Human Impacts - Water Flashcards

1
Q

Reasons for water demand increases in the last 50 years

A
  • Population increased
  • Use of water in agriculture increased
  • Industrial and social development increased
  • Decreasing rainfall in some areas
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2
Q

A problem with water availability has to do with unequal supply and demand in an area. Explain?

A
  • Population density varies.
  • E.g. Settlement in cities equal areas of very high demand, often with low supply.
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3
Q

A short term solution to the limited supply of water?

A

Water rationing

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4
Q

Constructions designed store large amounts of water to meet a varied demand in a particular area

A

Dams

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5
Q

Disadvantages of dam construction

A
  • Rivers dry up
  • Natural flow rates changes
  • Vegetation changed along banks of rivers
  • Ecosystems disrupted
  • Soil erosion
  • Rivers and dams fill with silt
  • Loss of water through evaporation from dam
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6
Q

Advantages of dam construction

A
  • Immediate access to water
  • Easier for council to budget water use
  • Hydroelectric potential
  • Other economic benefits include engineering, construction and investment possibilities
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7
Q

Wetlands are?

A
  • Found in and around river systems
  • Where flow of water slows down as it reaches the ocean
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8
Q

Examples of wetlands

A
  • Vleis
  • Springs
  • estuaries
  • floodplains
  • bogs
  • swamps
  • lakes
  • marshes
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9
Q

Vegetation characterizing wetlands

A
  • Reeds
  • Sedges
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10
Q

Animals characterizing wetlands

A
  • Water birds
  • Aquatic insects
  • Small fish
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11
Q

Wetland ecosystem services

A
  • Store water
  • Control flooding
  • Reduce sediment load in rivers
  • Maintain river flow
  • Improve water quality
  • Provide habitat for wildlife
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12
Q

Causes of wetland destruction

A
  • Lowered water table (by overuse)
  • Drainage of wetlands (for other land use)
  • Pollution
  • Overexploitation of wildlife (e.g. fishing)
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13
Q

Working for Wetlands program

A
  • Government initiative for Monitoring
  • Reclaiming
  • Managing
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14
Q

Farming practices that affect water availability

A
  • Wasting water (e.g. sprinklers with lots of evaporation)
  • Farming too close to river systems (soil erosion)
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15
Q

Exotic species

A

Species not naturally occurring in a particular area or region

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16
Q

Planting only one type of plant in agriculture of forestry

A

Monoculture

17
Q

Effect of exotic species on water availability?

A
  • These trees consume more water than indigenous species
  • Indigenous species deprived of water
18
Q

Examples of exotic plantation trees?

A
  • Eucalyptus
  • Pines
  • Wattles
19
Q

Other problems caused by some exotic species

A
  • Spread very fast
  • Grow faster than indigenous species, outcompeting
  • Transform the habitats of indigenous species
  • Change fire intensity and frequency
20
Q

An underground layer of water-bearing permeable rock or sediment from which ground water can be extracted

A

Aquifer

21
Q

Depletion of aquifers is caused by

A

Over-pumping using:

  • Boreholes
  • Well-points
22
Q

Consequences of the over-pumping of aquifers

A
  • Water supply for rural areas depleted
  • Sink holes
  • Increased salinity of underground water in coastal areas
23
Q

South Africa’s policy of free water and the cost of water

A
  • Every household may receive first six kilolitres of water used each month free.
  • Water is thus charged on a sliding scale.
  • More used, the greater the cost per kilolitre each month.
24
Q

List at least 5 domestic water pollutants

A
  • Detergents
  • Cleaning agents
  • Toiletries
  • Garden sprays (e.g. Pesticides)
  • Cooking oils
  • Grey water (basins and baths)
  • Black water (sewage)
25
Q

List at least 5 industrial water pollutants

A
  • Heavy metal compounds
  • Metal compounds
  • Salts
  • Sulphates
  • Chlorides
  • Acids
  • Oil byproducts
  • Carcinogens
  • Petrochemicals
  • Thermal pollution (hot waste water)
26
Q

Environmentally friendly cleaning liquid recipe

A
  • 1 cup bicarbonate of soda
  • 1/2 cup of vinegar
  • 2 teaspoons of salt
  • 2 table spoons of lemon juice
27
Q

List at least 3 agricultural water pollutants

A
  • Fertilizers
  • Pesticides
  • Herbicides
  • Manure waste and other organic wastes
28
Q

List at least 3 mining water pollutants

A
  • Arsenic
  • Metals e.g. chromium
  • Sulphates
  • petrochemicals
  • Various acids
29
Q

List at least 3 water borne diseases sometimes caused by untreated sewage affecting drinking water

A
  • Escherichia coli (E. coli)
  • Cholera
  • Hepatitis A
  • Dysentery
  • Gastroenteritis T
  • yphoid fever
30
Q

Algal blooms and depleted oxygen levels caused by excess nutrient runoff into waterbodies

A

Eutrophication

31
Q

Process of eutrophication

A
  • Excess nutrients enter water
  • Algae and weeds grow
  • Increased decomposers
  • Bacteria use up all oxygen in water
  • Fish and other animals die
  • Increased anaerobic bacteria decomposers
  • Harmful toxins released by anaerobic bacteria
32
Q

Hot waste water released into waterways

A

Thermal pollution

33
Q

Places where large amounts of water cleaned for domestic use

A

Water purification plants

34
Q

Effects exotic aquatics plants have on water systems

A
  • Eutrophication
  • Shut out sunlight for indigenous aquatic plants
  • Clog up waterways disrupting flow
  • Block irrigation pipes and canals
35
Q

Introduction of natural pest species to attack invasive exotic species

A

Bio-control

36
Q

Examples of harmful exotic aquatics

A
  • Water hyacinth
  • Kariba weed
  • Water lettuce
  • Parrots feather
37
Q

Use of indigenous organisms as indicators of the quality of certain ecosystems

A

Bio-monitoring

38
Q
A
39
Q

Renewable resource

A
  • A natural resource which can replenish with the passage of time
  • Through biological reproduction or naturally recurring processes (e.g. Cycles)