scholarly journals Predicted Infiltration for Sodic/Saline Soils from Reclaimed Coastal Areas: Sensitivity to Model Parameters

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Dongdong Liu ◽  
Dongli She ◽  
Shuang’en Yu ◽  
Guangcheng Shao ◽  
Dan Chen
Keyword(s):  
Water Movement ◽  
Soil Surface ◽  
Coastal Areas ◽  
Model Parameters ◽  
Wetting Front ◽  
Sodic Soils ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Soil Physical Quality ◽  
Cumulative Infiltration

This study was conducted to assess the influences of soil surface conditions and initial soil water content on water movement in unsaturated sodic soils of reclaimed coastal areas. Data was collected from column experiments in which two soils from a Chinese coastal area reclaimed in 2007 (Soil A, saline) and 1960 (Soil B, nonsaline) were used, with bulk densities of 1.4 or 1.5 g/cm3. A 1D-infiltration model was created using a finite difference method and its sensitivity to hydraulic related parameters was tested. The model well simulated the measured data. The results revealed that soil compaction notably affected the water retention of both soils. Model simulations showed that increasing the ponded water depth had little effect on the infiltration process, since the increases in cumulative infiltration and wetting front advancement rate were small. However, the wetting front advancement rate increased and the cumulative infiltration decreased to a greater extent whenθ0was increased. Soil physical quality was described better by theSparameter than by the saturated hydraulic conductivity since the latter was also affected by the physical chemical effects on clay swelling occurring in the presence of different levels of electrolytes in the soil solutions of the two soils.

A Forecasting Method of Kostiakov Infiltration Model Parameters Based on Back-Propagation Model

2012 ◽  
Vol 610-613 ◽  
pp. 2899-2903
Author(s):  
Chong Wen Cao ◽  
Gui Sheng Fan
Keyword(s):  
Back Propagation ◽  
Influence Factors ◽  
Propagation Model ◽  
Water Infiltration ◽  
Physical Parameters ◽  
Model Parameters ◽  
Soil Infiltration ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Bp Model

Based on test data of field soil water infiltration, Back-propagation (BP) model of predicting Kostiakov infiltration model parameters was established after analyzing the primary influence factors of water infiltration model parameters. The results indicate that BP model can reflect the non-linear relationship between the model parameters and the physical parameters of the soil; BP model is high accuracy for prediction soil infiltration model parameters. It can be referred as a new method to predict soil infiltration process using soil physical parameters.

Analysis of salinity profiles in lateritic soils of south-western Australia

Soil Research ◽  
1982 ◽  
Vol 20 (1) ◽  
pp. 37 ◽  
Author(s):  
JD Watson
Keyword(s):  
Steady State ◽  
Western Australia ◽  
Water Movement ◽  
Saline Water ◽  
Water Flux ◽  
Soil Surface ◽  
State Model ◽  
Model Parameters ◽  
Lateritic Soils ◽  
Steady State Model

Salinity profiles in deeply weathered lateritic soils of south-western Australia frequently exhibit very high concentrations in the unsaturated zone above a less saline water table. A one-dimensional steady-state model using the simultaneous mass balance equations for water and solute is used to predict salt profiles which are compared with those observed. The model assumes input of salt in rainfall and water uptake by plants. Model parameters imply magnitudes of transpiration, water flux rates and possible mechanisms for water movement to the saturated zone. Some salt profiles cannot be accounted for with the steady-state model. In some cases there appears to be an injection of low salinity water at depth which could occur by movement through preferred pathways from the soil surface. In other cases the probable explanation is that the profiles are accumulating salts under the present hydrologic regime.

scholarly journals Effects of the Grain Size on Dynamic Capillary Pressure and the Modified Green–Ampt Model for Infiltration

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yi-Zhih Tsai ◽  
Yu-Tung Liu ◽  
Yung-Li Wang ◽  
Liang-Cheng Chang ◽  
Shao-Yiu Hsu
Keyword(s):  
Grain Size ◽  
Capillary Pressure ◽  
Dynamic Effect ◽  
Pressure Head ◽  
High Flow ◽  
Model Parameters ◽  
Wetting Front ◽  
Grain Sizes ◽  
Cumulative Infiltration ◽  
Capillary Pressures

Darcy-scale capillary pressure is traditionally assumed to be constant. By contrast, a considerable gap exists between the measured and equilibrium capillary pressures when the same moisture saturation is considered with a high flow rate, and this gap is called the dynamic effect on the capillary pressure. In this study, downward infiltration experiments of sand columns are performed to measure cumulative infiltration and to calculate the wetting front depth and wetting front velocity in sands with different grain sizes. We estimate the equilibrium capillary pressure head or suction head at the wetting front using both the classical Green–Ampt (GAM) and modified Green–Ampt (MGAM) models. The results show that the performance of MGAM in simulating downward infiltration is superior to that of GAM. Moreover, because GAM neglects the dynamic effect, it systematically underestimates the equilibrium suction head in our experiments. We also find that the model parameters α^ and β of MGAM are affected by the grain size of sands and porosity, and the dynamic effect of the capillary pressure increases with decreasing grain size and increasing porosity.

