2006 Impaired Streams Metadata

AUID = Assessment Unit ID, a waterbody identifier that is the eight digit subbasin code and the three digit reach number. This AUID constitutes a unique identifer for each reach in the dataset.

ENTITY_ID = A Waterbody Identifier that is the two letter state abbreviation 'MN' concatenated with the AUID. This ID format is transmitted to EPA for reporting purposes.

NAME = Name of the AUID.

DESCRIPT = Text description of the begin/end points of the AUID.

AFFECTED_U = Impaired Use
Values:
'Aquatic Consumption'
'Aquatic Recreation'
'Aquatic Life'
any combination of these values

CATEGORY = EPA Consolidation Assessment and Listing Methodology [CALM] which integrates the 305(b) Report with the 303(d) TMDL List.
The five categories in CALM are as follows:
Category 1: all designated uses are meeting water quality standards
Category 2: some uses are meeting water quality standards and there are insufficient data to assess other uses
Category 3: there are insufficient data to assess any uses
Category 4: at least one use is impaired, but a TMDL is not required
Category 5: at least one use is impaired and a TMDL is required. These become the List of impaired waters.

A reach can only be placed into one Category. For example, if a reach is impaired for one pollutant but the other uses are being met, and a TMDL is required, that reach would be placed into Category 5. Furthermore, if the reach is impaired for more than one pollutant, the reach must stay in Category 5 until ALL pollutants have EPA-approved TMDL plans.

For 'bookkeeping' purposes, these Categories can be sub-divided. Category 4 has the following four sub-categories:
4A: Impaired, but a TMDL study has been approved by EPA
4B: Impaired, but a TMDL study is not required because water quality standards are expected to be met in the near future
4C: Impaired, but a TMDL study is not required because the impairment is not caused by a pollutant
4D: An assessment unit is impaired or threatened but doesn't require a TMDL because the impairment is due to natural conditions with only insignificant anthropogenic influence. To be considered 'insignificant', the elimination of the anthropogenic influence would not lead to the attainment of water quality standards and it would not be included in formal pollution reduction goal-setting activities. A reach-specific water quality standard based on local natural conditions has yet to be determined. Upon determination, the assessment unit will be considered non-impaired for the natural conditions and re-categorized to an appropriate category.

Category 5 has the following three sub-categories:
5A: Impaired by multiple pollutants and no TMDL study plans are approved by EPA
5B: Impaired by multiple pollutants and at least one TMDL study plan is approved by EPA
5C: Impaired by one pollutant and no TMDL study plan is approved by EPA

NEEDS_PLN = The pollutant(s) for which TMDL plans must be developed and approved. Categories: 5A, 5B and 5C

APPRVD_PLN = The reach is impaired, but TMDL plan(s) have been approved for the pollutant(s) for this reach. Categories: 4A, 5B-15

NO_PLAN = The reach is impaired, but does not need a TMDL plan. Categories: 4B, 4C and 4D


Pollutant/Stressor Abbreviations found in NEEDS_PLN, APPRVD_PLN and NO_PLAN
A= Ammonia
AT = Absence of Trout
B-F= Fish IBI
B-I = Invertebrate IBI
B-FI = Fish IBI and Invertebrate IBI
BP = Bioaccumulative Pesticides
Cl = Chloride
FC = Fecal Coliform
Hg = Mercury
DO = Dissolved Oxygen
PCB = PCBs
pH = pH
T = Turbidity
Tm = Temperature