Vertical Infiltration Of Water Research Articles

Evaluation of Unsaturated Water Flow Features of Compacted Soil Subjected to Horizontal and Vertical Water Infiltration

Evaluation of Unsaturated Water Flow Features of Compacted Soil Subjected to Horizontal and Vertical Water Infiltration

Ecosystem engineering by periphyton in Alpine proglacial streams

AbstractStream periphytons are candidate ecosystem engineers in proglacial margins. Here, we quantify the extent to which they are engineers for the case of hillslope‐fed tributaries in the terrace zones of proglacial margin alluvial plains. Candidate ecosystem engineering effects relate to periphyton‐driven changes in (1) vertical infiltration of water, which in turn could aid plant colonization and hence local surface stabilization, and (2) near‐bed hydraulics, notably near‐bed turbulence properties. We ran two flume experiments in parallel in the proglacial margin of the Otemma glacier (Switzerland), reproducing the environmental conditions found in terrace streams. In both experiments, we followed periphyton development on initially bare sediments for 28 days. Then, whilst the experiment continued undisturbed in one flume, in the second and over a further 26 days, we introduced disturbances in the form of desiccation events. Throughout the entire experiment length, we collected imagery for close‐range SfM‐MVS photogrammetry, data on vertical infiltration, and near‐bed hydraulics. The experiments showed that periphyton development significantly changed the streambed properties. First, periphyton development over the timescale of a few days reduced bed roughness and clogged the benthic interstitial space, reducing water infiltration. These effects were insensitive to the disturbance regime. Second, the changes in streambed roughness modified the near‐bed turbulent structures, and this resulted in a reduction of bursting events and in the modification of the turbulent kinetic energy at the near‐bed layer. The latter, however, appeared to be less important in these environments as compared with the impacts on infiltration. Given the low water retaining capacity of glacial sediments, the observation that periphyton can reduce vertical infiltration explains wider observations of their importance in glacial floodplains where vegetation succession is critically constrained by water availability. The relatively reduced impacts on near‐bed turbulence also contribute to explaining why disturbance in proglacial margin streams remains a key limit on ecological succession.

Response and prediction of unsaturated permeability of loess to microstructure

The study of water infiltration helps to investigate the pollutants' migration, grasp the mechanism of the water cycle, and correctly evaluate water resources. This paper reveals the mechanism of compacted loess's one-dimensional vertical water infiltration characteristics using a low-cost water infiltration device. In addition, it investigates particle arrangement and pore size distribution characteristics using nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). The test finding suggests that the loess's early-stage infiltration rate is significant, and the dry density is not related to the infiltration characteristics. With the advance of the wetting front, the infiltration rate decreases under air resistance. The unsaturated permeability decreases with dry density at lower matric suction while unaffected by the dry density at higher matric suction. Moreover, the volume and connectivity of pores mainly control the water infiltration characteristics. Finally, based on the test results, a method for rapidly predicting the unsaturated permeability of loess is proposed. The results of the study help predict contaminant transport and guide groundwater extraction and management.

Study on Water Vertical Infiltration Characteristics and Water Content Simulation of Sandstone Overlying Loess

Research on the infiltration characteristics of surface water is fundamental for understanding the entire hydrological process. Therefore, studying the water infiltration process of sandstone slopes overlaid with loess and predicting soil moisture content are of great importance for investigating hydrological processes and controlling soil erosion in the hilly and gully areas of the Loess Plateau in China. This study mainly focuses on the simulation of the vertical water infiltration characteristics and water movement patterns of four kinds of sandstone (feldspathic and argillaceous sandstone) structures covered with thin layers of loess. In the one-dimensional vertical infiltration experiment and Hydrus-1D model simulation, the interlayer transition planes of loess–feldspathic and loess–feldspathic–argillaceous sandstones were found to present two conditions: fine soil covering coarse soil and coarse soil covering fine soil. Therefore, water infiltration reduced permeability. The existence of a transition layer between loess and feldspathic sandstone decreased the water infiltration rate and infiltration amount and decelerated the speed of the wetting front, thereby further affecting the ability of water infiltration. By using the Hydrus-1D model, 15 sets of soil hydraulic parameters, including θx (0.028–0.05795 cm3/cm3), θs (0.2306–0.4786 cm3/cm3), α (0.01899–0.06071 cm−1), n (1.438–6.408), and Ks (1.96·10−4–0.0576 cm/s) were inverted and optimized for each 20 cm soil layer (total of 60 cm). The Van Genuchten model constructed using these parameters demonstrated high accuracy in the simulation of water content in the vertical infiltration process of sandstone covered by loess with the coefficient of determination R2 > 0.849 and relative error RE < 5.311.

