TY  - JOUR
AU  - Rahman, M.
AU  - Rosolem, R.
AU  - Kollet, Stefan
AU  - Wagener, T.
TI  - Towards a computationally efficient free-surface groundwater flow boundary condition for large-scale hydrological modelling
JO  - Advances in water resources
VL  - 123
SN  - 0309-1708
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - FZJ-2019-00356
SP  - 225 - 233
PY  - 2019
AB  - Shallow groundwater is a critical component of the terrestrial water cycle. It sustains baseflow in rivers, supplies root zones with soil moisture during dry periods, and directly influences the land-atmosphere exchange processes. Nonetheless, the integration of groundwater into large-scale hydrological models remains challenging. The most detailed way of representing groundwater dynamics is to incorporate three-dimensional, variably saturated flow processes in the subsurface representation of hydrological models. However, such detailed modelling is still a challenge for global hydrological applications, mainly due to its high computational demand. In this study, a free-surface boundary condition called the Groundwater Flow Boundary (GFB) is developed to represent groundwater dynamics in a more computationally-efficient manner than the full three-dimensional models do. We evaluate GFB using two synthetic test cases, namely an infiltration experiment and a tilted-v catchment, which focus on groundwater recharge and discharge processes, respectively. The simulation results from GFB are compared with a three-dimensional groundwater flow model and with an over-simplified approach using a free-drainage lower boundary condition to assess the impact of our assumptions on model results. We demonstrate that GFB is computationally more efficient compared to the three-dimensional model with limited loss in model performance when simulating infiltration and runoff dynamics.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000453714000016
DO  - DOI:10.1016/j.advwatres.2018.11.015
UR  - https://juser.fz-juelich.de/record/859504
ER  -