karst Areas underlain by soluble bedrock (e.g., limestone, dolomite) that are generally characterized by surface and subsurface features (e.g., sinkholes, caves) formed by the dissolution of rock by ground and surface water. These landscapes can describe an area containing specific, solutionally-modified land forms as well as areas underlain by solutionally-derived conduit aquifer systems.

karstian geology An area predominantly underlain by limestone, dolomite, or gypsum and characterized by rapid, underground drainage. Such areas often feature sinkholes, caverns, and sinking or disappearing creeks. In Virginia, this generally includes all that area west of the Blue Ridge and, in Southwest Virginia, east of the Cumberland Plateau.

Kessener Brush A cylindrical, metal brush used to maintain circulation and provide oxygen in the activated sludge process.

keystone species A species whose removal causes marked changes to the community.

kilo 1) A prefix meaning "thousand" used in the metric system and other scientific systems of measurement. 2) A kilogram. 3) A kilometer.

kilogram One thousand grams.

kilometer One thousand meters.

kiloton An explosive force equivalent to that of 1,000 tons (907,000 kg) of TNT.

kilowatthour (kWh) A unit of energy equivalent to one thousand watthours.

kinetic data Recorded measurements used to determine rates of dynamic changes, such as microorganism growth and substrate removal.

kinetic energy Energy possessed by a moving body of matter, such as water, as a result of its motion.

kinetic rate coefficient A number that describes the rate at which dynamic changes occur, such as how fast the biological chemical oxygen demand or dissolved oxygen in water, rises or falls.

kingdom One of the primary divisions into which natural objects are classified— called mineral kingdom, plant kingdom, or animal kingdom.

Kjeldahl nitrogen Nitrogen in the form of organic proteins or their decomposition product ammonia, as measured by the Kjeldahl Method.

knot A speed unit of 1 international nautical mile (1,852.0 meters or 6,076.115,49 international feet) per hour.

Kraus Process A modification of the activated sludge process in which liquid from anaerobic digesters is added to the aeration basins as a source of additional nutrients.

Ku-band Most popular type of satellite transmission for uplinking and downlinking. Ku-band operates on a higher frequency than C-band transmissions and requires smaller antennas.