Chapter 15

Glacier

large, slow-moving mass of ice and snow

Alpine Glacier

a glacier that forms in the mountains

Freshwater

water that has less than 0.2 percent salt dissolved in it

Ice core

long column of ice taken from glaciers

Ice sheet

glacier that spreads out over land in all directions

Sea ice

ice that forms when seawater freezes

Estuary

coastal area where freshwater from rivers and streams mixes with salt water from seas or oceans

Lake

large body of water that forms in a basin, or hollow area, surrounded by land

Runoff

water that flows over Earth’s surface

Stream

body of water that flows within a channel

Watershed

area of land that drains runoff into a particular stream, lake, ocean or other body of water

Aquifer

area of permeable sediment or rock that holds significant amounts of water

Groundwater

water that lies on the ground

Permeability

the measures of water’s ability to flow through rock and sediment

Porosity

the measure of rock’s ability to hold water

Water table

the upper limit of the saturated zone of groundwater

Wetland

an area of land that is saturated with water for part or all of the year