A Deep Learning-Based Approach for a Numerical Investigation of Soil–Water Vertical Infiltration with Physics-Informed Neural Networks

The infiltration of water into the soil can lead to slope instability, which is one of the important causes of many geological hazards (such as landslides and debris flows). Therefore, the numerical investigation of the soil–water infiltration process provides the prerequisite for the determination of slope stability, which is of great significance for geological hazard prevention. In this study, we propose a deep learning-based approach for a numerical investigation of soil–water vertical infiltration with physics-informed neural networks and perform a comprehensive evaluation and analysis of the soil–water infiltration process in different soil types. In the proposed approach, the partial differential equation for soil–water infiltration is combined with the neural network based on physics-informed neural networks (PINNs) to obtain numerical analysis of the soil–water infiltration process. The results indicate that (1) compared with the traditional numerical method, the PINN-based method for the numerical investigation of soil–water vertical infiltration proposed in this study has a smaller error and can obtain more accurate numerical results. (2) During vertical infiltration of water in the different soil types, the light loam is the fastest, the heavy-loam the second and the medium loam the slowest. medium-loam soils are less susceptible to water infiltration of the three soil types and are more suitable for the filling of artificial slopes and dams. The proposed approach could be employed for the simulation of soil–water infiltration processes, not only for the discrimination of slope stability under rainfall conditions, but also for the selection of artificial slopes and dams to fill soil to prevent slope instability.

Effects of different biomass materials as a salt-isolation layer on water and salt migration in coastal saline soil.

The aim of this study was to find a material suited for the prevention of evaporative water loss and salt accumulation in coastal saline soils. One-dimensional vertical water infiltration and phreatic evaporation experiments were conducted using a silty loam saline soil. A 3-cm-thick layer of corn straw, biochar, and peat was buried at the soil depth of 20 cm, and a 6-cm-thick layer of peat was also buried at the same soil depth for comparison. The presence of the biochar layer increased the upper soil water content, but its ability to inhibit salt accumulation was poor, leading to a high salt concentration in the surface soil. The 3-cm-thick straw and 6-cm-thick peat layers were most effective to inhibit salt accumulation, which reduced the upper soil salt concentration by 96% and 93%, respectively. However, the straw layer strongly inhibited phreatic evaporation and resulted in low water content in the upper soil layer. Compared with the straw layer, the peat layer increased the upper soil water content. Thus, burying a 6-cm-thick peat layer in the coastal saline soil is the optimal strategy to retain water in the upper soil layer and intercept salt in the deeper soil layer.

Interpreting regolith data to infer groundwater potential contamination in Piracicaba, Brazil

Interdisciplinary concepts have been used to manage the environmental crisis of the 21st century. Ecological problems and solutions require an increasingly comprehensive soil study and this has been carried out in order to consider the entire regolith profile. Regoliths are the entire column of materials above the fresh rock, whether this is saprolite (literally “rotten rock”) or soil, material with intense biological and chemical process. Groundwater contamination is particularly enhanced in shallow, porous regolith profiles, due to the easiness of surface water flow into the groundwaters. This is particularly critical in the Guarani aquifer, which waters supplies 15 million people in 4 countries. Several morphological, chemical, physical and mineralogical analyses were applied to samples collected in three regolith profiles to infer, based on weathering and pedogenesis characteristics, their susceptibility to allow groundwater contamination. A particular challenge was that most of the weathering indices were proposed for igneous rocks, and the studied profiles had sedimentary rocks as parent materials. The most weathered profile (P2) had the least potential for groundwater contamination due to its higher cation exchange capacity (CEC) and clay activity, differentiated structure and consistency in the Bi horizon that can favor the lateral flow and the greatest thickness. Profile P1 had sandy texture, small CEC and thickness that facilitate the passage of soluble contaminants towards the groundwater. Some anox features in the Cr layer suggest the existence of a physical limitation that may delay infiltration or diverge water flow to surface outlets. The profile P3 had the greatest potential for groundwater contamination because it had low CEC, weathering degree and thickness. The only feature to prevent the polluted infiltration water to reach groundwaters in this profile was its sub-horizontal structure and transition from soft/very friable consistency in CA layer to very hard/unbreakable consistency in Cr layer, which also may diverge or delay the vertical infiltration of water. However, no anox features were found in it. Results indicate the importance of understanding the soil weathering and relate with their potential on underground water contamination, and thus, to bring light to public environmental monitoring policies.

