simultaneous scaling of soil water retention and hydraulic conductivity functions
نویسندگان
چکیده
abstract scaling methods, which are based on similar media theory, are used to simplify the statistic description of soil spatial variations. to simulate the water flow in heterogeneous soils, simultaneous scaling of soil hydraulic functions, including soil water retention and unsaturated hydraulic conductivity functions, is highly desirable. in the similar media theory, the simultaneous scaling is expected for geometrically similar soils. in this paper, it is indicated that although the geometric similarity is a necessity, it is not sufficient for validation of the similar media theory in the reality. it is shown that, in addition, the values of kshm2 (β) must be identical in all similar soils (where ks is the saturated hydraulic conductivity and hm is the median suction head in the water retention curve). to evaluate the theory, method of tuli et al. (13) was used which applies the similar media theory to the similar soils of kosugi and hopmans (4) with identical σ (standard deviation in the log-normal hydraulic models). the method was also generalized such that it can well scale the soil hydraulic functions of the similar soils even where the β values are not identical. the theoretical descriptions were tested by data of 26 soils from unsoda database. the soils were classified into six groups of similar soils based on the equality of their σ. as it was expected, the method of tuli et al. did not perform well in the groups in which β values were significantly different. the results also showed that the proposed method can considerably improve the performance of the method of tuli et al. it was indicated that the performance of the proposed method do not depend on β values and the geometric similarity is the only condition for that.
منابع مشابه
Measurement Scale Effect on Prediction of Soil Water Retention Curve and Saturated Hydraulic Conductivity
Soil water retention curve (SWRC) and saturated hydraulic conductivity (SHC) are key hydraulic properties for unsaturated zone hydrology and groundwater. In particular, SWRC provides useful information on entry pore-size distribution, and SHC is required for flow and transport modeling in the hydrologic cycle. Not only the SWRC and SHC measurements are time-consuming, but also scale dependent. ...
متن کاملscaling of soil hydraulic conductivity function using effective capillary drive
abstract to estimate spatial variability of soil hydraulic functions, scaling methods were developed and have been widely used. among these functions, physically based methods have been found more desirable because of possibility of estimating soil hydraulic functions from soil physical properties. in this paper, a new and physically based method has been described for scaling soil hydraulic co...
متن کاملMultiscale Pedotransfer Functions for Soil Water Retention
Soil hydraulic properties are needed in globaland regionalscale circulation models for hydrologic and climate forecasting. They are also necessary in pointand nonpoint-source contaminant transport models. Prediction accuracy of these models is highly dependent on the quality of the model parameters. Collecting the required soil hydraulic parameters by direct measurement at any model grid scale ...
متن کاملAn improved simulation of void structure, water retention and hydraulic conductivity in soil with the Pore-Cor three-dimensional network
We present a new method of characterizing the void structures of soils from water retention curves as the primary source of data. The method avoids the problems of other current approaches, which use smoothing curves and can miss the subtleties of soil structure, and usually ignore the shielding of large pores by the small connecting throats surrounding them. In the new method, software we have...
متن کاملDetermination of unsaturated hydraulic conductivity by internal drainage assuming a uniform soil water profile
متن کامل
Estimating the Saturated Hydraulic Conductivity of Soil Using Gene Expression Programming Method and Comparing It with the Pedotransfer Functions
Saturated hydraulic conductivity of soil is an important physical property of soil that affects water movement in soil, Since the measurement of saturated hydraulic conductivity by direct methods in the field or in the laboratory is hard, time-consuming and costly, the indirect methods are being used.The aim of this study is to estimate the saturated hydraulic conductivity from other soil prope...
متن کاملمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
آب و خاکجلد ۲۴، شماره ۲، صفحات ۰-۰
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023