allows labor to earn higher revenue at sufficient watersupplies. Thus, it should be promoted where labor is relatively limiting.

16

Simulation of Water and Air Distribution in Growing Media
Rüdiger Anlauf* and Peter Rehrmann
Osnabrück University of Applied Sciences, P. O. Box 1940, 49009 Osnabrück, Germany*
Presenting author

Water and particularly air content in growing media in plant containers is important
information for the grower. To optimize crop growth, the relative importance of substrate
type and irrigation strategy on water uptake of growing media must be known. Describing
water uptake and distribution in the container with a dynamic simulation model may
overcome the disadvantages of static parameters such as container capacity and air capacity.
Water uptake and redistribution was investigated for an ebb-and-flow irrigation system withtwo different growing media, a coarse white peat and a fine seedling substrate, two flooding
depths (1 and 4 cm) and three flooding durations (5, 10 and 15 min).
The results were used to evaluate the use of HYDRUS-1D to describe water uptake andredistribution. The hydraulic functions water retention curve and hydraulic conductivity
needed for the simulation model were determined in the laboratory.
Hysteresis becomes especially important in irrigation systems where the water is applied
from the bottom of the container, such as ebb-and-flow irrigation. Preliminary simulations
with HYDRUS-1D made clear that hysteresis of the water retention curve must be taken into
account for growing media to get reliable simulation results. Water retention drying curves
were determined by standard sand box apparatus. Wetting curves were determined withequipment where the water content in growing media was measured in an experimental
container with a constant flooding depth. Under the assumption that the water content at
equilibrium is analogous to the water retention curve, the water content of the growing media
above the water surface will correspond to distinct pF values. Drying and wetting curve wereparameterized to be used in HYDRUS-1D.
The simulation was divided into a flooding cycle with a constant head lower boundary
condition and a drainage cycle with a seepage phase boundary condition. The simulated watercontent at the end of the flooding cycle was used as initial condition for the drainage cycle.
The results show that substrate properties and flooding height are the main parameters
determining water uptake during ebb-and-flow irrigation while flooding time has a minor
effect only.
HYDRUS-1D is able to describe water uptake and redistribution in containers filled withgrowing media sufficiently well, but only if the hysteresis of the water retention curve istaken into account. This correct representation of the water balance in plant containers is an
important basis for future work on oxygen concentration changes in growing media.

17

Application of the HYDRUS (2D/3D) Inverse Solution Module for
Evaluation of the Soil Hydraulic Parameters of a Quaternary
Complex in Northern Bulgaria
Dimitar Antonov1*, Dirk Mallants2, Jirka Šimůnek3, Doncho Karastanev1
1

Geological Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria
2
CSIRO Land and Water, Urrbrae, South Australia
3
Environmental Sciences Department, University of California Riverside, California, USA*Presenting Author

The characterization and numerical modeling of the unsaturated zone is among the key
factors in the prognostic fate and transport studies of the contaminants migration in theenvironment. The paper deals with the use of the HYDRUS (2D/3D) (Šimůnek et al., 2006)
code for determination of hydraulic parameters of the 10-m deep vadose zone from borehole
infiltration tests by inverse modeling. The investigated soil profile is located in the
Pleistocene loess complex near the town of Kozloduy, Northern Bulgaria, in the vicinity of
the Kozloduy Nuclear Power Plant (NPP).
Four constant-head infiltrometer tests were carried out at several meters below the groundsurface to determine the unsaturated hydraulic properties of particular layers, namely silty
loess, clayey loess, clayey gravel, and a highly carbonated zone. Infiltration tests provided
data on cumulative infiltration and the movement of the wetting front in the initiallyunsaturated sediments surrounding the infiltrometer. A cylindrical time-domain reflectometry
TRIME-IPH/T3 probe, operated by the TRIME-HD device, was used to measure watercontent variations with time during the movement of the wetting front. Special polycarbonate
access tubes for the TRIME probe were installed at a distance of 0.3 to 0.5 m from theinfiltrometers. An axisymmetric model was developed in HYDRUS (2D/3D) for each of thefour infiltrometers. The vertical dimension of the model was limited to the soil layers thatwere immediately influenced by the infiltrating water. By means of an inverse optimization
routine implemented in the finite element code HYDRUS (2D/3D), field-scale soil hydraulicparameters θr, θs, α, n, and Ks were derived for all layers of interest.
Apparently, the size of the affected volume of soil was large enough to reduce the effect of
spatial variability and to produce average field-scale hydraulic parameters that are relevant
for large-scale predictions of flow patterns and radionuclide migration pathways in the regionof Kozloduy NPP.
Keywords: unsaturated zone, soil hydraulic parameters, field experiment, HYDRUS (2D/3D)
ReferencesŠimůnek J., M. Th. van Genuchten, and M. Šejna, The HYDRUS Software Package for Simulating
Two- and Three-Dimensional Movement of Water, Heat, and Multiple Solutes in VariablySaturated Media, Technical Manual, Version 1.0, PC Progress, Prague, Czech Republic, pp. 241,
2006.

18

Modeling Surface-Active Solute Transport with HYDRUS
Gilboa Arye1 and Jirka Šimůnek2
1

The Blaustein Institutes for Desert Research, Ben-Gurion University
Department of Environmental Sciences, University of California Riverside

2

Surface active solutes (SAS) or surfactants are organic compounds that contain bothhydrophilic and hydrophobic groups. When water is the solvent, the polar or ionic functionalgroup imparts favorable solubility properties, whereas the nonpolar hydrophobic part distorts
the solvent structure and promotes orientation at the interface. The result of this process is the
reduction of surface tension at the water-air interface (γLV). Assuming that soil pores consistof bundles of capillary tubes of different sizes, the effect of γLV on the capillary pressure (Ψ)
can be inferred from the Laplace equation. Accordantly, for a given unsaturated watercontent (θ) and contact angle (ε), a reduction in γLV will be associated with a similar relative
reduction in Ψ. In a similar manner, for a given θ and γLV, Ψ is linearly proportional to cos(ε).
Consequently, the capillary pressure saturation relationships, Ψ(Θ), can be significantly
affected by these quantities.
Following the above concept, the overall working scheme of our modeling effort is:
γLV(C) ⇒ ε(γLV, θ) ⇒ Ψ(C, θ, γLV, ε) ⇒ Ψ-gradient ⇒ unsaturated water flow
γLV(C) represents the concentration (C) dependence of γLV during solute transport, namely,
variations of γLV in time and space as a function of the SAS transport characteristics. In
general, γLV is inversely related to C down to a point where no additional reduction in γLVoccurs due to aggregation and/or precipitation of the SAS. A reduction in the dissolved SASconcentration can occur due to adsorption to the solid phase. As a result, the surface
properties of the solid phase may change and, thus, may be expressed in a variation of ε.

ε(γLV,θ) emphasizes the dependency of ε on both γLV and θ. Specifically, for a given soil
property, an increase in θ and/or the reduction in γLV reduces ε to a point where ε = 0.
Ψ(C,θ, γLV, ε) indicates that the reciprocal relations between all four quantities can be
expressed by the value of Ψ. The Ψ-gradient – a driving force for unsaturated water flow inthe porous media – is the result of the temporal and spatial variations in Ψ(C, θ, γLV, ε).
To enable modeling of this complex system of processes, empirical and/or physically-based
equations of Ψ(θ, γLV, ε, C) and K(θ, η (viscosity), C) were incorporated into the HYDRUS1D code (Šimůnek et al., 2008) for modeling transient water flow and solute transport invariably-saturated soils. In the current presentation, a sensitivity analysis probing the effectsof the above quantities and their reciprocal relations on unsaturated water flow will bedemonstrated.
ReferenceŠimůnek, J., M. Šejna, H. Saito, M. Sakai, and M. Th. van Genuchten, The HYDRUS-1D Software
Package for Simulating the Movement of Water, Heat, and Multiple Solutes in Variably
Saturated Media, Version 4.0, HYDRUS Software Series 3, Department of Environmental
Sciences, University of California Riverside, Riverside, California, USA, pp. 315, 2008.

19

The Root System as a Hydraulic Architecture: Principles andApplications
Valentin Couvreur1, Félicien Meunier1, Jan Vanderborght2, and M. Javaux1,2
1

Earth and Life Institute, Université catholique de Louvain, Croix du Sud, 2, bte L7.05.02, 1348 Louvain-laNeuve, Belgium (valentin.couvreur@uclouvain.be, felicien.meunier@uclouvain.be,mathieu.javaux@uclouvain.be)2
Institute of Bio-und Geosciences, IBG-3: Agrosphere, Forschungszentrum Juelich GmbH, 52425 Juelich,
Germany (j.vanderborght@fz-juelich.de, m.javaux@fz-juelich.de)

Many hydrological models including the process of root water uptake (RWU) do not consider
the dimension of root system hydraulic architecture (HA) because explicitly solving waterflow in such a complex system is too time consuming. However, they might lack process
understanding when basing RWU and plant water stress predictions on functions of variables
such as the root length density distribution.
On the basis of analytical solutions of water flow equations in a HA, we developed andvalidated a macroscopic model for both RWU distribution and plant water stress, which
respects physical principles of water flow in root systems of any complexity. Rather thanthousands of local parameters defined at the root segment scale, the new model has threemacroscopic parameters defined at the plant scale: (i) the standard sink fraction distribution
SSF, (ii) the root system equivalent conductance Krs and (iii) the compensatory RWU
conductance Kcomp. It is simple, computationally light, clearly decouples the process of water
stress from compensatory RWU, and its structure is appropriate for hydraulic lift simulation.
In a further study, the model was coupled to Richards’ equation in the Windows-based
computer software package HYDRUS-3D. A sensitivity analysis of soil water dynamics to
RWU parameters was performed, and the feasibility of model inverse parameterization fromsynthetic soil water dynamics data, on different soil types, was questioned.

20

Using HYDRUS-HP1 to Estimate 226Ra Transport in Soils
Following the Use of Phosphogypsum in Agriculture
Camila R. Bezerra Coelho1, Marcia S. Batalha1, Diederik Jacques2, Maria Claudia Barbosa1,
and Martinus Th. van Genuchten3
1Department of Civil Engineering, COPPE, Federal University of Rio de Janeiro,
UFRJ, Rio de Janeiro, RJ 21945-970, Brazil
2
Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK•CEN),
Boeretang 200, B-2400 Mol, Belgium
3
Department of Mechanical Engineering, COPPE/LTTC, Federal University of Rio de Janeiro,
UFRJ, Rio de Janeiro, RJ 21945-970, Brazil

Agricultural soils often require the use of fertilizers and soil conditioners to optimize
production. In this study we provide an analysis of the subsurface transport of radionuclides
released from phosphogypsum (PG) when used as a fertilizer or amendment in agriculture.
PG (dihydrated calcium sulfate), a residue of the phosphate fertilizer industry, can containrelatively high amounts of impurities from the host rock, including heavy metals andradionuclides such as 238U and especially 226Ra. It is important to assess the environmental
risks caused by the long-term use of PG in agriculture. During the phosphate production
process, the naturally present radionuclides tend migrate to both the fertilizer (especially 238U
and 234U) and phosphogypsum (226Ra and 210Pb).
Our study focused on the transport of 226Ra when PG is applied annually to a typical soil
profile in the Brazilian Cerrado. Expected water flow and solute transport processes were
estimated first using the HYDRUS-1D software package assuming linear equilibriumtransport, followed by similar simulations using the HP1 multicomponent transport module of
HYDRUS-1D. Analyses with HP1 considered a range of geochemical and physicalparameters affecting 226Ra transport in the vadose zone. We studied especially the effects ofvarying calcium concentrations on 226Ra transport, showing that this variable is relatively
important when making predictions. Several aspects related to the modeling approach, suchas the use of daily versus monthly weather data and the influence of assuming different
transport regimes in the vadose zone (e.g., transient versus long-term steady-state flow) are
discussed also.

21

Optimization of Triggered Irrigation Using a SystemDependent Boundary Condition in HYDRUS (2D/3D)
Sharon Dabach1,4, Jiří Šimůnek2, Alon Ben-Gal3, Jianchu Shi3,4 and Naftali Lazarovitch4
1

Seagram Center for Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food andEnvironment, The Hebrew University of Jerusalem, 76100 Rehovot, Israel.
2
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.
3
Department of Environmental Physics and Irrigation, Agricultural Research Organization, Gilat ResearchCenter, Israel.
4
Wyler Department of Dryland Agriculture, French Associates, Institute for Agriculture and Biotechnology of
Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer
Campus, Midreshet Ben-Gurion, Israel.

Water productivity and efficiency of irrigation systems can be improved by optimizing water
application regimes. One way to do this is to automate irrigation such that application amounts andtiming are a direct response to changes in soil water pressure head. Managers are challenged, whenusing in such systems, to correctly choose the sensor location and pressure head threshold values,
especially in light of the spatial heterogeneity of soil-plant systems. Little work has been done toinvestigate the relationship between irrigation scheduling, soil water potential threshold values, watersalinity, and an irrigation application volume, and their dependence on the sensor location and soil
heterogeneity.
We propose that numerical modeling can be applied to quickly and accurately optimize theoperational parameters required in automated feed-back irrigation scheduling. A system-dependent
boundary condition, which initiates irrigation whenever the matric head at a predetermined location
drops below a certain threshold, was implemented in the HYDRUS 2D/3D code. The model was used
to evaluate experimental data and subsequently optimize the operational parameters.
Three field experiments were conducted to evaluate the effects of different potential transpiration
rates, irrigation water salinity and irrigation management strategies on a triggered irrigation system. In
all experiments, irrigation was controlled by a closed loop irrigation system linked to tensiometers.
The results showed that HYDRUS 2D/3D predictions of irrigation events, matric heads and soil
salinity were in good agreement with experimental data, and that the code could be used to optimize
irrigation thresholds and water amounts applied, as a function of water salinity, to increase waterproductivity and maximize yield.
Results of HYDRUS 2D/3D simulations also indicate that the location of the sensor relative to thewater source has a crucial effect on irrigation efficiency. Sensors that control the irrigation systemshould be placed very close to the water source to avoid the effect of heterogeneity of soil properties
on water flow dynamics. The further away the sensor, the higher variability in the irrigation system
operation. As plants grow and transpiration increases, the irrigation threshold needs to be adjusted inorder to supply the increased water uptake. Increasing the water volume in each irrigation pulse might
not be a good solution, since more water is wasted, especially in sandy soils. Irrigation duration
should be based on water volume or time rather than measurements of pressure head since variability
in measurements increases during irrigation. When irrigating with saline water, decreases in plant
uptake result in higher matric head, hence fewer irrigations, which in turn may cause even higher
salinity. Therefore, irrigation with saline water cannot be based on tensiometers alone but has to becomplemented by soil salinity monitoring.

22

Dynamic Non-Equilibrium Water Flow in Variably Saturated
Porous Media
Efstathios Diamantopoulos* and Wolfgang DurnerInstitut für Geoökologie, Technische Universität Braunschweig, Germany*
Corresponding Author: ediamant@tu-bs.de, Phone +49 531 391 5931

During the last 50 years, experimental observations have shown that the soil hydraulicproperties estimated under static and dynamic methods can differ substantially. Theseobservations are often described by the term “dynamic non-equilibrium” or “dynamic
effects”, and they occur under different experimental boundary conditions. For a given
pressure head boundary condition non-equilibrium effects appear as a relaxation in the
cumulative outflow data while the pressure head remains constant inside the soil column. For
a given flux applied boundary condition, non-equilibrium effects appear as a relaxation of thepressure head over time, while the macroscopic water content distribution appears static.
These effects are often attributed to various processes such as: air-water-interface
reconfiguration, pore-water blockage, air entrapment, dynamic contact angles, among others.
We developed a simple non-equilibrium model to quantitatively describe these observations.
The model considers two continua at the macroscopic scale: one continuum is described by
the Richards equation and the second, associated with non-equilibrium water flow, by anextended Richards equation using the Ross and Smettem non-equilibrium approach. The newmodel was implemented by extending the Hydrus-1D code. This model can describe thedynamic effects occurring in transient flow experiments very well.

