scholarly journals Coupling of unsaturated and saturated flow modelling - a strong point of the small research catchment Uhlířská

2020 ◽  
Author(s):  
Tomas Vitvar ◽  
Martin Šanda ◽  
Jakub Jankovec
Keyword(s):  
Residence Time ◽  
Preferential Flow ◽  
Saturated Zone ◽  
Soil Matrix ◽  
Riparian Wetland ◽  
The Czech Republic ◽  
Strong Point ◽  
Matrix Flow ◽  
Entire Matrix ◽  
Zone Modeling

Modelling results in the small (1.78 km2) experimental catchment Uhlířská located in the northern part of the Czech Republic at the average elevation of 822 m a.s.l. are presented. While the basic hydrological and meteorological monitoring has started already in 1982, investigation of the subsurface flow adjoined in 1995. A detailed survey of water and isotope (18O, 2H, 3H, 3H/3He) fluxes across the catchment storage compartments has been in operation since 2006. The combined vadose/saturated zones modeling with support of partial extrapolation of 18O content in precipitation yielded the following mean balance for the period 1961-2014: 456 out of 1220 mm annual precipitation depth are percolating through the soil matrix domain and 534 mm through the preferential domain in the hillslope soil profile. The saturated zone is recharged annually by 416 mm, consisting of the entire matrix flow and 12,5 % of the preferential flow from the permeable hillslopes covered by Cambisols and Podzols, as well as by the contribution of 22 mm from the less permeable riparian wetland Histosols. The aquifer geometry was determined by means of electrical resistivity tomography (ERT) including inverse modelling (RES2DINV). Water and isotope fluxes were computed using a sequence of models. They include S1D software for the vadose zone modeling including 18O transport and Modflow, Modpath and MT3DS determining residence time and flow trajectories in the saturated zone. Isotopes 3H and 3H/3He improved the model confidence. The water residence time on the hillslopes does not exceed 1 year, while the saturated zone indicates about 10 years, with a 20% portion of water older than 100 years in the deepest part of the aquifer. The combination of numerical modelling approaches with computation of water balance and isotope-supported calibration is considered innovative, particularly the 3H/3He method to determine water residence times of young groundwater in the saturated zone.

scholarly journals Quantifying the Importance of Preferential Flow in a Riparian Buffer

2021 ◽  
Vol 64 (3) ◽  
pp. 937-947
Author(s):  
Lucie Guertault ◽  
Garey A. Fox ◽  
Todd Halihan ◽  
Rafael Muñoz-Carpena
Keyword(s):  
Preferential Flow ◽  
Riparian Buffers ◽  
Riparian Buffer ◽  
Design Tools ◽  
Soil Matrix ◽  
Innovative Method ◽  
Matrix Flow ◽  
Buffer Design ◽  
Flow Pathways ◽  
Preferential Flow Pathways

HighlightsRiparian buffers and vegetative filter strips are uniquely susceptible to preferential flow.An innovative method is proposed to partition infiltration into matrix and macropore domains.Riparian buffer matrix and plot-scale infiltration experiments were simulated with HYDRUS-1D and VFSMOD.Preferential flow accounted for 32% to 47% of infiltration depending on hydrologic conditions.Preferential flow mechanisms should be incorporated into riparian buffer design tools and models.Abstract. Riparian buffers are uniquely susceptible to preferential flow due to the abundance of root channels, biological activity, and frequent wetting and drying cycles. Previous research has indicated such susceptibility and even measured the connectivity of preferential flow pathways with adjacent streams and rivers. However, limited research has attempted to partition the riparian buffer infiltration between matrix and preferential flow domains. The objectives of this research were to develop an innovative method to quantify soil matrix infiltration at the plot scale, develop a method to partition infiltration into matrix and macropore infiltration at the plot scale, and then use these methods to quantify the significance of macropore infiltration at a riparian buffer site. This research further demonstrated the importance of considering preferential flow processes in design tools and models to evaluate riparian buffer effectiveness. Sprinkler and runon field experiments were conducted at an established riparian buffer site with sandy loam soil. Trenches were installed and instrumented with soil moisture sensors along the width of the riparian buffer (i.e., along the flow path toward the stream) for detecting non-uniform flow patterns due to preferential flow. Riparian buffer parameters, including soil hydraulic parameters, were estimated using HYDRUS-1D for the sprinkler experiments and VFSMOD for the runon experiments. This research partitioned the infiltration into matrix and preferential flow domains by assuming negligible exchange of water between the soil matrix and preferential flow pathways in comparison to the magnitude of soil matrix flow. For these experimental conditions with 0.20 to 0.48 L s-1 of runon and initial soil water contents of 0.29 to 0.32 cm3 cm-3, preferential flow accounted for at least 27% to 32% of the total runon water entering the riparian buffer. This corresponded to approximately 32% to 47% of the total infiltration. While increasing the riparian buffer plot soil hydraulic conductivity in single-porosity models can adequately predict the total infiltration and therefore the surface outflow from the buffer, design tools and models should specifically consider preferential flow processes to improve predictive power regarding the actual infiltration processes and correspondingly the non-equilibrium flow and solute transport mechanisms. Keywords: Flow partitioning, HYDRUS, Matrix flow, Preferential flow, Riparian buffer, VFSMOD.

