An analytical solution for the lateral transport of dissolved chemicals in overland flow-varying soil surface concentration

1997 ◽  
Vol 28 (1-2) ◽  
pp. 21-38
Author(s):  
Judith Rivlin ◽  
Rony Wallach ◽  
Galina Grigorin
Keyword(s):  
Analytical Solution ◽  
Overland Flow ◽  
Soil Surface ◽  
Surface Concentration ◽  
Lateral Transport ◽  
Dissolved Chemicals

scholarly journals Scale effect on overland flow connectivity at the plot scale

2013 ◽  
Vol 17 (1) ◽  
pp. 87-101 ◽  
Author(s):  
A. Peñuela ◽  
M. Javaux ◽  
C. L. Bielders
Keyword(s):  
Scale Effect ◽  
Overland Flow ◽  
Soil Surface ◽  
Real Field ◽  
Flow Paths ◽  
Essential Information ◽  
Elevation Data ◽  
Distributed Hydrological Models ◽  
Outflow Boundary ◽  
Degree Of Filling

Abstract. A major challenge in present-day hydrological sciences is to enhance the performance of existing distributed hydrological models through a better description of subgrid processes, in particular the subgrid connectivity of flow paths. The Relative Surface Connection (RSC) function was proposed by Antoine et al. (2009) as a functional indicator of runoff flow connectivity. For a given area, it expresses the percentage of the surface connected to the outflow boundary (C) as a function of the degree of filling of the depression storage. This function explicitly integrates the flow network at the soil surface and hence provides essential information regarding the flow paths' connectivity. It has been shown that this function could help improve the modeling of the hydrograph at the square meter scale, yet it is unknown how the scale affects the RSC function, and whether and how it can be extrapolated to other scales. The main objective of this research is to study the scale effect on overland flow connectivity (RSC function). For this purpose, digital elevation data of a real field (9 × 3 m) and three synthetic fields (6 × 6 m) with contrasting hydrological responses were used, and the RSC function was calculated at different scales by changing the length (l) or width (w) of the field. To different extents depending on the microtopography, border effects were observed for the smaller scales when decreasing l or w, which resulted in a strong decrease or increase of the maximum depression storage, respectively. There was no scale effect on the RSC function when changing w, but a remarkable scale effect was observed in the RSC function when changing l. In general, for a given degree of filling of the depression storage, C decreased as l increased, the change in C being inversely proportional to the change in l. However, this observation applied only up to approx. 50–70% (depending on the hydrological response of the field) of filling of depression storage, after which no correlation was found between C and l. The results of this study help identify the minimal scale to study overland flow connectivity. At scales larger than the minimal scale, the RSC function showed a great potential to be extrapolated to other scales.

A General Analytical Solution for the Concentration Profiles of Ion-Exchanged Planar Waveguides

1991 ◽  
Vol 244 ◽  
Author(s):  
Xiaoming Li ◽  
Paul F. Johnson
Keyword(s):  
Ion Exchange ◽  
Analytical Solution ◽  
Boundary Conditions ◽  
Surface Concentration ◽  
Concentration Profiles ◽  
Concentration Boundary ◽  
Glass Waveguides ◽  
General Analytical Solution ◽  
Exchange Processes ◽  
One Step

ABSTRACTDuring the recent years, a great variety of ion-exchange processes, including one-step or two-step electric field assisted ion-exchange processes, have been developed to fabricate different kinds of passive planar glass waveguides, e.g., surface waveguides, which correspond to surface maximum concentration, or buried waveguides, which correspond to inside maximum concentration [1,2,3]. Theoretical calculation of ionic concentration distribution has been of interest since refractive index is generally a linear function of concentration. A general analytical solution to calculate both surface and buried concentration distributions from different ion-exchange processes, however, has not yet been presented. In addition, traditional ion-exchange has been carried out only with constant surface concentration boundary conditions. Little attention has been paid, either experimentally or theoretically, to ion-exchange processes with variable boundary conditions. In fact, the time-dependent surface concentration is experimentally observed for the ion-exchange of GRIN glass in molten salt bath [4]. Very recently, a novel one-step technique [5,6] involving electric field assisted ion-exchange of Na+ in glass by Ag+ from molten AgNO3 bath with decaying silver concentration has been developed to produce buried Ag+ concentration profiles in glass. As the accurate and reproducible processes are very important for fabricating ion-exchanged glass waveguides, theoretical modeling and analysis on the new process are needed.In this paper, the one-dimensional field-assisted linear diffusion equation has been analytically solved by Laplace transformation to theoretically calculate concentration profiles produced by field enhanced ion-exchange process with exponentially decaying surface concentration boundary conditions. The applications of the solution to a variety of ion-exchange processes with different boundary or processing conditions for optical waveguide fabrication have been discussed. The theoretical results prove that the solution is a general analytical solution which can be used to calculate either surface concentration profiles or buried concentration profiles.