23

Dual-Drip Subsurface Irrigation System:
Can it Act as a Hydraulic Barrier?
Mohammad El-Nesr, N. B.1, Abdurrahman Alazba1, and Jiří Šimůnek2
1

2

Alamoudi Chair for Water Researches, King Saud University, Riyadh, Saudi Arabia.
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.

Subsurface drip irrigation systems, compared to other irrigation systems, enhance delivery ofwater and chemicals directly into the root zone. However, in light-textured soils, certain
quantities of water may percolate below the root zone due to the subsurface position of drip
lines. The main objective of this paper is to evaluate three technologies to enhance a spatial
distribution of water and solutes in the root zone and to limit downward leaching. The threetechnologies include a) a physical barrier, b) a dual-drip system with concurrent irrigation,and c) a dual-drip system with sequential irrigation. To achieve this objective, we performed
computer simulations and field experiments. Numerical simulations were carried out using
the HYDRUS (2D/3D) software for both bare and cultivated soils. The results indicate thatthe physical barrier is more efficient than dual-drip systems in enhancing the water
distribution in the root zone while preventing downward leaching. On the other hand, thedual-drip system with sequential irrigation, followed by the dual-drip system with concurrent
irrigation, is the most efficient in limiting downward leaching of solutes. The results of thestudy suggest that the system that combines the physical barrier with the hydraulic barrier due
to sequential irrigation by a dual-drip system provides the largest benefits in terms ofenhancing the spatial distribution of both water and solutes in the root zone and preventing
their downward leaching.
Keywords: Drip Irrigation, HYDRUS (2D/3D), Leaching, Root Zone24

Phosphorus Leaching Potentials from Re-constructed Soil
Columns Using HYDRUS-1D Model
Abdirashid Elmi
Department of Environmental Technology Management, College for Women, Kuwait University, P.O. Box 5969
- Safat 13060 Kuwait; a.elmi@ku.edu.kw, abdirashid.elmi@mail.mcgill.ca

Modern agricultural production uses phosphorus (P) extensively to meet the challenges of
feeding rapidly growing population and changing lifestyles, making P a leading source ofimpairment for rivers and streams in Canada. Developing effective management strategies toreduce P losses from agro-ecosystems requires improved understanding of P transport
pathways in the soil. The purpose of our study was to investigate vertical distribution andtransport processes of phosphate (PO4) in reconstructed soil columns using HYDRUS-1Dmodel. Results obtained from field experiments were used to calibrate and validate the
HYDRUS-1D model. The results showed that 98% of the total P applied was concentrated in
the top 0.2 m of the columns, and decreased progressively with soil depth. The model overpredicted PO4 adsorption, leading to a weak correspondence between the simulated and themeasured results for PO4. This is a suggestion that the HYDRUS-1D model could notaccount accurately for the different soil structures found in the undisturbed soil columns andthe preferential flow that occurs in these columns. This may be due to the fact that Freundlich
isotherm, which is part of the transport equations, could not adequately describe PO4
adsorption onto the soil particles.

25

Using HYDRUS-1D for Estimating Hydraulic Conductivities of
the Soil Aggregates and their Clay-Organic Coatings from
Capillary Rise Data
Miroslav Fér* and Radka Kodešová
Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Dept. of Soil
Science and Soil Protection, Kamýcká 129, CZ-16521 Prague 6, Czech Republic*Corresponding author: mfer@af.czu.cz

Soil aggregates are in some soils and their horizons covered by organomineral coatings,
which may significantly influence water and solute transfer into the aggregates. Knowledgeof a coating occurrence, their structure and hydraulic properties is required for a more precise
description of water flow and contaminant transport in soils using dual-permeability models.
The aim of this study was to describe hydraulic properties of clay and organic matter coatings
in the iluvial (Bt2) horizon of Haplic Luvisol. Sets of 30 unsorted aggregates, 24 aggregateswith mostly clay coatings and 24 aggregates with clay-organic coatings, respectively, werestudied to evaluate an impact of various coating composition. The coatings were removed
from a half of the aggregates of each set. First, the wetting soil-water retention curve wasmeasured on all soil aggregates. Parameters of the soil-water retention curves were obtainedusing the RETC program. Then the capillary rise from the saturation pan into the multiple
aggregates (set of 14 or 15 aggregates) at boundary pressure heads of -5 and -1 without andwith coatings was measured. The saturated hydraulic conductivities of the aggregates, Ks,aggr,
and their coatings, Ks,coat, were numerically optimized using the HYDRUS-1D program andthe cumulative infiltration in time measured for the aggregates without and with coatings,
respectively.
Data of the soil-water retention curves, measured on aggregates with and without coatings,
did not allow distinguishing between retention curve parameters of the soil aggregates andtheir coatings. Therefore the same parameters were evaluated for both. Capillary rise into thesoil aggregates without coatings was always faster than into the aggregates with coatings. As
result the optimized saturated hydraulic conductivities, Ks,coat, of the clay and the organic
matter coatings (the average values for unsorted, mostly clay and clay-organic coatings were3.69 10-7, 2.76 10-7 and 1.81 10-7 cm min-1, respectively) were one to two order of magnitude
lower than the saturated hydraulic conductivities, Ks,aggr, of the aggregates (the averagevalues for corresponding aggregates were 3.87 10-6, 6.52 10-6 and 1.11 10-5 cm min-1,
respectively). Slightly variable Ks,aggr (or Ks,coat) values were obtained for different bottompressure heads, and the lower Ks,aggr (or Ks,coat) values were estimated from the second run of
the tests compare to the first run of tests for each set of aggregates. No statistically significant
differences between Ks,coat values obtained for coatings of various compositions were found(Fér and Kodešová, 2012).
ReferenceFér, M., and R. Kodešová, Estimating hydraulic conductivities of the soil aggregates and their clayorganic coatings using numerical inversion of capillary rise data, Journal of Hydrology, 468-469,
229-240, 2012.

26

Numerical Modeling of Water Flow and Nitrate Dynamics on
Zero Tension Plate Lysimeters Using HYDRUS-2D
Vilim Filipović1*, Radka Kodešová2, Dragutin Petošić1
1

Department of Soil Amelioration, Faculty of Agriculture, University of Zagreb, Svetošimunska 25, 10000
Zagreb, Croatia
2
Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech
University of Life Sciences, Kamýcká 129, Prague 6, Czech Republic*presenting author: vfilipovic@agr.hr

Lysimeter experiments generally simulate actual field conditions and can be the closest to
real field conditions. The efficiency of the zero tension plate lysimeters, which were
implanted in silty-clay soils as well model (HYDRUS-2D) ability to simulate water flow andnitrate dynamics were evaluated. Low efficiency of lysimeters during the vegetation period
was mostly caused by high crop water demand and possible water diversion to the sides when
the groundwater table was low. The HYDRUS-2D model was able in some degree toreproduce observed outflows. Water and solute diverged from the plate towards the dryer
unsaturated soil when groundwater table was low. Pressure head and nitrate concentration
distributions simulated around the lysimeter plate illustrated that the lysimeter plate had asignificant impact on the water regime and nitrate dynamics within the soil. This paper
represent part of results which were published by Filipović et al. (2013).
Keywords: Zero tension plate lysimeter, water flow, nitrate dynamics, modeling, HYDRUS2D
Reference

Filipović, V., and R. Kodešová, and D. Petošić, Experimental and mathematical modeling of water
regime and nitrate dynamics on zero tension plate lysimeters in soil influenced by highgroundwater table, Nutrient Cycling in Agroecosystems, DOI 10.1007/s10705-012-9546-5, 95,
23-42, 2013.

27

Single and Double Porosity Modeling of Solute Transport in
Intact Soil Columns – Effects of Texture, Slurry Placement, andIntermittent Irrigation
Nadia Glæsner1,2,3 and Horst H. Gerke3
1

Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
2
Faculty of Science and Technology, University of Aarhus, Tjele, Denmark
3
Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V., Müncheberg, Germany
nadia.glaesner@gmail.com

We investigated the effect of injection and surface application of dairy slurry on leaching ofnonreactive slurry components (Br tracer applied to slurry) and water flow (tritium tracer
applied with irrigation water) for differently textured soils and irrigation regimes. The studies
were performed on intact soil columns (20 cm diam., 20 cm high) from the plow layer of aloam, sandy loam, and loamy sand. The experiments were carried out during unsaturated
conditions with low suction (5 hPa) applied at the lower boundary.
In the fine-textured soils, placing slurry within the soil matrix by injection reduced leachingof the Br tracer without influencing transport of the tritium tracer, indicating the mechanismof retention of slurry solutes in small pores (immobile region), inaccessible by the flowing
water, as the active flow volume did not change as a result of the injection procedure. Astransport occurred through a larger fraction of the loamy sand, no effect was observed in thismore coarse-textured soil.
Irrigation interruptions during intermittent irrigation induced retention of the tritium tracer
and increased leaching of the Br tracer in the slurry injected loam soil. We hypothesize
increased mass exchange of solutes between mobile and less mobile pore regions ascompared with steady flow during continuous irrigation for both tracers; meaning transport of
the tritium tracer from mobile to immobile pore regions during interruptions, and transport ofBr from immobile to mobile pore regions during interruptions.
These hypotheses and mechanisms were tested by simulations using single- and double
porosity models implemented in HYDRUS-1D numerical code. Partitioning of the soil into
two coupled pore domains for which separate hydraulic and transport properties are definedwith mass transfer parameters for solute concentrations and water flow seem relevant for
describing transport during intermittent irrigation.

28

The Use of HYDRUS-1D for Groundwater Recharge
Estimation in Boreal Environments
Sergey Grinevskiy and Sergey Pozdniakov
Moscow State University, Geology Dept, Hydrogeology Division

The well-known package HYDRUS-1D was used for groundwater recharge simulation basedon long term meteorological data with daily resolution. For boreal climate, with a long winterperiod, initial meteorological data such as precipitation can’t be used directly as theatmospheric boundary condition input file. This data must be preprocessed to take into
account snow accumulation and snow melting, evaporation from snow and vegetation coverand soil freezing-defrosting processes. For this a special preprocessing code SurfBal for
simulating surface water and energy balances and generating upper boundary for HYDRUS1D was developed. SurfBal calculates using known daily values of precipitation, solar
radiation and maximum and minimum temperature surface water balance including:interception by canopy, surface (leaf and snow) evaporation, snow accumulation,
consolidation of snowpack and its melting and surface runoff as well as initial potential
values of evaporation and transpiration and input water flow for HYDRUS-1D.
The results of water balance and groundwater recharge simulations using SurfBal and
HYDRUS-1D for climate conditions of middle European part of Russia shows the principalrole of spring-period surface-soil water budget for groundwater recharge under various
landscapes and soil cover and due to different groundwater level depth.

29Simulation of Uranium Tailing Leaching using VS2DRT
Sosina S. Haile* and Broder J. Merkel
Department of Geology, Technische Universität Bergakademie Freiberg, Gustav-Zeuner-Str. 12 09596
Freiberg/Sa., Germany, merkel@geo.tu-freiberg.de*Presenting author: wedatnsos@yahoo.com

Uranium contamination of surface and ground water from passive and active uranium tailingis a serious environmental problem in many industrialized nations like US. Reactive transportmodels can be used to predict the potential environmental impacts of new uranium tailingsites as well as to assess level of contamination from existing uranium tailing sites. Hence,
reactive transport models are useful tools to visualize potential treats as well as emanate
dangerous and to design preventive and remedial measures to protect and rehabilitate thewater resources. In the present study a newly developed two dimensional multi-species
coupled reactive transport model, VS2DRT, is used to simulate uranium tailing leaching. The
problem is adapted from HYDROGEOCHEM-5 and HP2 manuals and deals with the releaseand subsequent migration of uranium from a uranium tailing pile towards the ground waterand a river. The simulation does not involve redox reaction and shows the application of
VS2DRT in simulating uranium migration in the subsurface.

30

Infiltration Into Stony Soils: Modeling of the Process Using
the HYDRUS Codes
Hana Hlaváčiková*, Viliam Novák, and Marek Rodný
Institute of Hydrology, Slovak Academy of Sciences, Račianska 75, 83102 Bratislava, Slovakia*
Presenting author

Mountainous soils usually contain a large number of rock fragments (particle diameter≥ 2mm), which strongly influence the soil physical and hydrophysical properties andsubsequently the movement of water in and through such soils. This work presents the resultsof the study evaluating the effects of rock fragments (quantitatively expressed as stoniness)on water infiltration into the soil and water percolation through stony soil layers into therelatively impermeable strata using the Darcy´s approach. Rock fragments as a part of stonysoils significantly decrease their retention capacity as well as hydraulic conductivity. Stones
simply decrease the effective cross-section of a more conductive soil matrix; the stones'
hydraulic conductivity is negligible in comparison to the soil matrix (fine-textured particles).
Input data were measured in the field and in laboratory. The so-called effective parameters
were estimated using the Darcy´s approach. It means that soil characteristics represent a bulk
soil with both fine particles and rock fragments. To do this, all stony soil characteristics were
evaluated using the representative elementary volume (REV), the dimension of which
depends mainly on the size of the rock fragments and is orders of magnitude larger thansample volumes, used for the soil matrix (the Kopecky's cylinders). For a soil with stones ofabout 10 cm in diameter, the REV was estimated to be 1 m3. Since it would be technicallyextremely difficult to measure hydraulic characteristics on a soil sample this big, we used thesimulation model HYDRUS-2D (simulating the classical Darcy's approach) to estimate thesaturated hydraulic conductivity using numerical experiments. Resulting data were thenimplemented in the simulation model HYDRUS-1D.
Simulation results of an infiltration process have shown the importance of stoniness ininfiltration kinetics. However, the initial soil water content was found to be a dominant factor
in this particular case (for a stony soil at Western Tatras, Slovakia). Soil skeleton decreases
the effective hydraulic conductivity and retention capacity of stony soils. During infiltration
with the rainfall rate lower than the saturated effective hydraulic conductivity, the penetration
rate of the infiltration front in stony soils will be higher than through non-stony soils. From
the above it follows that the formation of the subsurface runoff is being modified by soil
stoniness. The higher stoniness, the earlier appearance of the surface runoff can be expected.

31

Simulation of Different Rainfall Intensities Impact on theReactive Transport of Mine Tailing Metal Contaminants
Fatemeh Izadi Tame1, Ali Motalebi Damuchali2, Gholamreza Asadollah Fardi3, and Ahmad
Khodadadi4
1

MSc Student, Civil Engineering Department of Kharazmi University, Tehran, Iran2
MSc, Environmental Engineering, Kharazmi University, Tehran, Iran
3
Associate Professor, Civil Engineering Department of Kharazmi University, Tehran, Iran
4
Associate Professor, Engineering faculty of Tarbiat modares University, Tehran, IranContamination of the underling aquifer beneath a mining area is one of the environmental
problems that can be modeled in order to minimize the contamination of groundwater andriver flow systems. Interpreting the geochemistry and achieving a good understanding of theinvolved processes is necessary to mitigate the environmental damages. Extensive internalrisk predication models often fail to predict where catastrophes will arise. In this study thepotential risk of metals contamination around the mining sites is evaluated, and the metals
reactive transport sensitivity to different leachate fluxes is estimated. The PHREEQC
numerical model is applied to simulate the reactive transport of three metals (Cd, Ni and Mn)from Zanjan (Iran) Zinc leaching plant tailings, with variable leachate fluxes in 30 days. The
simulation showed that different rainfall rates induce variable metal speciations. Decreasingwater contents lowered the soil solution pH and produce new cation exchange conditions.
The simulation results were generally in good accordance with the experimental results.
Incompatibility in some scenarios may be attributed to PHREEQC linear cation retardation
assumption. Of the three considered metals, the modeled Ni concentrations were the least
compatible in different scenarios. We conclude that variations in water fluxes cansignificantly influence metals mobility and availability and hence, specific risk assessmentsfor past and present hydrological regimes are highly suggested for mining disposal sites.

