Ground/Surface Water Interactions

From GeoMod

Using a combination of numerical modeling, sandbox modeling and field work, we are investigating the effects of groundwater discharge on surface flow and geomorphology.

1 Articles
2 Conceptual/Numerical Modeling
- 2.1 Base simulation
  - 2.1.1 Semi-confined model sensitivity analysis
3 Large Scale Field Assessment
- 3.1 Validating the large scale model
4 Reach scale groundwater-surfacewater interactions
- 4.1 Dan Neilans' thesis
- 4.2 Followup on the Neilans reach
5 Sand box model
6 Technology
7 Links

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Articles

Urbano et al., 2006

Urbano, L., Waldron, B., Larsen, D. and Shook, H., 2006. Groundwater–surfacewater interactions at the transition of an aquifer from unconfined to confined, Journal of Hydrology', v. 321, n. 1-4, p. 200-212.
- Link on ScienceDirect: Article
- pdf preprint

Dan Neilans Thesis Page - analysis of the impact of ground-water discharge on the geomorphology of a small stream.

Neilans, D., and Urbano, L.D., Assessing meter-scale heterogeneity of groundwater discharge using streambed thermal mapping, Journal of Hydrology, (in review) (manuscript: Seepage Meter Paper - version 10)

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Conceptual/Numerical Modeling

Generic model domain used to investigate the groundwater discharge pattern at the confined-unconfined aquifer transition. The two streams crossing the top are for symmetry.

The following series of simulations demonstrate the effect of hydrogeology, specifically the subcropping of a clay unit such as at the edge of a shallow sedimentary basin, on the groundwater discharge pattern to a stream flowing perpendicular to the strike of the dipping units.

Basic model geometry. Dimensions and boundary conditions of model representing the flank of a shallow sedimentary basin. Hash marks indicate no-flow boundaries. (a) Cross-section of model showing the hydrogeology of the conceptualized unconfined–confined transition zone, and the two vertical segments of the downdip boundary condition. (b) Map view showing the locations of the two stream channels.

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Base simulation

Basic generic simulation that best represents the actual field conditions.

Observe the peak in groundwater discharge to the stream at the confined/unconfined transition.
The limited area of the capture zone between the rivers.

Block view	Map view showing capture zone

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Semi-confined model sensitivity analysis

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Large Scale Field Assessment

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Validating the large scale model

Ongoing field work has indicated that there is a change in groundwater discharge to the Loosahatchie River near the emergence of the Memphis Sand as an unconfined aquifer.

Map of the Mississippi Embayment, major and minor rivers, and the spatial limits of its confining units including where the confining units do not outcrop at the surface.

Stream flow discharge measurement locations along the Loosahatchie River of western Tennessee. The unconfined area of the Memphis aquifer is shaded and the area of subcropping upper Claiborne confining unit is unshaded.

Measuring stream flow in the Loosahatchie River, TN.

Stream discharge rates measured in the Loosahatchie River in September 2003. The error bars indicate a 5% standard error range for the discharge measurements. Locations of discharge measurements are shown on Image:Loosahatchie map i.jpg

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Reach scale groundwater-surfacewater interactions

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Dan Neilans' thesis

Dan Neilans Thesis Page

continuing the field work on the Loosahatchie River. Taking meter scale measurements of bed elevation and temperature, Dan identified groundwater discharge foci, and investigated the interaction between the bedform geomorphology (migrating sandbars) and the stability of these foci.

Dan.

His field area.

His field assistant.

His results.

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Followup on the Neilans reach

In July 2007, approximately 1 year after Dan Neilans' field work, an undergraduate student (Mr. Cole Parrish) and I went back to Dan's reach to see how things had changed.