GLOSSARY OF TERMS
303(d List) - List of impaired and threatened waters (stream/river segments, lakes) that the Clean Water Act requires all states to submit for EPA approval every two years. The states identify all waters where required pollution controls are not sufficient to attain or maintain applicable water quality standards, and establish priorities for development of TMDLs based on the severity of the pollution and the sensitivity of the uses to be made of the waters, among other factors.
Ambient monitoring program - Monitoring conducted beyond the immediate influence of a discharge pipe; includes water quality conditions and living resources.
Ambient Water quality standard - Enforceable limits on the concentration of pollutants designed to protect a designated use of the waterbody. Standards are promulgated by NY State and approved by the U.S. Environmental Protection Agency.
Assimilative capacity - The capacity of a natural body of water to receive wastewaters or toxic materials without deleterious effects to its designated use (e.g., without damage to aquatic life or humans who consume the water).
BAP – Biological Assessment Profile - An index or score of overall impact to the macroinvertebrate community comprised of seven benthic macroinvertebrate community metrics used for water quality assessment. The lower the score, the more impacted the community.
Best management practices (BMPs) - An agricultural practice, forestry practice, construction practice or method of storm water management that has been determined to be an effective, practical means of preventing or reducing nonpoint source pollution.
Chlorophyll-a - Plant pigment indicative of algal abundance
Combined sewer overflows (CSOs) - A discharge of untreated sewage and stormwater to a water body; CSOs occur when the capacity of a combined storm/sanitary sewer system is exceeded by storm runoff.
Ecosystem - An interrelated and interdependent community of plants and animals, and abiotic environmental conditions that sustain the living community.
Fecal coliform bacteria - Microscopic single-celled organisms found in the wastes of warm-blooded animals. Their presence in water is used to assess the sanitary quality of water for body-contact recreation or for consumption. Their presence indicates contamination by the wastes of warm-blooded animals and the possible presence of pathogenic (disease producing) organisms.
Frustules – Silica-rich external cell walls of diatoms.
Guidance value - Best professional judgment of the maximum concentration of certain pollutants that will protect a designated use.
HBI – Hilsenhoff Biological Index - This index uses species-defined pollution tolerance levels to assess the overall tolerance level of a community of organisms, and is an indicator of water quality.
Hypolimnion - Deep, cold waters of a stratified lake; portion of the lake volume that remains isolated from atmospheric exchange during periods of thermal stratification
Indicator bacteria - Bacteria used to indicate the potential presence of pathogenic (disease-causing) microorganisms in water (see also fecal coliform bacteria).
Interrelatedness - Pathways of interaction between species in an ecosystem
Littoral - Shallow water zone, where light reaches the sediment surface.
Metrics - Quantifiable physical, chemical and/or biological attributes of an ecosystem that respond to human disturbances; also, measurable attributes of the ecosystem that indicate whether a desired state has been achieved. Good metrics are cost-effective to measure, associated with low uncertainty, relevant to stakeholders and sensitive to anticipated changes.
Pelagic - Associated with the open-water zone (off shore, not associated with the sediments)
Photic zone - Upper layer of the water column where light penetration is sufficient for photosynthesis
Phytoplankton - The community of algae and cyanobacteria present in the water column.
PMA - Percent Model Affinity - This is a measure of similarity of a sampled community to a model non-impacted community, using percent abundance of 7 major groups to quantify the community structure. The closer the similarity of the sampled community structure is to the model non-impacted community structure, the more likely that the sampled community is non-impacted.
Redox (oxidation-reduction potential, ORP) - A measure (in volts) of the affinity of a substance for electrons. The value is compared to that for hydrogen, which is set at zero. Substances that are more strongly oxidizing than hydrogen have positive redox potentials (oxidizing agents); substances more reducing than hydrogen have negative redox potentials (reducing agents). In Onondaga Lake’s hypolimnion, ORP declines as organic material is decomposed.
Secchi disk - A round disk, 25 cm in diameter, with alternating quadrants of black and white. It is lowered into the water on a calibrated line, and the depth at which it is no longer visible is recorded; thus indicating water clarity.
Sonde - Compact monitoring devices that include one or more sensors or probes to measure water quality conditions directly, eliminating the need to collect samples and transport them to a laboratory for analysis.
Species diversity - Measure of the abundance and relative frequency of species
Stoichiometric - The ratio of required elements needed for a chemical reaction; in this context, refers to the ratio of N and P required by cells for metabolism.
TMDL- Total Maximum Daily Load - An allocation of the mass of a pollutant that can be added to a water body without deleterious effects to its designated use
Trophic condition - The status of a water body with regard to its nutrient supply and consequent productivity.
Volume-days of anoxia - A metric that integrates the volume of the lake water affected by low dissolved oxygen (DO) conditions and the duration of the low DO.
Water year - The continuous 12-month period, October 1 through September 30, in U.S. Geological Survey reports dealing with the surface-water supply. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months. Thus, the year ending September 30, 2010, is referred to as the “2010 water year.
Watershed - The land area contributing surface flow to Onondaga Lake, through its tributary streams and direct runoff.