Evaluation of the potential to dispose of sewage-sludge. 1. Soil hydraulic and overland-flow properties of Pinus plantations in Queensland

Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 1041 ◽  
Author(s):  
A Costantini ◽  
RJ Loch ◽  
SF Glanville ◽  
DN Orange
Keyword(s):  
Sewage Sludge ◽  
Ground Water ◽  
Overland Flow ◽  
Water Movement ◽  
Soil Surface ◽  
Water Infiltration ◽  
Podzolic Soils ◽  
Antecedent Conditions ◽  
Ground Water Pollution ◽  
Sludge Application

The studies reported in this paper were designed to evaluate the potential for disposal of sewage sludge in commercial Pinus plantations at Beerburrum, 50 km north of Brisbane. Soil descriptions and measurements of hydraulic properties were made in three soils, covering the range of perceived site suitability for sludge application. Disc permeameters and a rainfall simulator were used to characterize surface infiltration properties both with and without sludge, and ponded rings were used to assess permeability of the upper B horizon. Although surface hydraulic conductivities were potentially high, infiltration into dry soil was reduced by water repellence associated with fungal matting at the soil surface and mycelia extending through the Al horizon. Surface runoff could be generated from dry soils by relatively low intensity rainfall events, and the rate and volume of runoff was not increased by broadcast sludge application. Hydraulic conductivities of the upper Bt horizons in the lateritic and yellow podzolic soils were high, suggesting that persistent perched watertable development was unlikely. However, the presence of bleached A2 horizons and gleyed Bt horizons with prominent mottling in these soils were interpreted as evidence of periodic regional ground-water intrusion. By contrast, hydraulic conductivity in the Bt horizon of the soloth was low, suggesting that locally restricted drainage occurs. Likely pathways of water movement were inferred for three representative soil types in the proposed sludge application project. There is potential for both Hortonian runoff when antecedent conditions are dry, and saturated runoff during prolonged wet periods. Potential off-site pollution could therefore occur if either solids or solutes from the sludge are susceptible to transport. In addition, preferential how paths of water infiltration were demonstrated, and the potential for accelerated water and solute movement to ground watertables was inferred. The studies reported in this, and the second, paper in the series were used to appraise the potential for either surface water or ground water pollution from land-based sludge disposal.

Effects of Near Soil Surface Characteristics on Soil Detachment by Overland Flow in a Natural Succession Grassland

2014 ◽  
Vol 78 (2) ◽  
pp. 589-597 ◽  
Author(s):  
Bing Wang ◽  
Guang-Hui Zhang ◽  
X.C. Zhang ◽  
Zhen-Wei Li ◽  
Zi-Long Su ◽  
...  
Keyword(s):  
Overland Flow ◽  
Soil Surface ◽  
Surface Characteristics ◽  
Natural Succession

scholarly journals Surface Detention on Cropland, Rangeland, and Conservation Reserve Program Areas

2018 ◽  
Vol 61 (3) ◽  
pp. 955-966
Author(s):  
John . E Gilley
Keyword(s):  
Overland Flow ◽  
Thin Sheet ◽  
Conservation Reserve Program ◽  
Soil Surface ◽  
Field Studies ◽  
Rainfall Simulation ◽  
Vegetative Cover ◽  
No Till ◽  
Corn Residue ◽  
Study Sites

Abstract. One of the factors contributing to overland flow on upland areas is water stored temporarily in a thin sheet on the soil surface as surface detention. This study was conducted to quantify surface detention on selected cropland, rangeland, and Conservation Reserve Program (CRP) sites. Surface detention was determined from the recession portion of runoff hydrographs corresponding with the period when rainfall had ceased but runoff continued. The hydrographs were generated from six previously reported rainfall simulation studies conducted on paired 3.7 m wide × 10.7 m long plots on which approximately 128 mm of rainfall was applied. Surface detention values were found to increase as crop residue or vegetative cover increased. Eleven fallow cropland sites in the eastern U.S. had surface detention values that varied from 1.7 to 4.6 mm. Surface detention on plots in southwestern Oklahoma containing Old World bluestem, no-till wheat, and conservation-till wheat was 9.4, 7.3, and 5.2 mm, respectively. No-till sorghum, tilled sorghum, no-till wheat, and tilled wheat plots in southeast Nebraska had surface detention values of 6.7, 4.5, 6.7, and 4.6 mm, respectively. Mean surface detention on no-till and tilled cropland sites in southwest Iowa containing corn residue was 7.2 and 5.9 mm, respectively. CRP study sites in southwestern Iowa had mean surface detention of 10.8 mm. When data from the six field studies were combined, mean surface detention values for fallow cropland, tilled cropland, no-till cropland, rangeland, and CRP areas were 3.1, 5.0, 6.9, 9.6, and 10.8 mm, respectively. Keywords: Depressional storage, Hydrographs, Hydrologic modeling, Overland flow, Runoff volume, Surface detention.