32

Investigation the Effect of Acidic Rain pH on Reactive
Transport of Groundwater Metal Contaminants
Fatemeh Izadi Tame1, Gholamreza Asadollah Fardi2, and Ahmad Khodadadi3
1

2

MSc Student, Civil Engineering Department of Kharazmi University, Tehran, Iran
Associate Professor, Civil Engineering Department of Kharazmi University, Tehran, Iran
3
Associate Professor, Engineering faculty of Tarbiat modares University, Tehran, IranMulticomponent reactive transport in porous media is a complex process, owing to a
combination of variability in the processes involved and the inherent heterogeneity of nature.
In recent years, various multicomponent reactive transport models have been developed to
study the mobility of potentially toxic heavy metals in the subsurface. Heavy metals andother contaminants might release from mining sites, especially from waste dumps or tailingponds. Soil and groundwater contamination due to mining activities is a worldwide
environmental problem. Among the inorganic toxicants of great concern in mine tailings,
Pb2+, Zn2+ and Cd2+ figure prominently due to their abundance and potential toxicity. This
study investigated the effect of pH on the transport of these metals through Lakan (Iran) leadand zinc leaching plant tailings. The local equilibrium assumption (LEA) was adopted andHP1 model and PHREEQC database were employed to simulate heavy metals movement
through saturated soil at the laboratory column scale, in a 15 days period. Not surprisingly,
lower pH increased metal transport. However the simulation result generally agreed well withpreviously column study results, they indicate that physical and chemical parameters must be
carefully determined and used in the simulation procedure. The use of 2D and 3D models andkinetic modeling approach is highly suggested to more accurately simulate the related
reactions and to improve the results precision.

33

Comparison of Two Numerical Modeling Codes for Hydraulicand Transport Calculations in the Near Field
Jan Kalin1*, Borut Petkovšek1, Philippe Montarnal2, Alain Genty2, Estelle Deville2, and Jure
Krivic3
Slovenian National Building and Civil Engineering Institute, Dimičeva 12, SI-1000 Ljubljana, Slovenia*
Presenting author: jan.kalin@zag.si, borut.petkovsek@zag.si
2
CEA/Saclay, DM2S/SFME/LSET, F-91191 Gif-sur-Yvette Cedex, France
philippe.montarnal@cea.fr, alain.genty@cea.fr, estelle.deville@cea.fr
3
Geological Survey of Slovenia, Dimičeva 14, SI-1000 Ljubljana
jure.krivic@geozs.si

1

In the past years the Slovenian PA/SA team has performed many generic PA/SA studies forthe future Slovenian LILW repository, most recently a Special Safety Analysis (SSA) for the
Krško site. The modeling approach taken was to split the problem into three parts: near-field(detailed model of the repository), far-field (i.e., geosphere) and biosphere. In the SSA thecode used to perform near-field calculations was Hydrus2D.
Recently the team has begun a cooperation with CEA/Saclay and, as a part of thiscooperation, begin investigations into using the Alliances numerical platform for near-fieldcalculations in order to compare the overall approach and calculated results.
The article presents the comparison between these two codes for a silo-type repository thatwas considered in the SSA. We will present the physical layout and characteristics of therepository and develop and implement a hydraulic and transport model of the repository in
Alliances. Some analysis of sensitivity to mesh fineness and to simulation timestep have been
preformed and will also be presented. The compared quantity will be the output flux ofradionuclides on the boundary of the model. We will compare the results and comment on
differences/similarities.

34

Characterization and Modeling of Water Movement and Salts
Transfer in a Semi-Arid Region of Tunisia
Sabri Kanzari1, Mohamed Hachicha1, Rachida Bouhlila2, and Jorge Battle-Sales312National Institute of Research of Rural Engineering, Waters and Forests of Tunis
National Engineering School of Tunis, Modeling in Hydraulic and Environment Laboratory, (Tunisia)
3
University of Valencia - Department of Plant Biology

The semi-arid region of Bou Hajla (Kairouan – Central Tunisia) is exposed to the risk of soils
and aquifers salinization. A characterization of water movement through the use of TDR
probes installed at up to 4 m in depth, and of salts transfer by soil sampling was conducted tohighlight this risk. At the same time, climatic parameters were monitored. The results weregathered over the period of approximately one year (June 12, 2006 to May 08, 2007). The
water movement and salts transfer were simulated by Hydrus-1d model, and inverse
modeling was used to optimize the required hydrodynamic parameters. It was found that thesimulated profiles of volumetric humidity and the electrical conductivity of soil are close to
those measured. The calculated RMSE values are low, indicating the reliability of Hydrus-1d
for the simulation of the hydro-saline dynamics in field conditions.
Keywords : Soil, Salinization, Hydrus-1d, Aquifer, Semi-arid region, Tunisia.

35

Characterization and Modeling of Water and Salt Dynamic in a
Sandy Soil Under the Effect of Surface Drip Irrigation
Sabri Kanzari1, Ibrahima Ba2, Mohamed Hachicha1, and Rachida Bouhlila2
1National Institute of Research of Rural Engineering, Waters and Forests of Tunis
National Engineering School of Tunis, Modeling in Hydraulic and Environment Laboratory, Tunisia

2

In a global context of water scarcity and salinization, there is a more pressing need for an
efficient use of the irrigation management through alternative localized irrigation’s
techniques. Characterization and two-dimensional modeling of water movement and salts
transport is important to manage such irrigation system. Nevertheless, that is not highly
valued in most numerical modeling studies of two-dimensional flows and solute transport
under drip irrigation. For this purpose, an experiment of two monoliths was implemented by asandy soil equipped with TDR probes to monitor water content and Watermark sensors formonitoring soil pressure head. Soil salinity was measured according the method of the soil
diluted extract (soil/water ratio of 1/5). Preliminary tests on small monoliths were carried todetermine hydrodynamic parameters of this soil. The monoliths were saturated, one, with adistilled water and the other with a saline water (electrical conductivity = 4 dS.m-1).
Characterization results show a more important axial dynamic of water than lateral movement
and the formation of a saline bulb around 20 cm in depth. Modeling of water movement andsolute transport was performed with Hydrus-2D. Four types of hydrodynamic parameters
were used for model calibration on the monolith irrigated with distilled water. The best
calibration was obtained with the parameters estimated using RETC software from retention
curve data measured by the evaporation method. Model validation was performed on the dataobtained from the monolith irrigated with saline water. Modeling results showed a good
agreement between measured and predicted values. A scenario highlighting the effect ofsignificant evaporation (8 mm.day-1) during an irrigation cycle revealed a potential soil
salinization risk with the formation of a saline bulb of medium salinity (3.5 dS.m-1) aroundthe emitter. This bulb extends to 30 cm in depth. In the long-term, after several cycles ofirrigation, salinity risk can be aggravated and affect the soil physical properties and, inconsequence, crops production.
Key words: Soil, Salinization, Irrigation, Modeling, Hydrus-2D.

36

Hydraulic Properties and Reduction of COD, Phosphorus andNitrogen in Sand Filters Used for Greywater Treatment –Simulation and Verification
Susanna Ciuk Karlsson*, Håkan Jönsson, Sahar Dalahmeh, Cecilia Lalander
Department of Energy and Technology, Swedish University of Agricultural Science, Uppsala, Sweden*
Presenting author: susanna.ciuk.karlsson@slu.se

Greywater can, after suitable treatment, be a sustainable resource for irrigation, cleaning andstrengthening the groundwater by infiltration. A vertical flow sand filter is a simple, effective
and inexpensive system for treating greywater. The performance of sand filters treating
artificial greywater was tested in the laboratory over a period of 113 days. The filters
consisted of columns (0.2 m diameter) filled with sand to a height of 0.6 m. The hydraulicproperties of the filters were measured as well as the inflow and outflow concentrations of
COD, BOD5, total and phosphate phosphorus and total-, ammonia- and nitrate nitrogen.
To get a better quantitative understanding of the treatment processes inside the filters, the
HYDRUS-CW2D computer software was used to simulate the filters. The simulation ofwater flow through the filter could be well fitted to the measured flow by adjusting threemodel parameters: the air entry value; pore size distribution index and pore connectivity
parameter.
For the COD reduction the simulated results agreed well with experimental data after
adjustment of the microbial lysis parameters of HYDRUS-CW2D. The simulated reductionof COD was 65 % while 72 % reduction was measured for the filters in the lab. Simulated
reduction of phosphorus in the sand filter effluent corresponded well to the measured
reduction: the simulated reduction of phosphorus was 72 % while the experimental filters
achieved a 79 % reduction. Also the simulated effluent concentration of nitrate comparedquite well to the measured values. Almost no reduction (4 %) in total nitrogen took place inthe experimental filters which agreed with the simulated reduction (0 %). For the phosphorus
and nitrate components in HYDRUS-CW2D, so far no changes have been made to the default
parameters.
Using HYDRUS-CW2D for running simulations has so far improved our understanding of
our lab scale sand filters by pointing towards the possibility that some water passes by thefilter by running along the filter column walls. The simulations also indicated that thebiological activity and COD reduction mainly took place in the very top of the filter which
agreed with experimental observations.
The laboratory setup includes also vertical filters with bark and charcoal as filter materials
and our next challenge is to simulate their performance using HYDRUS-CW2D.

37

Predicting Soil CO2 Dynamics in Arable Land of Andisol inWestern Suburb of Tokyo
Chihiro Kato*, Taku Nishimura, Hiromi Imoto, and Tsuyoshi Miyazaki
Dept. of Biological and Environmental Engineering, Graduate School of Agricultural andLife Sciences, Univ. of Tokyo, 1-1-1, Yayoi,Bunkyo-ku, Tokyo.
*
Corresponding Author: kato@soil.en.a.u-tokyo.ac.jp

Recently, carbon capture and storage at both shallow and deep soil layers is recognized as afunction of agricultural fields. When discussing global warming mitigation such as proper
agricultural practices and/or appropriate depth of incorporating composts in agricultural lands
for carbon storage, prediction of not only CO2 efflux but vertical distribution of CO2
concentration of soil air phase is important. Few studies, however, had evaluated the model
performance of simulated profiles of soil CO2 concentration. The purpose of this study is topredict soil CO2 dynamics which include both CO2 flux from the surface and profiles of CO2
concentration in arable bare lands using SOILCO2 in HYDRUS-1D.
The study site was Institute for Sustainable Agro-ecosystem Services of the University ofTokyo (ISAS-UT) in western suburb of Tokyo, where Andisol is distributed. For model
validation, 10 m square bare area was prepared and continuous monitoring data of soil
moisture, temperature and CO2 concentration at depths of 10, 20 and 50cm has been obtained
every 20 minutes from Aug. 2010 to Oct. 2011. CO2 efflux from the surface was measured
with closed chamber method in both summer and winter. Meteorological data was obtained
from ISAS-UT and AMeDAS weather station located near the field.
Since there is no common way in determining parameters describing soil CO2 production, we
tried to determine the parameter of soil CO2 production dependence with depth with themeasured profile of dissolved organic carbon (DOC). Durner-Mualem model was employed
for soil hydraulic function and parameters were determined by inverse analysis with
evaporation experiments. In the inverse analysis, porosity of the field soil was employed asvolumetric water content at saturation θs, since θs is an important parameter to predict
diffusion of CO2 through air filled pores in a variably saturated soil. This is very important forsoil with large porosity such as Andisol.
Simulated results agreed with observed daily and seasonal variation of soil moisture,temperature and CO2 concentration. Quick response of soil moisture and soil CO2
concentration to rainfall, which observed in the field, was also well described. As well,
predicted cumulative CO2 flux for a year was comparable to the value which was estimatedwith observed data. We concluded that the parameter of CO2 production dependence withdepth were properly determined with measured profile of DOC concentration and soil CO2
dynamics in arable bare land could be predicted by using SOILCO2 model.

38

Transfer at Low Water Content: New and Simple Experimental
Approach for Inverse Determination of van Genuchten
Transport Coefficients
M. B. Kébré1,2*, F. Ouédraogo2, F. Cherblanc1, and F. Zougmoré2
1

Laboratoire de Mécanique et Génie Civil (LMGC), Université Montpellier 2 (France)
2Laboratoire de Matériaux et Environnement (LAME), Université de Ouagadougou (Burkina Faso)*
Presenting author: mkebre@hotmail.com

The unsaturated soil hydraulic properties (soil water characteristic curve and relative
permeability) are key factors for soil sciences fields and civil engineering. Because of thestrong dependence of these hydrodynamic parameters with water content, their determination
is subject to considerable experimental and numerical problems. Difficulties increase when
the soil tends to oven- dry situation, the state characteristic of arid and semi-arid areas. And
costs (time, money) of the methods for determination of these properties are relatively high.
In this article, we present:- In short review, the problem of the determination of the soil – water characteristic
curve and relative permeability in all the range of soil water content: experiments,
models of unsaturated soil hydraulic properties and associated numerical methods;- A simple, robust and less costly experimental method for the inverse determination ofhydrodynamic parameters. The principle of this experiment is to create a strong
gradient of water content in a column of homogeneous soil under conditions ofconstant flux (null) on the extremities in a fairground temperature controlled. Ideally,a single transfer phenomenon namely liquid phase filtration should be predominant
in the column.
- The numerical isothermal water transfer model and the formulation of the inverse
problem (MINPACK’s lmdif and lmder algorithms and Downhill simplex algorithm).
The state variables chosen are the gravimetric water content and the vapor pressure.
The van Genuchten (1980) - Mualem (1976) model for soil - water characteristic curve andrelative permeability is applied. ROSETTA code is used to determine initial values of VGM
model parameters. Different scenarios on the model taking into account the residual watercontent (wr), Mualem tortuosity parameter (L) and permeability parameter at saturation (Ks or
K0) will be simulated and discussed. A discussion is presented in consideration of water
vapor flow in the soil under our experimental conditions and the validity of isothermaltransport.
Key words: soil water characteristic; relative permeability; inverse problem; van Genuchten
parameters

39Root Water Uptake Under Deficit Irrigation: Model
Calibration and Comparison
Leilah Krounbi and Naftali Lazarovitch
Wyler Department of Dryland Agriculture, French Associates, Institute for Agriculture and Biotechnology of
Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer
Campus, Ben-Gurion, Israel.

