Exam 3

Question 1

What is groundwater?

Answer 1

Water found in the void spaces beneath the surface of the earth. Can exist within layers of saturated rock, in cracks of material, etc.

Question 2

Water Budget Equation

Answer 2

P= R+ ET + I +(delta)S
P-Precipitation
R-Runoff
ET-Evapotranspiration
I-Interception
S-GW Storage

Question 3

What percentage of water is groundwater? Answer both in terms of all water and in terms of freshwater

Answer 3

95% of liquid freshwater is GW, and 13% of all fresh water is liquid

Question 4

Where does GW come from?

Answer 4

Precipitation recharges groundwater stores

Question 5

Vadose Zone

Answer 5

All the material between Earth’s surface and the Zone of Saturation

Question 6

Zone of Saturation

Answer 6

Area where GW flows beneath earth surface, all spaces between rock particles are filled with water

Question 7

Water Table

Answer 7

The upper boundary of the Zone of Saturation in an unconfined aquifer

Question 8

Capillary Fringe

Answer 8

Material of varying thickness that overlies the Water Table, water is drawn up into it through capillary action

Question 9

When is the World Day for Water (UN)?

Answer 9

March 22, established in 1998

Question 10

How does GW affect politics?

Answer 10

GW is an important resource for drinking water. Overpumping from one country could mean drought for another country, causing cross-border issues when it comes to aquifers. The distribution of water can dictate how much of a country’s budget goes towards purchasing or pumping drinking water

Question 11

Lithology

Answer 11

Physical characteristics of a mineral composition (grain size, density of material)

Question 12

Stratigraphy

Answer 12

described composition and age of sediment

Question 13

Structures

Answer 13

Cracks folds, physical characteristics of geologic landscape

Question 14

Is GW basic or acidic? (generally)

Answer 14

GW is ty[ically acidic, able to dissolve rock and carry minerals (carbonic acid from limestone)

Question 15

Karst

Answer 15

Terrain composed of numerous depressions in the landscape-sinkholes formed due to dissolution of limestone; lack of surface drainage (streams)

Question 16

What are caverns composed of? And how is it formed?

Answer 16

Dripstone; formed from the continual deposition of minerals which are dissolved in water and stay when water evaporates

Question 17

Glacial Till

Answer 17

rock debris (clays, sands, gravel and boulders)

Question 18

Glacial Outwash

Answer 18

deposits of rock transported due to the melting of glaciers

Question 19

Alluvial Valleys

Answer 19

permeable formation which can hold a considerable amount of water

Question 20

Alluvium

Answer 20

sediment deposited by flowing rivers

Question 21

Tectonic Formations

Answer 21

Fissures/ fractures formed through tectonic activity

Question 22

What is an issue with recharge in urban areas?

Answer 22

Impermeable surfaces, such as parking lots, prevent percolation through the vadose zone and reduce the rate of recharge, this can lead to downstream flooding

Question 23

Pressure Surface/Potentiometric Surface

Answer 23

The level at which water appears when a confined aquifer is drilled through- due to release of pressure through small opening (the level to which the water will rise in a well)

Question 24

Aquifer

Answer 24

Underground water bearing geologic formation that stores and yields usable water

Question 25

Consolidated Rock

Answer 25

Tightly bound geologic material, impervious, does not allow GW to flow easily

Question 26

Unconsolidated Rock

Answer 26

Loosely bound geologic material (sand or gravel) that allows GW to flow

Question 27

Fractured Aquifer

Answer 27

In consolidated rock that has enough fractures and fissures to store usable water

Question 28

Unconfined Aquifer

Answer 28

Aquifer with no confining layer between water table and earth's surface

Question 29

Confined aquifer

Answer 29

Aquifer overlain with confining layer

Question 30

Saturated Thickness

Answer 30

Total water bearing thickness of an aquifer

Question 31

Aquitard

Answer 31

Geologic formation that prevents water flow from one aquifer to another

Question 32

Aquiclude

Answer 32

Formation containing water which does not transmit significant amounts of water

Question 33

Aquifuge

Answer 33

formation that does not contain or transmit water

Question 34

Perched Aquifer

Answer 34

Localized zone of saturation above water level held by impermeable layer

Question 35

Ogallala Aquifer

Answer 35

Largest aquifer in US, about 175,000 sq mi, has been overpumped by US

Question 36

Porosity Equation

Answer 36

Porosity= Vvoid/Vtotal or Specific Retention + Specific Yield

Question 37

Porosity

Answer 37

Ratio of void space to the total volume of formation, expressed in percentage

Question 37

Primary Porosity

Answer 37

intergranular porosity formed during primary formation of rock

Question 37

Secondary Porosity

Answer 37

Spaces created by tectonic activity (fractures and fissures) or anything post rock formation

Question 38

Total Porosity

Answer 38

All pore space in the sample

Question 39

Effective Porosity

Answer 39

Only interconnected pore space of the sample

Question 40

REV

Answer 40

Representative elementary volume, a large enough sample size to define a mean porosity

Question 41

Transmissivity

Answer 41

Rate at which water moves laterally through saturated thickness of aquifer (with hydraulic gradient of 1)

Question 42

Transmissivity Equation

Answer 42

i=dh/dl=1

Question 43

Specific Yield

Answer 43

ratio of the volume of water that drains from the saturated rock to the total volume of rock; can also be gathered from ternary diagram

Question 44

Specific Yield Equation

Answer 44

S=V water drain due to gravity/V Total sample

Question 45

Specific Retention

Answer 45

ratio of volume of water an aquifer can retain against gravity drainage per the total volume of aquifer

Question 46

Permeability

Answer 46

k; the ability of a material to transmit a fluid, a measure of how fast a fluid can travel through sediment

Question 47

The smaller the size of the sediment grains...

Answer 47

The larger the surface contacts

Question 48

Increased frictional resistance...

Answer 48

decreased intrinsic permeability

Question 49

Poorly sorted material is...

Answer 49

less conductive

Question 50

Hydraulic conductivity (K)

Answer 50

The proportionality constant in Darcy's law, which relates the amount of water which will flow through a unit cross-sectional area of an aquifer under a unit gradient of hydraulic head OR Coefficient that describes the ratio at which water can move through a permeable medium

Question 51

Bernoulli's Equation

Answer 51

formulation of energy loss during fluid flow

Question 52

Groundwater flows...

Answer 52

from the top aquifer to the bottom aquifer

Question 53

Hydraulic Gradient

Answer 53

Slope of GW table

Question 54

Darcy's Law Equation

Answer 54

Q=A x K x delta H/L a-cross sectional area of flow k-hydraulic conductivity delta h-change in height L-length

Question 55

Darcy's Law Definition

Answer 55

rate at which a fluid flows through a permeable medium

Question 56

Seepage/ Average velocity

Answer 56

specific discharge/ effective porosity