Responsible: DEEP & LEHNA – G. Lipeme Kouyi & L. Lassabatere
Participants: DEEP, LEHNA, UoM & University of Palermo
The main objective of this task is to develop a user-friendly industry-focused numerical tool named “INFILTRON-mod” to simulate preferential flow at the infiltrometer scale. A novel multi-permeability approach will be developed to account for preferential flow and its effect on infiltration & filtration functions. The concept implemented relates to the multi-permeability approach combined with the mass balance approach, accounting for key dynamics related to each zone (fast flow and slower flow, referred to as ‘matrix flow’) with specific permeability and transfer properties, along with hydric and hydraulic loadings. The ability to model complex systems in a detailed way, while also giving the degree of uncertainty, will provide great assistance to designers and decision-makers. INFILTRON-mod will be implemented in an original numerical platform named Hydrobox (a powerful hydrological platform that supports the implementation of CANOE software – www.canoe-hydro.com).
Description of work
The model will be built by implementation of the modified multi permeability (van Genuchten – Mualem) approach that represents global physically-based laws previously tested at smaller scales and then validated against experimental data from tasks 1 and 3. The main goal of this task concerns the definition of an appropriate upscaling method for defining a model based on simple laws and which are usable at large scales (scales of the infiltrometer and work scales). The first part requires the analysis of physically based macroscopic laws tested against data from Tasks 1 and 3. Then, these laws will be implemented in a simplified way, based on the multi-permeability approach, to consider flow variability due to lithological heterogeneity, and variability of water content and hydric conditions. Preliminary tests have been successfully done by the partners in the case of vertical flow constructed wetlands . The comparison of modelled quantities obtained with INFILTRON-mod against those derived from tools based on more complex and detailed approaches will give the required level of accuracy of the integrated and simplified model. These comparisons will also allow the optimization of efficient parameters for several case studies: water infiltration, water redistribution, homogeneous profile versus heterogeneous profile, etc. INFILTRON-mod will also be validated against experimental results derived from the Little Stringybark Creek research program , in collaboration with Pr. Tim Fletcher (UoM). This work will allow to define a methodology of use of INFILTRON-mod data across scales, from the meter scale to the work scale and up to the catchment scale. The comparison of the two approaches; the complex and the integrated model, will demonstrate the level of accuracy and savings in calculation time. The last part of the task will consist in programming a user-friendly graphical user interface. The INFILTRON-mod modelling platform will thus constitute a numerical tool for the quantification of preferential flow and its effects on infiltration & filtration functions at the scale of infiltrometer with also information valuable for larger scales.
Role of participants
DEEP will oversee the upscaling procedure and mathematical algorithm of INFILTRON-mod. For this purpose, IFSTTAR, LEHNA and DEEP will combine their efforts for modelling experimental data from column and field experiments with the support of University of Palermo. DEEP will also be responsible for development of the graphical user interface and with the support of ALISON (www.alison-envir.com). The validation of INFILTRON against experimental data obtained at larger scales from Little Stringybark Creek programme will be carried out with the support of UoM and Monash.
Risks and contingency plan
This task depends on the progress of tasks 1 and 3, essentially. There remains a strong need to develop a simplified tool even if macroscopic laws may not be totally appropriate for a detailed description of preferential flow and pollutant transfer. In this case, the most robust approach will help representing the “worst case” scenario in terms of impact on preferential flow on pollutant retention and migration. This approach will allow the calculation of the worst situation for the infiltration and filtration functions of urban soils. The second challenge lies also in the development and the use of INFILTRON-mod results across scales. The scientific stay of G. Lipeme Kouyi in T. Fletcher’s team is a great opportunity to benefit from the data resources of the Little Stringybark Creek research program, which can help address the complex issue of scales.
Deliverables / milestones
- D4.1 User-friendly numerical tool “INFILTRON” for modelling preferential flows and transfers
- M4.1 Development of modelling strategy for experimental data
- M4.2 Design of an inversion algorithm for preferential flow & nano-tracers & bacteria transfer
- M4.3 Assessment of INFILTRON-mod on case study
- M4.4 Assessment of INFILTRON-mod on experimental data
- M4.5 Development of the GUI
- M4.6 Application to larger scales (e.g. catchment scales).