Numerous sink functions for root water uptake: microscopic and macroscopic, empirical andmechanistic, compensatory and non-compensatory, are indiscriminately employed in researchand referenced in the literature, indicating an absence of information regarding model
relevance for specified boundary conditions. This research is an attempt at filling theinformation gap concerning root-water-uptake model robustness. We present results from aparallel comparison and evaluation of the performance of two empirical and one semimechanistic model in solving for root water uptake under optimal and deficit-irrigation
conditions, in two soils: loess and fine sand, and with three crops: wheat, tomato, and sweetsorghum, each characterized by a unique root distribution.
A global optimization search algorithm was employed for model parameterization in
conjunction with a numerical model for solving Richards’ water transport equation. Systemvariables, including the spatial and temporal soil water potential measured from cropped soilcolumns, served as input data. Model calibration was validated by comparing the measured
transpiration of deficit-irrigated plants, cultivated in a rotating lysimeter system, to modeledtranspiration values. Model performance under varying degrees of compensation was
evaluated, along with the effect of initial soil water potential conditions.
The quality of algorithm convergence during the calibration stage was relied on for apreliminary evaluation of model robustness in predicting soil water dynamics. Algorithm
convergence quality was compared using indices representing both the ratio between the 95%
confidence interval parameter range and the corresponding most likely parameter value, as
well as the error in the modeled soil water potential value, calculated with most likely
parameter values, relative to observations. Indices revealed inter-model variation as well asinter-treatment variation in algorithm convergence quality, due to soil texture and plant type.
The soil water dynamics of wheat grown in loess and sand were best predicted when the sink
function of the Richards equation was solved with the modified Feddes (FD) and van
Genuchten (vG) models, respectively. The same pattern was seen for tomato. The soil water
dynamics of both sand and loess, cropped with sweet sorghum, were best predicted when the
Nimah and Hanks (NH) model was incorporated into the sink function. Water stress was themost significant in sand columns cropped with sweet sorghum, which may indicate that theaccuracy of NH increases as the soil water potential decreases, possibly due to NH's
consideration of the unsaturated hydraulic conductivity, which expresses a highly, non-linear
dependence on the soil water potential.
When calibrated models were validated in drought conditions, modeled transpiration values
calculated with vG showed a good fit with measured values for both wheat and tomato.
However, FD overestimated the transpiration of loess-grown wheat regardless of the initialsoil water content, and overestimated the transpiration of loess-grown tomato in an initiallyhydrostatic profile. The difference in model performance is attributed to the soil textures forwhich they were tested.
40

The effects of compensation and the root distribution decreased with decreasing soil watercontent, and the initial conditions greatly affected modeled transpiration results. Transpiration'overshoot' may be linked to the fact that potential transpiration values assigned to deficitirrigated plants were taken from plants kept under well-watered conditions, and are therefore
not representative of potential transpiration values for the smaller-sized plants that result
under drought conditions.
We conclude that model performance was affected by soil texture, root distribution, andirrigation regimes. Therefore, a more mechanistic approach, able to account for such factors,
should be incorporated into existing empirical models. In addition, continued testing should
be carried out with the NH model in order to better-understand its limitations and work
toward widening its applicability.

41

Sensitivity of Recharge Evaluation Results Using HYDRUS to
Parameters and Boundary Conditions Variations
Natalia Kurinova
Department of Hydrogeology, Geological Faculty, Lomonosov Moscow State University, Russia

We examine the dependence between the type of bottom boundary conditions using in model which
describe different geolandscape elements and results of groundwater recharge simulations.
Geolanscapes is the term emphasizing indicative types of environmental by plants and soil types,
geological cross-sections and groundwater levels.
For our research we choose part of Moscow river valley which was nearby Zvenigorod town. Thereis located MSU geology research-station. Studied area is a part of Moscow syneclise. The geologicalcross-section from top to bottom consist of Quatenary sand and loam, Jurassic dark clay, laying withdiscrete location, and Carboniferous limestone. This cross-section is usual for Moscow region.
The groundwater recharge modeling have two part. First part is the atmospheric moisturetransformation on surface (Grinevsky, Pozdnyakov, 2010), second – moisture transport in vadozone(Simunek, 2008).
Upper boundary conditions are described by result of modeling precipitation transformation on
surface by program “sur_bal”. Application this program allow take into account such conditions asplant type, composition of soil (sand, sandy-loam, loamy), temperature, sun insolation, daily volume
of precipitation. Bottom boundary conditions depend on the groundwater level depth. In this study weuse the condition constant and variable pressure head. The second type of bottom conditions was
defined by long-term monitor groundwater levels which take place in MSU geology research-station.
The findings in this study support the idea that the use variable pressure head conditions for definition
bottom boundary conditions are significant for modeling processes of moisture transport anddefinition recharge part of water balance.

References
Grinevsky S. O., and S. P. Pozdnyakov, Principles regional evaluation of groundwater infiltration
recharge basis on geohydrological model, Water Resources, 37(5), 638-652, 2010.
Šimůnek, J., M. Šejna, H. Saito, M. Sakai, and M. Th. van Genuchten, The HYDRUS-1D software
package for simulating the one-dimensional movement of water, heat, and multiple solutes invariably-saturated media, Version 4.0x, Hydrus Series 3, Department of Environmental Sciences,
University of California Riverside, Riverside, CA, USA, 2008.

42

Inverting Saturated Hydraulic Conductivity from Surface
Ground-Penetrating Radar Monitoring of Infiltration
Emmanuel Léger1, Albane Saintenoy2, and Yves Coquet3
1

Université Paris Sud, UMR8148 IDES. emmanuel.leger@u-psud.fr
Université Paris Sud, UMR8148 IDES. albane.saintenoy@u-psud.fr
3
Université Orléans, ISTO/OSUC. yves.coquet@univ-orleans.fr

2

Hydraulic properties of soils, described by the soil water retention and hydraulic conductivity
functions, strongly influence water flow in the vadose zone, as well as the partitioning of precipitation
between infiltration into the soil and runoff along the ground surface. Their evaluation has important
applications for modeling available water resources and for flood forecasting. It is also crucial toevaluate soil’s capacity to retain chemical pollutants and to assess the potential of groundwaterpollution.
The determination of the parameters involved in soil water retention functions, 5 parameters whenusing the van Genuchten function, is usually done by laboratory experiments, such as the water
hanging column. Hydraulic conductivity, on the other hand can be estimated either in laboratory, or insitu using inﬁltrometry tests. Among the large panel of existing tests, the single or double ringinﬁltrometers give the field saturated hydraulic conductivity by applying a positive charge on soils,
whereas the disk inﬁltrometer allows to reconstruct the whole hydraulic conductivity curve, byapplying different charges smaller than or equal to zero. In their classical use, volume of infiltrated
water versus time are ﬁtted to infer soil’s hydraulic conductivity close to water saturation. Those tests
are time-consuming and difficult to apply to landscape-scale forecasting of inﬁltration. Furthermore
they involve many assumptions concerning the form of the inﬁltration bulb and its evolution.
Ground-Penetrating Radar (GPR) is a geophysical method based on electromagnetic wave
propagation. It is highly sensitive to water content variations directly related to the dielectric
permittivity. Thus it appears to be an accurate tool for wetting front in ﬁltration monitoring.
In this study we used Hydrus-1D to simulate inﬁltration of water inside a ring inﬁltrometer during acertain time. We generated water content profiles associated with a saturated hydraulic conductivity
value, knowing the other van Genuchten parameters, at each time step with Hydrus-1D. The watercontent profiles obtained by Hydrus-1D were converted to permittivities profiles using Complex
Refractive Index Method relation. We then used GprMax suite programs to generate radargrams andfollow the wetting front using arrival time of electromagnetic waves coming from GPR.
The synthetical inverse problem was made in the same way as presented above, generating watercontent profiles according to one unknown saturated hydraulic conductivity, convert them topermittivities and compute GPR monitoring using GprMax2D. By minimizing the ﬁtmis
betweenarrival times, we inverted the saturated hydraulic conductivity.
Using this procedure we study the possibility to obtain other parameters (namely α and n), by MCMC
inversion. By the means of sensitivity and misﬁt diagrams we try to conclude on links between thoseparameters and the possibility to obtain them our inversion method.
We carried out experiments in a quarry of Fontainebleau sand, using a Mala RAMAC system withantennae centered on 1600 MHz. We obtained saturated hydraulic conductivity, our retrieved
saturated hydraulic conductivity from GPR data was compared to disk in ﬁltrometer measurements.

43

Groundwater Recharge Modelling in the Nete Catchment(Belgium) with HYDRUS-1D–MODFLOW Coupling
Bertrand Leterme, Matej Gedeon, and Diederik Jacques
Performance Assessments, Institute Environment, Health and Safety, Belgian Nuclear Research Centre,
Boeretang 200, B-2400 Mol, BelgiumThis study focuses on the characterization of groundwater recharge in the Nete catchment(1544 km²), in Northern Belgium. A calibrated catchment-scale MODFLOW groundwatermodel had been developed and reported previously (Gedeon and Wemaere, 2008) assuming
constant (in space and time) recharge. To better approximate how groundwater recharge
variations in space and time affect groundwater flow, we coupled a model of the vadose zonehydrology to the groundwater model. The HYDRUS package (Seo et al., 2007) for
MODFLOW-2000 (Harbaugh et al., 2000) was chosen to perform the coupling. This paper
describes the different steps and issues encountered for the practical implementation of thispackage in a real-world case study at the catchment scale.
The groundwater modelling domain for MODFLOW is discretized in cells of 400×400 m(9644 active cells in the top layer), grouped in a predefined number of zones for the coupling
between HYDRUS and MODFLOW. The number of zones is a compromise: increasing thenumber of zones reduces the impact of averaging recharge fluxes and groundwater levels foreach zone; while decreasing the number of zones diminishes CPU time. We based theclustering on three criteria: (i) groundwater depth estimated from the calibrated steady-state
groundwater flow model, (ii) soil type, and (iii) land cover type. In the preliminary work
presented here, only the first criterion was used to delineate 20 zones, while a unique soil
type (podzol) and land cover (grass) were assumed over the entire area.
Despite the reduced complexity, several issues had to be overcome during theimplementation of the coupling HYDRUS-MODFLOW. First, due to a shallow groundwatertable (<1-2 m) in a significant part of the Nete catchment and due to topography averaging
effects, groundwater level simulated by MODFLOW exceeded the ground level. The
HYDRUS package could not properly handle this (non-convergence) and therefore the code
was adapted to allow this water excess to be removed as a "seepage". Second, somenumerical instability sometimes occurred (notably when the number of zones was too low or
the number of coupling time steps insufficient in the early stress periods) and simulations
showed highly oscillating fluxes and heads (even if tested with steady-state atmospheric
input), and a non-convergence.
The coupled simulation was run for a 10 year time series (from 2000 to 2009) of daily
precipitation (P) and potential evapotranspiration (ET0). Average P and ET0 over the 10 years
are 941 mm y-1 and 562 mm y-1, respectively. A warming-up period of 10 years with constantaverage P and ET0 was included to achieve proper initial conditions preventing an artificial
trend in the modelling results. The first month of the warming-up period needed to include
from two to six MODFLOW time steps per day to prevent oscillations, followed by daily
MODFLOW time steps for the rest of the warm-up and the simulation period.
For each zone, simulated groundwater depths were compared with data available from a
network of piezometers in the study area showing generally good correspondence andidentifying zones where further calibration of the groundwater flow model is necessary.
44References
Gedeon, M., and I. Wemaere, Conceptual uncertainty assessment for a catchment scale model.
Calibration and Reliability in Groundwater Modelling. Credibility of Modelling. ModelCare
2007, Copenhagen, Denmark, 9-13 September 2007 IAHS, Wallington, United Kingdom, 2008.
Harbaugh, A. W., E. R. Banta, M. C. Hill, and M. G. McDonald, MODFLOW-2000, the U.S.
Geological Survey modular ground-water model user guide to modularization concepts and theground-water flow process, USGS, Denver, CO, 2000.
Seo, H. S., J. Šimůnek, and E. P. Poeter, Documentation of the HYDRUS Package for MODFLOW2000, the U.S. Geological Survey Modular Ground-Water Model. Golden, CO, Colorado Schoolof Mines, 96 p., 2007.

45

Hg Modelling in Soil Systems Using HP1
Bertrand Leterme and Diederik Jacques
Performance Assessments, Institute Environment, Health and Safety, Belgian Nuclear Research Centre,
Boeretang 200, B-2400 Mol, Belgium

The main objective of this work was to develop a reactive transport model for simulating
mercury fate and transport in the unsaturated zone, in order to gain insight in the fate andtransport of Hg following soil contamination. The relative importance of different processes
and parameters was assessed with a sensitivity analysis based on Morris (1991) method andevaluated for different initial speciation of Hg contamination and indicators for Hg fate.
The code HP1 (Jacques et al., 2006; 2008) ) is based on two computer codes that have been
extensively used and validated : HYDRUS-1D (Šimůnek et al., 2008) for water and solutetransport and PHREEQC (Parkhurst and Appelo, 1999) for geochemical calculations. The
database IM003_THERMODDEM (Blanc et al., 2012) was used for aqueous complexation,
augmented with some Hg speciation data from Skyllberg (2012). However, complexation
with organic compounds is not considered in IM003_THERMODDEM. Four organic
compounds (three representing humic and fulvic acids, and one representing thiols) were
therefore added. Interactions between Hg and these dissolved organic ligands were modelled
as aqueous complexation reactions.
The main processes accounted for in the model are : Hg aqueous speciation (including
complexation with dissolved organic matter (DOM) – humic and fulvic acids (HA and FA),and thiol groups), Hg sorption to solid organic matter (SOM) – also distinguishing humic andfulvic acids (HA and FA) and thiol groups, dissolution of solid phase Hg (e.g. cinnabar
HgS(s)), dissolution of Hg non-aqueous liquid phase (NAPL), sunlight-driven HgII reductionto Hg0, Hg0 diffusion in the gas phase and volatilization, and DOM sorption to soil minerals.
DOM production is not explicitly considered in the model but its effect is implemented bydefining a DOM concentration in the rain water. Colloid facilitated transport is implicitly
accounted for by solute transport of Hg-DOM complexes. Certain processes in contaminatedsites may be very specific due to local circumstances and thus may not be consistent withpredictions of thermodynamics. Therefore, some processes (e.g. HgII reduction to Hg0) need
to be modelled following kinetics rather than thermodynamic laws.
Using a 50 year time series of daily weather observations in Dessel (Belgium) and a 1-m deep
sandy soil with deep groundwater (free drainage, oxic conditions), we implemented asensitivity analysis using the elementary effects method (Morris, 1991). Processes andparameters identified as critical based on the sensitivity analysis differed from one scenario tothe other depending on pollution type (cinnabar, NAPL or aqueous Hg), on the indicator
assessed (leached Hg, Hg in soil horizon originally polluted…) and on time. However, ingeneral concentration of DOM in soil and rainwater was the most critical parameter. Other
important parameters were those related to Hg sorption on SOM (thiols, and humic and fulvic
acids), and to Hg complexation with DOM. Initial Hg concentration was also often identified
as a sensitive parameter. Interactions between factors and non linear effects as measured by
the elementary effect method were generally important, but again dependent on the type ofcontamination and on time.
References46

Blanc, P., A. Lassin, and P. Piantone, THERMODDEM a database devoted to waste minerals,
BRGM, Orléans, France. http://thermoddem.brgm.fr, 2012.
Jacques, D., J. Šimůnek, D. Mallants, and M. Th. van Genuchten, Operator-splitting errors in coupled
reactive transport codes for transient variably saturated flow and contaminant transport in layeredsoil profiles, Journal of Contaminant Hydrology, 88, 197–218, 2006.
Jacques, D., J. Šimůnek, J., D. Mallants, and M. Th. van Genuchten, Modelling coupled water flow,
solute transport and geochemical reactions affecting heavy metal migration in a podzol soil,
Geoderma, 145(3-4), 449-461, 2008.
Morris, M. D., Factorial sampling plans for preliminary computational experiments, Technometrics,
33(2), 161-174, 1991.
Parkhurst, D. L., and C. A. J. Appelo, User's guide to PHREEQC (Version 2)-a computer program forspeciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations,
Water-Resources Investigations Report 99-4259, U.S. Department of the Interior, U.S.
Geological Survey, Denver, Colorado, USA: 326 p., 1999.
Šimůnek, J., M. Šejna, H. Saito, M. Sakai, and M. Th. van Genuchten, The Hydrus-1D Software
Package for Simulating the Movement of Water, Heat, and Multiple Solutes in Variably
Saturated Media, Version 4.0, HYDRUS Software Series 3, Department of Environmental
Sciences, University of California Riverside, Riverside, California, USA, 315 p., 2008.
Skyllberg, U., Chemical Speciation of Mercury in Soil and Sediment, Environmental Chemistry and
Toxicology of Mercury, John Wiley & Sons, Inc., 219-258, 2012.

