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Flooding caused by intensive precipitation has been in the centre of attention of both general public and scientists. From the flood risk management perspective, an integrated approach to catchment management is necessary, in particular with regards to water retention capacity. Our research has been focused on the high intensity rainfall, its short duration, and an adequate infiltration capacity into the soil profile in the upper parts of the catchment, the same as on the impact of soil characteristics such as moisture content and suction pressure, in particular. The five-year research period in two sub-catchments – Červík A and B – in the Beskydy Mts. enabled monitoring of about 300 events, and seventy of them with higher rainfall intensity were selected for further analysis. The analysis showed that the retention of an intensive precipitation was positively dependent on the instantaneous soil moisture and suction pressure. A continuous monitoring of these properties made it possible to quantify the potential runoff and the tendency to cause flooding. The analysis also showed an inverse situation in terms of the relationship between retention (and consequently runoff), suction pressure, and soil moisture content. It was therefore necessary to eliminate these by proposing suitable preventive bio-technical measures.

A three-dimensional solute transport model was developed and linked to a three-dimensional transient model for soil water flow and root growth. The simulation domain is discretized into a grid of finite elements by which the soil physical properties are spatially distributed. Solute transport modeling includes passive and active nutrient uptake by roots as well as zero-and first-order source/sink terms. Root water uptake modeling accounts for matric and osmotic potential effects on water and passive nutrient uptake. Root age effects on root water and nutrient uptake activity have been included, as well as the influence of nutrient deficiency and ion toxicity on root growth. Examples illustrate simulations with different levels of model complexity, depending on the amount of information available to the user. At the simplest level, root growth is simulated as a function of mechanical soil strength only. Application of the intermediate level with root water and nutrient uptake simulates the influence of timing and amount of NO₃ application on leaching. The most comprehensive level includes simulation of root and shoot growth as influenced by soil water and nutrient status, temperature, and dynamic allocation of assimilate to root and shoot.

Soil water movement with root water uptake is a key process for plant growth and transport of water and chemicals in the soil-plant system. In this study, a root water extraction model was developed to incorporate the effect of soil water deficit and plant root distributions on plant transpiration of annual crops. For several annual crops, normalized root density distribution functions were established to characterize the relative distributions of root density at different growth stages. The ratio of actual to potential cumulative transpiration was used to determine plant leaf area index under water stress from measurements of plant leaf area index at optimal soil water condition. The root water uptake model was implemented in a numerical model. The numerical model was applied to simulate soil water movement with root water uptake and simulation results were compared with field experimental data. The simulated soil mairie potential, soil water content and cumulative evapotranspirationhad reasonable agreement with the measured data. Potentially the numerical model implemented with the root water extraction model is a useful tool to study various problems related to flow transport with plant water uptake in variably saturated soils.

A model is presented for the simultaneous, dynamic simulation of soil water movement and plant root growth. Root apices are translocated in individual growth events as a function of current local soil conditions. A threedimensional finite-element grid over the considered soil domain serves to define the spatial distribution of soil physical properties and as framework for the transient water flow model. Examples illustrate how field-observed morphology of root systems can be approximated by including even a coarsely discretized description of the soil environment. Intended as a tool for testing of hypotheses on soil-plant interaction, simulations can be performed for different levels of model complexity, depending on how much information is available. At the simplest level, root growth is simulated without soil water uptake, whereas the most comprehensive level includes growth of the shoot and dynamic assimilate allocation to root and shoot.

For the measurement of the infiltration speed under operational conditions, we were equipped by a rain simulator with the measuring surface of 0.5 square m. The infiltration speed is determined from the defined rain intensity and water surface runoff from the measured surface. The retained water mass from the surface runoff is recorded at regular time intervals over the whole measuring period. The beginning of the water runoff from the measured surface indicates the beginning of elutriation. The measuring time is finished after the infiltration speed has been stabilised. The beginning of elutriation and infiltration speed stabilisation are typical and mutually comparable characteristics for defined soil properties at the site followed.

