Chapter #7 Flashcards
(108 cards)
1
Q
Stealth disasters occur ____
A
Slowly
2
Q
Sinkholes
A
Land collapsing into circular depressions
3
Q
Land Subsidence
A
Land gradually sinking over a broad area
4
Q
Soil destruction is caused by….
A
Nutrient depletion, Soil contamination, Erosion
5
Q
Hydrologic Cycle
A
The water cycle.
The 4 main components
Evaporation, Convection, Precipitation and Collection.
6
Q
Water cycles through…
A
Land and Organisms
Lakes and Streams
Oceans and ice
Earth’s atmosphere
7
Q
Surface Water examples
A
Lakes, streams, wetlands, snow, and glaciers
8
Q
Soil moisture
A
Water clinging to minerals or organic material
9
Q
Ground water
A
Water underground in rock and sediment pores
10
Q
Most surface water is, drinkable or undrinkable?
A
undrinkable salt water
11
Q
Water consumption growth is caused by…
A
Growing human population
Improving living standards
12
Q
Fresh water withdrawals, list the main sectors
A
70% Agricultural
19% Industry
11% Municipally
13
Q
Fresh water consumption concerns for society
A
Political and economic factors can drive shortages.
Productivity disruptions
Military conflicts
14
Q
Watershed
A
An area that refills fresh water reservoirs
15
Q
Depletion
A
When extraction exceeds replenishment
16
Q
Pollution Sources (For water)
A
Garbage
Chemicals
Fertilizer
Pesticides
Animal Waste
17
Q
Eutrophication
A
Nutrients form fertilizer and sewage cause algal blooms.
Algae depletes water and oxygen when it dies
occurs when the environment becomes enriched with nutrients, increasing the amount of plant and algae growth to estuaries and coastal waters.
Eutrophication is considered to be a serious environmental concern since it often results in the deterioration of water quality and the depletion of dissolved oxygen in water bodies. Eutrophic waters can eventually become “dead zones” that are incapable of supporting life.
18
Q
Salinification
A
Evaporation > addition
Diverted freshwater inputs
Irrigation leaches soil salts
19
Q
Groundwater
A
water in pores of sediment and bedrock
20
Q
Recharge area
A
The region where water enters the ground
21
Q
Discharge area
A
The region where water returns to the surface
22
Q
Pores
A
Open spaces between mineral grains
23
Q
Porosity
A
percentage volume of open space
24
Q
Permiability
A
The degree of pore connectivity
25
Permeable Rock
Open conduits allow ground water flow
26
Impermeable rock
Cement between minerals blocks groundwater flow
27
Aquifer
Sediment or rock with high permeability and porosity
28
Aquitard
Sediment or rock with low permeablity
29
Unsaturated zone
pores contain just air, or both air and water
30
Saturated zone
water completely fills pores
31
Water table
Boundary between saturated and unsaturated zones
32
When does a water table rise and sink?
Rises during wet season, and sinks during dry season
33
Springs
Natural outlets where groundwater seeps to surface
34
Aquitards may produce....
perched water tables
35
Wells
Pits or holes into which groundwater seeps
36
Producing wells
Penetrate aquafers and produce water
37
Dry wells
Do not penetrate aquafers
38
Ordinary wells
Water is lifted by buckets or pumps
39
Artesian wells
water rises under its own pressure
40
Depleting ground water supplies can cause a specific threat, which is called
A societal threat
41
Drawdown
Water is pumped from a well faster than it can replenish. Causes the water table to sink
42
Groundwater depletion
May occur due to over extraction.
May occur due to damaged recharge areas
43
Recharging a depleted reservoir can take how long?
could take a millennia
44
Ground water should be viewed as a renewable or nonrenewable source?
Nonrenewable
45
Effects of ground water depletion
Shallow wells, lakes, reservoirs,
rivers, and wetlands dry up.
Pores in weakly cemented rock
collapse, causing land to sink.
46
Natural contamination
Can occur from minerals in an aquifer, Ex: Arsenic from pyrite may leach into groundwater.
47
Anthropogenic contamination
Injection wells
Chemical and sewage spills
Leaking underground oil tanks
48
Water security
Access to safe and affordable water.
Currently we have a growing lack of water security
49
Physical Scarcity (Water)
There is not enough water
50
Economic Scarcity
There is enough water, but economic reasons make water unfit or unobtainable/unavailable
51
Conservation
Decreases consumption
Lifestyle changes
Crop and irrigation changes
52
Can conservation and economic growth occur together?
Yes
53
What causes Water stress(Like what can cause us to be scared):
* Agriculture and urban use
* Surface water pollution
* Paved and/or deforested recharge areas
* Wetlands filled for housing
* Inadequate rainwater harvesting
* Inadequate purification and distribution
* Dropping precipitation rates
54
Caverns
Open underground spaces without sunlight
55
Cavern collapse
When the roof of a cavern collapses
56
Sinkholes
Circular pits caused by cavern collapse
57
Karst terrain
a landscape with numerous sinkholes
58
Caverns form at water table, because of:
Highest acidity at water table
Fastest flow at water table moves dissolved minerals
59
Caverns develop when?
