ecology exam 5

fresh water

water that contains less than 1,000 mg/L of dissolved solids

what percent of the worlds water is fresh water?

3%

water withdrawals

the extraction of water from natural resources for human use

largest percentage of water withdrawals in the US

energy production

water consumption

extraction of water from the environment that is then changed in form or removed from the water cycle (no longer available for other uses)

largest percentage of water consumption in the US

irrigation of crops

how does data centers for AI consume water

less than 1%

what is the most water intensive of the animal products

beef

what crop uses the most water

nuts

how many people lack safely managed drinking water

2.1 billion

what is the global trend with access to clean drinking water?

increasing over time

watersheds

stress when water demand (from power plants, agriculture, etc) exceeds 40% of availability

where are watersheds more popular

arid western regions (smaller pool of existing water resources)

chlorination

major Public Health Service meant to prevent the spread of waterborne illnesses

trend after chlorination programs

number of typhoid deaths significantly declined, now a very rare disease in the US

what major factor drives access to drinking water

armed conflict

what country had the largest cholera outbreak

yemen

water system (closed system)

water may change forms and locations, however its quantity on earth is fixed

where freshwater comes from

1. surface water

2. ground water

3. alternatives

surface water

dominant source of freshwater in US

population growth and water usage trends

not necessarily increasing

where does surface water come from

precipitation

global snowpack trends

declining

snowpack

dominant source of water in western US

what is still mostly fed by snowpack

tropical rivers

reservoirs

-naturally occurring or artificial

-created by damming or pumping water

man made reservoir

hetch hetchy

how does Fort Worth get its water

reservoirs (surface water)

how many natural lakes are there in north texas

zero

trend in global reservoir construction

declining

groundwater

underground sources of water

more stressed aquifers

low surface water and high industrial agriculture production

texas aquifer

ogallala

what has decreased water levels in aquifer

water withdrawals for irrigation of crops

land subsidence

large groundwater draws from can cause fine grain sediment to compact

desalination

-converting saltwater to freshwater

-very energy intensive

-done by reverse osmosis or thermal distillation

thermal distillation

-heat applied to generate evaporation which is condensed and collected as freshwater

-less energy intensive

-very slow

why desalination isn’t used more

-leaves behind large amounts of salt

-kills marine organisms during intake

-energy intensive

where mainly uses desalination

Middle East

water recycling

treating water from waste water plants and cycling this water back into public water supply

benefits to water recycling

-safe, high quality drinking water

-performed in fort worth (trinity river)

primary treatment

physical process, doesn’t remove fine scale pollutants

secondary treatment

biological to further purify water

tertiary treatment

specific targeted methods to remove contaminants