Large-scale lateral saturated soil hydraulic conductivity as metric for
the connectivity of the subsurface flow paths at hillslope scale
- Mario Pirastru,
- Massimo Iovino,
- Hassan Awada,
- Roberto Marrosu,
- Simone Di Prima,
- F. Giadrossich
Abstract
Lateral saturated soil hydraulic conductivity, Ks,l, is the soil
property governing subsurface water transfer in hillslopes, and the key
parameter in many numerical models simulating hydrological processes
both at the hillslope and catchment scales. Likewise, the hydrological
connectivity of lateral flow paths plays a significant role in
determining the intensity of the subsurface flow at various spatial
scales. The objective of the study is to investigate the relationship
between Ks,l and hydraulic connectivity at the hillslope spatial scale.
Ks,l was determined by the subsurface flow rates intercepted by drains,
and by water table depths observed in a well network. Hydraulic
connectivity of the lateral flow paths was evaluated by the
synchronicity among piezometric peaks, and between the latter and the
peaks of drained flow. Soil moisture and precipitation data were used to
investigate the influence of the transient hydrological soil condition
on connectivity and Ks,l. It was found that the higher was the
synchronicity of the water table response between wells, the lower was
the time lag between the peaks of water levels and those of the drained
subsurface flow. Moreover, the most synchronic water table rises
determined the highest drainage rates. The relationships between Ks,l
and water table depths were highly non-linear, with a sharp increase of
the values for water table levels close to the soil surface. Estimated
Ks,l values for the full saturated soil were in the order of thousands
of mm h-1, suggesting the activation of macropores in the root zone. The
Ks,l values determined at the peak of the drainage events were
correlated with the indicators of synchronicity. The sum of the
antecedent soil moisture and of the precipitation was correlated with
the indicators of connectivity and with Ks,l. We suggest that, for
simulating realistic processes at the hillslope scale, the hydraulic
connectivity could be implicitly considered in hydrological modelling
through an evaluation of Ks,l at the same spatial scale.01 Dec 2021Submitted to Hydrological Processes 05 Dec 2021Submission Checks Completed
05 Dec 2021Assigned to Editor
08 Dec 2021Reviewer(s) Assigned
19 Jan 2022Review(s) Completed, Editorial Evaluation Pending
25 Jan 2022Editorial Decision: Revise Major
09 May 20221st Revision Received
11 May 2022Submission Checks Completed
11 May 2022Assigned to Editor
11 May 2022Reviewer(s) Assigned
09 Jun 2022Review(s) Completed, Editorial Evaluation Pending
17 Jun 2022Editorial Decision: Revise Minor
21 Jun 20222nd Revision Received
21 Jun 2022Submission Checks Completed
21 Jun 2022Assigned to Editor
21 Jun 2022Reviewer(s) Assigned
30 Jun 2022Review(s) Completed, Editorial Evaluation Pending
30 Jun 2022Editorial Decision: Accept