In Situ Effectiveness of Alkaline and Cementitious Amendments to Stabilize Oxidized Acid-Generating Tailings

This study investigates the effectiveness of alkaline and cementitious additives in the in situ stabilization of localized acid-generating tailings from a closed gold mine in Abitibi–Témiscamingue, Québec (Eagle/Telbel mine site). Five field cells (including one control) were constructed and equipped with mechanisms for collecting vertical water infiltration and surface runoff. The five cells included: (C1) Control cell; (C2) 5 wt % limestone amendment; (C3) 10 wt % limestone amendment; (C4) 5 wt % half ordinary Portland cement and half fly ash amendment; and (C5) 5 wt % ordinary Portland cement amendment. The control cell showed an acidic behavior (pH < 4.5) with variable concentrations of Fe, Al, Zn, and Cu. The amendments were used to neutralize the acidic leachates and decrease dissolved metal concentrations. Leachates from surface runoff samples of amended cells were less loaded with metals compared to samples of vertical infiltration. All amendment formulations increased the pH of the leachates from approximately 4 to circumneutral values. Furthermore, metal and metalloid concentrations were greatly limited, except for Cr and As for the carbonate-based amendments. Metal(-oid) stabilization was successfully achieved using the different amendment formulations, with the exception of C2, which still released As.

Use of a modified chloride mass balance technique to assess the factors that influence groundwater recharge rates in a semi-arid agricultural region in China

The groundwater recharge potential in the West Liaohe Plain in northeast China was assessed using a modified chloride mass balance method to estimate the vertical infiltration of water through typical soil profiles at two study sites in the region: the Horqin Left Middle Banner (KZ) site and the Kailu County (KL) site. Samples of precipitation, groundwater, and soil water were collected at the KZ and KL sites to determine the effects of irrigation and soil texture on water infiltration in soil profiles. The results showed that the water infiltration rate at the KZ site is approximately 6–11 mm/a beneath farmland, with similar infiltration rates for mulched drip irrigation and flood irrigation methods, but the infiltration coefficient with a mulch cover was slightly higher than that of soils without a mulch cover. The infiltration rate in soils at the KL site was determined to be 25–41 mm/a beneath farmland and in this area the infiltration rate and infiltration coefficient in soils with a mulch cover were much higher than in soils without a mulch cover. Additionally, the infiltration rate and infiltration coefficient in sandy-textured soils at the KL site were higher than in clayey soils at the KZ site. The infiltration rate in bare land at the KL site with a similar soil texture to that of the farmland was determined to be approximately 16 mm/a, or approximately one-half the infiltration rate measured beneath the farmland. Water infiltration rates in cultivated soils were higher than those beneath non-cultivated areas; however, this does not mean that the actual groundwater recharge rate increased. The amount of irrigation water used is lower using mulched drip irrigation than in fields irrigated using flood irrigation, but the infiltration coefficient actually increased. This suggests that the mulched drip irrigation method can increase groundwater recharge in semi-arid regions such as the study area.

The role of hardpan formation on the reactivity of sulfidic mine tailings: A case study at Joutel mine (Québec)

