DOI: 10.5194/hess-21-2725-2017
Scopus记录号: 2-s2.0-85020485445
论文题名: Saturated hydraulic conductivity model computed from bimodal water retention curves for a range of New Zealand soils
作者: Alexander Paul Pollacco J ; , Webb T ; , McNeill S ; , Hu W ; , Carrick S ; , Hewitt A ; , Lilburne L
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2017
卷: 21, 期: 6 起始页码: 2725
结束页码: 2737
语种: 英语
Scopus关键词: Flow of fluids
; Forecasting
; Hydraulic conductivity
; Pore size
; Porosity
; Size distribution
; Soil moisture
; Uncertainty analysis
; Bimodal pore size distribution
; Historical measurements
; Pedotransfer functions
; Replicate measurements
; Saturated hydraulic conductivity
; Soil hydraulic properties
; Soil moisture retentions
; Water retention curve
; Soils
; Darcy law
; hydraulic conductivity
; hydrological modeling
; pedotransfer function
; pore space
; sandstone
; saturation
; siltstone
; size distribution
; soil moisture
; soil texture
; soil water potential
; subsoil
; topsoil
; tortuosity
; water retention
; New Zealand
英文摘要: Descriptions of soil hydraulic properties, such as the soil moisture retention curve, θ(h), and saturated hydraulic conductivities, Ks, are a prerequisite for hydrological models. Since the measurement of Ks is expensive, it is frequently derived from statistical pedotransfer functions (PTFs). Because it is usually more difficult to describe Ks than θ(h) from pedotransfer functions, Pollacco et al. (2013) developed a physical unimodal model to compute Ks solely from hydraulic parameters derived from the Kosugi θ(h). This unimodal Ks model, which is based on a unimodal Kosugi soil pore-size distribution, was developed by combining the approach of Hagen-Poiseuille with Darcy's law and by introducing three tortuosity parameters. We report here on (1) the suitability of the Pollacco unimodal Ks model to predict Ks for a range of New Zealand soils from the New Zealand soil database (S-map) and (2) further adaptations to this model to adapt it to dual-porosity structured soils by computing the soil water flux through a continuous function of an improved bimodal pore-size distribution. The improved bimodal Ks model was tested with a New Zealand data set derived from historical measurements of Ks and θ(h) for a range of soils derived from sandstone and siltstone. The Ks data were collected using a small core size of 10 cm diameter, causing large uncertainty in replicate measurements. Predictions of Ks were further improved by distinguishing topsoils from subsoil. Nevertheless, as expected, stratifying the data with soil texture only slightly improved the predictions of the physical Ks models because the Ks model is based on pore-size distribution and the calibrated parameters were obtained within the physically feasible range. The improvements made to the unimodal Ks model by using the new bimodal Ks model are modest when compared to the unimodal model, which is explained by the poor accuracy of measured total porosity. Nevertheless, the new bimodal model provides an acceptable fit to the observed data. The study highlights the importance of improving Ks measurements with larger cores. © Author(s) 2017. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/79160
Appears in Collections: 气候变化事实与影响
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作者单位: Landcare Research, P.O. Box 69040, Lincoln, New Zealand; New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch, New Zealand
Recommended Citation:
Alexander Paul Pollacco J,, Webb T,, McNeill S,et al. Saturated hydraulic conductivity model computed from bimodal water retention curves for a range of New Zealand soils[J]. Hydrology and Earth System Sciences,2017-01-01,21(6)