scholarly journals The determination of reasonable number of soil infiltration test in farmland

2019 ◽  
Vol 136 ◽  
pp. 07020
Author(s):  
Xu Yang ◽  
Jiamin Yu ◽  
Yangren Wang ◽  
Yanjie Li
Keyword(s):  
Statistical Analysis ◽  
Soil Infiltration ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Double Ring ◽  
Reasonable Number ◽  
Cumulative Infiltration ◽  
Infiltration Test ◽  
Experimental Base

At the experimental base of Tianjin Agricultural University, the infiltration process of water was measured by double - ring infiltration instrument at six points. Horton，Philip and Kostiakov-lewis (K-l) infiltration models were fitted with the infiltration data measured and the parameters were correspondingly obtained. Six sets of parameters of the corresponding infiltration model were obtained, and six sets of parameters were used for statistical analysis. The reasonable number of points of the corresponding model was obtained. Then, the statistical analysis of the cumulative infiltration amount was used to obtain the variation of the number of reasonable points in the three models with time. The results show that the imitative effect of accumulative infiltration water and time in K-l model is the best, and the curve of reasonable test points determined by K-l model with time is located under the other two models; The reasonable number of points determined by the parameter K in the K-l model is the least and most reasonable. In view of this, the number of reasonable points was determined by using the parameter K in the K-l model.

scholarly journals Spatial Variability Analysis of Farmland Soil Infiltration Based on Model Parameters

2019 ◽  
Vol 136 ◽  
pp. 07021
Author(s):  
Qingdao Xin ◽  
Hemin Zhu ◽  
Yangren Wang ◽  
Xinrui Fan
Keyword(s):  
Water Movement ◽  
Direct Method ◽  
Correlation Coefficients ◽  
Simulation Method ◽  
Spatial Uncertainty ◽  
Model Parameters ◽  
Soil Infiltration ◽  
Infiltration Process ◽  
Farmland Soil ◽  
Significant Difference

Research on the variation of soil infiltration is helpful to analyze the mechanism of soil water movement in farmland. At the same time, soil infiltration characteristics affect the surface irrigation. Based on the field test data, this study simulated and analyzed the soil infiltration with three soil infiltration models (Kostiakov-Lewis model, Philip model and Horton model). The infiltration uncertainty of farmland soil are investigated, and proposed by using two random simulation methods (direct method and parameter mean method) of infiltration. The evaluated indicators are the interval size and its stability of cumulative infiltration amount changed with 95% confidence. The effects of different random simulations methods and three models on the infiltration process are compared and analyzed. Finally, the model and stochastic simulation method suitable for the infiltration characteristics of the farmland are determined. The results show that the correlation coefficients of the three models are all above 0.98, and there is no significant difference in fitting accuracy. In terms of the degree of spatial uncertainty (determined by standard deviation): direct method > parameter mean method, in which the combination of the Kostiakov-Lewis model and the parameter mean method have less uncertainty, and the combined simulation effect is better, it is more suitable for the simulation of soil infiltration at farmland scale.

Numerical analysis of vertical water movement in a bounded profile

Soil Research ◽  
1975 ◽  
Vol 13 (1) ◽  
pp. 1 ◽  
Author(s):  
KK Watson ◽  
AA Curtis
Keyword(s):  
Water Movement ◽  
Sandy Loam ◽  
Air Pressure ◽  
Wetting Front ◽  
Flow Process ◽  
Compression Effect ◽  
Cumulative Infiltration ◽  
Computer Based ◽  
Air Compression ◽  
Made In

The usual assumption made in soil water studies that the effect of the air phase on the flow process is negligible is discussed in relation to certain profile configurations where such an assumption is not valid. A computer-based numerical solution of the equation describing water movement in an unsaturated soil is then modified by the inclusion of a time-dependent boundary condition, thus allowing the modelling of the air compression effect during infiltration. This analysis also satisfactorily models the drainage along primary draining scanning curves which occurs in the upper part of the profile as the air pressure increases. The analysis is limited to the Darcy flow regime which, for the system considered, terminates when the excess air pressure equals the air entry value of the porous material. Detailed results are presented for a sand and a sandy loam. Profile depths of 200 cm and 1000 cm have been analysed, and comparisons made of the effect of the air compression on the shape of the wetting front. The effect on cumulative infiltration is also noted.

scholarly journals Predicting the infiltration characteristics for semi-arid regions using regression trees

2021 ◽  
Author(s):  
Parveen Sihag ◽  
Munish Kumar ◽  
Saad Sh. Sammen
Keyword(s):  
Input Parameter ◽  
Regression Tree ◽  
Soil Surface ◽  
Infiltration Rate ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Infiltration Process ◽  
Data Set ◽  
Cumulative Infiltration ◽  
Tree Methods

