Naturally occurring water with low amounts of salt. Ocean water contains approximately 3.5 % salt and is not safe to drink for humans. Of all the water on Earth, 97% is ocean water, 3% is fresh water. Of that available freshwater, 2% is trapped in icecaps and glaciers and the remaining 1% is groundwater and available for human usage.

a mountain of ice, sometimes several square miles in area, that moves on the land. Glaciers trap large amounts of fresh water, and create many distinctive land forms through erosion and deposition.

water that is located below the Earth's surface in the soil or in the pores or crevices of rock

introduction of foreign substances or energy to an environment such that organisms in the environment are aversely affected.

referring to water, safe for humans to drink.

a resource that is replenished after it is used by living things in a short period of time. Generally, if the overall concentration of the resource on Earth does not change over time, it is considered renewable.

large holding area for fresh (or potable) water. This term may also refer to a generalized part of the water cycle (e.g. groundwater, glaciers).

any biotic or abiotic factor that is needed by living things to survive.

Water that exists on the Earth's surface, e.g. oceans, rivers, lakes.

a process occurring in plants where water is moved from the ground into the atmosphere. Unlike evaporation, transpiration occurs as a biological process.

Water that may be used by living things to survive. Usually this term is applied to use by humans, and therefore, refers to fresh water.

a generalized representation of the transitions and movements water undergoes throughout the atmosphere, hydrosphere, geosphere and biosphere. The water cycle is not an actual description of a path of water through time or space, but a summary of the transitions water undergoes as ice, water, and vapor.

an area of land where surface water and groundwater drain into a particular body of water; separated from each other by drainage divides; the entire geographic area directly affected by a body of water.

movement of water through a partition or medium, usually accompanied by the water dissolving substances as it moves through the partition.

the amount of space between particles in a partition or medium; the quality of being porous or full of tiny holes

soil or other material eroded and deposited by running water, wind, or other moving matter.

a smaller stream or river that empties into a larger stream or river.

a type of pollution that occurs because of widespread contamination, where no one source is the cause (e.g. agricultural runoff); source of pollution is not identifiable

a type of pollution that occurs from a specific location or a specific action (e.g. dumping raw sewage at a broken line); single and identifiable

sinking of land surface due to underlying shifting of Earth's materials as a result of the removal of groundwater

also known as the unsaturated zone; region between the Earth's surface and the water table; water from precipitation percolates through this zone and collects beneath the water table

the level of soil, under the ground, below which the ground is saturated with water (saturation zone)

holding as much water or moisture as can be absorbed

the zone below the water table that is saturated with groundwater

a type of rock that allows fluid, such as water, to pass through

a type of rock that does not allow fluids, such as water, to pass through

an underground layer of permeable rock that contains water or allows it to flow through to deeper layers.