Geology Self Test Ch. 17

The common, rock-forming mineral __________, which comprises the rock _______________, most readily dissolves in slightly-acidic groundwater? A. Calcite / limestone B. Quartz / chert C. Feldspar / shale D. Mica / schist

A

Which of the following characteristics are found in all good aquifers? A. High porosity and high permeability B. Low permeability and high potability C. High porosity and low permeability D. Low porosity and low permeability

A

Which of the following statements is INCORRECT with regard to the water table? A. The level of the water table never changes regardless of the time of year B. The water table is the boundary between the zone of aeration above and zone of saturation below C. The water table intersects the land surface at lakes, streams, and swamps D. The water table somewhat mimics the surface topography of the landscape

A

Which of the following statements regarding the mapping of the water table is INCORRECT? A. Groundwater flow lines parallel the water-table contour lines B. Groundwater flows in a downslope direction perpendicular to the water-table contour lines C. A landfill can contaminate wells located further downslope of the regional water table in the direction of groundwater flow D. Water table contours are drawn based on the depth of the water table as measured in nearby wells

A

A ________ is the icicle-like speleothem that grows down from the roof of a cavern. A. Karst tower B. Stalactite C. Stalagmite D. Sink hole

B

A perched water table develops when... A. The regional water table is overlain by a vertical aquitard; Fish within the groundwater are prevented from swimming across the aquitard. B. A horizontal aquitard above the regional water table prevents downward-percolating water from reaching the main aquifer. Downward percolating water accumulates above the aquitard to form a secondary zone of saturation above the main water table. C. The main aquifer below the regional water table is bounded above and below by aquitards. D. An aquitard above the regional water table reaches the surface, allowing birds to perch on it.

B

What does the following figure best illustrate? A. Saltwater contamination of groundwater along a coastal area B. Karst topography C. Natural cleansing of groundwater flowing through surrounding bedrock D. Formation of geysers and hot springs

B

Which of the following statements logically explains why parts of some cavern systems are aerated? A.The caves formed and later the water table rose B. A nearby, downcutting stream lowered the water table after the caves had formed. C. Streams formerly flowing on the surface were diverted into the groundwater system through sinkholes, causing the water table to rise D. The main water table is perched above the cavern roof, allowing air to enter

B

After ice sheets and glaciers, which of the following reservoirs contain(s) the next highest percentage of the Earth's freshwater? A. Atmosphere B. Lakes and rivers C. Groundwater D. Oceans

C

An aquifer is... A. The porous and permeable, saturated cone of depression in an aquitard B. A layer or stratum in which groundwater flows downward to the water table C. A saturated, porous, and permeable layer or stratum D. An unsaturated, influent-flow bed or stratum below a spring

C

An artesian well is one in which... A. The water is warm, fairly saline, and recharged by an affluent stream B. Pressurized groundwater rises from a deep, unsaturated aquifer but does not reach the surface C. Water rises above the top of the aquifer without any pumping D. The well is horizontal and the water table is perched

C

Contamination of wells by saltwater intrusion is commonly a problem in _______________ A. Landfills B. Perched water tables C. Coastal areas D. Volcanic rocks

C

What force pushes groundwater from pore to pore below the water table? A. Integrated saturation impulse B. Capillary action C. Pressure gradient or hydraulic gradient D.Osmosis

C

What is the relationship between drawdown and the cone of depression associated with a pumping well? A. The drawdown is the diameter of the cone of depression measured at the elevation of the original water table. B. The drawdown is the percentage of available water in the aquifer that has already been used. C. Drawdown is the distance between the original water table and the water level in the well. D. There is no relationship between drawdown and the cone of depression.

C

Which of the following rock types would have the largest capacity to naturally remove sewage pollutants? A. Fractured granite B. Well-sorted, coarse gravel C. Slightly clayey sand D. Limestone with solution channels and caverns

C

Excessive groundwater withdrawal can lead to which of the following results? A. An influent stream becomes an effluent stream. B. Expansion of the dewatered aquifer. C. Porosity in the aquifer increases as the water is removed. D. The water table drops or declines in elevation.

D

For unconfined aquifers, what hydrologic factor is approximated by the slope of the water table? A. Porosity head B. Hydro competency C. Affluent decline D. Hydraulic gradient

D

The water table is... A. A boundary between unsaturated bedrock and an underground river B. A boundary between unsaturated bedrock below and saturated bedrock above C. An underground mass of partly saturated bedrock D. A boundary between saturated rock below and unsaturated rock above

D

Which of the following accounts for the largest usage of groundwater in the United States? A. Water for livestock and poultry B. Domestic and municipal supplies C. Industrial uses D. Agriculture and irrigation

D

Which of the following describes the changes likely to occur in an unconfined aquifer around a pumping well? A. Inflowing groundwater forms a saturated bulge around the well B. Spiral motion of groundwater in an upward direction around the well raises the water table C. Groundwater initially flowing towards a newly-dug well reverses direction once pumping begins D. Cone of depression forms around the well

D

Which of the following statements best describes how geysers erupt? A. Water suddenly cools in disconnected voids and cracks above the water table, causing the aquifer to explosively fragment. B. Water slowly percolates downward in a network of vertical cracks above the water table; The buildup of water in the underlying aquifer pushes the rest of the water to the surface. C. Rising magma in the lower crust pushes overlying water upward through vertical fractures, causing the water to spill out on the surface. D. With a slight reduction in pressure, water in a saturated, natural conduit suddenly boils, sending a plume of steam and hot water into the air above the vent.

D

Which of the following statements concerning artesian wells is not true? A. The well penetrates an aquifer overlain by an aquitard B. The well penetrates an aquifer underlain by an impermeable bed C. The aquifer is generally inclined, and it is saturated to an elevation above the point where the well penetrates the aquifer D. When the well penetrates the aquifer, the groundwater reverses flow such that the water table drops in the well

D

In areas underlain by unconsolidated or weakly consolidated strata, lowering of the water table can cause the land to subside. T/F?

True

Water infiltrates down to the water table from influent streams. T/F?

True