Development of a couplinginterface for Hydrus-1D andMODFLOW 2005
Mateusz Pawłowicz1, Bartosz Baliś1, Adam Szymkiewicz2, Jirka Šimůnek3
1

AGH University of Science and Technology, PolandGdańsk University of Technology, Poland
3
University of California - Riverside, USA2

Why coupling ?
1D vadose zone models(soil proﬁles representativefor larger domains)

3D groundwater models(saturated ﬂow)

Why coupling ?
●improved representation of vadose zone processes in groundwater models○●

e.g. effects climate and land use change

usually less complex and more computationally eﬃcient than full 3Dsurface-subsurface models●

take advantage of well-developed codes for vadose and groundwater ﬂow●

vadose zone models can be applied only on a part of the domain○e.g. MAR applications

Previous work●

Hydrus package for MODFLOW 2000 (HPM)(Seo et al. 2007, Twarakavi et al. 2008)●

Hydrus package for MODFLOW 2005/OWHM (Leterme et al. 2013, 2015,Szymkiewicz et al. 2018, Beegum et al. 2018a)●

solute transport with Hydrus 1D and MT3D (Beegum et al. 2018b)●

HPM exists as a separate program - merged code of Hydrus-1D and MODFLOW●

diﬃcult maintenance and interoperability

New approach: external coupling●Python scripts using existing libraries (FloPy, PHydrus)●models can be prepared independently using the original Hydrus-1D andvarious MODFLOW GUIs●

workﬂow can be easily adapted to new versions of MODFLOW and othervadose zone models●

different coupling modes●

user interface

One-way coupling mode●

simulation with each Hydrus proﬁleis carried out with constant watertable position at the bottom●recharge ﬂux estimated fromHydrus is passed to MODFLOWTwo-way coupling mode●

after each MODFLOW time step theposition of water table in Hydrus
proﬁles is updated●

to avoid spurious oscillations waterpressure must be adjusted in a larger
zone above the bottom of the proﬁle(Beegum et al. 2018a)

Results for constant recharge rate

constant bottom pressure, bottom pressure updated, pressure in the lower zone updated

Interface overview
●
●
●
●
●
●

allows for coupling Hydrus-1D and Modﬂow 2005 in form of “Projects” toincrease simulation quality
Hydrus simulations run in parallel
Hydrus models’ results are applied to zones which can be deﬁned using
ZoneBudget or taken from .rch ﬁle in the Modﬂow Model
Hydrus input ﬁles can be overwritten with SWAT format .csv weather ﬁlesdeveloped as web application to avoid problems related deployment (noinstallation required, only a web browser needed)
3 deployments: desktop, Docker, Cloud (Kubernetes)

Interface overview - 3 deployments

Desktop●●●●an executable, which
creates local serverthat can be accessusing web browser
projects are stored
locallyrequires user to haveboth Hydrus-1D andModﬂow 2005
installed
launches simulations
as OS subprocesses

Docker●●●●a Docker image with all
the requirements - only
Docker engine isrequired to launch theapplication
projects are stored
locally using a volume
required to compile
Hydrus-1D under Linuxkernel (which waspossible thanks toprof. Jiri)
launches simulations
as other Docker
containers (all-in-one)

Cloud (Kubernetes)
●
●
●
●

●
●

Kubernetes manifests
leveraging Docker images
microservice architecture
projects are stored locallyusing cloud storage
uses the same Docker
images for Hydrus andModﬂow simulationeasily scalable
available under URL link(however accounts system
is yet to be implemented)

Video demoConclusions●an interface for loose coupling between Hydrus-1D and Modﬂow has beencreated and deployed in three versions●

currently only Hydrus-1D and Modﬂow 2005 are supported, but have beentested and proved to work properly●

further developments are planned (update to MODFLOW 6, solutetransport, new coupling mode ensuring mass conservation)

Acknowledgements
This work has been carried out as part of project WATERLINE, supported by
the National Science Centre, Poland (2020/02/Y/ST10/00065), under
CHIST-ERA IV programme, which has received funding from the EU Horizon
2020 Research and Innovation Programme, under Grant Agreement no857925.