EXAM II

WATER RESOURCES & POLLUTION

Hydrologic cycle

Movement of water through evaporation, precipitation, transpiration

Precipitation

Water falling from atmosphere (rain, snow, etc.)

Evapotranspiration

Combined evaporation and plant transpiration

Residence time

Time water stays in a specific location

Groundwater

Water stored underground in soil and rock

Water table

Top of the saturated groundwater zone

Aquifer

Underground layer that holds water

Recharge zone

Area where water enters an aquifer

Discharge

Amount of water flowing past a point over time

Water withdrawal

Total amount of water taken from a source

Virtual water

Water embedded in products like food

Main water use globally

Agriculture (~75%)

Subsidence

Land sinking due to groundwater removal

Drought

Extended period of water shortage

Surface water

Water in rivers, lakes, and wetlands

Why groundwater is important

Largest accessible freshwater source

Water distribution

Uneven globally due to climate and geography

Wetlands role

Slow runoff and recharge groundwater

Atmospheric water

Small amount but key for redistribution