Lecture 33

Ground-water Interaction with

Regional Aquifer, Lakes and

Wetlands

Fetter 8.7

Most lakes and wetlands interact with ground-water flow systems.

Figure 8.24 Some possible interactions among ground water, streams,

and lakes and wetlands.

Figure 8.25 Ground-water ¾ lake interactions: A. High water table

and interlake ground-water divide. B. Low water table and no

interlake divide. C. Depressed water table due to fringe of phreatophytes.

Source: Redrawn from P. Meyboom, Journal of Hydrology 5 (1967): 117-42.

Figure 8.27 Hydrogeologic cross section showing head distribution

in a one-lake system with a layered aquifer system. The high-conductivity

layer has a conductivity 1000 times as great as the low-conductivity layer.

The lake loses water to the aquifer. Source: T.C. Winter, U.S. Geological

Survey Professional Paper 1001, 1976.

Figure 8.26 Hydrogeologic cross section showing head distribution in a

one-lake system with a homogeneous, anisotropic aquifer system. Results

are based on a two-dimensional, steady-state, numerical-simulation model.

Source: T.C. Winter, U.S. Geological Survey Professional Paper 1001, 1976.

Location of study area in Wisconsin.

Water table configuration at Vandercook Lake: (a) June 1-2, 1982

(modified after Wentz and Rose [1991]), and (b) February 3, 1988.

(Gradients immediately adjacent to most of the lake are too large to

allow delineation of individual contours at the scale presented.)

Karst

 Limestone and dolomite are soluble in water that is mildly acidic.

	Recharging water is generally unsaturated w.r.t. dolomite or calcite.
	Water dissolves these minerals until ~ 99% saturated w.r.t. calcite.
	nearly linear dissolution rate

Flow through these axes initially function of fractures

	fractures become enhanced
	may form solution passages

Karst - topography formed over limestone, dolomite, gypsum

	characterized by sinkholes, caverns, lack of surface streams
	15% of earth’s land surface add salt and gypsum

Swallow (holes)

	shafts leading from surface streams to caverns
	may take entire flow of stream

Dissolution usually occurs near the water table

at or above

Figure 9.22 Effects of fissure density and orientation on the

development of caverns. Source: Modified from D.C. Ford

and R.O. Ewers, Canadian Journal of Earth Science (1978).

ENV 302 - Lectures