Subsurface flow and large-scale lateral saturated soil hydraulic conductivity in a Mediterranean hillslope with contrasting land uses

作者：Pirastru Mario^*; Bagarello Vincenzo; Iovino Massimo; Marrosu Roberto; Castellini Mirko; Giadrossich Filippo; Niedda Marcello

来源：Journal of Hydrology and Hydromechanics, 2017, 65(3): 297-306.

DOI：10.1515/johh-2017-0006

• Subsurface runoff
• Drain
• Pore connectivity
• Sprinkling experiments
• Land use change
• Maquis

The lateral saturated hydraulic conductivity, K-s,K-l,K- is the soil property that mostly governs subsurface flow in hillslopes. Determinations of K-s,K-l at the hillslope scale are expected to yield valuable information for interpreting and modeling hydrological processes since soil heterogeneities are functionally averaged in this case. However, these data are rare since the experiments are quite difficult and costly. In this investigation, that was carried out in Sardinia (Italy), large-scale determinations of K-s,K-l were done in two adjacent hillslopes covered by a Mediterranean maquis and grass, respectively, with the following objectives: i) to evaluate the effect of land use change on K-s,K-l, and ii) to compare estimates of K-s,K-l obtained under natural and artificial rainfall conditions. Higher K-s,K-l values were obtained under the maquis than in the grassed soil since the soil macropore network was better connected in the maquis soil. The lateral conductivity increased sharply close to the soil surface. The sharp increase of K-s,K-l started at a larger depth for the maquis soil than the grassed one. The K-s,K-l values estimated during artificial rainfall experiments agreed with those obtained during the natural rainfall periods. For the grassed site, it was possible to detect a stabilization of K-s,K-l in the upper soil layer, suggesting that flow transport capacity of the soil pore system did not increase indefinitely. This study highlighted the importance of the experimental determination of K-s,K-l at the hillslope scale for subsurface modeling, and also as a benchmark for developing appropriate sampling methodologies based on near-point estimation of K-s,K-l.

• 出版日期2017-9