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An integrated flow determination algorithm is proposed to calculate the spatial distribution of the topographic index to the channel network. The advantages of a single flow direction algorithm and other multiple flow direction schemes are selectively considered in order to address the drawbacks of existing algorithms. A spatially varying flow apportioning factor is introduced to distribute the contributing area from upslope cells to downslope cells. The channel initiation threshold concept is expanded and integrated into a spatially distributed flow apportioning algorithm to delineate a realistic channel network. The functional relationships between the flow apportioning factors and the expanded channel initiation threshold (ECIT) are developed to address the spatially varied flow distribution patterns considering the permanent channel locations. A genetic algorithm (GA) is integrated into the spatially distributed flow apportioning algorithm (SDFAA) with the objective function of river cell evaluation. An application of a field example suggests that the spatially distributed flow apportioning scheme provides several advantages over the existing approaches; the advantages include the relaxation of overdissipation problems near channel cells, the connectivity feature of river cells and the robustness of the parameter determination procedure over existing algorithms. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Sanghyun Kim 《水文研究》2012,26(22):3434-3447
The vertical and lateral profiles of temporal variations in soil moisture are important for understanding the hydrological process along hillside transects. In this study, relationships among measured soil moistures were explored to configure the hydrological contributions of different flowpaths. All the measured soil moistures included a common stochastic structure because rainfall, the hydrometeological driver, is the main factor that determines the soil moisture response feature, and the infiltration process through the topsoil at a shallow depth is also common in all measured soil moisture histories. Therefore, the relationships between the measured series are also affected by both rainfall and topsoil infiltration. The common stochastic structure of the soil moisture series was removed via a prewhitening procedure. A systematic analysis procedure is presented to delineate the exclusive causal relationships among multiple soil moisture measurements. A monitoring system based on multiplexed time domain reflectometry was used to obtain soil moisture time series along two transects on a steep hillslope during the rainy season. The application of the proposed method for monitoring points in two adjacent locations provided 8, 12, 14, and 13, 16, 22 causal relationships for vertical, lateral in parallel, and diagonal directions, respectively, along the two transects. The point‐based contributions of the internal flowpath can be evaluated as the correlation is normalized in the context of inflow and outflow. The hydrological processes in the soil layer, vertical flow, lateral flow, downslope recharge, and return flow were quantified, and the relative importance of each hydrological component was determined to improve our understanding of the hydrological processes along the two transects of the study area. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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In this study, the spatial distribution of measured soil moisture was analyzed on the platform of multivariate modeling. Soil moisture time series for two seasons were selected and used for analysis to reveal similarities and differences in soil moisture responses for a few rainfall events. The development of a soil moisture transport process that considers the representative element volume and uncertainty of soil media provides the hydrological basis for time series modeling. The systematic procedure of Box–Jenkins with noise modeling was used to delineate the final models for all monitoring points. The physical basis of mass balance and the continuity in inflow contribution, as well as statistical criteria, were used in the model selection procedure. Heuristic approaches provide the spatial distribution of selected models along the transect of a hillside. Comparative analysis for two different depths and seasons provide an understanding of the variation in soil moisture transfer processes at the hillslope scale. Differences in soil moisture models for both depths and seasons are associated with eco-hydrological processes. The relationships between distributed topographic features and modeling results were explored to configure dominant hydrological processes for each season. 相似文献
5.