Abstract The study of infiltration process is considered as essential and necessary for all hydrology studies. Therefore, accurate predictions of infiltration characteristics are required to understand the behavior of subsurface flow of water through the soil surface. The aim of the current study is to simulate and improve the prediction accuracy of infiltration rate and cumulative infiltration of soil using regression tree methods. Experimental data recorded with a double ring infiltrometer for 17 different sites are used in this study. Three regression tree methods: Random tree, Random forest (RF) and M5 tree are employed to modelling the infiltration characteristics using the basic soil characteristics. The performance of the modelling approaches is compared in predicting the infiltration rate as well as cumulative infiltration, obtained results suggest that performance of RF model is better than other applied models with coefficient of determination (R2) = 0.97 & 0.97, root mean square error (RMSE) = 8.10 & 6.96 and mean absolute error (MAE) = 5.74 & 4.44 for infiltration rate and cumulative infiltration respectively. RF model is used to represent the infiltration characteristics of the study area. Moreover, parametric sensitivity is adopted to study the significance of each input parameter in estimating the infiltration process. Results suggest that time (t) is the most influencing parameter in predicting the infiltration process using this data set.

scholarly journals Research on Influence of Soil Moisture Content of Farmland on Infiltration Model Parameters

2020 ◽  
Vol 189 ◽  
pp. 01011
Author(s):  
Zhiwei Zheng ◽  
Zhuozhuo Gao
Keyword(s):  
Moisture Content ◽  
Soil Column ◽  
Initial Moisture Content ◽  
Test Method ◽  
Model Parameters ◽  
Initial Water Content ◽  
Initial Water ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Kostiakov Model

In order to study the influence of the initial moisture content on the parameters of the infiltration model using an indoor soil column test method, and the relationship between the initial moisture content and each model parameter was analyzed by using the Green-Ampt model, the Kostiakov model, and the Horton model. The results show that there is a certain relationship between the initial water content and the parameters of the infiltration model. Based on comprehensive considerations, the Kostiakov model is the best surface irrigation infiltration model, and the Kostiakov model has the best effect when the observation time is not less than 80 minutes to simulate the soil infiltration process.

Modeling Infiltration-Runoff under Multi-Layered Soil during Rainfall

2013 ◽  
Vol 864-867 ◽  
pp. 2392-2402
Author(s):  
Yong De Gan ◽  
Yang Wen Jia ◽  
Kang Wang
Keyword(s):  
Soil Surface ◽  
Layered Soil ◽  
Layered Soils ◽  
Wetting Front ◽  
Soil Columns ◽  
Soil Infiltration ◽  
One Dimensional ◽  
Cumulative Infiltration ◽  
Runoff Rate

The generalized Green-Ampt models, based on the Green-Ampt approach, is suitable for simulating infiltration into layered soils during unsteady rainfall, however, there are still some problems with using this approach. The objective of this paper is to improve the generalized Green-Ampt model, and then evaluate the performance of the generalized Green-Ampt model in modeling the infiltration-runoff into multi-layered soil during rain. Firstly, based on the generalized Green-Ampt model, we propose and improvement to the generalized Green-Ampt model to overcome deficiencies in it. Then, one-dimensional infiltration-runoff experiments during rainfall were performed in multi-layered soil columns, and the runoff rate, cumulative infiltration and wetting front distance from soil surface were calculated with the modified generalized Green-Ampt model, and compared with the observed data in the experiments. The results indicate that the modified generalized Green-Ampt model predicts the multi-layered soil infiltration-runoff process well.

scholarly journals Application of Philip infiltration model to film hole irrigation

2018 ◽  
Vol 19 (3) ◽  
pp. 978-985 ◽  
Author(s):  
Yanwei Fan ◽  
Jiaguo Gong ◽  
Ying Wang ◽  
Xiaoxia Shao ◽  
Tong Zhao
Keyword(s):  
Influencing Factors ◽  
Power Function ◽  
Water Depth ◽  
Soil Texture ◽  
Hole Diameter ◽  
Model Parameters ◽  
Initial Water Content ◽  
Infiltration Model ◽  
Cumulative Infiltration ◽  
Function Relationship

Abstract Numerical simulations were carried out with HYDRUS-2D to investigate the influence of soil texture, initial water content, film hole diameter and water depth on cumulative infiltration from a film hole. Soil texture, film hole diameter and water depth are the dominant influencing factors. Philip infiltration model was used to fit the simulated results of the dominant influencing factors. For the same soil, the sorptivity (s) is a power function relationship with film hole diameter, while the steady infiltration rate (a) is a power function relationship with film hole diameter and water depth. On that basis, the calculation formulas for predicting s and a were established, and a simplified film hole infiltration model including the film hole diameter and water depth was proposed. The effectiveness of the model was verified by laboratory experiments and literature data. The predicted values of the model were in good agreement with the experimental observations. The model parameters can be determined only by a set of film hole infiltration experiment, which simplifies the experimental design and can be used as a tool for irrigation engineers or farmers to estimate cumulative infiltration.

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