Water tables drop
60
Speleothems
Calcite formations within caverns
61
How to Karst landscapes develop
as caverns collapse
62
Dissolution sinkholes
Water dissolves surface rock and creates a depression
63
Cover-subsidence sinkholes
Loose sediment washes into underground space
64
Collapse Sinkholes
The roof of the cavern suddenly falls to the cavern floor
65
Collapse can be triggered by...
Heavy rain
Building construction
Lowering water table
66
Does expanding communities increase sinkhole disaster risk?
Yes
67
LIDAR
Light detection and ranging
Is used to detect sinkholes, even those covered by vegetation
68
Resistivity survey
Measures underground electricity flow.
Air-filled voids have lower-relative conductivity
69
Gravity survey
Measures local gravity field.
Air-filled voids have lower relative gravity.
70
Ground-penetrating radar
Radar may reveal a cavers roof and floor
71
Seismic reflection profiling
Seismic waves may reveal air filled voids
72
Sediment liquefaction
When soil is transformed into a liquid-like slurry.
Due to sudden ground shaking or influx of water.
73
Evaporites
* Sedimentary rock containing halite and gypsum.
* Halite and gypsum quickly dissolve in water.
* Evaporite sinkholes can develop in just hours.
74
What will the government do and not do regarding sink holes?
Does Not: Asses sinkhole likelihood, does not fill sinkholes on private land
Will do: Buy sinkhole insurance
75
What are the signs of an evolving sinkhole?
* Cracks in sidewalks
* A growing ground depression
* Ill-fitting doors and windows
* Cloudy well water
* Dropping well water level
* Tilting telephone poles
76
Subsidence
When land sinks over a broad area
77
Water in pore spaces supports what?
unconsolidated sediment
78
Removing water from pores casues?
sediment to pack together
79
Pore collapse decreases..
rock and sediment porosity, as well as thickness of sedimentary beds
80
Subsidence is not uniform:
* Some areas may begin tilting.
* Large fissures, hundreds of meters long, may open.
* Flooding may increase.
* Slope changes may cause streamflow and ecosystem disruptions.
* Sewer lines and water mains may stop flowing properly.
81
Deltas
Wedges of sediment deposited by a river
82
Flood Plains
Flat lands bordering a river that regularly flood
83
Coastal Plains
Low-lying lands along some continental margins
84
Subsidence occurring for 3 reasons:
* Dams and levees prevent flooding and thus sediment deposition.
* Surface sediment has dried out, shrunk, and oxidized.
* Groundwater, oil, and gas extraction have caused pore collapse.
85
Longwall coal mining (Subsidence):
* Mine collapses as grinder and enclosure move.
* Overlying land sinks.
86
Roof-and-pillar coal mining (Subsidence):
* Weak pillars may fail, causing overlying land to sink.
87
Coal bed fires also cause....
subsidence
88
Salt mines may collapse if...
water dissolves halite
89
Modifying agents of soil(Good things):
Rain, air, organisms and decaying organic matter
90
Soil destruction is a ______disaster. Which can create problems of...
stealth disaster.
* Food production is at risk.
* Famine may result.
91
3 processes form soil:
* Weathering breaks rock into sediment.
* Rain percolates through sediment.
* Organisms physically and chemically alter sediment.
92
Zone of leaching
Where percolating water picks up ions and clay flakes
93
Zone of accumulation
* Where minerals precipitate from percolated water
* Where clay is deposited
94
Topsoil
* Modified by leaching
* Contains the most organic matter and nutrients
* Supports plant growth
95
Subsoil
* Lacks significant carbon
* Poor soil for plant growth
96
Soil diversity caused by many interacting factors:
* Climate
* Source rock
* Slope
* Vegetation
* Time
97
Soil degradation includes:
* A reduction in the quantity
* A reduction in fertility
98
Soil depletion:
* Crops absorb soil’s nutrients.
* Fertility declines over time.
99
Soil texture. Good example and what can ruin the texture
* Good soil is porous, permeable, and a bit sticky.
* Plowing, heavy equipment, and animals can ruin texture.
100
Soil contamination
* Chemicals, overfertilization, oil spills, and landfills
* Salt deposits
101
Soil Erosion
Wind and water pick up and carry away soil particles.
Deforestation removes soil’s protective vegetation cover
102
Soil Erosion effects on Agriculture
* Commercial crops have lower root densities.
* Farm fields lie exposed to wind and water most of the year.
* Heavy farm equipment breaks surface soil particles.
103
Dust storms
* A wall of dust up to 1.5 km high
* Reduce visibility and coat everything in fine sediment
* May cause silicosis (damaged lungs) from repeated exposure
* May contain toxic agricultural chemicals
104
Mitigation measure against dust storms
* Prevent intensive farming
* Change plowing methods
* Leave post-harvest stubble
* Grow windbreaks
* Plant cover crops
105
Soil Conservation techniques
* Constructing fewer impervious (asphalt and concrete) surfaces
* Modifying plowing techniques
* Rotating crops
* Planting cover crops
* Practicing no-till farming
106
Expansive Soil
Soil that expands and shrinks due to wetting and drying
107
Potential problems with expansive soil
Unequal wetting and drying may crack foundations
Buildings, homes, roads, and pipelines may be damaged.
108
Protection for buildings against Expansive soil
* Build foundations on deep piles, below movement layer
* Improve drainage around buildings.
