Authors
1
Department of Water Engineering, Faculty of Agriculture, Ferdowsi University of Mashhad
2
Professor Department of Water Engineering ,College of Agriculture, Ferdowsi University of Mashhad, Respectively
3
Assistant Professor, Department of Water Engineering ,College of Agriculture, Ferdowsi University of Mashhad, Respectively
4
Research Assistant Professor Utah State University
Abstract
Infiltration is one of the most important physical parameters of the soil, which plays an important role in the hydrological cycle. The locaton variability in analyzing issues of water flow in the soil, at large levels such as the catchment area, is very difficult and costly. The use of scaling methods is a practical solution to the problems of soil variability. After presenting the theory of similar environments, scaling methods were proposed to overcome the problem of soil variability. In this research, the Richards equation was solved in a wide range of moisture (saturated moisture up to the remaining moisture content) for sandy soil, and the scale of accumulated penetration values was presented using the scaling of the results of solving this equation. These values were approximated with the triple-form of the Philip equation and, using regression models, for each sentence of this equation, an empirical relation was established for water penetration in soil. Then, using two sandy soils and clay in a specific moisture, the experimental effect was measured for both scaled time scales of 0.1 and 0.01 which included short and long periods. Then, using two sandy soils and clay in a specific moisture, the experimental Efficiency was measured for both scaled time scales of 0.1 and 0.01 which included short and long periods evaluated. Of the four available scenarios, the highest mean square error value was obtained at 0.0053 for clay and for long periods of time. cuase to the fact that this criterion was high in relation to other scenarios, the effect of gravity was calculated in long periods of time. The condition of applying the scaling method used in the research is not the effect of gravity on the capillary force. Also, the influence of the proposed relationship with the comparison of field data measured by Barry et al. (1995) on a sandy soil with a fixed height of water on the soil surface of Boehne et al. (1993) using the Rain simulator , Conducted penetration tests on two clay soils under cultured and uncoated conditions was evaluated. The results showed that the aforementioned relationship can provide an acceptable estimate (with the highest root mean square error of 3%) compared to the measured values of water penetration in the soil.
Keywords
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