A new tool for hillslope hydrologists: spatially distributed groundwater level and soilwater content measured using electromagnetic induction

Sherlock, Mark D.; McDonnell, Jeffrey J.

doi:10.1002/hyp.1221

Cited by 75 publications

(53 citation statements)

References 14 publications

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“…We assumed that the change in soil water content was the main control of the temporal variation in ECa values during our repeated EMI surveys from January to June 2008 (note that all temperatures were corrected to a standard value). This is consistent with some previous studies that reported strong correlation between soil ECa and soil water storage (e.g., Sherlock and McDonnell, 2003;Reedy and Scalon, 2003). Thus, the higher and less stable ECa values in areas closer to the simulated flow paths (Fig.…”

Section: Discussionsupporting

confidence: 93%

“…Previous studies have used soil ECa from EMI surveys to represent soil water content. For example, Sherlock and McDonnell (2003) reported that soil ECa from EM38 (Geonics, Mississauga, Canada) vertical dipole mode could explain over 70% of gravimetrically determined soil-water variance. Reedy and Scanlon (2003) used the same sensor to explain 80% of the averaged volumetric water content in the soil profile.…”

Section: Introductionmentioning

confidence: 99%

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Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape

Zhu

Lin

2009

Hydrol. Earth Syst. Sci.

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Abstract. The importance of soil water flow paths to the transport of nutrients and contaminants has long been recognized. However, effective means of detecting concentrated subsurface flow paths in a large landscape are still lacking. The flow direction and accumulation algorithm based on single-direction flow algorithm (D8) in GIS hydrologic modeling is a cost-effective way to simulate potential concentrated flow paths over a large area once relevant data are collected. This study tested the D8 algorithm for simulating concentrated lateral flow paths at three interfaces in soil profiles in a 19.5-ha agricultural landscape in central Pennsylvania, USA. These interfaces were (1) the interface between surface plowed layers of Ap1 and Ap2 horizons, (2) the interface with subsoil water-restricting clay layer where clay content increased to over 40%, and (3) the soil-bedrock interface. The simulated flow paths were validated through soil hydrologic monitoring, geophysical surveys, and observable soil morphological features. The results confirmed that concentrated subsurface lateral flow occurred at the interfaces with the clay layer and the underlying bedrock. At these two interfaces, the soils on the simulated flow paths were closer to saturation and showed more temporally unstable moisture dynamics than those off the simulated flow paths. Apparent electrical conductivity in the soil on the simulated flow paths was elevated and temporally unstable as compared to those outside the simulated paths. The soil cores collected from the simulated flow paths showed significantly higher Mn content at these interfaces than those away from the simulated paths. These results suggest that (1) the D8 algorithm is useful in simulating possible concentrated subsurface latCorrespondence to: H. S. Lin (henrylin@psu.edu) eral flow paths if used with appropriate threshold value of contributing area and sufficiently detailed digital elevation model (DEM); (2) repeated electromagnetic surveys can reflect the temporal change of soil water storage and thus is a useful indicator of possible subsurface flow path over a large area; and (3) observable Mn distribution in soil profiles can be used as a simple indicator of water flow paths in soils and over the landscape; however, it does require sufficient soil sampling (by excavation or augering) to possibly infer landscape-scale subsurface flow paths. In areas where subsurface interface topography varies similarly with surface topography, surface DEM can be used to simulate potential subsurface lateral flow path reasonably so the cost associated with obtaining depth to subsurface water-restricting layer can be minimized.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape

Zhu

Lin

2009

Hydrol. Earth Syst. Sci.

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“…Less destructive methods such as ground penetrating radar, fibre optics, and electrical conductivity have been tested, but they require expensive equipment and have seen limited successes (e.g. Holden et al, 2002;Sherlock and McDonnell, 2003).…”

Section: Introductionmentioning

confidence: 99%

Dye staining and excavation of a lateral preferential flow network

Anderson

Weiler²,

Alila

et al. 2009

Hydrol. Earth Syst. Sci.

106

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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.

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“…[5] Burns et al [2005], Sherlock and McDonnell [2003], and Heisig [2000], working in the New York City (NYC) water supply area, and Poor and McDonnell [2007] working in Oregon analyzed runoff production from catchments in a mix of land uses. While peak flows increase with development, there is also some evidence of base flow and nitrate export augmentation by septic fields in the New York catchments.…”

Section: Introductionmentioning

confidence: 99%

Streamflow distribution of non–point source nitrogen export from urban‐rural catchments in the Chesapeake Bay watershed

Shields

Band

Law

et al. 2008

Water Resources Research

141

122

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[1] Nitrogen (N) export from urban and urbanizing watersheds is a major contributor to water quality degradation and eutrophication of receiving water bodies. Methods to reduce N exports using best management practices (BMP) have targeted both source reduction and hydrologic flow path retention. Stream restoration is a BMP targeted to multiple purposes but includes increasing flow path retention to improve water quality. As restorations are typically most effective at lower discharge rates with longer residence times, distribution of N load by stream discharge is a significant influence on catchment nitrogen retention. We explore impacts of urbanization on magnitude and export flow distribution of nitrogen along an urban-rural gradient in a set of catchments studied by the Baltimore Ecosystem Study (BES). We test the hypotheses that N export magnitude increases and cumulative N export shifts to higher, less frequent discharge with catchment urbanization. We find that increasing development in watersheds is associated with shifts in nitrogen export toward higher discharge, while total magnitude of export does not show as strong a trend. Forested reference, low-density suburban, and agricultural catchments export most of the total nitrogen (TN) and nitrate (NO 3 À ) loads at relatively low flows. More urbanized sites export TN and NO 3 À at higher and less frequent flows. The greatest annual loads of nitrogen are from less developed agricultural and low-density residential (suburban/exurban) areas; the latter is the most rapidly growing land use in expanding metropolitan areas. A simple statistical model relating export distribution metrics to impervious surface area is then used to extrapolate parameters of the N export distribution across the Gwynns Falls watershed in Baltimore County. This spatial extrapolation has potential applications as a tool for predictive mapping of variations in export distribution and targeting stream channel restoration efforts at the watershed scale.

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A new tool for hillslope hydrologists: spatially distributed groundwater level and soilwater content measured using electromagnetic induction

Cited by 75 publications

References 14 publications

Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape

Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape

Dye staining and excavation of a lateral preferential flow network

Streamflow distribution of non–point source nitrogen export from urban‐rural catchments in the Chesapeake Bay watershed

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