The former Eagle and Telbel mine site (hereafter referred to as Joutel mine), located near the town of Joutel in the Nord-du-Québec (Canada) houses a tailings storage facility (TSF) that has been inactive since 1996. Fresh, unweathered tailings (beneath 10–30 cm of oxidized horizon) are characterized by an average sulfide content of 6–7 wt% and an average Fe-Mn-carbonate content of 20–40 wt%. The oxidation of Joutel's tailings under atmospheric conditions resulted in the precipitation of secondary phases such as ferric oxyhydroxides and gypsum. Accumulation of these secondary phases throughout the TSF caused cementation and agglomeration of grains, which decreased the porosity of the material in a horizon below the surface. This horizon, which is referred to as hardpan, is frequently encountered within fine, reactive tailings. Characterizations showed that hardpans have a highly compact texture. The formation of hardpans limits vertical water infiltration and oxygen diffusion and these layers greatly affect the global geochemical behavior of underlying tailings in the Joutel TSF by protecting the unweathered material from oxidation. As a result, the water quality of the TSF is largely controlled by the reactivity of the upper oxidized tailings horizon.Joutel's oxidized tailings showed an acidic behavior early during laboratory kinetic leaching tests despite the near absence of sulfides and neutralizing minerals. However, when unweathered tailings were added under oxidized tailings, the water became neutral and metal leaching rates were reduced. After over a year of laboratory leaching tests, hardpans formed within the columns and the natural phenomenon was reproduced under laboratory conditions.

Functional Extremum Solution and Parameter Estimation for One‐Dimensional Vertical Infiltration using the Brooks–Corey Model

Core Ideas Least action and variational principles were used to simulate unsaturated vertical infiltration. A functional extremum explicit solution to Richards' equation was obtained. A new method describes nonlinear relationships between cumulative infiltration, infiltration rate and wetting‐front depth. The method could be used to accurately predict soil water content and estimate soil hydraulic parameters. A simple analytical solution of one‐dimensional vertical infiltration of soil water is of great importance for the estimation of soil hydraulic properties and for precision irrigation. We use a new approximate analytical method based on the principle of least action and the variational principle for simulating the vertical infiltration of water in unsaturated soil for a constant‐saturation upper boundary and for estimating infiltration parameters. The method proposes the functional extremum problem of one‐dimensional vertical infiltration of water in unsaturated soil using the Brooks–Corey model. A functional extremum solution (FES) to Richards' equation was obtained using the Euler–Lagrange equation and the integral mean‐value theorem. A modified functional extremum solution (MFES) was also proposed empirically to improve precision based on the FES of horizontal absorption and numerical data simulated by Hydrus‐1D. The relationships between a parameter derived by the value theorem of the integral (α), the air‐entry suction (hd), and the wetting front depth (zf) were analyzed by comparing MFES with the numerical distribution of soil water content. The MFES was used to describe the nonlinear relationship between cumulative infiltration and zf, with the relative error (Re) of < 4.1% and the coefficient of determination (R2) > 0.986. The MFES was also used to describe the nonlinear relationship between the infiltration rate (i) and the reciprocal of zf for soils with hd ≥10 cm, with Re < 6.0% and R2 > 0.8453. A simple method for estimating soil saturated hydraulic conductivity (Ks) was proposed from the nonlinear relationship between i and zf, and the sensitivities of parameters in the Brooks–Corey model were also analyzed.

Radial basis function partition of unity method for modelling water flow in porous media

Water flow in variably-saturated porous media is modelled by using the highly nonlinear parabolic Richards’ equation. The nonlinearity is due to the hydraulic conductivity and moisture content variables. The latter were estimated by using experimental models, including Gardner, Burdine, Mualem and van Genuchten models. The aim of this work is to develop a new technique based on the radial basis function partition of unity method (RBFPUM) and Gardner model in order to solve Richards’ equation in one and two dimensions. We have used Gardner model to handle the nonlinearity issue and the RBFPUM is used to approximate the solution of the linearized Richards’ equation. Our proposed algorithm is based on testing many configurations of the partitions number and selecting the optimal shape parameter for each case. Then we pick up the optimal configuration (partitions number-shape parameter) that yields the best solution in terms of error and conditioning number. By following this procedure, an optimal solution is ensured for our given problem. As numerical tests, we consider the vertical infiltration of water in soils in order to validate our proposed method.

