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Glossary
hindcast: To estimate the probability of some past event or condition as a
result of rational study and analysis of available data.
hydrologic(al) event: Pertaining to increased water flow or discharge resulting from rainfall or snowmelt.
hydrologic flow paths: Surface and subsurface routes by which water travels
from where it is deposited by precipitation to where it drains from a
watershed.
hydrology: The science that studies the waters of the earth—their occurrence,
circulation, and distribution; their chemical and physical properties;
and their reaction with their environment, including their relationship to living things.
hypolimnion: The layer of water in a thermally stratified lake that lies below
the thermocline, is noncirculating, and remains perpetually cold.
Index of Biotic Integrity (IBI): Provides assessment of biological condition,
based on a combination of metrics.
index period: A relatively narrow period of time for synoptic sampling (often
a 2-month window during spring, summer, or fall) intended to represent the lake or stream chemistry for that year.
invasive species: A species aggressively expanding its range and population
density into a region in which it is not native, often through outcompeting or otherwise dominating native species.
labile monomeric aluminum: Operationally defined as aluminum that does
not pass through a cation exchange column; assumed to represent
inorganic monomeric aluminum (Al i ).
leaching: The removal of soil elements or applied chemicals by water movement through the soil.
littoral zone: Shallow-water zone around the lake margin.
macrophyte: Rooted aquatic plant.
MAGIC: Model of Acidification of Groundwater in Catchments; a watershed
ion balance model.
mitigation: Generally described as amelioration of adverse impacts caused
by a stressor such as acidic deposition at the source (e.g., emissions
reductions) or the receptor (e.g., lake liming).
model: An abstraction or representation of a system, generally on a smaller scale.
monomeric aluminum: Aluminum that occurs as a free ion (Al 3+ ); simple
inorganic complexes such as Al(OH) n
3-n , AlF n
3-n ; or simple organic
complexes, but not in polymeric forms; operationally, extractable aluminum measured by the pyrocatechol violet method or the methylisobutyl ketone method (also referred to as the “oxine” method) is
assumed to represent total monomeric aluminum. Monomeric aluminum can be divided into labile and nonlabile components using a cation exchange column.
Glossary
hindcast: To estimate the probability of some past event or condition as a
result of rational study and analysis of available data.
hydrologic(al) event: Pertaining to increased water flow or discharge resulting from rainfall or snowmelt.
hydrologic flow paths: Surface and subsurface routes by which water travels
from where it is deposited by precipitation to where it drains from a
watershed.
hydrology: The science that studies the waters of the earth—their occurrence,
circulation, and distribution; their chemical and physical properties;
and their reaction with their environment, including their relationship to living things.
hypolimnion: The layer of water in a thermally stratified lake that lies below
the thermocline, is noncirculating, and remains perpetually cold.
Index of Biotic Integrity (IBI): Provides assessment of biological condition,
based on a combination of metrics.
index period: A relatively narrow period of time for synoptic sampling (often
a 2-month window during spring, summer, or fall) intended to represent the lake or stream chemistry for that year.
invasive species: A species aggressively expanding its range and population
density into a region in which it is not native, often through outcompeting or otherwise dominating native species.
labile monomeric aluminum: Operationally defined as aluminum that does
not pass through a cation exchange column; assumed to represent
inorganic monomeric aluminum (Al i ).
leaching: The removal of soil elements or applied chemicals by water movement through the soil.
littoral zone: Shallow-water zone around the lake margin.
macrophyte: Rooted aquatic plant.
MAGIC: Model of Acidification of Groundwater in Catchments; a watershed
ion balance model.
mitigation: Generally described as amelioration of adverse impacts caused
by a stressor such as acidic deposition at the source (e.g., emissions
reductions) or the receptor (e.g., lake liming).
model: An abstraction or representation of a system, generally on a smaller scale.
monomeric aluminum: Aluminum that occurs as a free ion (Al 3+ ); simple
inorganic complexes such as Al(OH) n
3-n , AlF n
3-n ; or simple organic
complexes, but not in polymeric forms; operationally, extractable aluminum measured by the pyrocatechol violet method or the methylisobutyl ketone method (also referred to as the “oxine” method) is
assumed to represent total monomeric aluminum. Monomeric aluminum can be divided into labile and nonlabile components using a cation exchange column.