47

Modeling Phytoextraction and Contaminant Transport
Processes Using HYDRUS-1D
Francesco Lugli1, Martinus Th. van Genuchten2, and Claudio F. Mahler1
1Department of Civil Engineering, COPPE, Federal University of Rio de Janeiro, UFRJ
Rio de Janeiro, RJ, 21945-970, Brazil
2
Department of Mechanical Engineering, COPPE/LTTC, Federal University of Rio de Janeiro
UFRJ, Rio de Janeiro, RJ , 21945-970, Brazil

Phytoextraction is an in situ remediation technique involving the uptake of contaminants byplant roots and their accumulation in plant tissues. Phytoextraction is dependent upon acomplex set of interactive and generally nonlinear soil, plant, contaminant and atmosphericprocesses and parameters. The objective of this study was to use HYDRUS-1D tonumerically estimate the effectiveness of the phytoextraction of Cd2+ , Pb2+ and Zn2+ fromcontaminated soil using Vetiver grass. Vitever is a perennial grass known for its tolerance todrought, resistance to diseases and fire, and ability to take up heavy metals.
In a previous study we calibrated HYDRUS-1D against observed greenhouse remediation
experiments. Several scenarios were tested, including different planting densities andirrigation schemes. Results of our numerical analyses showed that the efficiency ofphytoextraction increases significantly for more mobile contaminants, depending upon theadvective contaminant transport rate in the soil root zone, the potential transpiration rate, andprevailing water stress conditions in the root zone. Our study provided useful insight into thedesign of more elaborate laboratory- and field-scale phytoremediation experiments that may
be needed in the future.

48

Which Hydraulic Model to Use in Vertical Flow ConstructedWetlands?
Ania Morvannoua*, Nicolas Forqueta, Marnik Vancloosterb and Pascal MolleaaIrstea, Freshwater systems, ecology and pollution research unit, 3bis quai Chauveau - CP 220 - 69336 LYON
cedex 09, FrancebEarth and Life Institute, Environmental Sciences, Université catholique de Louvain, Croix du Sud 2 Box 2, B1348 Louvain-la-Neuve, Belgium*
Presenting author: ania.morvannou@irstea.fr

Modelling water flow in a Vertical Flow Constructed Wetland (VFWC) is a prerequisite tomodel wastewater treatment using process based filtering models. The material used in
VFCW is very susceptible to generate preferential flow. If this occurs, water will bypass mostof the soil porous matrix in a largely unpredictable way. Even if it is possible to simulate
water content variations within a VFCW, we cannot correctly model outflow with thestandard van Genuchten-Mualem function if preferential flow occurs. A number of various
model approaches have been proposed to overcome this problem. These models mostly try toseparately describe flow and transport in preferred flow paths and slow or stagnant poreregions. The objective of this study was to study and simulate the hydrodynamic behaviour
and the solute transport through a simplified representation of a French VFCW by using botha classical equilibrium model and a non-equilibrium model (dual-porosity model: mobileimmobile water model, with water content mass transfer) included in the HYDRUS-1D
software package. Modelling results were compared to a solute breakthrough curve obtained
from a tracer experiment, carried out on an existing VFCW. Inlet concentrations were firstcorrected to take into account tracer loss and experimental uncertainties. Then, both thehydraulic parameters of the mobile and immobile regions (θr-mo/θs-mo and θr-imo/θs-imo) and thetransfer coefficient (ω) were optimized to fit the tracer experimental breakthrough curve. The
comparison between measured and simulated tracer breakthrough curves indicates that the
non-equilibrium approach seem to be the most appropriate for simulating preferential flow
paths.
Keywords. Dual-porosity model, non-equilibrium, preferential flow path, vertical flow
constructed wetland

49

Parameter Estimation of Soil Hydraulic Functions and Thermal
Properties for Unsaturated Porous Media Using HYDRUS-2D
Code
Mohammad Nakhaei1 and Jirka Šimůnek2
1

Department of Geology, Kharazmi University, Tehran, Iran, nakhaei@khu.ac.ir
Department of Environmental Sciences, University of California Riverside, Riverside, USA,
Jiri.Simunek@ucr.edu

2

Soil and water resources are of great importance to the mankind. The combined effects ofdifferent soil temperatures and water inputs on water redistribution under field conditions
have not been fully studied. The objective of this study was to estimate the water flow
parameter (the residual water content θr, the saturated water content θs, empirical shapeparameters α and n, and the saturated hydraulic conductivity KS) and heat transport parameter(coefficients b1 and b2 in the thermal conductivity functions). Real-time sensors built byauthors were used to monitor soil temperatures at depths of 40, 80, 120, and 160 cm during
10 hours. Water temperature in a single infiltration ring was monitored simultaneously at thesame location. The soil thermal conductivity is estimated from temperature measurements bysolving a two-dimensional, inverse water flow and heat transport problem.
HYDRUS-2D, a two-dimensional software package for simulating movement of water andheat in variably-saturated porous media, was used to simulate water flow and heat transport
under such conditions. The simulated soil temperatures during ring infiltration experimentcompared favorably with their corresponding observed values. Soil hydraulics and heattransport parameters are optimized using the HYDRUS-2D code by solving the inverse
problem.

50

Using HYDRUS Programs for Simulating Al and SO42Leaching from Forest Soils
Antonín Nikodem1*, Radka Kodešová1, and Libuše Bubeníčková2
1

Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Dept. of Soil
Science and Soil Protection, Kamýcká 129, CZ-16521 Prague 6,Czech Republic
2
Czech Hydrometeorological Institute, Na Šabatce 17, 143 06 Prague, Czech Republic*Corresponding author: nikodem@af.czu.cz

The aim of this study was to assess the impact of different vegetation on the distribution of
rainfall (due to throughfall and stemflow), water regime, and Al and SO42- leaching fromforest soils. The study was performed at two elevation transects on the Paličník and Smědava
Mountain in Jizera mountains. Podzols and Cambisols were prevailing soil units in this area.
The impact of the precipitation redistribution under a beech tree on the water regime and Al
transport within the one- and two-dimensional soil profiles was simulated using the
HYDRUS-1D and HYDRUS 2D/3D simulation models (Nikodem et al., 2010). The waterflow and Al and SO42- transport under a grass cover, beech or spruce trees were modeledusing HYDRUS-1D (Nikodem et al., 2013). The simulation results for the 1D and 2D
scenarios (Nikodem et al., 2010) showed that the spatially redistributed precipitation underthe beech tree caused funneled water flow and solute transport near the stem base, which
resulted in the intensive simulated Al leakage around the tree stem. It was also shown(Nikodem et al., 2013) that the effect of the precipitation redistribution on water regime wasconsiderable in the beech forest, while it was almost negligible in the spruce forest.
Redistribution of precipitation under trees caused runoff (in one case), increased water
discharge through the soil profile bottom, reduction of water storage in the soil, and thus
reduction of root water uptake. Simulated Al leaching from the soil profile was determined
mainly by the initial Al content in the soil profile bottom. Leaching of SO42- was mainly
determined by its initial content in the soil and to a lesser extent by redistributed precipitationand SO42- deposition. The results suggest that spatially redistributed precipitation in beech
forest should not be neglected when predicting potential leaching of toxic substances toward
ground and surface water bodies.
References

Nikodem, A., R. Kodešová, and L. Bubeníčková, Simulation of the influence of rainfall redistribution
in spruce and beech forest on the leaching of Al and SO42- from forest soils, Journal of
Hydrology and Hydromechanics, 61(1), 39-49, 2013.
Nikodem, A., R. Kodešová, O. Drábek, L. Bubeníčková, L. Borůvka, L. Pavlů, and V. Tejnecký, A
numerical study of the impact of precipitation redistribution in a beech forest canopy on waterand aluminium transport in a Podzol, Vadose Zone Journal, 9, 238-251, 2010.

51

Agro-Ecological Application of Soil Hydrological Data: Two
Local-Scale Modelling Examples
Martina Nováková*, Jozef Takáč, and Rastislav Skalský
Soil Science and Conservation Research Institute, Gagarinova 10, 827 13 Bratislava, Slovak Republic*
Presenting Author: m.novakova@vupop.sk

Many soil and landscape (agro-ecosystem) processes are influenced by spatial and temporal changesof soil moisture. The content of soil water in root zone is crucial for crop development and crop
production. The aim of paper is i) to present the ecological and geographical approach to the analyze
and interpretation of the soil moisture in the context of crop production process and crop production,ii) to present examples and the results of WOFOST and DAISY models application at different spatial
levels (soil profile, farm) with emphasis on those hydrological soil properties and processes which
influence the crop production process intensity and the level of crop production. Weather data wereobtained from weather stations (Slovak Hydrometeorological Institute), soil data (soil retention andsoil hydraulic data) were prepared according to models requirements on the base of soil database of
the Soil Science and Conservation Research Institute in Bratislava (data on soil samples) and/or on thebase of detailed soil research at model area. Two models WOFOST and DAISY were applied tosimulate crop development and crop production including the soil moisture conditions at day step
within the vegetation season. Two models differ in the method of soil moisture content calculation.
Model WOFOST model works with simple vertically homogenized soil profile and the soil watercontent in root zone is calculated on the base of soil water balance equation. Model DAISY is moredetailed and requires the soil profile to be vertically differentiated into several horizons, which aredescribed individually and Richards’s equation is implemented to describe the soil water content andmovement. Case study Hurbanovo weather station: Model DAISY was applied to simulate soil
moisture conditions and several crop productions in the period 1961 – 2010. Crop rotations of fivecrops (spring barley, winter wheat, maize, sugar beet, potato) were set up. The water regime wassimulated in 2 variants: rainfed and irrigated. Irrigation was applied automatically after decreasing ofsoil water content below 50% of available water capacity for each evaluated crop. Irrigation amount
30 mm was simulated. The soil water regime was evaluated using the ecological classification of soil
water regime. The semiuvidic interval of the soil moisture is dominant. In winter period prevailed
semiuvidic interval whereas in the summer period the semiarid interval. The most extreme drought
occurred in the year 1990 when the duration of the arid and semiarid intervals in the topsoil was 292
days. Extreme drought occurred also in the years 1971, 1978 and 1982 when the duration of the arid
and semiarid intervals in the topsoil was more than 200 days. Droughts negatively affect crop
productivity. Decrease of water availability and consequently increase of days with water stress result
in decrease of water productivity; irrigation positively affects the water productivity. Case study
Selice farm: Model WOFOST was applied to simulate the grain maize production process including
the soil moisture content in the root zone in the period 1961 - 2010; the number of days with waterand oxygen stress and grain maize production were calculated in 1961 – 2010 and analyzed. As well,there was analyzed the spatial pattern of spatial variability related to grain maize production in two
years (2000 and 2008) different from the rainfall and different soil moisture conditions in root zone
points of view. The results of analyses confirmed the strong relations between rainfall, soil watercontent and grain production which are reflected by spatial variability related to simulated soil
moisture and production indices. The geographical and ecological interpretations of analyticalhydrological soil properties and processes especially in the context of crop development and crop
production extend their applications in interdisciplinary research.

52

Slope Drainage by Logging Roads and its Contribution to the2011 Flood Peak in the Píla Village.
Simulation with HYDRUS-2D.
Tomáš Orfánus
Department of Soil Hydrology, Institute of Hydrology, Slovak Academy of Sciences, Račianska 75, 831 02
Bratislava, Slovakia

One of the most discussed environmental problems in Slovakia has become the effect ofwood logging on hydrological processes. Especially, the more frequent occurrence of floods
in sub mountainous villages reported during the last two decades has been ascribed byvarious nongovernmental organizations to the devastative clear-cut forest management. The
High Tatra Mt. wind-throw calamity in November 2004 provided a very good opportunity to
study hydrological effects of large land cover changes in mountainous areas. 12,600 ha of the
spruce forest were completely cut down and forest was subsequently replaced by other typesof vegetation (grasses, herbs and shrubs). No significantly more positive effect of forests onstorm floods was either predicted or observed when compared to other types of vegetation.
However, mathematical simulations correctly predicted seasonal changes in the water balance
towards enhanced soil water content and less evapotranspiration after deforestation. The
qualitative effect of the clear-cut forest management on the water balance can be expectedsimilar to that of the wind-throw.
There was a flood in the Píla village on June 7, 2011 after 104 mm rainfall during 3 hours.
The usual “up-to-knee” deep base flow suddenly changed to a 3-m high wave, causing
catastrophic damages in the village. The estimated total flood discharge was about 560,000
m3. The area of the Gidra river catchment above the Píla village is 32 km2. The catchment isforested by more than 90%. Visiting the place and investigating the state of the forest floor
we found that there was an extremely high density of forest and logging roads, especially inthe lower part of the catchment. The forest road density in the left part of the Gidra rivercatchment was up to 10 km/km2. The average width of the roads is about 3-4 m and the roads
are often deepened by harvesters and erosion by up to 2 m. Thus, the area of compacted
surfaces (mostly roads) in the left part of the Gidra catchment was estimated to 0.7 km2 (2.2%of the total area). The road density was not measured in the right part of the catchment. The
direct forest-road discharge (i.e., water, which falls directly on their surface minus
infiltration) was estimated to be about 56,700 m3, which is about 10% of the estimatedcumulative flood discharge.
The HYDRUS-2D simulations revealed that the drainage process, collecting water from upslopes in deep logging roads (here estimated as 10% of all roads), transformed another 39,936
m3 of subsurface flow to surface flow, which theoretically could contribute to the direct flood
discharge. Then, the total contribution of logging roads to the flood discharge could be morethan 17%. Although we do not know what was the real density of deep logging roads in the
Gidra catchment it can be concluded that their contribution to the flood discharge in June
2011 was substantial. It was concludes that in forested catchments it is not the change ofvegetation (natural or human-induced) but the presence of compacted surfaces (logging
roads) that can significantly contribute to floods.

53Seasonal Simulation of Water and Salinity Dynamics Under
Different Irrigation Applications of Almond in Pulsed andContinuous mode
Vinod Phogat1,*, Mark A. Skewes1, M. Mahadevan1, J. W. Cox1,21South Australian Research and Development Institute, G.P.O. Box 397, Adelaide, SA 5001
2

The University of Adelaide, PMB1 Glen Osmond SA 5064

*Corresponding Author: vinod.phogat@sa.gov.au

The quantification of components of water balance is essential for designing strategies for
improving irrigation efficiency and water productivity of crops under different irrigation
systems and also needed for minimising the offsite movement of nutrients out of therhizosphere. The HYDRUS-2D was used to simulate water balance and salinity distribution
under full pulsed (FIp), sustained deficit pulsed (SDIp; 65% ETC) and full continuous (FIc)
irrigation of surface drip irrigated almond over a season. The weekly measured and predictedvalues of moisture content at different distances from the dripper and at different soil depths
matched well showing small variation in RMSE values. The sap flow underestimated thealmond water uptake by 31% as compared to the modelled value. Water uptake efficiency
under SDIp (68%) was higher compared to full water application conditions under FIp and FIc(54-55%). The leaching fraction was estimated to be 0.14 under SDIp and 0.25 in FIp and FIc
treatments. The higher irrigation amounts under 100% ETC treatments (FIp and FIc) largely
contributed to non-productive water fluxes (deep drainage losses and evaporation). The
seasonal water uptake by almonds under pulsed (FIp) and slow discharge continuous
irrigation (FIc) remained almost on par, indicating that pulsing didn’t provide any added
advantage, although it is a viable alternative to slow discharge continuous irrigation. The
average modelled soil solution salinity (ECsw) of the profile also remained below thethreshold for yield reduction during the growing season in all treatments. The irrigation waterproductivity (WPI) increased substantially (37%), yield was reduced by 8% and about 35% of
irrigation water was saved under sustained deficit irrigation (SDIp) compared to full irrigation(FIp). The SDIp concluded to be a promising deficit irrigation strategy for almond cultivation.
These outcomes can be utilized to improve irrigation efficiency and system design for drip
irrigation of almonds.