scholarly journals AN ANALYTICAL SOLUTION OF KINEMATIC WAVE EQUATIONS FOR OVERLAND FLOW UNDER GREEN-AMPT INFILTRATION

2010 ◽  
Vol 41 (1) ◽  
pp. 41 ◽  
Author(s):  
Giorgio Baiamonte ◽  
Carmelo Agnese
Keyword(s):  
Analytical Solution ◽  
Wave Equations ◽  
Rainfall Intensity ◽  
Overland Flow ◽  
Kinematic Wave ◽  
Transitional Regime ◽  
Infiltration Process ◽  
Storage Model ◽  
Present Solution ◽  
Additional Resistance

This paper deals with the analytical solution of kinematic wave equations for overland flow occurring in an infiltrating hillslope. The infiltration process is described by the Green-Ampt model. The solution is derived only for the case of an intermediate flow regime between laminar and turbulent ones. A transitional regime can be considered a reliable flow condition when, to the laminar overland flow, is also associated the effect of the additional resistance due to raindrop impact. With reference to the simple case of an impervious hillslope, a comparison was carried out between the present solution and the non-linear storage model. Some applications of the present solution were performed to investigate the effect of main parameter variability on the hillslope response. Particularly, the effect of hillslope geometry and rainfall intensity on the time to equilibrium is shown.

scholarly journals Hydrological connectivity inferred from diatom transport through the riparian-stream system

2015 ◽  
Vol 19 (7) ◽  
pp. 3133-3151 ◽  
Author(s):  
N. Martínez-Carreras ◽  
C. E. Wetzel ◽  
J. Frentress ◽  
L. Ector ◽  
J. J. McDonnell ◽  
...  
Keyword(s):  
Overland Flow ◽  
Riparian Zone ◽  
Stream Water ◽  
Soil Surface ◽  
Species Assemblages ◽  
Hydrological Connectivity ◽  
Diatom Species ◽  
Hydrograph Separation ◽  
Algal Groups ◽  
Runoff Events

Abstract. Diatoms (Bacillariophyta) are one of the most common and diverse algal groups (ca. 200 000 species, ≈ 10–200 μm, unicellular, eukaryotic). Here we investigate the potential of aerial diatoms (i.e. diatoms nearly exclusively occurring outside water bodies, in wet, moist or temporarily dry places) to infer surface hydrological connectivity between hillslope-riparian-stream (HRS) landscape units during storm runoff events. We present data from the Weierbach catchment (0.45 km2, northwestern Luxembourg) that quantify the relative abundance of aerial diatom species on hillslopes and in riparian zones (i.e. surface soils, litter, bryophytes and vegetation) and within streams (i.e. stream water, epilithon and epipelon). We tested the hypothesis that different diatom species assemblages inhabit specific moisture domains of the catchment (i.e. HRS units) and, consequently, the presence of certain species assemblages in the stream during runoff events offers the potential for recording whether there was hydrological connectivity between these domains or not. We found that a higher percentage of aerial diatom species was present in samples collected from the riparian and hillslope zones than inside the stream. However, diatoms were absent on hillslopes covered by dry litter and the quantities of diatoms (in absolute numbers) were small in the rest of hillslope samples. This limits their use for inferring hillslope-riparian zone connectivity. Our results also showed that aerial diatom abundance in the stream increased systematically during all sampled events (n = 11, 2011–2012) in response to incident precipitation and increasing discharge. This transport of aerial diatoms during events suggested a rapid connectivity between the soil surface and the stream. Diatom transport data were compared to two-component hydrograph separation, and end-member mixing analysis (EMMA) using stream water chemistry and stable isotope data. Hillslope overland flow was insignificant during most sampled events. This research suggests that diatoms were likely sourced exclusively from the riparian zone, since it was not only the largest aerial diatom reservoir, but also since soil water from the riparian zone was a major streamflow source during rainfall events under both wet and dry antecedent conditions. In comparison to other tracer methods, diatoms require taxonomy knowledge and a rather large processing time. However, they can provide unequivocal evidence of hydrological connectivity and potentially be used at larger catchment scales.

