A branch of engineering concerned with the design, construction, and maintenance of environmental facilities conducive to public health, such as water supply and waste disposal.

A system of artificial or natural drains, generally used for the disposal of liquid wastes.

The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.

Water particles that fall from the ATMOSPHERE.

A large or important municipality of a country, usually a major metropolitan center.

Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).

Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.