54

HYDRUS-1D Modeling Applications to Waste Disposal
Problems in Brazil
Elizabeth M. Pontedeiro, Victoria O. Almeida de Sousa, and Martinus Th. van Genuchten
Departments of Nuclear, Civil and Mechanical Engineering, COPPE, Federal Universityof Rio de Janeiro, UFRJ, Rio de Janeiro, RJ, 21945-970, Brazil

In this study we used the HYDRUS-1D software package to investigate the performance of
three types of waste disposal sites or repositories in Brazil: a conventional mining installation
containing naturally occurring radioactive materials (NORMs), a municipal landfill and aradioactive waste repository.
The first application involved NORM waste disposed of in an industrial landfill on top of abase of earth materials to ensure integrity of the deposit over relatively long geologic times(thousands of years). HYDRUS-1D was used to predict long-term radionuclide transportvertically through both the landfill and the underlying unsaturated zone, and then laterally ingroundwater. Calculations were carried out for both a best-case scenario assuming
equilibrium transport in a fine-textured (clay) subsurface, and a worst-case scenario involving
preferential flow through a more coarse-textured subsurface. Preferential flow and soil
texture both were found to have a major effect on the results, depending upon the specificradionuclide involved.
The second study concerned water fluxes into and through a municipal solid waste (MSW)
landfill in the city of Rio de Janeiro. Two cover systems were considered that would
minimize infiltration into the landfill. One used a capillary barrier made from MSW compost,
and another one a vegetation cover using grasses and native species from the area. Results forthe capillary barrier system compared closely with observed leachate rates at the landfill.
The third application involved a near-surface repository containing Cs-137 wastes resulting
from decontamination of Goiania city in Brazil after the 1987 accident with a CsCl
teletherapy source. The study provided estimates of water fluxes through the soil cover into
and through the repository and concrete liners towards underlying groundwater. This wasdone by first applying a detailed water balance to the soil cover accounting for local
precipitation and evapotranspiration rates, including root water uptake by grass on the cover.
Performance of the cover system and engineered barriers was followed for a 400-year period,
which included accounting for the effects of concrete degradation on the hydraulic propertiesof concrete. HYDRUS-1D was used next to simulate Cs-137 transport from the repository
through the concrete liner below the waste and the underlying vadose into the groundwateraquifer below the site. Simulations provided estimates of future radionuclide fluxes into
groundwater, and hence possible exposure to the public.

55

Simulation of Groundwater Evapotranspiration with
HYDRUS-1D in Desert Environments
Sergey Pozdniakov1*, Ping Wang2, Sergey Grinevskiy1, and Jingjie Yu2
1

Department of hydrogeology, Moscow State University, GSP-1, Leninskie Gory, Moscow, 119899, Russia
Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences andNatural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing,
100101, P. R. China*Corresponding author: sppozd@geol.msu.ru, Tel. / Fax: +7(495)9392613
2

Groundwater evapotranspiration (ETG) is an important part of the water balance forwetlands/riparian zones in desert environments; however, ETG estimate in these regions still
remains a challenge due to the difficulties involved in quantifying the atmosphericevaporative demand, the soil hydraulic properties, the vegetation parameters, and the changes
in water tables. In this study we present a statistical approach toward reducing uncertainties
in ETG estimating from diurnal water table fluctuations. A one-dimensional saturatedunsaturated soil water flow model with HYDRUS-1D program (Šimůnek et al, 2008) wasused to simulate daily and seasonal groundwater fluctuations in a desert area of northwest
China for the period of 2009-2011. Simulations were conducted for four different soil profiles(sand, loam, silt, and sandy clay) and two typical vegetation covers (Populus and Tamarix)
with temporal variability of precipitation, potential evaporation and transpiration input data,
which was produced using special preprocessing code SurfBal 3.60 (Pozdniakov, 2012).
The results show that a strong linear relationship exists in all model settings between the ETG
values and the standard diversion of water table fluctuations. However, for low hydraulicconductivity aquifers (silt and sandy clay), root water uptake induces a considerably watertable depression. In this case, the proposed method based on water-table fluctuation
overestimates the prescribed ETG. In contrast, for coarse aquifer type (sand and loam) the
proposed method underestimates the ETG rate because the decreasing storage can be readily
recovered due to the high hydraulic conductivities. To correct the proposed method by using
diurnal water table fluctuations, the “scaling factor ( k )”, which depends on the soil physicalcharacteristics, were introduced in ETG estimating.

56

Modeling Water and Nitrogen Fate in Plots with Sweet
Sorghum Irrigated with Fresh and Blended Saline Waters
Using HYDRUS-2D
Tiago B. Ramos1*, J. Šimůnek2, M. C. Gonçalves3, 1, J. C. Martins3, A. Prazeres3, andL. S. Pereira1
1

CEER-Biosystems Engineering, Institute of Agronomy, Technical University of Lisbon, Tapada da Ajuda,
1349-017 Lisbon, Portugal
2
Department of Environmental Sciences, University of California, Riverside, CA, 92521, USA
3
National Institute of Agronomic and Veterinarian Research, Quinta do Marquês, Av. República, 2784-505
Oeiras, Portugal*
Presenting author

The Alentejo region in southern Portugal faces water scarcity and environmental problems asa result of high atmospheric evapotranspirative demand and irregular rainfall. The need toreduce irrigation water demand and non-point source pollution in the region has made sweetsorghum [Sorghum bicolor (L.) Moench] an interesting alternative crop to other traditional
summer crops due to its lower water and nutrient requirements. This paper describes resultsfrom a long term simulation study where HYDRUS-2D was used to assess the fate ofnitrogen in a plot planted with sweet sorghum, while considering drip irrigation scenarioswith different levels of nitrogen and salty waters. HYDRUS-2D simulated water contents,
ECsw, and N-NH4+ and N-NO3− concentrations continuously between 2007 and 2010, while
producing RMSE between simulated and measured data of 0.030 cm3 cm−3, 1.764 dS m−1,
0.042 mmolc L−1, and 3.078 mmolc L−1, respectively. Transpiration varied between 360 and
457 mm depending upon the crop season and the irrigation treatment. Sweet sorghum showed
to be tolerant to saline waters only during one crop season. After that, the continuous use of
saline waters led to soil salinization, and to root water uptake reductions due to the increasing
salinity stress. N-NO3− uptake was higher when fertigation events were more numerous andthe amounts applied per event smaller. The yield function developed from the N-NO3− uptake
and the dry biomass yield (R2 = 0.71) estimated nitrogen needs between 130 and 180 kg/ha.
The movement of N out of the root zone was dependent on the amount of water flowing
through the root zone, the amount of N applied, the form of N in the fertilizer, and the timing
and number of fertigation events. The effect of the osmotic stress on nitrogen leaching was
only minimal. The simulations with HYDRUS-2D were thus useful to understand the best
strategies toward increasing nutrient uptake and reducing nutrient leaching.
Reference

Ramos, T. B., J. Šimůnek, M. C. Gonçalves, J. C. Martins, A. Prazeres, and L. S. Pereira, Twodimensional modeling of water and nitrogen fate from sweet sorghum irrigated with fresh andblended saline waters, Agricultural Water Management, 111, 87-104, 2012.

57

Simulation of Peak Loads for Horizontal Flow ConstructedWetlands
Anacleto Rizzo1 and Günter Langergraber2
1

Department of Environment, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Italy.
Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life
Sciences, Vienna (BOKU), Vienna, Austria

2Constructed wetlands (CWs) are a wastewater treatment technology that exploits thephysical, chemical, and biological processes developed in soil in order to improve the water
quality. The low operation and maintenance costs allow for a widespread use of CWs,
especially in treating wastewater from small communities (up to 2000 population). Despite
the wide application of CWs, many aspect of CW behavior in real environment still needs to
be investigated, including buffering capacity to sudden peak loads. Indeed, the stochastic
behavior of real influent loads are generally neglected during the typical CW design
procedure, and CW parameters should highly overestimated to face real load variability.
Hence, further efforts are still need to improve the ability to properly design CWs. Here a
process-based model approach is used to better understand the response of a horizontal flow
(HF) CW subjected to peak loads. Laboratory experiments were conducted by Galvão andMatos [2012], where HW-CWs were subjected to sudden load of different intensities. Data
from these laboratory experiments are used to calibrate a model of the HF-CW set-up using
the HYDRUS wetland module [Langergraber and Šimůnek, 2012]. The calibrated model fits
the data well and is further used to explore different loading scenarios. In this way, we areable to understand in which case the CW fails the maximum allowed effluent concentrations.
In future, we will use the calibrated model to investigate the behavior of HF-CW to stochastic
processes such as loading and temperature seasonal variations.
ReferencesGalvão, A., and J. Matos, Response of horizontal sub-surface flow constructed wetlands to suddenorganic load changes, Ecol. Eng., 49, 123-129, 2012.
Langergraber, G., and J. Šimůnek, Reactive Transport Modeling of Subsurface Flow ConstructedWetlands Using the HYDRUS Wetland Module. Vadoze Zone J., 11(2) Special Issue "Reactive
Transport Modeling", doi:10.2136/vzj2011.0104, 2012.

58

Longitudinal Dispersivity Determination Using Conservative
Tracer in the Field
Stanko Ružičić*, Zoran Kovac, Marta Mileusnic, and Kristijan Posavec
Faculty of Mining, Geology and Petroleum Engineering, Department of Mineralogy, Petrology and Mineral
Resources, Zagreb, Croatia*
Presenting Author

Solute transport parameters determination in the unsaturated zone is of great importance forgroundwater pollution risk assessment. The subject of study was Fluvisol developed on thefloodplain of Sava River. The goal of the study was estimation of longitudinal dispersivity
which is one of the main solute transport parameters. Purpose of this paper is presentation ofproblems that occurred during experiment which led to doubtful results.
Field experiment using conservative tracer calcium chloride was carried out. Longitudinal
dispersivity was estimated by modeling chloride concentration using HYDRUS-1D.
Investigated site is situated about eight hundred meters from right bank of Sava River at
Kosnica regional well field. The experimental site was equipped with two time domainreflectometry (TDR) probes, two electrical conductivity (EC) probes and four suction
lysimeters. All vegetation was removed from the research area and the surface was levelled.
The plot of 0.7 m2 was irrigated with a 200 l tracer solution over two hours. During theexperiment, soil moisture (using TDR probes) and electrical conductivity (using EC probes)
were measured every twenty minutes. Percolating solution is sampled by suction lysimeter
installed at 40 cm depth. Chloride concentrations in leachate were analyzed using ion
chromatography (IC).
Due to collapse of pedological pit during application of tracer and sampling of percolating
solution, field experiment was not completed. Therefore, estimation longitudinal dispersivity
was performed on incomplete data set.
Keywords: Fluvisol, field experiment, solute transport parameters, HYDRUS-1D59

Modelling Horizontal Flow Constructed Wetlands Treating
Effluents of Wastewater Treatment Plants
David Sanchez-Ramos1 and Günter Langergraber2
1

School of Civil Engineering, University of Castilla-La Mancha, Ciudad Real, Spain
Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life
Sciences, Vienna (BOKU), Vienna, Austria

2

The HYDRUS Wetland Module has been used to estimate the efficiency of a constructedwetland (CW) system, designed for the treatment of effluents from wastewater treatment
plants near the Tablas de Daimiel National Park (Spain). The purpose is to restore this natural
wetland with the effluents of several plants in the surroundings, improving the water quality
throughout CWs, so the quality requirements are higher than standards.
The main aim for the simulation was to verify the treatment system design of horizontal flow
(HF) CWs consisting in several cells. The HF beds have a length of 23 m (including a 0.4 m
inlet area), a width of 22 m and a depth of 0.6 m for the treatment of 96 m3 d-1 each one,
resulting in an hydraulic loading rate of 19 cm d-1. The effluents characterization indicatedthat the system should be able to treat water with high concentrations of organic matter andammonium. The influent concentrations have been considered 125 mg O2 L-1 and 15 mg N L1
for COD (mainly as slowly biodegradable particulate COD) and ammonium, respectively.
The implementation in HYDRUS used the CWM1 biokinetic model formulation simulating
reactive transport in CWs, since it is considered more appropriate than CW2D for HF CWs(because CWM1 also models anaerobic processes). The influence of plants in wetlands has
been considered in this implementation, with the typical values reported for common reed fortranspiration rate and specific O2 release: 7.4 mm d-1 and 5 g m-2 d-1.
The first simulation results showed an excessive heterotrophic bacteria growth, especiallynear the inlet and the water table, with unrealistic values over 50000 mg kg-1 after 6 days
simulation. Some kinetic and stoichiometric parameters have been then modified with respect
to their original values in CWM1 to fix the heterotrophic bacteria development: maximum
aerobic growth rate, rate constant for lysis, saturation/inhibition coefficient, fractions
generated in biomass lysis and hydrolysis rate constant. After several simulations combining
different values for these parameters, a steady state was found. A 30 days simulation basedon this implementation shows better treatment efficiency than expected in the design: 66% of
COD removal and 39% of NH4 removal.
Key words: Constructed Wetlands, CWM1, HYDRUS wetland module, Tablas de Daimiel
National Park.

60

Predicting the Impact of Treated Wastewater on Groundwater
Recharge by Simulating Reactive Transport in the Unsaturated
Zone
Cristina Sandhu*, Thomas Fichtner, Issa Hasan, Peter-Wolfgang Gräber
Institute of Waste Management and Contaminated Sites, Dresden University of Technology, Germany*
Presenting author

According to the European Water Frame Directives, all EU member states shall protect,enhance and restore all bodies of groundwater, ensure a balance between abstraction andrecharge of groundwater, with the aim of achieving a good chemical and ecological status
until 2015. Since a significant part of groundwater recharge comes from wastewater,
important steps in collecting and disposing it have been taken by the member states. The
objective of this work is to use the soil natural treatment capacity to artificially recharge thegroundwater system using treated wastewater effluent from small-scale treatment plants,
thereby generating reserves for drinking water production and irrigation. For this purpose, the®
software tool PCSiWaPro developed at the Technical University Dresden, Institute of Waste
Management and Contaminated Site, and based on the SWMS2D model by SIMUNEK & VAN®
GENUCHTEN is further enhanced. PCSiWaPro offers an application-oriented interface to theSWMS2D model for the simulation requirements of specific real-life applications, in thiscase for wastewater effluent prognosis. To account for the relevant biogeochemical reactions®
in unsaturated zone PCSiWaPro is coupled to the geochemical software PHREEQC as well®
as to the groundwater model PCGEOFIM . The impact of leaching of biologically treatedwastewater can differ locally and depends on the hydrogeological and hydrologicalconditions. To forecast the physicochemical and microbiological processes and to detect theconcentration of infiltrated treated wastewater into unsaturated zone, a series of scenarios are®
modeled with the help of the software PCSiWaPro . To validate the enhanced simulation
software, a series of column experiments were conducted. The results of the modeling and lab
experiments have improved the understanding of the complex processes in unsaturated zone
and its relationship with groundwater zone. It is now possible to efficiently design andoperate small-scale wastewater treatment plants and also to predict groundwater recharge.
References
DIN 4261, Kleinkläranlagen, Teil 1, 2, 4, 11, and 31.
Gräber, P-W., Natürliche unterirdische Reinigung und Speicherung von Niederschlags- undgereinigtem Abwasser [Bericht]. - Damaskus, Syrien : Deutsch-Syrischer Kongress, 2007.
Gräber, P-W., et al, SiWaPro DSS – Beratungssystem zur Simulation von Prozessen derunterirdischen Zonen [Buchabschnitt] // Simulation in Umwelt- und Geowissenschaften /Buchverf. Wittmann Jochen und Müller Mike / Hrsg. Müller Mike. - Leipzig : Shaker Verlag,
ISBN 3-8322-5132-4, 2006.
Šimůnek, J., and M. Th. van Genuchten, The CHAIN-2D code for simulating the two-dimensional
movement of water, heat and multiple solutes in variably-saturated porous media version 1.1,
Research Report No. 136, US. Salinity Laboratory, USDA-ARS. Riverside, California, 1994.

