Geology of Groundwater Occurrence

Question 1

True or False. Hydrogeologists are concerned with the distribution of earth materials as they affect the porosity and hydraulic conductivity of the earth.

Answer 1

TRUE

Question 2

Amount of voids contained in a particular volume of the rock mass.

Answer 2

Porosity

Question 3

Capacity of a porous rock or soil to transmit a fluid.

Answer 3

Permeability or Hydraulic Conductivity

Question 4

The water that cannot be pumped out of a well.

Answer 4

Specific Retention

Question 5

The water can be pumped from a well; part of the water that would drain under the influence of gavity.

Answer 5

Specific Yield

Question 6

Water held in pore spaces between grains of sand, gravel, clay, or rock fragments.

Answer 6

Unconsolidated Aquifer

Question 7

A gently sloping plain consisting of alluvium.

Answer 7

Alluvial valleys

Question 8

Normally delimited by uplands on either side that rise above the level of the valley to varying heights.

Answer 8

Alluvial Valleys

Question 9

Many major valley systems are products of tectonic activity rather than of fluvial or glacial erosion.

Answer 9

Alluvium in Tectonic Plates

Question 10

During the mountain building episodes, the uplift of mountain masses will result in ______________ being formed.

Answer 10

Intermontane basins

Question 11

__________ can also be created by down-dropping of large crustal pieces along faults.

Answer 11

Fault-block valleys

Question 12

________ are one of the most productive terrains for recovering groundwater.

Answer 12

Alluvial valleys

Question 13

______ and _______ form a large part of the stream alluvium.

Answer 13

Sand and gravel

Question 14

_______ and ______ are considered to be sedimentary deposits, with the original sediments being organic.

Answer 14

Coal and lignite

Question 15

_________ are typically composed of silicate, carbonate, or clay minerals.

Answer 15

Clastic sedimentary rocks

Question 16

________________ are primarily limestone, dolomite, salt, or gypsum.

Answer 16

Chemically precipitated sedimentary rock

Question 17

Sedimentary rock sequence were formed with _________ laid down upon older ones.

Answer 17

younger bed

Question 18

Rarely do sedimentary rock occur as a __________; there is typically a sequence of many beds.

Answer 18

single unit

Question 19

Real hindrance of groundwater exploration.

Answer 19

Complex stratigraphy

Question 20

___________ and ___________ of sedimentary rock can create a very complex hydrogeologic system, in which the determination of the locations of recharge and discharge zones and flow systems in confounded.

Answer 20

Folding and faulting

Question 21

Based on primary permeability is a function of grain size, shape, and sorting of the original sediments.

Answer 21

Hydraulic conductivity (clastic)

Question 22

True or False. Chemically precipitated rocks can have very low porosity and permeability.

Answer 22

TRUE

Question 23

True or False. Bedding plane cannot be zones of high primary porosity and permeability.

Answer 23

FALSE. Can be.

Question 24

95% of the total groundwater and best aquifer are coarse-grained unconsolidated sediments.

Answer 24

Sedimentary rocks

Question 25

This type of sediment is easy to drill/dig and also cheap. It can be found in valleys with shallow groundwater levels and its usual locations are near rivers where recharge is strong. It also have a high permeability.

Answer 25

Unconsolidated sediments

Question 26

Is also a good aquifer but often coarser-grained rocks. Permeability depends on the degree of compaction, cementation, and fracturing. Finer sediments such as silt and clay act as impermeable beds.

Answer 26

Consolidated sediments

Question 27

True or False. For groundwater occur in metamorphic and igneous rock, there must be openings developed through fracturing, faulting, or weathering.

Answer 27

TRUE

Question 28

True or False. Volcanic rock have low permeabilities.

Answer 28

FALSE. low to high

Question 29

Enumerate the reason volcanic aquifers have high permeabilities.

Answer 29

Gas bubbles (vesicles)
Fractures and joints
Development of leached zone
Sand and gravel trapped between flows

Question 30

True or False. Plutonic rocks are porous.

Answer 30

FALSE. not porous.

Question 31

Groundwater in plutonic rocks have a presence of ___________ by tectonic processes and in ____________.

Answer 31

open fracture;
leached or weathered zone

Question 32

True or False. All metamorphic rock have low permeability.

Answer 32

FALSE. Marble have high permeability

Question 33

Groundwater in metamorphic rocks occurs and moves through _________ and __________.

Answer 33

Fracture and leached zones

Question 34

Marble, like limestones, could have well-developed _________ or even caverns where large groundwater flow occurs.

Answer 34

solution openings

Question 35

Desert areas received _________ of precipitation or less each year.

Answer 35

10 (25 cm)

Question 36

The Nubian aquifer has _________ and _____ thick.

Answer 36

3000 ft;
900 thick

Question 37

How old are North Africa and Arabia’s groundwater?

Answer 37

35,000 radiocarbon years

Question 38

Aquifers located next to tidal bodies are subjected to short-term fluctuations in the head, due to the tide.

Answer 38

Tidal effect

Question 39

_________ exist in areas of stable basement rock as well as in those areas where the basement is sinking.

Answer 39

Coastal plains

Question 40

Regional features bounded on the continental side by highlands and seaward by coastline.

Answer 40

Coastal-plain aquifers