Human Impacts - Water Flashcards
Reasons for water demand increases in the last 50 years
- Population increased
- Use of water in agriculture increased
- Industrial and social development increased
- Decreasing rainfall in some areas
Renewable resource
- A natural resource which can replenish with the passage of time
- Through biological reproduction or naturally recurring processes (e.g. Cycles)
A problem with water availability has to do with unequal supply and demand in an area. Explain?
- Population density varies.
- E.g. Settlement in cities equal areas of very high demand, often with low supply.
A short term solution to the limited supply of water?
Water rationing
Constructions designed store large amounts of water to meet a varied demand in a particular area
Dams
Disadvantages of dam construction
- 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
Advantages of dam construction
- Immediate access to water
- Easier for council to budget water use
- Hydroelectric potential
- Other economic benefits include engineering, construction and investment possibilities
Wetlands are?
- Found in and around river systems
- Where flow of water slows down as it reaches the ocean
Examples of wetlands
- Vleis
- Springs
- estuaries
- floodplains
- bogs
- swamps
- lakes
- marshes
Vegetation characterizing wetlands
- Reeds
- Sedges
Animals characterizing wetlands
- Water birds
- Aquatic insects
- Small fish
Wetland ecosystem services
- Store water
- Control flooding
- Reduce sediment load in rivers
- Maintain river flow
- Improve water quality
- Provide habitat for wildlife
Causes of wetland destruction
- Lowered water table (by overuse)
- Drainage of wetlands (for other land use)
- Pollution
- Overexploitation of wildlife (e.g. fishing)
Working for Wetlands program
- Government initiative for Monitoring
- Reclaiming
- Managing
Farming practices that affect water availability
- Wasting water (e.g. sprinklers with lots of evaporation)
- Farming too close to river systems (soil erosion)
Exotic species
Species not naturally occurring in a particular area or region
Planting only one type of plant in agriculture of forestry
Monoculture
Effect of exotic species on water availability?
- These trees consume more water than indigenous species
- Indigenous species deprived of water
Examples of exotic plantation trees?
- Eucalyptus
- Pines
- Wattles
Other problems caused by some exotic species
- Spread very fast
- Grow faster than indigenous species, outcompeting
- Transform the habitats of indigenous species
- Change fire intensity and frequency
An underground layer of water-bearing permeable rock or sediment from which ground water can be extracted
Aquifer
Depletion of aquifers is caused by
Over-pumping using:
- Boreholes
- Well-points
Consequences of the over-pumping of aquifers
- Water supply for rural areas depleted
- Sink holes
- Increased salinity of underground water in coastal areas
South Africa’s policy of free water and the cost of water
- 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.
List at least 5 domestic water pollutants
- Detergents
- Cleaning agents
- Toiletries
- Garden sprays (e.g. Pesticides)
- Cooking oils
- Grey water (basins and baths)
- Black water (sewage)
List at least 5 industrial water pollutants
- Heavy metal compounds
- Metal compounds
- Salts
- Sulphates
- Chlorides
- Acids
- Oil byproducts
- Carcinogens
- Petrochemicals
- Thermal pollution (hot waste water)
Environmentally friendly cleaning liquid recipe
- 1 cup bicarbonate of soda
- 1/2 cup of vinegar
- 2 teaspoons of salt
- 2 table spoons of lemon juice
List at least 3 agricultural water pollutants
- Fertilizers
- Pesticides
- Herbicides
- Manure waste and other organic wastes
List at least 3 mining water pollutants
- Arsenic
- Metals e.g. chromium
- Sulphates
- petrochemicals
- Various acids
List at least 3 water borne diseases sometimes caused by untreated sewage affecting drinking water
- Escherichia coli (E. coli)
- Cholera
- Hepatitis A
- Dysentery
- Gastroenteritis T
- yphoid fever
Algal blooms and depleted oxygen levels caused by excess nutrient runoff into waterbodies
Eutrophication
Process of eutrophication
- 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
Hot waste water released into waterways
Thermal pollution
Places where large amounts of water cleaned for domestic use
Water purification plants
Effects exotic aquatics plants have on water systems
- Eutrophication
- Shut out sunlight for indigenous aquatic plants
- Clog up waterways disrupting flow
- Block irrigation pipes and canals
Introduction of natural pest species to attack invasive exotic species
Bio-control
Examples of harmful exotic aquatics
- Water hyacinth
- Kariba weed
- Water lettuce
- Parrots feather
Use of indigenous organisms as indicators of the quality of certain ecosystems
Bio-monitoring
