Preferential Flow Effects on Subsurface Contaminant Transport in Alluvial Floodplains

2010 ◽  
Vol 53 (1) ◽  
pp. 127-136 ◽  
Author(s):  
D. M. Heeren ◽  
R. B. Miller ◽  
G. A. Fox ◽  
D. E. Storm ◽  
T. Halihan ◽  
...  
Keyword(s):  
Contaminant Transport ◽  
Preferential Flow ◽  
Flow Effects ◽  
Alluvial Floodplains

Preferential Flow Path Effects on Subsurface Contaminant Transport in Alluvial Floodplains

2009 ◽  
Author(s):  
Derek M Heeren ◽  
Ron B Miller ◽  
Garey A Fox ◽  
Daniel E Storm ◽  
Chad J Penn ◽  
...  
Keyword(s):  
Contaminant Transport ◽  
Preferential Flow ◽  
Flow Path ◽  
Alluvial Floodplains ◽  
Preferential Flow Path

Development of a method for estimating the likelihood of crack flow in Canadian agricultural soils at the landscape scale

2010 ◽  
Vol 90 (1) ◽  
pp. 129-149 ◽  
Author(s):  
H. Dadfar ◽  
S E Allaire ◽  
R. De Jong ◽  
E. van Bochove ◽  
J -T Denault ◽  
...  
Keyword(s):  
Contaminant Transport ◽  
Best Management Practices ◽  
Water Contamination ◽  
Management Practices ◽  
Preferential Flow ◽  
Agricultural Soils ◽  
Landscape Scale ◽  
Tile Drainage ◽  
Risk Indicators ◽  
Subsurface Water

Indicators of risk of water contamination by agricultural pollutants are developed in Canada to assess sustainability of agriculture. Crack flow (CF), a key pathway for sub-surface contaminant transport, is part of the transport-hydrology algorithm used in two of these risk indicators. The objective was to develop a methodology for predicting the likelihood of CF in Canadian agricultural soils at the landscape scale. The algorithm considers soil clay content, crack development followed by a runoff event based on water budget, tile drainage, and crops. More than 40% of Canadian farmlands had moderate to very high likelihood of CF, mainly in Manitoba, Ontario and Quebec, due to frequent runoffs on cracked clay soils potentially contributing to groundwater contamination. In Ontario and Quebec, farmlands with high CF likelihood correspond to regions under intensive tile drainage, which increases the risk of lateral translocation of contaminants to surface water bodies. Besides being a component of risk indicators of water contamination by phosphorus and coliforms, the CF algorithm and maps can be used to identify areas at risk of subsurface water contamination. Best management practices, adapted to reduce CF can then be targeted to these areas.Key words: Agrichemicals, contaminant transport, macropore flow, preferential flow, risk assessment, risk indicators

Ponded infiltration into soil with biopores — field experiment and modeling

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Michal Dohnal ◽  
Jaromír Dušek ◽  
Tomáš Vogel ◽  
Milena Císlerová ◽  
Ľubomír Lichner ◽  
...  
Keyword(s):  
Water Flow ◽  
Preferential Flow ◽  
Water Pressure ◽  
Three Dimensional ◽  
Detailed Knowledge ◽  
Dye Tracer ◽  
Simulation Based ◽  
Flow Through ◽  
Flow Effects ◽  
Infiltration Experiment

AbstractPreferential movement of water in macropores plays an important role when the process of ponded infiltration in natural porous systems is studied. For example, the detailed knowledge of water flow through macropores is of a major importance when predicting runoff responses to rainfall events. The main objectives of this study are to detect preferential movement of water in Chernozem soil and to employ numerical modeling to describe the variably saturated flow during a field ponded infiltration experiment. The infiltration experiment was performed at the Macov experimental station (Calcari-Haplic Chernozem in Danubian Lowland, Slovakia). The experiment involved single ring ponded infiltration. At the quasi steady state phase of the experiment dye tracer was added to the infiltrating water. Then the soil profile was excavated and the penetration pattern of the applied tracer was recorded. The abundance of biopores as a product of fauna and flora was found. To quantify the preferential flow effects during the infiltration experiment, three-dimensional axisymmetric simulations were carried out by a two-dimensional dual-continuum numerical model. The water flow simulations based on measured hydraulic characteristics without consideration of preferential flow effects failed to describe the infiltration experiment adequately. The 3D axisymmetric simulation based on dual-permeability approach provided relatively realistic space-time distribution of soil water pressure below the infiltration ring.

