Deposits of boulders, gravel,
sand, clay or tillmoved and
deposted by a glacier or the water
from a melting glacier.

A community of interaction among
animals, plants, and
microorganisms, and the physical
and chemical environment in which
they live.

Liquid flowing out of a system,
such as a discharge of liquid
waste from a factory or water
leaving a sewage treatment plant.

Substances (usually pollutants)
discharge into the air.

U.S. Environmental Protection
Agency -- the federal agency that
administers federal environmental
regulations and programs.

Most lakes form three distinct
layers of water during summertime
weather. The epilimnion is the
upper layer and is characterized
by warmer and lighter water.

Environmental Responsibility and
Liability Act. The Minnesota State
Superfund.

The wearing away of land surfaces
by the action of wind or water

A lake that has a high level of
plant nutrients and biological
productivity and a low oxygen
content.

The aging process by which lakes
are fertilized with nutrients.
Natural eutrophication will very
gradually change the character of
a lake. Cultural eutrophication is
the accelerated aging of a lake as
a result of human activities.