Innovative Analytical Solutions to 1, 2 and 3D Water Infiltration into Unsaturated Soils for Initial-Boundary Value Problems

Fluid infiltration into unsaturated soil is of vital significance from many perspectives. Mathematically, such transient infiltrations are described by Richards' equation; a nonlinear parabolic Partial Differential Equation (PDE) with limited analytical solutions in the literature. The current study uses separation of variables and Fourier series expansion techniques and presents new analytical solutions to the equation in one, two, and three dimensions subject to various boundary and initial conditions. Solutions for 1-D horizontal and vertical water infiltration are derived and compared to numerical finite difference method solutions, whereby both solutions are shown to coincide well with one another. Solutions to 2- and 3-D vertical water infiltration are derived for constant, no-flow, and sinusoidal boundary and initial conditions. Presented analytical solutions are such that both steady and unsteady solutions may be obtained from a single closed form solution. The solutions may be utilized to test numerical models that use different computational techniques

Early formation of preferential flow in a homogeneous snowpack observed by micro‐CT

AbstractWe performed X‐ray microtomographic observations of wet‐snow metamorphism during controlled continuous melting and melt‐freeze events in the laboratory. Three blocks of snow were sieved into boxes and subjected to cyclic, superficial heating or heating‐cooling to reproduce vertical water infiltration patterns in snow similarly to natural conditions. Periodically, samples were taken at different heights and scanned. Results suggest that wet‐snow metamorphism dynamics are highly heterogeneous even in an initially homogeneous snowpack. Consistent with previous work, we observed an increase with time in the thickness of the ice structure, which is a measure of grain size. However, this was coupled with large temporal scatter between consecutive measurements of the specific surface area and of the statistical moments of grain thickness distributions. Because of marked differences in the right tail, grain thickness distributions did not show shape invariance with time, contrary to previous analyses. In our experiments, wet‐snow metamorphism showed two strikingly different patterns: homogeneous coarsening superimposed by faster heterogeneous coarsening in areas that were affected by preferential percolation of water. Liquid water movement in snow and fast structural evolution may be thus intrinsically coupled by early formation of preferential flow at local scale. These observations suggest that further experiments are highly needed to fully understand wet‐snow metamorphism and infiltration patterns in a natural snowpack.

Sedimentological characteristics and geochemistry of lake waters of the Rio Grande basin, west of Bahia State (Brazil)

ABSTRACTThe lacustrine system of the Rio Grande basin is placed where it gathers singularities from both geological and climatic points of view. In order to understand the origin and dynamics of this system, a faciological description of the deposits from two lakes considers both textural and mineralogical elements via XRD analyses. This was followed by a chemical analysis of a dozen lakes' water, in order to standardize the evolution of the lowlands which form the lakes. The hydrochemical data revealed two trends: one group of lakes presented sodium and base, and the other group calcium and acid. Both these groups also presented some differences in their sediment characteristics, registering round pebbles, a higher percentage of sand and presence of mica in one of the lakes, contrasting with the muddy texture with predominance of quartz and kaolinite in the other lake. Such results allowed the proposition of two evolutionary models for the lakes of the São Francisco Lowlands, which share the same climate; evidence that the other landscape elements affect the system's dynamics. One of the models is represented by lakes that evolved from little permeable sedimentary rocks. These rocks, however, are more fractured, favouring the lakes area expansion and more water permanence with recent links to the river network. On the other proposed model, the lakes evolved from permeable but less fractured carbonic rocks with rapid vertical water infiltration and less water permanence, which reflects more atmospheric than lithological influence in their geochemical characteristics. This study provides important information for the comprehension of this landscape evolution.

Effect of tree roots on water infiltration rate into the soil

ABSTRACT- To study the effect of tree roots on increasing water infiltration in soil and also to determine and assess the coefficients of different infiltration models, some infiltration tests were performed in three tree plantation areas in Badjgah, Fars province with different soil textures (clay loam for pear plantation, sandy loam for grape plantation, loamy sand for pine trees). In each plantation, four double rings were installed, whereas two double rings were placed under the tree in two sides of the tree truck with 50 cm distance and the other two double rings were placed on open space between the trees. Vertical infiltration of water into the soil was measured and the coefficients of five models of infiltration (i.e. Kostiakov, Kostiakov-Lewis, Philip, Soil Conservation Service (SCS) and Horton) were assessed. Furthermore, soil texture and initial soil water content were determined in these points. Results showed that all models accurately fitted to the measured values. The infiltration rate under the trees was higher than those between the trees due to the occurrence of roots and root channels that improved the rate of infiltration of water into the soil. The 180-minute infiltration under the trees increased 69% and 354% in loamy sand and clay loam, respectively compared with those on open space between the trees.

Effect of Pisha sandstone on water infiltration of different soils on the Chinese Loess Plateau

The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density (BD), porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity (Ks). The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1:3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.

