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