Environmental Hydrogeology - Exam I Name __________________

DARCYS LAW - Answer two (2) of the following (10 points each).

1 - Describe how Darcy set up his famous experiment and how he derived his "law".

2 - What is the differences between hydraulic conductivity and intrinsic permeability?

3 - Define primary and secondary porosity and give examples of each.

AQUIFERS - Answer two (2) of the following (10 points each).

1 - Explain the difference between storativity of a confined and water-table (unconfined) aquifer.

2 - Comment on the following statement: "transmissivity is a constant for an artesian aquifer (confined) but is variable, changing seasonally, for a water-table aquifer".

3 - Explain the differences between the concepts of homogeneity versus heterogeneity, and isotropy versus anisotropy in aquifers, give examples.

WATER BUDGET - everybody answers this (10 points).

Apply the water budget concept (hydrologic equation) to the hydrology of this hillslope. Label the topographic and groundwater divides and draw in some flowlines.

Why is the water table a subdued representation of the topography?

DIAGRAMS - Answer five (5) of the following (10 points each).

1 - Draw what a water table aquifer might look like in an arid and humid environment.

2 - Draw arrows showing the general flow of water through each sandbox. Assume the piezometers shown are open only at their lower ends.

3 - Label the flow path for a parcel of water moving in the water table aquifer (below) under the following conditions: (1) change only in elevation head, and (2) change only in pressure head (you need to draw in flow paths).

4 - Three piezometers are placed in the lake below. Show the water level in each well and separate the elevation from the pressure head for each case.

5 - Assuming equal discharge through all cross sections of the confined aquifers shown below, and the ascribed hydraulic conductivities, draw in the relative hydraulic gradient across each flow path.

6 - Below are two map views of streams and elevations of the water surface along those streams. Draw flow lines and equipotential lines for A. a losing (influent) stream and B. a gaining (effluent) stream.

BONUS: (5 points)

Does the transmissivity change across the aquifer in question 5 (where K1=K2). Yes or no and why?