WATER RESOURCES

Question 1

what percentage of earths surface is water

Answer 1

71%

Question 2

what percentage of water is available to humans

Answer 2

1% = accessible surface freshwater

Question 3

Two major sources of liquid water for humans

Answer 3

Groundwater
Surface freshwater

Question 4

what is groundwater

Answer 4

• Water beneath the surface held within pores in soil or rock
• Water located below the water table
• Flows slowly high -> low pressure areas
• 20% of earth’s fresh water
• Contained within Aquifers

Question 5

whats an aquifer

Answer 5

Porous formations of rocks, sand gravel that hold water

Question 6

what is surface freshwater

Answer 6

• accounts for 1% freshwater
  » Rivers, streams, ponds, lakes, freshwater wetlands

Question 7

3 types of streams

Answer 7

• Effluent stream: flow maintained during dry season by ground water
• Perennial stream: flows all year
• Influent stream: flows only in response to precipitation

Question 8

what are streams

Answer 8

body of water with a current, formed from run-off

Question 9

whats a river

Answer 9

natural flowing watercourse, flowing towards the ocean lake or another river

Question 10

whats a watershed

Answer 10

area of land drained by a river and all its tributaries

Question 11

whats a lake

Answer 11

an area filled with standing water, localized in a basin, that is surrounded by land
- most found in northern hemisphere at higher latitudes
- Most have at least one natural outflow (river or stream)

Question 12

whats a freshwater wetland

Answer 12

• Systems in which the soil is saturated with water
• shallow standing water with ample vegetation e.g. marshes (herbaceous plants), swamps (woody plants), bogs (floating mats of vegetation), vernal pools
• Important ecosystem service - slow run-off, reduce flooding, recharging aquifers and filtering pollutants
• Half of wetlands in the US have been lost

Question 13

how do surface water and groundwater interact

Answer 13

• Should be considered part of the same resource
• Groundwater – surface water (springs, human drilled
  wells)
• Example: withdrawal of groundwater can lower stream flow or lake levels

Question 14

how do marine, coastal and freshwater systems interact

Answer 14

Majority of rivers empty into oceans

Question 15

what are estuaries

Answer 15

transition zone between river + maritime environments

Question 16

what’s a water footprint

Answer 16

The average per capita use of water
- lowest = Central Africa + Asia
- highest = America, Australia

Question 17

whats the Water footprint of a
product

Answer 17

the volume of fresh water used to produce the actual product -> virtual water use

Question 18

whats virtual water

Answer 18

amount of water embedded in food / other products needed for its production e.g. water footprint of a cow - need water to grow its food + for it to drink, transportation of its meat etc

Question 19

2 types of Off-stream water use

Answer 19

1. Consumptive use = not returned to its source
   * Plant or animal water use (evaporates in the tissue)
   * Industrial use
2. Non-consumptive = returned to source after use

Question 20

3 types of water use

Answer 20

– Domestic: non-consumptive
– Industrial: both consumptive and non-consumptive
– Agricultural: consumptive

Question 21

how was water transported Ancient civilizations in vs now

Answer 21

• Ancient: construct canals + aqueducts to transport water
• Now: Water moved from areas of abundant precipitation to areas of high usage e.g. California moves water from north to south via the states California State Water Project

Question 22

what type of water do we use the most

Answer 22

Withdrawal of surface water > withdrawal of groundwater

Question 23

biggest reason we use water

Answer 23

for irrigation (agriculture) + the thermoelectric industry

Question 24

Common sources of water

Answer 24

– Surface water
– Groundwater
– Desalination
– Treated wastewater
- conservation of water

Question 25

what factors determine Which sources are used at a particular place

Answer 25

– Location – Water quality – Water availability – Available technology – Water demand – Preferences

Question 26

what factors in the hydrologic cycle does water supply depend on

Answer 26

- Rates of precipitation, evaporation, transpiration * Stream flow * Subsurface flow

Question 27

whats a water budget

Answer 27

Model that balances the inputs, outputs, and storage of water in a system

Question 28

3 components of water use

Answer 28

– Agricultural use (largest) – Public supply and domestic use – Industrial and manufacturing use

Question 29

suggestions for conserving water in agriculture

Answer 29

– Price agricultural water – Use lined / covered canals that reduce seepage and evaporation – Use computer monitoring and schedule release of water for maximum efficiency – Integrate the use of surface water and groundwater to more effectively use the total resource – Irrigate at times when evaporation is minimal – Use improved irrigation systems that more effectively apply water to crops e.g. Sprinklers / drip irrigation – Improve the soil to increase infiltration and minimize runoff – development of crops that require less water

Question 30

suggestions for conserving water in Public supply and domestic use

Answer 30

* In semiarid regions, replace lawns with decorative gravels and native plants / drought resistant plants * Use more efficient bathroom fixtures * Turn off water when not needed * Flush the toilet only when necessary * Fix all leaks quickly * Purchase efficient dishwashers / washing machines * Quick shower vs bath * Use gray water to water vegetation * Water lawns / plants at cool times to reduce evaporation

Question 31

Sustainable water use definition

Answer 31

- Use of water resources in a way that allows society to develop and flourish – Use of water without degrading the hydrologic cycle or the ecological systems that depend on it

Question 32

Options for minimizing potential problems for managing water

Answer 32

– Alternating water supplies + managing existing supplies better – Towing icebergs – As price goes up many innovative programs are possible ... become more economic

Question 33

forms of water development that often surrounds a good deal of controversy

Answer 33

Dams - a structure built across a stream or river to hold water back – development involves input from a variety of government and public groups - generally designed to be multifunctional structures e.g. flood control, generate electricity, ensure stable water supply

Question 34

Environmental effects of dams

Answer 34

– Loss of land, cultural resources + biological resources – flood hazard should they fail – Storage of sediment behind the dam that would otherwise move downstream to coastal areas – Downstream changes in hydrology – Fragmentation of ecosystems (above vs. below) – Restrict movement upstream and downstream of organic material, nutrients and aquatic organisms