scholarly journals Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

2019 ◽  
Vol 23 (12) ◽  
pp. 5017-5031 ◽  
Author(s):  
Aaron A. Mohammed ◽  
Igor Pavlovskii ◽  
Edwin E. Cey ◽  
Masaki Hayashi
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Preferential Flow ◽  
Frozen Soil ◽  
Time Lags ◽  
Runoff Generation ◽  
Frozen Ground ◽  
Soil Matrix ◽  
Frozen Soils ◽  
Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when the ground is still frozen; thus frozen soil processes play an important role in snowmelt routing, and, by extension, the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterized by numerous topographic depressions where the ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35 %–85 %) of snowmelt under uplands (i.e. areas outside of depressions), even when the ground was frozen, with soil moisture responses indicating flow through the frozen layer. The refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 d between snow cover depletion on uplands and ponding in depressions demonstrated the role of a shallow subsurface transmission pathway or interflow through frozen soil in routing snowmelt from uplands to depressions. At all sites, depression-focused infiltration and recharge began before complete ground thaw and a significant portion (45 %–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both the lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flow paths may facilitate preferential mass transport to groundwater.

scholarly journals Dye staining and excavation of a lateral preferential flow network

2009 ◽  
Vol 13 (6) ◽  
pp. 935-944 ◽  
Author(s):  
A. E. Anderson ◽  
M. Weiler ◽  
Y. Alila ◽  
R. O. Hudson
Keyword(s):  
Slope Stability ◽  
Solute Transport ◽  
Preferential Flow ◽  
Runoff Generation ◽  
Flow Paths ◽  
Soil Matrix ◽  
Preferential Flow Paths ◽  
Dye Staining ◽  
Hillslope Scale ◽  
Surrounding Soil

Abstract. Preferential flow paths have been found to be important for runoff generation, solute transport, and slope stability in many areas around the world. Although many studies have identified the particular characteristics of individual features and measured the runoff generation and solute transport within hillslopes, very few studies have determined how individual features are hydraulically connected at a hillslope scale. In this study, we used dye staining and excavation to determine the morphology and spatial pattern of a preferential flow network over a large scale (30 m). We explore the feasibility of extending small-scale dye staining techniques to the hillslope scale. We determine the lateral preferential flow paths that are active during the steady-state flow conditions and their interaction with the surrounding soil matrix. We also calculate the velocities of the flow through each cross-section of the hillslope and compare them to hillslope scale applied tracer measurements. Finally, we investigate the relationship between the contributing area and the characteristics of the preferential flow paths. The experiment revealed that larger contributing areas coincided with highly developed and hydraulically connected preferential flow paths that had flow with little interaction with the surrounding soil matrix. We found evidence of subsurface erosion and deposition of soil and organic material laterally and vertically within the soil. These results are important because they add to the understanding of the runoff generation, solute transport, and slope stability of preferential flow-dominated hillslopes.

The Daisy agroecological system model: A physically based model for preferential water flow and solute transport in drained agricultural fields

2021 ◽  
Author(s):  
Efstathios Diamantopoulos ◽  
Maja Holbak ◽  
Per Abrahamsen
Keyword(s):  
Solute Transport ◽  
Water Flow ◽  
Preferential Flow ◽  
Column Experiment ◽  
Soil Matrix ◽  
Physically Based Model ◽  
Physically Based ◽  
Rapid Transport ◽  
Preferential Water

<p>Preferential water flow and solute transport in agricultural systems affects not only the quality of groundwater but also the quality of surface waters like streams and lakes. This is due to the rapid transport of agrochemicals, immediately after application, through subsurface drainpipes and surface water. Experimental evidence attributes this to the occurrence of continuously connected pathways, connecting the soil surface directly with the drainpipes. We developed a physically-based model describing preferential flow and transport in biopores and implemented it in the agroecological model Daisy. The model simulates the often observed rapid transport of chemicals from   the upper soil layers to the drainpipes or to deeper layers of the soil matrix. Based on field investigations, biopores with specific characteristics can be parameterized as classes with different vertical and horizontal distributions. The model was tested against experimental data from a column experiment with an artificial biopore and showed good results in simulating preferential flow dynamics. We illustrate the performance of the new approach, by conducting five simulations assuming a two-dimensional simulation domain with different biopore parametrizations, from none to several different classes. The simulation results agreed with experimental observations reported in the literature, indicating rapid transport from the soil to the drainpipes. Furthermore, the different biopore parametrizations resulted in distinctly different leaching patterns, raising the expectation that biopore properties could be estimated or constrained based on observed leaching data and direct measurements.</p>