Effect of temporal rainfall distribution and soil type on soil moisture and runoff generation in semi-arid Zimbabwe

2007 ◽  
Vol 38 (3) ◽  
pp. 249-263 ◽  
Author(s):  
F.T. Mugabe ◽  
M.G. Hodnett ◽  
A. Senzanje
Keyword(s):  
Soil Moisture ◽  
Overland Flow ◽  
Daily Rainfall ◽  
Soil Surface ◽  
Runoff Generation ◽  
Stream Channels ◽  
Wet Season ◽  
Sodic Soils ◽  
Rainfall Distribution ◽  
Semi Arid

This paper examines the effect of temporal rainfall distribution on soil moisture and runoff generation in the 5.9 km2 Mutangi catchment in semi-arid Zimbabwe. Rainfall, soil moisture and runoff were measured during the 1999/00 and 2000/01 rainy seasons during which periods 755 mm and 615 mm of rainfall were received, respectively. The percentage of rainfall totals in these periods were 58% and 69%, respectively, in February. The total catchment runoff was 102 mm and 63 mm, of which 52% and 49% were recorded over 6 and 4 d in 2000 and 2001, respectively. Baseflow was negligible. Rainfall intensities were generally low. In the 1999/00 season there were 2 and 8 h with intensities >20 mm h−1 and 10 mm h−1, respectively. Some runoff appears to be generated by Hortonian overland flow (HOF), mainly in the early wet season before ploughing creates a rougher soil surface. The dominant process of runoff in this catchment was saturated overland flow (SOF), which occurs when the soils become saturated from below. The sodic soils along the stream channels appear to generate most of the runoff because of their small capacity to store water before saturation. The ridge soils are coarse sands, with a large capacity to store rainfall. The transitional (slope) soils have an intermediate capacity to store water. If there is a sequence of daily events that completely fills the storage available in both the sodic and transitional soils, and which begins to saturate the ridge soils, there could be very large amounts of runoff (>50% of the daily rainfall). The occurrence of such runoff events depends very heavily on the distribution of rainfall. Dry spells between rain events create storage, thereby reducing the risk of runoff from the next events.

scholarly journals Assessing soil surface roughness decay during simulated rainfall by multifractal analysis

2008 ◽  
Vol 15 (3) ◽  
pp. 457-468 ◽  
Author(s):  
E. Vidal Vázquez ◽  
R. García Moreno ◽  
J. G. V. Miranda ◽  
M. C. Díaz ◽  
A. Saá Requejo ◽  
...  
Keyword(s):  
Multifractal Analysis ◽  
Laser Scanning ◽  
Overland Flow ◽  
Soil Surface ◽  
Data Sets ◽  
Simulated Rainfall ◽  
Initial State ◽  
Surface Microrelief ◽  
Elevation Data ◽  
Soil Surface Roughness

Abstract. Understanding and describing the spatial characteristics of soil surface microrelief are required for modelling overland flow and erosion. We employed the multifractal approach to characterize topographical point elevation data sets acquired by high resolution laser scanning for assessing the effect of simulated rainfall on microrelief decay. Three soil surfaces with different initial states or composition and rather smooth were prepared on microplots and subjected to successive events of simulated rainfall. Soil roughness was measured on a 2×2 mm2 grid, initially, i.e. before rain, and after each simulated storm, yielding a total of thirteen data sets for three rainfall sequences. The vertical microrelief component as described by the statistical index random roughness (RR) exhibited minor changes under rainfall in two out of three study cases, which was due to the imposed wet initial state constraining aggregate breakdown. The effect of cumulative rainfall on microrelief decay was also assessed by multifractal analysis performed with the box-count algorithm. Generalized dimension, Dq, spectra allowed characterization of the spatial variation of soil surface microrelief measured at the microplot scale. These Dq spectra were also sensitive to temporal changes in soil surface microrelief, so that in all the three study rain sequences, the initial soil surface and the surfaces disturbed by successive storms displayed great differences in their degree of multifractality. Therefore, Multifractal parameters best discriminate between successive soil stages under a given rain sequence. Decline of RR and multifractal parameters showed little or no association.

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