Preferential Flow Effects on Infiltration and Runoff in Grassland and Forest Soils

2011 ◽  
Vol 10 (1) ◽  
pp. 367-377 ◽  
Author(s):  
A. Alaoui ◽  
U. Caduff ◽  
H.H. Gerke ◽  
R. Weingartner
Keyword(s):  
Forest Soils ◽  
Preferential Flow ◽  
Flow Effects

scholarly journals Preferential Flow Effects on NO3-N Losses with Tile Flow

2013 ◽  
Author(s):  
A. Bakhsh ◽  
R. S. Kanwar ◽  
D. B. Jaynes ◽  
T. S. Colvin ◽  
and L. R. Ahuja
Keyword(s):  
Preferential Flow ◽  
N Losses ◽  
Flow Effects ◽  
Tile Flow

scholarly journals Simple estimation of fastest preferential contaminant travel times in the unsaturated zone: application to Rainier Mesa and Shoshone Mountain, Nevada

2010 ◽  
Vol 7 (3) ◽  
pp. 3879-3930
Author(s):  
B. A. Ebel ◽  
J. R. Nimmo
Keyword(s):  
Simple Model ◽  
Contaminant Transport ◽  
Unsaturated Zone ◽  
Preferential Flow ◽  
Test Site ◽  
Water Sources ◽  
Travel Times ◽  
Saturated Zone ◽  
Recharge Rates ◽  
Unsaturated Zones

Abstract. Simulating contaminant transport in unsaturated zones with sparse hydraulic property information is a difficult, yet common, problem. When contaminant transport may occur via preferential flow, simple modeling approaches can provide predictions of interest, such as the first arrival of contaminant, with minimal site characterization. The conceptual model for unsaturated zone flow at two areas within the Nevada Test Site, Rainier Mesa and Shoshone Mountain, establishes the possibility of preferential flow through lithologies between potential radionuclide sources and the saturated zone. Lithology, saturated or near-saturated conditions in portions of the rock matrix, and relatively high recharge rates may act in concert at Rainier Mesa to promote preferential flow, despite the semi-arid climate. After identifying preferential flow as a possible contaminant transport process at Rainier Mesa and Shoshone Mountain, we apply a simple model to estimate fastest unsaturated travel times for conservatively-transported radionuclides to initially reach the saturated zone. Preferential flow travel times at Rainier Mesa are tens to hundreds of years for non-ponded water sources and one to two months for continuously-ponded water sources. If preferential flow occurs at Shoshone Mountain, the fastest travel times are approximately twice the Rainier Mesa estimates. A siliceous rock unit is present at Shoshone Mountain that may provide a barrier to preferential flow; if so, estimated transport times increase to more than a thousand years. Our analysis of unsaturated transport of radionuclides via preferential flow, using a relatively simple model, suggests that contaminated locations associated with continuously-supplied water sources, such as effluent ponds and water-filled tunnels, may have significantly shorter radionuclide travel times than locations not associated with such sources. The simple approach demonstrated here for estimating travel times can be useful in situations where predictions are needed by managers for the fastest arrival of contaminants, yet budgetary or time constraints preclude more rigorous analysis, and when additional model estimates are needed for comparison (i.e. model abstraction).

scholarly journals Microplastics and nanoplastics barely enhance contaminant mobility in agricultural soils

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Stephanie Castan ◽  
Charlotte Henkel ◽  
Thorsten Hüffer ◽  
Thilo Hofmann
Keyword(s):  
Contaminant Transport ◽  
Organic Contaminants ◽  
Preferential Flow ◽  
Agricultural Soils ◽  
Groundwater Resources ◽  
Agricultural Practices ◽  
Flow Conditions ◽  
Contaminant Mobility ◽  
Farmland Soils ◽  
Partitioning Coefficients

AbstractFarmland soils are prone to contamination with micro- and nanoplastics through a variety of agricultural practices. Concerns are recurrently raised that micro- and nanoplastics act as vector for organic contaminants to deeper soil layers and endanger groundwater resources. Whether and to what extent micro- and nanoplastics facilitate the transport of organic contaminants in soil remains unclear. Here we calculated the ratio between transport and desorption time scales using two diffusion models for micro- and nanoplastics between 100 nm and 1 mm. To identify micro- and nanoplastics bound contaminant transport we evaluated diffusion and partitioning coefficients of prominent agrochemicals and additives and of frequently used polymers e.g., polyethylene and tire material. Our findings suggest that the desorption of most organic contaminants is too fast for micro- and nanoplastics to act as transport facilitators in soil. Contaminant transport enabled by microplastics was found to be relevant only for very hydrophobic contaminants (logKow >5) under preferential flow conditions. While micro- and nanoplastics might be a source of potentially harmful contaminants in farmland soils this study suggests that they do not considerably enhance contaminant mobility.

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