61

Temporal Variations of Soil Hydraulic Properties and its Effecton Soil Water Simulations
Andreas Schwen1, Gernot Bodner2, and Willibald Loiskandl2
1Institute of Hydraulics and Rural Water Management, University of Natural Resources and Life Sciences(BOKU), Vienna, Austria; andreas.schwen@boku.ac.at2
Institute of Agronomy and Plant Breeding, University of Natural Resources and Life Sciences (BOKU), Vienna,
Austria

Simulating shallow soil water dynamics is challenging since this soil compartment is
temporally highly dynamic as response to climate and crop growth. For accurate simulations
the soil hydraulic properties have to be properly known. These properties may be subject totemporal changes as a response to both tillage and natural impact factors. The impact ofdifferent tillage techniques – conventional (CT), reduced (RT), and no-tillage (NT) – on thesoil hydraulic properties and their temporal dynamics were observed by repeated experiments
using tension infiltrometers. The experimental data was analyzed in terms of the nearsaturated hydraulic conductivity, inversely estimated parameters of the van
Genuchten/Mualem (VGM) model, and the water-conducting porosity. In a second step, theinversely estimated VGM parameters were incorporated into a soil water simulation. By
using temporally variable versus constant sets of VGM parameters, the impact on soil waterbalance components was tested. Simulated water dynamics were compared to observed datain terms of the soil water content and water storage in the near-surface soil profile (0-30 cm).
The results show that the near-saturated hydraulic conductivity was in the order CT > RT >NT, with larger treatment-induced differences where water flow is dominated by mesopores.
The VGM model parameter αVG was in the order CT < RT < NT, with high temporalvariations under CT and RT, whereas the parameter n was hardly affected. The results giveindirect evidence that NT leads to greater connectivity and smaller tortuosity of macropores,
possibly due to a better established soil structure and biological activity. Simulations withtemporally constant hydraulic parameters led to underestimations of soil water dynamics inwinter and early spring and overestimations during late spring and summer. The use of
temporally variable hydraulic parameters significantly improved simulation performance forall treatments, resulting in average relative errors below 13 %. Since simulation results
agreed with observed water dynamics in two seasons, the applicability of inversely estimatedhydraulic properties for soil water simulations was demonstrated. Our results also showedthat simulations addressing applied questions in agricultural water management can be
improved by time-variable hydraulic parameters. We currently work on the description of
temporal changes of the hydraulic properties and its underlying pore-size distribution on aphysically basis by accounting for swelling/shrinking cycles, crop root development and rootsize distribution.

62

New Developments in the HPx Reactive Transport Code:
Extensions to Two- and Three-Dimensional Flow and Transport
ProblemsJiří Šimůnek1 and Diederik Jacques2
1

Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA,jiri.simunek@ucr.edu
2
Performance Assessment, Belgian Nuclear Research Institute, Mol, Belgium, djacques@sckcen.be

A large number of interacting physical, chemical, and biological processes determine the fateof major cations and anions, contaminants (e.g., heavy metals, pesticides), and colloids in soil
systems. Also, modeling of soil CO2 sequestration requires consideration of water flow, heattransport, gas diffusion, and microbiological soil respiration processes. The HP1 simulator(Jacques et al., 2008) is a state-of-the-art model that was specifically developed to evaluate
these and similar processes in the unsaturated zone. HP1 couples the one-dimensionalvariably-saturated flow and transport model HYDRUS-1D (Šimůnek et al., 2008) with thegeneric geochemical model PHREEQC (Parkhurst and Appelo, 1999). Although HP1 is aversatile code for implementing different geochemical and transport conceptual models invariably-saturated porous media, one of its main limitations is that flow and transport isrestricted to one dimension. Therefore, PHREEQC has recently been coupled also with
HYDRUS (2D/3D) (Šimůnek et al., 2011) to handle flow and transport problems, which
require a higher dimensionality (HP2/3). Typical examples are flow and transport in soil
systems with tiled drains, or with drip and furrow irrigation, or in sloped layered orheterogeneous systems. A typical two-dimensional flow and transport problem illustrating thecapability of the HP2 simulator will be presented. The HP2/3 code uses the graphical userinterface of HYDRUS (2D/3D) for input and output processing, enabling definitions andfinite element discretization of very complex flow domains.

References

Jacques, D., J. Šimůnek, D. Mallants, and M. Th. van Genuchten, Coupling hydrological andchemical processes in the vadose zone: A case study on long term uranium migration following
mineral P-fertilization, Vadose Zone J., 7, 698-711, 2008.
Parkhurst, D. L., and C. A. J. Appelo, User’s guide to PHREEQC (version 2) – a computer programfor speciation, batch-reaction, one-dimensional transport and inverse geochemical calculations.
Water Resources Investigation, Report 99-4259, Denver, CO, USA, 1999.
Šimůnek, J., M. Šejna, H. Saito, M. Sakai, and M. Th. van Genuchten, The HYDRUS-1D software
package for simulating the one-dimensional movement of water, heat and multiple solutes invariably-saturated media, Version 4.08, HYDRUS Software Series 3, Department ofEnvironmental Sciences, University of California Riverside, Riverside, California, USA, 2008.
Šimůnek, J., M. Th. van Genuchten, and M. Šejna, The HYDRUS software package for simulating
two- and three dimensional movement of water, heat, and multiple solutes in variably-saturated
media, Technical Manual, Version 2.0, PC Progress, Prague, Czech Republic, 2011.

63Hillslope Application of the HYDRUS-Wetland Wetland
ModulePhilip J. Smethurst1 and Günter Langergraber2*
1

CSIRO Ecosystem Sciences, CRC for Forestry, and Landscape Logic CERF, Private Bag 12, Hobart TAS 7001,
Australia: Philip.Smethurst@csiro.au
2
Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life
Sciences Vienna (BOKU), Muthgasse 18, A-1190 Vienna, Austria, guenter.langergraber@boku.ac.at*presenting author

We applied HYDRUS-Wetland to the simulation of nitrate dynamics in a rural headwater
catchment (Smethurst et al., 2013), i.e., production in soil and its delivery to a stream via
surface and subsurface processes. A two-dimensional (hillslope) modeling approach wasused. Total flow was mathematically separated into quick- and slow-flow components, andthe latter was routed through the HYDRUS software with a nitrogen module designed forconstructed wetlands. The model accurately accounted for nitrate turnover, leading to the
hypotheses that denitrification was a minor flux (<3 kg N ha-1) compared to uptake (98-127
kg N ha-1), and that trees next to the stream would reduce denitrification if they lowered thewater table. This research provides an example of the measurement and modeling of nitrate
dynamics at a small-catchment scale with high spatial and temporal resolution. Moreinformation on the simulation results can be found in the publications (Smethurst et al., 2010,2013) and will be presented in the poster. In this abstract we summarize our experiences
regarding limitations that we faced when simulating a hillslope.
Several modeling limitations were identified that, if addressed, could improve the HYDRUS
wetland module applications in this context:
1. Overland flow was simulated by pre- and post-HYDRUS processing. Temporal
patterns of concentration in overland flow can be critical to accurately predicting
solute export. Note that although an overland flow module for HYDRUS is now
available, it does not consider overland solute transport yet.
2. Preferential flow was not possible while using the wetland module
3. Runoff as saturation excess is possible as a variable seepage zone, but rainfall was notcontinued on that portion of the slope. Hence, the water balance was altered.
4. Without a variable seepage zone, conditions that approach saturation near the surface
dramatically slow or stop the model due to mathematical difficulties.
5. Only one root type was specified, wherever they are placed in the simulation domain.
However, a two-root-type version of HYDRUS was being tested (Šimůnek pers.
comm.).
6. Nutrient uptake is simulated only as the mass flow component. This might not be aserious issue for nitrate, for which uptake in many systems is predominantly via
massflow. However, for nutrients that are taken up mainly via diffusive processes,
e.g. ammonium, phosphorus and potassium, simulated uptake is likely to be greatly
underestimated using HYDRUS. A version of HYDRUS is now available that
includes active and passive compensated uptake (Šimůnek and Hopmans 2009).
7. For hillslope applications of HYDRUS, with or without the wetland module, it would
be very useful to include outputs of pools and fluxes of both water and nitrate on a per
area basis.
8. The wetland module was probably over-specified for our application, e.g. organic andmicrobial pools are not required for simpler, useful soil N dynamics models.
64

9. Over-specification contributed to slow performance (7 hours for an annual simulation
using daily rainfall).
10. Denitrification doesn’t split N gasses into N2 and N2O.
11. We were unable to parameterise O diffusion into the soil in a way that maintained arealistic O profile.
12. Nitrification sensitivity to soil water content needs further testing.
These simulations were also data-limited:
1. Data were not available for a full definition of the spatial and temporal heterogeneityof the initial and boundary conditions for soil water and nitrate, including preferential
flow, saturated and unsaturated hydraulic conductivity, nitrogen turnover and root
distribution and activity.
2. The solute dynamics of overland flow are highly complex, because they depend on
poorly understood and poorly predicted interactions between overland flow andsurface soil.
3. In situ rates of denitrification are extremely difficult to measure in a way that captures
spatial and temporal variability.
Although these types of simulations can only be a gross simplification of reality, using a 2D
hillslope modeling approach as demonstrated would probably be useful also for many othertypes of applications.

ReferencesŠimůnek, J., and J. W. Hopmans, Modeling compensated root water and nutrient uptake, EcologicalModelling, 220, 505–521. doi:10.1016/j.ecolmodel.2008.11.004., 2009
Smethurst, P. J., K. C. Petrone, C. C. Baillie, D. Worledge, and G. Langergraber, Streamside
management zones for buffering streams on farms: Observations and nitrate modeling,
Landscape
Logic
Technical
ReportNo.
28,
Hobart,Australia,
31p.
(http://www.landscapelogicproducts.org.au/site/system/files/57/original/Tech_report_28_Stream
side_management_zones.pdf?1300224477), 2010.
Smethurst, P. J, K. Petrone, G. Langergraber, C. Baillie, and D. Worledge, Nitrate dynamics in a rural
headwater catchment: measurements and modeling, Hydrological Processes, (in press)(http://onlinelibrary.wiley.com/doi/10.1002/hyp.9709/pdf), 2013.

65

CO2 Fluxes to Aquifers Beneath Cropland:
Merging Measurements and Modeling
Eike M. Thaysen1, E. Laloy2, and D. Jacques2
1

Department of Chemical and Biochemical Engineering, Center for Ecosystems and Environmental
Sustainability, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark2

Performance Assessment Unit, SCK•CEN, B-2400 Mol, Belgium

The global flux of CO2 into the groundwater is <1 % of the diffusion flux of CO2 from soils
to the atmosphere. The potential for storage of dissolved inorganic carbon (DIC) in aquifers
was investigated as a strategy to mitigate increasing atmospheric CO2 concentrations. Data
from unplanted and planted soil mesocosms were modeled using the HP1 software packagewith the objective to identify the main drivers in DIC transport to aquifers.
Soil was collected from the A and C horizon of cropped alluvial sand and packed into
mesocosm columns above a bottom plate with an embedded suction disc. The hydraulicconnection between the C horizon and the suction disc was optimized by means of a thinlayer of quarts flour and a layer of quartz flour mixed with C horizon. For the modeling, theselayers and the suction disc were regarded as one unit. Inverse modeling of the water flow was
carried out by applying a coupling of the Monte Carlo algorithm and HYDRUS-1D to search
for the global minima for the retention parameters of all three materials. The retention
parameters were then inserted into HP1 for forward modeling of water contents. Equations
for CO2 production by microorganisms and roots from the SOILCO2 model (Simunek andSuarez 1993) were programmed into HP1 using only few modifications.
Preliminary results showed the model simulated water content throughout depth and timequite well, in particular in unplanted mesocosms. Due to a pressure drop across the suction
disc and the lack of retention parameters for the quartz flour/C horizon layer, outflow wassimulated less accurately than water content. The model provided a good fit to measured DIC
efflux, CO2 partial pressure (pCO2) and alkalinity in both unplanted and planted mesocosms.
However, the CO2 efflux from the mesocosm top was significantly underestimated in
unplanted mesocosms.
Data will be presented to show that DIC storage in aquifers is controlled by drainage volume,
pH and pCO2. If nutrient availability is not decreased, lime amendment could be a way toincrease natural (plant-mediated) CO2 storage in aquifers.

66

Fate and Transport of Nitrogen in Soils Based on a Coupled
Nitrogen-Carbon Cycling Model Using the HP1 CodeNobuo Toride and DaiWen Chen
Graduate School of Bioresources, Mie University, 1515 Kurimamachiya, Tsu 514-8507, Japan

In order to predict fate and transport of nitrogen as a result of decomposition of organic
matters in soils, we implemented a coupled carbon and nitrogen cycling model based on
Johnsson (1987) and the LEACHM code (Hutson, 2005) using the PHREEQC program. Twotypes of principal organic matter were defined: a first cycling pool for litter and a slow
cycling pool for stabilized humus. Separate litter pools were used for organic matters having
a different decay rate and carbon-to-nitrogen (C/N) ratio such as plant residue and manure.
Decay processes from the organic-C to biomass-C, humus-C, and carbon dioxide were
described with a first-order kinetic. The biomass-C was recycled into the decomposable litter
pool, forming the litter-decomposer complex. Decompositions from the organic-N tobiomass-N and humus-N were related to the carbon cycle using the C/N rations of the organic
matter, biomass and humus. Mineralization of ammonium from the organic matter andimmobilization of ammonium to the organic matter were determined based on the available N
in the litter pool and the N demand for the formation of biomass and humus. Nitrogentransformations were also described with first-order chain reactions for ammonification fromuera, nitrification from ammonium, and denitrification from nitrate.
All the first-order kinetics equations for the carbon and nitrogen cycles described in
PHREEQC were linked with water flow, root water uptake, solute transport, and passive root
nutrient uptake in HYDRUS-1D using the HP1 code. Various nitrogen transport scenarios
were demonstrated for the application of organic matters to a variable-saturated soil under anonisothermal condition.