Estimation of evapotranspiration losses in the vadose zone using stable isotopes and chloride mass balance method

This study used stable isotope and chloride data of porewater to evaluate water fluxes through the vadose zone and thereby estimate evapotranspiration water losses in parts of the Nabogo catchment of the White Volta Basin in Ghana. The overall objective was to develop a framework so that the recharge regime can be properly conceptualized for numerical hydrological modeling. Unsaturated zone material was sampled at regular intervals of 50 cm to a maximum depth of 300 cm in four different locations in the study area. Rainwater, groundwater and surface water were simultaneously sampled and analyzed for their δ18O and δ2H characteristics. Porewater, extracted from the unsaturated zone material was analyzed for the δ18O and δ2H and chloride content and profiles were created to gauge the isotopic evolution of precipitation and estimate evaporative losses at each interval of the sampling. The chloride mass balance technique was used to estimate the fraction of infiltrating water remaining at each interval of the sampling. Transpiration losses through the entire profile were then estimated. This study finds that the vertical infiltration of water through the vadose zone is dominated by piston flow and a mixture of piston and preferential flows. In the shallow subsurface (0.0–3.0 m), evaporative losses estimated from stable isotope data fall in the range of 29.3–52.4 % (322.3–576.4 mm/year) of the annual precipitation, with an average of 40 % (or 440 mm/year). Estimated vadose zone recharge at the maximum depth of sampling ranges between 11.1 and 185 mm/year with an average of 32.9 mm/year, representing 1.1, 18.5, and 3.29 % of the annual precipitation, respectively. Estimated transpiration losses within this interval range between 29.1 % (290 mm/year) and 69.5 % (695 mm/year), with an average of 54.7 % (547 mm/year) of the annual precipitation. Transpiration losses appear to increase down the profile and apparently account for a significant percentage of water losses in the vadose zone. A significant proportion of the original precipitation is lost within the upper 300 cm (3 m) of the vadose zone. The Water Table Fluctuations method was independently used to estimate saturated zone groundwater recharge and indicates that recharge rates range between 64.65 and 151.2 mm/year with an average of 102.5 mm/year which, respectively represent 5.9, 13.7, and 9.3 % of the average annual precipitation in the area. The apparently higher estimates from the water table fluctuations method may arise from uncertainties in the specific yield values used for the vadose zone material.

Infiltration Characteristics of Topsoil in Reclamation Farmland Filled with Yellow River Sediment

Infiltration is an important indicator of water and nutrient holding capacity of soil. Lap infiltration apparatus was used to measure vertical water infiltration process in the third year of Yellow River sediment filling reclamation. Five infiltration models were selected to fit the infiltration characteristic curves, analyzed the infiltration experimental results during 3 years of reclamation. The results showed that, the mean initial infiltration rate and mean stable infiltration rate of filling farmland in the third year were 17.06mm/min and 2.38mm/min, and were 8.81mm/min and 0.99 mm/min higher than that of the first year, 3.58mm/min and 0.39mm/min higher than that of the second year. It indicated that, infiltration rate of filling farmland increased significantly after cultivation due to the farming practices and roots development, and the role of soil microorganisms and small animals. Filling farmland has some self-recovery capabilities. In addition, Kostiakov model has better fitting effect than Mezencev model for both filling farmland and control farmland.

산사태해석을 위한 GIS기반의 강우침투-지하수흐름 예측 기법 제안

This paper describes a GIS-based geohydrologic methodology, called YSGWF (YonSei GroundWater Flow) for predicting the rainfall infiltration-groundwater flow of slopes. This physical-based model was developed by the combination of modified Green-Ampt model that considers the unsaturated soil parameters and GIS-based raster model using Darcy`s law that reflects the groundwater flow. In the model, raster data are used to simulate the three dimensional inclination of bedrock surface as actual topographic data, and the groundwater flow is governed by the slope. Also, soil profile is ideally subdivided into three zones, i.e., the wetting band zone, partially saturated zone, and fully saturated zone. In the wetting band and partially saturated zones the vertical infiltration of water (rainfall) from surface into ground is modeled. When the infiltrated water recharges into the fully saturated zone, the horizontal flow of groundwater is introduced. A comparison between the numerical calculation and real landslide data shows a reasonable agreement, which indicate that the model can be used to simulate real rainfall infiltration-groundwater flow.