This study has been conducted with the aim to analyse the hydrology balance in the experimental watershed Uhlířská under the actual atmospheric conditions and expected climate changes in the upcoming years. The main accent is put on the water availability for the water root uptake by the dominant grass vegetation (Calamagrostis villosa). Special attention is paid to the seasonal potential evapotranspiration estimation under mountain climatic conditions. Three methods for the potential evapotranspiration quantification are analysed in order to find out the most acceptable approach for future periods for which no adequate weather data are available. The future precipitation and temperature data are simulated by the regional climate model HIRHAM which is driven by global climate model HadCM3. The data are simulated for the period from 2071 to 2100. The modelling of the soil water movement (using S1D model) is carried out on selected 18 years from the period of 1961–2005 and on selected 10 climate-change-affected years with extremely low precipitations high temperatures. The results of the scenario presented do not indicate that the climatic changes should significantly affect the hydrological balance in the studied area in terms of evapotranspiration up to the year 2100. Due to the lower seasonal precipitation and higher air the temperature, was increased in the results of simulations under the defined approach, however, the local vegetation cover did not suffer from insufficient water supply. These considerations are close to the simulation models used.

Poultry production in Kentucky increased almost 200% between 1991 and 1995. Their waste is typically land applied, and fecal pathogen runoff and infiltration may cause nonpoint source groundwater pollution. We looked at the preferential flow of fecal coliforms through undisturbed soil blocks since fecal bacteria typically infiltrate the soil profile to contaminate groundwater. Poultry manure was uniformly distributed on top of sod-covered or tilled (upper 12.5 cm) soil blocks and the blocks were irrigated. Drainage was collected in 100 uniformly spaced cells beneath each block and analyzed for fecal coliform content and drainage volume. The spatial distribution of drainage and fecal coliforms through the soil blocks was not uniform. Fecal coliforms appeared where most drainage flowed. Drainage water from each soil block consistently exceeded 200 000 fecal coliforms per 100 mL and was as great as 30 million fecal coliforms per 100 mL of leachate collected. Fecal coliforms leached as a pulse, but the breakthrough of fecal coliforms through tilled blocks was delayed with respect to the breakthrough of fecal coliforms through sod-covered blocks. Rainfall on a well-structured soil will cause the preferential movement of fecal bacteria, even with unsaturated flow conditions, and could contribute to fecal coliform concentrations in shallow groundwater that exceed standards for domestic discharge and primary contact water in Kentucky (200 fecal coliforms/100 mL)

Aluminium (Al) mobilisation in the forest soils is a serious problem due to the soil acidification. The rate and magnitude of leaching of Al and other elements and compounds from soils can be examined by means of percolation experiments. Aluminium elutriation was studied under laboratory conditions using undisturbed samples of forest topsoil from the Paličník area in the Jizera Mountains (Czech Republic), which originated under two different vegetation covers: European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst). Ponding infiltration was performed using three subsequently applied solutions. KCl solution was used to simulate the soil solution. Solutions with sulphates and nitrates addition (of two different pH values) were used to simulate acid rainfall. Passing liquid phase was analysed with respect to Al content and aluminium speciation. Differences were found in Al content and transport between different soils under spruce and beech covers. The soil sample under the spruce forest (SF sample) had a higher initial Al content than the soil sample under the beech forest (BF sample). As a result, the aluminium leaching from the spruce soil sample and the final content of water-extractable Al in the soil (Al content after the leaching experiment) were higher compared to the beech soil sample. This suggests that Al mobility and potential toxicity in the beech forest are grater than those in the spruce monoculture when studied in the acidification endangered areas.

A series of ground-water flow and tracer experiments were performed on an undisturbed column of fractured clay-rich till 0.5 m diameter by 0.5 m long. in a pressure-controlled cell. The measured hydraulic conductivity of the sample was 1.0 to 1.2 X 10-6 m/sec and the average hydraulic gradient during the tracer experiments ranged from 0.45 to 0.49. The experiments clearly show that ground-water flow and contaminant migration through the sample is primarily controlled by fractures and root holes. Tracer experiments using a solute (chloride) colloid-sized bacteriophage (PRD-1 and MS-2) and uncharged latex microspheres indicated very fast transport rates of 4 to 360 m/day. These rates are similar to fracture flow velocities calculated on the basis of the measured bulk hydraulic conductivity of the column and measured fracture spacing. using the cubic law for flow through parallel-walled fractures. Fracture aperture values calculated from the ground-water now data (35 to 56 micrometers) are of the same magnitude as values calculated from the breakthrough of tracers (13 to 120 micrometers). Aperture values calculated for fractures (I to 94 micrometers) and root holes (2 to 188 micrometers) on the basis of measured immiscibile creosote entry pressures are also comparable with these values. The injected creosote a DNAPL, penetrated most of the visible and a few invisible fractures and root holes indicating that. for this till. fractures and root holes are important conduits for the transport of DNAPL's