1.  Aquatic life.  "Aquatic life" means any plants or animals which live at least part of their life cycle in fresh water.  

2.  As naturally occurs.  "As naturally occurs" means conditions with essentially the same physical, chemical and biological characteristics as found in situations with similar habitats free of measurable effects of human activity.  

2-A.  Color pollution unit.  "Color pollution unit" means that measure of water color derived from comparison with a standard measure prepared according to the specifications of the current edition of "Standard Methods for Examination of Water and Wastewater," adopted by the United States Environmental Protection Agency, or an equivalent measure.  

2-B.  Combined sewer overflow.  "Combined sewer overflow" means a discharge of excess wastewater from a municipal or quasi-municipal sewerage system that conveys both sanitary wastes and storm water in a single pipe system and that is in direct response to a storm event or snowmelt. Combined sewer overflow discharges do not include dry weather discharges that occur as a result of nonstorm events or are caused solely by groundwater infiltration.  

3.  Community function.  "Community function" means mechanisms of uptake, storage and transfer of life-sustaining materials available to a biological community which determines the efficiency of use and the amount of export of the materials from the community.  

4.  Community structure.  "Community structure" means the organization of a biological community based on numbers of individuals within different taxonomic groups and the proportion each taxonomic group represents of the total community.  

5.  Direct discharge.  "Direct discharge" means any discernible, confined and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation or vessel or other floating craft, from which pollutants are or may be discharged.  

6.  Domestic pollutants.  "Domestic pollutants" means any material, including, without limitation, sanitary wastes, waste water from household activities or waste waters with similar chemical characteristics, which are generated at residential or commercial locations.  

7.  Estuarine and marine life.  "Estuarine and marine life" means any plants or animals which live at least part of their life cycle in salt water.  

8.  Indigenous.  "Indigenous" means supported in a reach of water or known to have been supported according to historical records compiled by State and Federal agencies or published scientific literature.  

8-A.  Invasive species.  "Invasive species" means an invasive animal as determined by the Department of Inland Fisheries and Wildlife or an invasive aquatic plant as listed under section 410-N or as determined by the department. A species may be determined to be invasive for all waters or for specific waters.  

9.  Natural.  "Natural" means living in, or as if in, a state of nature not measurably affected by human activity.  

9-A.  Overboard discharge.  "Overboard discharge" means discharge to the surface waters of the State of domestic pollutants not conveyed to and treated in municipal or quasi-municipal sewerage treatment facilities.  

9-B.  Quasi-municipal.  "Quasi-municipal" means any form of ownership and management by a governmental unit embracing a portion of a municipality, a single municipality or several municipalities which is created by law to deliver public waste water treatment services, but which is not a state governmental unit.  

9-C.  Pounds per ton as unit of measure.  "Pounds per ton" means the unit for measurement of color in the discharge from the production of wood pulp. The numerator of this unit is the product of the number of color pollution units multiplied by 8.34 multiplied by the volume of effluent discharged measured in millions of gallons. The denominator of this unit is measured in tons of actual production of unbleached wood pulp as measured on an air dried basis.  

10.  Resident biological community.  "Resident biological community" means aquatic life expected to exist in a habitat which is free from the influence of the discharge of any pollutant. This shall be established by accepted biomonitoring techniques.  

10-A.  Sustenance fishing designated use.  "Sustenance fishing designated use" is a subcategory of the applicable fishing designated use that protects human consumption of fish for nutritional and cultural purposes and applies only to those water body segments that are identified in this article as subject to a sustenance fishing designated use.  

11.  Unimpaired.  "Unimpaired" means without a diminished capacity to support aquatic life.  

11-A.  Use attainability analysis.  "Use attainability analysis" means a structured scientific assessment of the factors affecting the attainment of a designated use in a water body. The assessment may include consideration of physical, chemical, biological and economic factors.  

12.  Without detrimental changes in the resident biological community.  "Without detrimental changes in the resident biological community" means no significant loss of species or excessive dominance by any species or group of species attributable to human activity.