Naslov
Simulating Subsurface Lateral Flow in Eroded Soils with Contrasting Horizon Properties Using HYDRUS-2D

Autori
Filipović, Vilim ; Gerke, Horst H. ; Filipović, Lana ; Sommer, Michael

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
HYDRUS Software Applications to Subsurface Flow and Contaminant Transport Problems / Jirka Šimůnek/Radka Kodešová - Prag, 2017, 21-21

ISBN
978-80-213-2749-8

Skup
5th International Conference HYDRUS Software Applications to Subsurface Flow and Contaminant Transport Problems

Mjesto i datum
Prag, Češka Republika, 30.03.2017. - 31.03.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Subsurface preferential flow, Eroded soils, HYDRUS-2D

Sažetak
Subsurface lateral flow can be important pathway for water flow and consequently transport of solutes (e.g., nutrients, pesticides, trace metals, antibiotics) in soil. This type of preferential flow is generally initiated when water percolates vertically through an unsaturated soil profile, meets an impeding layer of soil on hillslope, and is diverted laterally downslope when approaching saturated conditions. Such conditions can be found in the hummocky arable soil landscape where tillage and water erosion has shaped the surface topography and modified the soil horizons above a relatively dense glacial till. Objective of this work was to explore subsurface lateral flow occurrence using explicit soil profile information in combination with 2D modeling performed using HYDRUS software. The field data was collected from CarboZALF-D experimental trial. The soil profile was equipped with FDR probes and tensiometers at different depth (i.e., 10, 20, 40, 80, 130 and 200 cm) and additional climatic data collected daily at the site. Modeling was performed for a period from October 2009 till August 2014 for a 500 cm x 200 cm vertical cross-section using field morphological and profile layering descriptions with crop rotation included. First forward simulations using laboratory measured hydraulic parameters derived from 300 cm3 soil cores did not satisfactorily describe the observed field water dynamics. Inverse modeling and optimization was then performed on shorter periods to improve the model performance. With the improved parameter sets from the fitting, two daily rainfall events with same large intensity (74.6 mm/day) were evaluated for reproducing lateral subsurface flow more closely. These events led to saturated conditions in the profile above the C horizon, which had a sloping upper boundary and relatively low hydraulic conductivity. Pressure head and velocity vectors distribution in the soil profile efficiently captured the extent of subsurface lateral flow. After isolating these events with lateral flow occurrence, bromide tracer was inserted into the model just above the C horizon. This modeling exercise showed effects of subsurface lateral flow on solute flow pathways, which was evidently shifted in the sloping direction and distribution of tracer in the whole soil profile. Although the sloping landscape was qualitatively known for the lateral subsurface flow, the simulations still revealed relatively little tendency towards lateral flow during the long simulation period. This indicates that processes such as non-equilibrium type of preferential flow and the small scale layering with potential anisotropy of the hydraulic conductivity should be explored more precisely.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

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