The zone between land surface and the water table where the moisture content is less than saturation (except in the capillary fringe) and pressure is less than atmospheric.

Natural pathway water follows as it changes between liquid, solid, and gaseous states; biogeochemical cycle that moves and recycles water in various forms through the ecosphere.

Water containing waste including greywater, blackwater or water contaminated by waste contact, including process-generated and contaminated rainfall runoff.

Precipitation which is a mixture of rain and ice.

Precipitation in the form of branched hexagonal crystals, often mixed with simple ice crystals, which fall more or less continuously from a solid cloud sheet.

Direct transfer of water from the leaves of living plants to the atmosphere

Any method, technique, or process designed to remove solids and/or pollutants from solid waste, waste-streams, and effluents

Lack of motion in water that holds pollutants in place.

Precipitation that does not infiltrate into the ground or evaporate due to impervious land surfaces but instead flows onto adjacent land or water areas and is routed into drain/sewer systems.

Removal from wastewater of traces or organic chemicals and dissolved solids that remain after primary treatment and secondary treatment

Those pollutants or combinations of pollutants, including disease-causing agents, which after discharge and upon exposure, ingestion, inhalation or assimilation into any organism can, on the basis of information available, cause death, disease, behavioral abnormalities, cancer, genetic mutations, physiological malfunctions or physical deformation in such organism or their offspring.

The layer of atmosphere closest to the Earth, extending seven to ten miles above the surface, containing most of the clouds and moisture.

Thick or opaque with matter in suspension.

The area above the water table where soil pores are not fully saturated, although some water may be present.

Degradation of a body of water by a substance or condition to such a degree that the water fails to meet specified standards or cannot be used for a specific purpose.

Land area from which water drains toward a common water course in a natural basin.

A region in the Earth above the water table.

Collection of wells, pipes, tanks, and other equipment and appurtenances that comprise a water delivery system.

water recycling is the treatment of wastewater making it suitable for reuse

Water quality is the chemical, physical, biological, radiological, and thermal condition of water.

Zooplankton is a large aquatic animals eaten by fish.

surface water is a water that flows in lake and rivers and in natural lakes, in wetlands, and in reservoirs constructed by humans.

River is a general term for a body of flowing water.