Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

2020 Assessment Summary - Category 5 - Water is impaired or threatened and a TMDL is needed

303(d) List of Impaired Waters

The State's Section 303(d) list of impaired waters. The waterbody is impaired and a total maximum daily load (TMDL) is needed.
View Map of Impaired Segments
TMDL Priorities

Iowa DNR prioritizes TMDLs that are able to address impairments on waterbodies with a high potential for social impact. The TMDL priority does not necessarily indicate the severity or significance of the impairment

Tier I
impairments with a realtively high social impact and relatively low complexity and/or cost for TMDL development
Tier II
impairments with a realtively high social impact and relatively high complexity and/or cost for TMDL development
Tier III
impairments with a realtively low social impact and relatively low complexity and/or cost for TMDL development
Tier IV
impairments with a realtively low social impact and relatively high complexity and/or cost for TMDL development
Note: Mouse over (or click on a mobile device) the icon for descriptions of those field values. Additional information can be found in the reference codex.
NS
Not Supported
PS
Partially Supported
WINOFI
Water In Need of Further Investigation
A1
Recreation: Primary contact
A2
Recreation: Secondary contact
A3
Recreation: Children's contact
BCW1
Aquatic Life: Cold Water Type 1
BCW2
Aquatic Life: Cold Water Type 2
BLW
Aquatic Life: Lakes and wetlands
BWW1
Aquatic Life: Warm Water Type 1
BWW2
Aquatic Life: Warm Water Type 2
BWW3
Aquatic Life: Warm Water Type 3
C
Drinking Water
HH
Human Health
GenUse
General Use water
OIW
Outstanding Iowa Water
5*
303(d)-impaired last cycle; fully supporting this cycle; potential de-listing.
5a
Pollutant-caused impairment. TMDL needed.
5b
Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.
5b-t
Biological - tentative
5b-v
Biological - verified
5p
Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.
Waterbody ADB Code Type Use Support Code Cause of Impairment Listing Info