In: Journal of Hydrology and Hydromechanics, vol. 63, no. 1
Martin Wegehenkel - Horst H. Gerke
Details:
Year, pages: 2015, 82 - 92
Keywords:
Weighable lysimeters; Modelling; Hydrus-1D; Drainage; Boundary condition.
Original source URL: http://www.ih.savba.sk/jhh
About article:
Weighing lysimeters can be used for studying the soil water balance and to analyse evapotranspiration (ET).
However, not clear was the impact of the bottom boundary condition on lysimeter results and soil water movement. The
objective was to analyse bottom boundary effects on the soil water balance. This analysis was carried out for lysimeters
filled with fine- and coarse-textured soil monoliths by comparing simulated and measured data for lysimeters with a
higher and a lower water table. The eight weighable lysimeters had a 1 m2 grass-covered surface and a depth of 1.5 m.
The lysimeters contained four intact monoliths extracted from a sandy soil and four from a soil with a silty-clay texture.
For two lysimeters of each soil, constant water tables were imposed at 135 cm and 210 cm depths. Evapotranspiration,
change in soil water storage, and groundwater recharge were simulated for a 3-year period (1996 to 1998) using the
Hydrus-1D software. Input data consisted of measured weather data and crop model-based simulated evaporation and
transpiration. Snow cover and heat transport were simulated based on measured soil temperatures. Soil hydraulic
parameter sets were estimated (i) from soil core data and (ii) based on texture data using ROSETTA pedotransfer
approach. Simulated and measured outflow rates from the sandy soil matched for both parameter sets. For the sand
lysimeters with the higher water table, only fast peak flow events observed on May 4, 1996 were not simulated
adequately mainly because of differences between simulated and measured soil water storage caused by ET-induced soil
water storage depletion. For the silty-clay soil, the simulations using the soil hydraulic parameters from retention data (i)
were matching the lysimeter data except for the observed peak flows on May, 4, 1996, which here probably resulted
from preferential flow. The higher water table at the lysimeter bottom resulted in higher drainage in comparison with the
lysimeters with the lower water table. This increase was smaller for the finer-textured soil as compared to the coarser
soil.
How to cite:
ISO 690:
Wegehenkel, M., Gerke, H. 2015. Water table effects on measured and simulated fluxes in weighing lysimeters
for differently-textured soils. In Journal of Hydrology and Hydromechanics, vol. 63, no.1, pp. 82-92. 0042-790X (until 2019) .
APA:
Wegehenkel, M., Gerke, H. (2015). Water table effects on measured and simulated fluxes in weighing lysimeters
for differently-textured soils. Journal of Hydrology and Hydromechanics, 63(1), 82-92. 0042-790X (until 2019) .