Lateral saturated hydraulic conductivity of soil horizons evaluated in large-volume soil monoliths

Mario Pirastru*, Roberto Marrosu, Simone Di Prima, Saskia Keesstra, Filippo Giadrossich, Marcello Niedda

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

Evaluating the lateral saturated hydraulic conductivity, Ks,l, of soil horizons is crucial for understanding and modelling the subsurface flow dynamics in many shallow hill soils. A Ks,l measurement method should be able to catch the effects of soil heterogeneities governing hydrological processes at the scale of interest, in order to yield Ks,l representative values over large spatial scales. This study aims to develop a field technique to determine spatially representative Ks,l values of soil horizons of an experimental hillslope. Drainage experiments were performed on soil monoliths of about 0.12 m3 volume, encased in situ with polyurethane foam. Median Ks,l of 2450 mm·h-1 and 552 mm·h-1 were estimated in the A and B horizon, respectively. In the upper part of the B horizon, the median Ks,l was 490 mm·h-1, whereas it mostly halved near the underlying restricting layer. The decline of Ks,l values with depth was consistent with the water-table dynamics observed at the same site in previous studies. Moreover, the Ks,l from the monoliths were in line with large spatial-scale Ks,l values reported from the hillslope in a prior investigation based on drain data analysis. This indicated that the large-scale hydrological effects of the macropore network were well represented in the investigated soil blocks. Our findings suggest that performing drainage experiments on large-volume monoliths is a promising method for characterizing lateral conductivities over large spatial scales. This information could improve our understanding of hydrological processes and can be used to parameterize runoff-generation models at hillslope and catchment scale.
Original languageEnglish
Article number862
JournalWater (Switzerland)
Volume9
Issue number11
DOIs
Publication statusPublished - 1 Nov 2017

Keywords

  • Hillslope
  • Macropore network
  • Polyurethane foam
  • Soil block
  • Spatial scale
  • Subsurface flow

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