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Quiz 7: Edwards Hydrology Expert

This quiz will test your knowledge of some important features of Edwards Aquifer hydrology.


In the Edwards, the honeycombed rock matrix stores 95% of the water. To move long distances, water leaves the matrix and enters a well-defined conduit, where it may be transmitted very far rather quickly.

a) true
b) false

The Edwards Aquifer formation is confined by:

a) the Glen Rose limestone below and the Del Rio clay on top
b) the Del Rio clay below and the Glen Rose limestone on top
c) Limestones both above and below
d) clay both above and below

The fresh water/saline water interface, usually known as the "bad water line" is the convergence of two flow systems within the Aquifer. It is actually a zone and not a line.

a) true
b) false

Edwards wells that produce hot, sulfurous, smelly water are common near the fresh/saline water interface.

a) true
b) false

A confined aquifer lies between two relatively impermeable rock layers. Most of the Edwards is this type of aquifer.

a) true
b) false

A water table aquifer is confined only by atmospheric pressure, not layers of rock or clay. The Edwards is this type of aquifer only in its recharge zone, where no other layers are on top of it.

a) true
b) false

The sinking down of part of the earth's crust due to underground excavation such as the removal of groundwater is called ____________ and is not much of a problem in the Edwards region.

a) subsidence
b) uplift
c) drawdown
d) sublimation

Not all the water in the Edwards is available to be pumped out. Some water is in pore spaces that are not connected to other pores. Water held in saturated material that it is not available as a source of water for pumping is called ________ groundwater.

a) fixed
b) available
c) oligotrophic
d) eutrophic

Lots of caves in the Edwards contain ____________, deposits of calcium carbonate that include stalactites, stalagmites, columns, and cave pearls.

a) pyrite
b) gypsum
c) dripstone
d) granite

At San Marcos Springs, the "bad water line" is remarkably close to the Spring outlets. It runs through the Aquarena Center parking lot only about a thousand feet from the Springs.

a) true
b) false