Dual permeability soil water dynamics and water uptake by roots in irrigated potato fields

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
František Doležal ◽  
David Zumr ◽  
Josef Vacek ◽  
Josef Zavadil ◽  
Adriano Battilani ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Preferential Flow ◽  
Water Movement ◽  
Root Zone ◽  
Water Pressure ◽  
Boundary Curve ◽  
Water Dynamics ◽  
Permeability Model ◽  
Soil Matrix

AbstractWater movement and uptake by roots in a drip-irrigated potato field was studied by combining field experiments, outputs of numerical simulations and summary results of an EU project (www.fertorganic.org). Detailed measurements of soil suction and weather conditions in the Bohemo-Moravian highland made it possible to derive improved estimates of some parameters for the dual permeability model S1D_DUAL. A reasonably good agreement between the measured and the estimated soil hydraulic properties was obtained. The measured root zone depths were near to those obtained by inverse simulation with S1D _DUAL and to a boundary curve approximation. The measured and S1D _DUAL-simulated soil water pressure heads were comparable with those achieved by simulations with the Daisy model. During dry spells, the measured pressure heads tended to be higher than the simulated ones. In general, the former oscillated between the simulated values for soil matrix and those for the preferential flow (PF) domain. Irrigation facilitated deep seepage after rain events. We conclude that several parallel soil moisture sensors are needed for adequate irrigation control. The sensors cannot detect the time when the irrigation should be stopped.

Effects of Grass and Forests and the Infiltration Amount on Preferential Flow in Karst Regions of China

2020 ◽  
Author(s):  
Xiaoqing Kan ◽  
Jinhua Cheng
Keyword(s):  
Organic Matter ◽  
Preferential Flow ◽  
Water Movement ◽  
Vegetation Restoration ◽  
Water Infiltration ◽  
Rocky Desertification ◽  
Restoration Planning ◽  
Karst Areas ◽  
Matrix Flow ◽  
Natural Grassland

<p>  Preferential flow is an important water infiltration phenomenon in karst regions because it can quickly transport surface water to deep soil and increases available water for underground root growth. The response of preferential flow to vegetation restoration requires urgent investigation due to the special soil structure of karst regions. In order to study the effect of vegetation restoration on water movement in karst regions, four kinds of ponded water infiltration experiments were carried out in Pinus Yunnanensis plantation forestland, secondary forestland, and natural grassland. A brilliant blue dyeing experiment was conducted to visualize the distribution of water infiltration in soil (a total of 150 stained images from vertical soil slices). Results showed that the average depth of matrix flow in natural grassland was approximately six times those in plantation and secondary forestlands. An increase in matrix flow will have a negative effect on the development of preferential flow. Water transported in preferential flow paths affects the distribution of nutrients and organic matter in the soil. However, preferential flow in grassland can promote the accumulation of available nutrients, and preferential flow in plantations can inhibit the loss of organic matter. Preferential flow in grasslands and forest plantations is less than that in native forests soils. The results of SEM showed that preferential flow increases the percolation of water in soils. The effect is that preferential flow can obstructs water uptake by the roots under low rainfall conditions, and decreases surface runoff before soil saturation under high rainfall conditions. In the process of nutrient element migration, preferential flow has a good contribution, which is conducive to the migration and accumulation of elements required for surface vegetation growth. The contribution of preferential flow needs to be considered in studies on vegetation restoration planning and land degradation. Reasonable allocation of plantation forests has a certain mitigation effect on soil erosion in Karst areas, and preferential flow under this special geomorphological type is worth studying. Preferential flow can transport nutrients to deeper soil for roots according to the data of this study. Therefore, plantation is feasible under karst landform conditions, but it is better to combine herbaceous plants in a plantation. The results could provide suggestions for the restoration of rocky desertification and the advantages or disadvantages of vegetation restoration engineering in karst areas.</p>

Transport of iodide in structured soil under spring barley during irrigation experiment analyzed using dual-continuum model

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Jaromír Dušek ◽  
Ľubomír Lichner ◽  
Tomáš Vogel ◽  
Vlasta Štekauerová
Keyword(s):  
Continuum Model ◽  
Preferential Flow ◽  
Root Zone ◽  
Spring Barley ◽  
Soil Matrix ◽  
Iodide Transport ◽  
Loam Soil ◽  
Water Drops ◽  
Structured Soil ◽  
The One