Estimation of mean water transit time on a steep hillslope in South Korea using soil moisture measurements and deuterium excess 
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下载免费PDF全文 A method for estimating daily mean transit time (DMTT) within a soil layer was proposed using field measurements of soil moisture. Vertical profiles of soil moisture time series were used for storage estimation. Water fluxes were evaluated through matrix and bypass flow. Variations in soil moisture and soil thickness were used to evaluate matrix flow. Exponential decay in depth of macropores was also used for bypass flow approximation. DMTT evaluation was compared to results obtained from a stable water isotope model using two years of data acquired on a steep granite hillslope in the Sulmachun watershed, South Korea. Various uncertainties in transit time evaluation such as model structure, non‐stationary assumption and data acquisition of existing approaches can be accounted for in the proposed methodology, and the flowpath contribution can be further configured in conjunction with hydrometric measurements. Probability density functions of isotope analyses were partially explained by transit time distributions that were based on soil moisture measurements. Supplementary sensitivity analyses for uncertainty configurations indicate that matrix flow is the primary process in determining transit time distribution while the impact of bypass flow is minor. The feasibility of a DMTT approach over isotope‐based methodologies highlights not only the strength of this proposed method, both in cost and time, but also its further application potential for existing soil moisture measurements. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
In this study, a soil monitoring system for a hillslope with steep relief and shallow soil depth was designed and installed to represent efficiently the spatial and temporal features of soil moisture. The study was conducted on a mountainous hillslope of the Sulmachun catchment (northeastern South Korea). The positions of soil moisture sensors were determined through a sequential procedure including intensive geomorphologic surveying of the study area, surface and subsurface terrain analysis, and inverse surveying. Using 26 sensors, soil moisture data from 11 locations were measured and recorded at hourly intervals over 380 h from 6 to 22 November 2003. Soil moisture response patterns were captured for a few consecutive rainfall events. The monitoring results are discussed in the context of soil moisture variations with terrain attributes. The immediate recharge and fast recession after a peak are the primary features of soil moisture in the upper zone. Stability and significant storage increase are distinct characteristics of soil moisture in the buffer zone and the flow path zone respectively. Spatial distribution of temporal soil moisture variations can be characterized in terms of recession, stability and recharge depending upon the topographic classification of a hillslope for this approach. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
7.
A phase-field approach for fluid-driven fracture propagation in porous media with varying constant compatible stress boundary conditions is discussed and implemented. Since crack opening displacement, fracture path, and stress values near the fracture are highly dependent on the given boundary conditions, it is crucial to take into account the impact of in situ stresses on fracturing propagation for realistic applications. We illustrate several numerical examples that include the effects of different boundary conditions on the fracture propagation. In addition, an example using realistic boundary conditions from a reservoir simulator is included to show the capabilities of our computational framework. 相似文献
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We present a framework for the coupling of fluid-filled fracture propagation and a genetic inverse algorithm for optimizing hydraulic fracturing scenarios in porous media. Fracture propagations are described by employing a phase field approach, which treats fracture surfaces as diffusive zones rather than of interfaces. Performance of the coupled approach is provided with applications to numerical experiments related to maximizing production or reservoir history matching for emphasizing the capability of the framework. 相似文献
9.
Quantification of the saturation degree of nonaqueous phase liquid in the vadose zone using hydrocarbon partitioning tracers 总被引：1，自引：1，他引：0
Partitioning tracer tests, as an alternative to the core sampling method, were conducted to quantify the degree of saturation
of water and nonaqueous phase liquids (NAPL) in the vadose zone. Hydrocarbon gases, which have less effect on global warming
than conventional tracers, were used as partitioning tracers. Column tests using CH4, C3H5, and C4H10 as non-partitioning and partitioning tracers were performed to determine the retardation factor and partition coefficient
of the tracer into water and NAPL. The retardation factors of these tracers were estimated to be in the range of 1.0–7.0 based
on breakthrough curves of the tracers. The partition coefficient of C3H5 to water and diesel phase was calculated to be 0.57 and 8.45, respectively. For a heavier tracer, C4H10, the partition coefficient to the water and diesel phases was 1.2 and 40.5, respectively. The average value of water and
diesel saturation estimated from column tests agreed well with known values in unsaturated soil. A residence time longer than
7.5 h within soil pores was found to provide local equilibrium partitioning of the tracer to the diesel phase. The concentration
of tracer had no effect on the partitioning process. 相似文献
10.
The salinity of groundwater in an estuarine delta plain is sometimes related to the presence of an estuarine dam. To understand groundwater processes and salinity variation, time series data on the river water level, groundwater level, and groundwater electrical conductivity were collected for the Nakdong River in southeastern Republic of Korea. Sampling was undertaken upstream of the estuarine barrage system, which is opened and closed depending on upstream flow and seawater level. Comprehensive correlation analysis was performed between the groundwater and river water levels using bubble plots between groundwater electrical conductivity and the hydrological variables. Comparative analysis between the correlations and the field measurements of the hydrological variables indicated a negligible flux connection between the river and groundwater. Oscillatory pressure wave propagation from the river boundary explains the response patterns of the groundwater level. There were different response times for the rising and falling of the river water. Electrical conductivity in groundwater is not directly associated with that of the river except in one well close to the river boundary. The response patterns of groundwater electrical conductivity were explained by potential anthropogenic activity. Further transfer modeling results also indicate a spatial explanatory response pattern for the groundwater level. No spatial patterns in the models of electrical conductivity indicate that the hydrological processes are different with respect to the groundwater level and electrical conductivity.
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