6.1 water resources and usage https://app.peardeck.com/student/tbirjimmi
freshwater availability
distribution on earth
oceans: 96.5%
saline ground water:0.93%
saline lakes: 0.07%
freshwater:2.5%
glaciers/ice caps:68.6%
groundwater:30.1% (biggest source of drinkable water)
surface water/other freshwater:1.3%
ice/snow:73.1%
lakes:20.1%
soil moisture: 3.52%
swamps/marshes:2.53%
rivers: 0.46%
bio water: 0.22%
atmospheric water: 0.22%
hydrologic cycle: freshwater supply recycled, purified, distributed
freshwater in spaces between layers
top collection is water table
aquifers: underground layer of water permeable rock materials
caverns w rivers
large long sponges
recharged by
precipitation
lakes, streams, rivers
unconfined: water seeps from ground above it
confined: impermeable rock prevents water seep into it from ground above
artesian well: doesnt require pump/pressure for water to come up
water use
primary USA use
fails when
overload with pollutants
take it away from underground
surface wastes faster than nature restores it
problems:
environment:
fail water tables
shrink lakes
wetlands disappear
water pollution
reduced fish pop
extinctions
degraded ecosystems
economy
food production threats
energy threats
national/global security:
tensions between nations over water access increase
global health
World Health Organization WHO: 4100ppl die of thrist or water disease/day
equality/poberty:
WHO: 52% of ppl have water services at home
electric power plant cooling 41%
irrigation 37%
livestock production 4%
industry 5%
publc water supply 13%
US household use
showers 17%
washing clothes 22%
dishwashers 1%
toilets 27%
baths 2%
leaks 14%
faucets 15%
other use 2%
virtual/embedded water: not directly consumed, used for food/others
large water footprints in developed countries
India
USA
China
importing crops: when not enough spaces=water footprint not show entire virtual one
uneven distribution
agriculture industry contamination
East: water used for power plants
West: irrigation uses 85% freshwater
freshwater scarcity stress: use is higher/availability
depletion of aquifers
50% americans (95% rurals), 50% humans rely on it
50% irrigation water, feeds 40% streams/rivers, 1/3 used by industries
pumps used to surface groundwater
irrigation
households
industries
aquifers=renewable
using faster than refill process for irrigation
contaminated by industries
advantages
useful for drinking/irrigation
everywhere
renewale if not overpumped/contaminated
cheap to extract
disadvantages
depletion from overpumping
land sinks (subsides) from overpumping
deep=nonrenewable
pollution can last centuries
problems:
increasing poverty/civil unrest: limits on food produce, prices rise=hunger
inequality: costs more to drill and pump, farmers cant pay land
saltwater seeping
land subsidence: water supports rock, rock collapses into gaps=sinkholes
solutions
prevention
efficient water use
subsidize water conservation
limit well numbers
no water invasive crop growth in dry areas
control
raise price ro discourage waste
tax water pumped from wells near surface water
build rain gardens in urbans
permeable use on pavement materials
increase freshwater availability: water transfers
heavy pop=water shortages=transfer from rich to poor areas
dams
pumps
lined canals=aqueducts
enviro, econ, social costs
lost water thru evaporation/leaks in system
ecosystems degraded
habitat reduction
pollutants not diluted/flushed out
less water for communities near
capture/store runoff from river
control floods
make electricity
recreational use
swimming
fishing
boating
6/10 of rivers have 1 dam=800k worldwide
increase 33% of reliable runoff/year
provide for 50% of irrigated cropland/supply 50% electricity in 65 countries
problems:
downrivers dramatic water increase
80% dry up before reaching sea
1/5 fish/plants extinct due to dams reducing water flow
upriver flooded
displaces communities
terrestrial habitats destroyed cz floods
reservoirs not useful for long
full of deposits:mud/silt make it useless for drink/energy=useless after 50 yrs
climate change=lower water levels
increase freshwater availability:desalinization
process of removal dissolved salts off sea in aquifers/lakes=increase supplies
distilation: heating saltwater til evaporates, salts turn solid, freshwater condenses
reverse osmosis: high pressure to filter saltwater to remove salt
problems:
high cost
chem use
waste salt
using freshwater sustainably
recycle water industry
reduce leaks
reduce toilet flush volume/showers
dont water lawns
reduce meat consumption
home water can be reused/recycled
50-75% house gray water=reused for lawns, flushes, washes
athtubs
showers
sinks
dishwashers
clothes washers
reduce agriculture waste
drip irrigation
irrigate at night
grow less thirsty crops
organic/polyculture farming=retain soil moisture
preventing flooding
floodplain
adjacent area to stream where freshwater stream overflows normal channel
+freshwater>-freshwater=natural flooding by rain or melting snow
urban runoff
areas covered with pavement/buildings increase runoff
human activities:
vegetation that absorbs water/protects soil removed
wetlands drained