AbstractTransport of radioactive iodide 131I− in a black clay loam soil under spring barley in an early ontogenesis phase was monitored during controlled field irrigation experiment. It was found that iodide bound in the soil matrix could be mobilized by the surface leaching enhanced by mechanical impact of water drops and transported below the root zone of crops via soil cracks. The iodide transport through structured soil profile was simulated by the one-dimensional dual-continuum model, which assumes the existence of two inter-connected flow domains: the soil matrix domain and the preferential flow domain. The model predicted relatively deep percolation of iodide within a short time, in a good agreement with the observed vertical iodide distribution in soil. The dual-continuum approach proved to be an adequate tool for evaluation of field irrigation experiments conducted in structured soils.

An event-based hydrologic simulation model for bioretention systems

2015 ◽  
Vol 72 (9) ◽  
pp. 1524-1533 ◽  
Author(s):  
A. Roy-Poirier ◽  
Y. Filion ◽  
P. Champagne
Keyword(s):  
Preferential Flow ◽  
Hydrologic Model ◽  
Soil Water Storage ◽  
Storm Event ◽  
System Modelling ◽  
Storm Events ◽  
Hydrologic Simulation ◽  
Soil Matrix ◽  
Improved Accuracy ◽  
Native Soils

Bioretention systems are designed to treat stormwater and provide attenuated drainage between storms. Bioretention has shown great potential at reducing the volume and improving the quality of stormwater. This study introduces the bioretention hydrologic model (BHM), a one-dimensional model that simulates the hydrologic response of a bioretention system over the duration of a storm event. BHM is based on the RECARGA model, but has been adapted for improved accuracy and integration of pollutant transport models. BHM contains four completely-mixed layers and accounts for evapotranspiration, overflow, exfiltration to native soils and underdrain discharge. Model results were evaluated against field data collected over 10 storm events. Simulated flows were particularly sensitive to antecedent water content and drainage parameters of bioretention soils, which were calibrated through an optimisation algorithm. Temporal disparity was observed between simulated and measured flows, which was attributed to preferential flow paths formed within the soil matrix of the field system. Modelling results suggest that soil water storage is the most important short-term hydrologic process in bioretention, with exfiltration having the potential to be significant in native soils with sufficient permeability.

scholarly journals Impacts of rainfall features and antecedent soil moisture on occurrence of preferential flow: A study at hillslopes using high-frequency monitoring

2016 ◽  
Author(s):  
Zhenyang Peng ◽  
Hongchang Hu ◽  
Fuqiang Tian ◽  
Qiang Tie ◽  
Sihan Zhao
Keyword(s):  
Soil Moisture ◽  
High Frequency ◽  
Preferential Flow ◽  
Rainfall Amount ◽  
Average Intensity ◽  
Wetting Front ◽  
Antecedent Soil Moisture ◽  
Soil Matrix ◽  
Surface Cover ◽  
Frequency Monitoring

Abstract. In order to evaluate influences of rainfall features and antecedent soil moisture on occurrence of preferential flow, observation was conducted at 12 sites within a 7-km2 catchment, by applying the high-frequency monitoring approach. Totally 65 rainfall events were selected to compare among sites, and preferential flow was inferred when (i) responses of soil moisture did not follow a linear sequence with depth, or (ii) penetration velocity of wetting front in at least one horizon exceeded the threshold, which was set to be 5–10 times of the saturated hydraulic conductivity of soil matrix at different depths. Results showed that frequency of preferential flow was 40.7 % in average, but varied from 17.9 % to 74.3 % among the sites. Correlations between the frequency and rainfall features, i.e. rainfall amount, duration, maximum and average intensity, were well fitted by logarithmic curves. Rainfall amount, which was most prominently correlated with frequency (R2 = 0.93), was regarded as the dominant driving factor of preferential flow, while average intensity was in second (R2 = 0.90). Antecedent soil moisture was also significantly correlated with the frequency. However, this should largely be attributed to the differences of soil moisture among sites, since varying range of soil moisture at a specific site was not wide enough to influence the frequency significantly. Further examination suggested that topography and surface cover (dead leaves and humus) were the controlling factors of both infiltration amount and occurrence of preferential flow, as water was more readily to infiltrate into soils and preferential flow was more readily to occur when slope gradient was small and surface cover was thick, while soil moisture was more likely to be a consequence of water storage capacity, rather than an inducer of preferential flow. This knowledge could be helpful in understanding the partitioning of surface runoff and infiltration, as well as runoff processes in catchments with complex topography and underlying conditions.

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