67

Simulation of Metal Transport in the Soil and into the Willows
Using the HYDRUS Program
Lukáš Trakal*, Radka Kodešová, and Michael Komárek
Faculty of Environmental Sciences, Czech University of Life Sciences Prague,Kamýcká 129, Praha 6 – Suchdol, Czech Republic, 165 21*
Presenting author: trakal@fzp.czu.cz

The main aim of this study was to validate the HYDRUS program for the simulation of Cd,
Cu, Pb and Zn transport within a soil column and for their willow uptake. A simulation of
metal transport and accumulation into the willow was implemented using the HYDRUS2D/3D code (version 1.11). Two scenarios of the column experiment were compared: filled
by contaminated soil (C) and filled by contaminated soil with planted willow (V). Seeping
water, soil water content and actual transpiration were measured over the period of time.
Metal contents in soil water and willows were also analysed. The single-porosity model(applied for isotropic soil media) was sufficient for scenario C. The single-porosity (applied
for anisotropic soil media) and dual-porosity models (characterizing non-equilibrium waterflow) were explored in scenario V due to vertical roots modification of the soil structure.
Simulated cumulative water and metal (Cd, Cu, Pb and Zn) outflow from the soil column inscenario C moderately approximated the measured data, when the isotropic single porosity
system was used. On the other hand, for scenario V the best correspondence of modelled tothe measured data was observed in case of dual-porosity model consideration. Additionally,measured cumulative Cd and Zn root uptake showed a 20- and 10-fold increased
accumulation respectively in comparison with the model, due to the accumulation not only
from the water soluble fraction (used for HYDRUS calculations). The modelled Pb uptake
was modified by reducing the maximum value of the root uptake concentration croot due to avery low accumulation and relatively high water soluble concentration. Measured andmodelled Cu uptake was similar. No significant impact of anisotropy or dual-porosity soil
media consideration has been revealed for this case. In summary, the HYDRUS-2D/3D code(version 1.11) was usable for modelling of Cd, Cu, Pb and Zn transport and their willow
uptake. Additionally, consideration of dual porosity (also anisotropy) soil media was suitable
for the experiment with roots presence in the soil.
Keywords: Soil column; HYDRUS-2D/3D code; Numerical optimization; Anisotropy anddual-porosity soil media; Metal transport; Root metal uptake
Reference
Trakal, L., R. Kodešová, and M. Komárek, Modelling of Cd, Cu, Pb and Zn transport in metal
contaminated soil and their uptake by willow (Salix × smithiana) using HYDRUS-2D program,
Plant and Soil, DOI 10.1007/s11104-012-1426-x, in print, 2013.

68Investigation of Recharge Fluxes under Different Land-Useswith Calibrated Models to Transient Deep Vadose Zone Data
Tuvia Turkeltaub1,2*, O. Dahan2, and D. Kurtzman1
1

Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization,
POB 6, Bet Dagan 50250, Israel
2
Dept. of Hydrology & Microbiology, Zuckerberg Institute for Water Research, Blaustein Institutes for Desert
Research, Ben Gurion University of the Negev, Sde Boker Campus, Negev 84990, Israel*
Presenting author: tuviat@post.bgu.ac.il

Recharge component plays a crucial role in determined groundwater quantity and quality
assessments. Development of recharge estimation and prediction tool contributes toimproving the management of groundwater resources. Vadose zone monitoring systems(VMS) were implemented under crop-field, grapefruit orchard and natural sand-dune. The
VMSs have enabled the acquisition of continuous information on both the temporal variationof water content and the chemical composition of the sediments pore water at multiple depths
in the deep vadose zones (~ 20 m). Vertical unsaturated flow models were calibrated to thetransient data. Subsequently, the calibrated models provided an opportunity to investigate thetemporal characteristics of groundwater recharge through long periods with variable rain
patterns under the different sites. The models simulations resulted in low average recharge
flux of 134 mm yr-1 under the orchard, 206 mm yr-1 under the crop-field and 341 mm yr-1
under the natural sand-dune which is 10%, 40% and 66% of the annual surface-water inputs,
respectively. In addition, the calibrated models were implemented for examining the impacts
on recharge quantity and quality due to climate change and land use change scenarios. A
climate change scenario was performed with the calibrated model of the crop-field andrevealed that reduction of 19% in total rain amount led to a drop of 46% in average recharge.
Simulations of conversion of the natural sand dune to a commercial tomato greenhouse
displayed a decrease in average recharge (from 341 to 150 mm yr-1).

69

Microtopographic Enhancement of Soil-Based Wastewater
Treatment
Sean R. Tyrrell1*, Tim Hess1, Sean F. Tyrrel1 and David Knaggs2
1

School of Applied Sciences, Cranfield University, Bedfordshire, United Kingdom.
2
Albion Water ltd. Harpenden. Hertfordshire, United Kingdom*
Presenting Autho:r s.r.tyrrell@cranfield.ac.uk

Tertiary treatment of wastewater has become increasingly important. One option for tertiary
treatment is the use of soil-based treatment systems. These may simply be vegetated plots
irrigated with secondary treated wastewater. This enables the water quality regulatingprocesses found within soils to be exploited.
There is evidence (Wolf et al., 2011) to suggest that enhancing the microtopography (MT) ofa soil-based treatment system may influence nutrient cycling. For example, an increase indenitrification potential may occur within the depressions of a microtopographicallyenhanced system as a result of: a lower redox potential; an accumulation of organic matter;and a larger population of denitrifying microorganisms. It may also be the case thatvegetation species richness can be increased with enhanced MT (Moser et al., 2007).
In order to test the application of these theories to soil-based treatment of wastewater andevaluate the potential benefits and drawbacks, a field trial has been established at a treatment
works in Hampshire, UK. The trial consists of several grass plots, each irrigated withsecondary treated wastewater from the adjacent wastewater works. Excluding the control
plots, the surface MT of each plot has been enhanced by the introduction of ridge-andfurrows. The MT of each plot has been characterised using various indices; subsurface soil
water is monitored for NH4, NO3, PO4, total nitrogen and total phosphorus concentrations;soil moisture and redox potentials are monitored over the course of irrigation cycles; and soil
samples are periodically analysed for total and extractable nitrogen and phosphorus, total
carbon, organic matter, pH, electrical conductivity and sodium adsorption ratio (SAR).
To extrapolate the findings of this study beyond the limitations of a field trial, the HYDRUS2D program with the Wetland Module will be employed. The hydraulic and biogeochemical
processes within the soils of the trial plots will be modeled. Once validated, parameters
within the model will be changed to allow hypothetical modeling of soil-based treatment
systems for a number of soil types, over a range of microtopographic values and irrigation
loading rates. The results of this modeling may then be used to: optimise microtopographic
design of soil-based treatment systems; estimate removal rates; and inform risk assessments
for their use.
References
Moser, K., C. Ahn, and G. Noe, Characterization of microtopography and its influence on vegetation
patterns in created wetlands, Wetlands, 27(4), 1081-1097, 2007..
Wolf, K. L., C. Ahn, and G. B. Noe, Microtopography enhances nitrogen cycling and removal increated mitigation wetlands, Ecological Engineering, 37(9), pp. 1398, 2011.

70

Using HYDRUS and HP1 Codes to Study Possible Impacts of
Irrigation with Non-Conventional Water Under Two Different
Vadose Zone Monitoring Strategies
Javier Valdes-Abellan1, Joaquin Jiménez-Martínez2, and Lucila Candela3
1

Dept. of Civil Engineering, University of Alicante, Alicante, Spain, presenting author: javier.valdes@ua.es
2
Geosciences Rennes, UMR 6118 CNRS, Université de Rennes I. Rennes, France. joaquin.jimenezmartinez@univ-rennes1.fr
3
Dept. of Geotechnical Engineering and Geoscience, UPC-Barcelona, Jordi Girona 1-3, 08034 Barcelona,
Spain, lucila.candela@upc.es

South-east of Spain is a region characterized by low annual rainfall (200-300mm) and high potential
evapotranspiration rates (~1200 mm/year). Joint with that situation, an endemic scarcity of water
resources is presented, and the potential development of the region is hindered by this lack of water.
In the last years, desalination of both brackish groundwater and seawater has become a new andimportant water source; firstly to satisfy urban demands and lately for agricultural purposes too. The
effects of non-conventional water use on the vadose zone might produce impacts in porous media
which could lead to changes in soil hydraulic properties, among others. In this context, monitoring
vadose zone water dynamics is a key aspect to study those possible impacts and to manage the scarcewater resources. According to the available literature, different monitoring systems have been carriedout independently, however less attention has received comparative studies between different
techniques.
A 9x5 m2 experimental plot was set with automatic and non-automatic sensors to control θ and h up to
1.5m depth. The automatic system composed of five 5TE sensors (Decagon Devices®) installed at 20,
40, 60, 90 and 120 cm for θ measurements and one MPS1 sensor (Decagon Devices®) at 60 cm
depth for h. Installation took place laterally in a 40-50 cm length hole bored in a side of a trench thatwas excavated. All automatic sensors hourly recorded and stored in a data-logger. The non-automatic
system consisted of ten Jet Fill tensiometers at 30, 45, 60, 90 and 120 cm (Soil Moisture®) and apolycarbonate access tube of 44 mm (i.d) for soil moisture measurements with a TRIME FM TDR
portable probe (IMKO®). Vertical installation was carefully performed; measurements with thissystem were manual, twice a week for θ and three times per week for h. Boundary conditions were
controlled with a volume-meter and with a meteorological station. ET was modelled with PenmanMonteith equation. A complete soil characterization was carried out in laboratory to determine grain
size distribution, bulk density, gravimetric water content and water retention curves. Unsaturated soil
hydraulic parameters were model-fitted through SWRC-fit code and ROSETTA based on soil textural
fractions when laboratory data were no available.
Simulation of water flow using automatic and non-automatic date was carried out by HYDRUS-1D. A
good agreement from collected automatic and non-automatic data and modelled results can berecognized. General trend was captured, except for the outlier values as expected. Slightly differenceswere found between hydraulic properties obtained from laboratory determinations, and from inverse
modelling from the two approaches. Differences up to 14% of flux through the lower boundary weredetected between the two strategies. According to results, automatic sensors were more accurate andso more appropriated to detect subtle changes of soil hydraulic properties. Nevertheless, if the aim of
the research is to control the general trend of water dynamics, no significant differences wereobserved between the two systems. Finally geochemical processes simulation is being carried out with
HYDRUS and PHREEQC (HP1).

71

Simulation of Heavy Metal Transport in Unsaturated Soil: Useof Scale Factors to Quantify Variable Sorption Isotherms
Han Xiao1*, Jürgen Böttcher1, and Jiří Šimůnek2
1

Institute of Soil Science, Leibniz University of Hannover, Germany
Dept. of Environmental Sciences, Univ. of California, Riverside, USA*
Presenting author

2

Heavy metals are toxic soil pollutants. They are stored in soils by sorption processes. At asmall scale (soil sample) the sorption process can be observed and quantified by sorption
isotherms. However, environmental issues have to be treated at large scales (e.g., a field
scale). At the field scale heavy metal sorption isotherms are mostly highly variable in space.
This variability makes representative quantification of the sorption process (e.g., for soil
protection and management of soil functions) and its consideration in reactive transportmodeling (e.g., for groundwater protection) hard. Many transport simulation studies therefore
treat the soil as homogeneous to avoid complex datasets and calculations. In the present study
we use a recently developed method - calculation of scale factors - to quantify the spatial
variability of heavy metal sorption in soils at the field scale. This method reduces the wide
spread of the sorption isotherms into a single average relation, while at the same timepreserving their variation through the use of the scale factors. We investigated the spatial
variability of heavy metal sorption isotherms for an agricultural field on a Luvisol developed
in loess material near Hannover, Germany. 50 samples were taken from each A and B
horizons along a 250 m transect. Sorption isotherms for heavy metals and soil properties as
pH, CEC, and texture were measured, and scale factors were calculated. The heavy metaltransport is simulated with HYDRUS with a unique reference sorption isotherm (derived
from the scale procedure or from the mixed soil sample, respectively). Spatial variability ofsorption at every sampling point is represented using a scale factor, which was directly
calculated (scaling procedure), or indirectly estimated (transferred) by regression models
from another heavy metal or from soil properties, respectively.
In our contribution we will present results on (1) a numerical simulation of the heavy metaltransport in unsaturated soil, considering the sorption variability by directly calculated andindirectly estimated scale factors, and (2) a comparison with the transport behavior simulatedwith the sorption isotherms measured at each sampling point.

72

Comparison of Ion (Salt) Movement in the Soil Profile Subject
to Leaching with the HYDRUS-1D Simulations
Engin Yurtseven1, Jiří Šimůnek2, S.Avcı3, and H. S. Öztürk4
Department of Farm Structures and Irrigation, Faculty of Agriculture, University of Ankara, 06110 Dışkapı,
Ankara, Turkey, yurtsev@ankara.edu.tr
2
Department of Environmental Sciences, University of California, Riverside, CA 92521, USA,jiri.simunek@ucr.edu
3
Department of Farm Structures and Irrigation, Faculty of Agriculture, University of Ankara, 06110 Dışkapı,
Ankara, Turkey, sertan.avci@gmail.com
4
Department of Soil Science, Faculty of Agriculture, University of Ankara, 06110 Dışkapı, Ankara, Turkey,
H.Sabri.Ozturk@agri.ankara.edu.tr
1

There is an increasing trend to require more efficient use of water resources, both in urban
and rural environments. Drainage water can be beneficially reused for agricultural irrigation
before being discarded after its use. The quality of the discarded water depends on manyfactors, including the irrigation water quality and irrigation management, i.e., the salt content
and the quantity of irrigation water to be applied during the vegetation period.
A variety of analytical and numerical models have been developed during the past several
decades to predict water and solute transfer processes between the soil surface andgroundwater table. The HYDRUS-1D software package is one of such models simulatingwater movement and solute transport in the soil. In this study, we use HYDRUS-1D toanalyze water flow and solute transport in soil columns 115 cm long and with a diameter of
40 cm, irrigated with waters of different quality at different leaching rates. Three different
irrigation water salinities (0.25, 1.5, and 3.0 dS/m) and four leaching fractions (10, 20, 35,
and 50% more water than required) were used in a fully randomized factorial design
experiment. Each experiment was run in three replicates, resulting in the total of 36
lysimeters. Following every irrigation, the drainage waters were collected using the plastic
pods situated under each lysimeter. Water fluxes, concentrations of individual ions (Na+, K+,
Ca2+, Mg2+, Cl-, SO42-, CO32-, and HCO3-), EC of the soil solution, and SAR were monitored
at five depths (20, 40, 60, 80, and 100 cm) in all soil columns. The soil used for theexperiments was SCL. In all leaching experiments, the salts accumulated in the profile due toirrigation with salty water could be leached out from the soil. More soluble salts, such as Cl-,
leached more easily than the less soluble salts, such as CO3-2 and HCO3-.
The results showed that HYDRUS-1D was able to successfully simulate soil water salinity
and movement of salts (ions) in the soil profile. The RMSE values for all treatments and for
different soil depths varied for EC (dS/m) between 2.50-5.21 and 1.36-4.38 and for SAR
between 1.26-3.18 and 1.45-1.88 during the first (2010) and second (2011) experimental
year, respectively. The RMSE values for ions Ca2+, Mg2+, Na+, K+, SO42-, and Cl- were
between 0.50-24.14 in 2010, and 0.28-14.25 in 2011. HYDRUS-1D proved to be a powerfultool for analyzing solute concentrations related to overall soil salinity.

73

4th International Conference HYDRUS Software Applications to Subsurface Flow andContaminant Transport Problems
Edited by Jirka Šimůnek and Radka Kodešová
Czech University of Life Sciences Prague
Faculty of Agrobiology, Food and Natural Resources
Department of Soil Science and Soil Protection
Czech RepublicBook of Abstracts
100
74 pagesFirst Printing
2013
ISBN: 978-80-213-2368-1
74