Water Quality Standards
The DNR manages water quality through the implementation of the State's water quality standards. These standards are found in Chapter 61 of the Iowa Administrative Code. The State's water quality standards help ensure that all Iowans have surface waters that are fishable and swimmable to the fullest extent practicable and water resources that are put to their best beneficial uses.
Antidegradation

Antidegradation refers to federal regulations designed to maintain and protect high quality waters and existing water quality in other waters from unnecessary pollution. For further information please visit the Antidegradation webpage.

Water Quality Criteria

61.3(3) Table 1 and general water quality criteria described in 61.3(2). Numeric criteria apply to designated waters and general water quality criteria are applicable to all surface waters including general use and designated use waters. The following documents share information about specific criteria.

Copper criteria documents

Site-Specific Water Quality Criteria

Clean Water Act rules allow for site-specific water quality criteria approved by the EPA. Site-specific water quality criteria are established when localized water quality parameters are used to derive criteria in accordance with Iowa’s water quality standards (567 Iowa Administrative Code Chapter 61). For example, the copper biotic ligand model (BLM) may be used to establish site-specific copper criteria as described in the rule-referenced Implementation Procedure for Copper BLM.

Site-specific water quality criteria implemented in Iowa are shown in the table below.


Copper Criteria

Water body Upstream latitude
(degrees)
Upstream longitude
(degrees)
Downstream latitude
(degrees)
Downstream longitude
(degrees)
Acute copper criterion (µg/L) Chronic copper criterion (µg/L)

Floyd River

43.1824

-95.8676

43.0684

-95.9153

55.8

33.4

DNR contact: Katie Greenstein katie.greenstein@dnr.iowa.gov

Triennial Review

Under the Clean Water Act, a state shall, from time-to-time, hold public meetings for the purpose of reviewing applicable water quality standards and, as appropriate, modifying and adopting standards. See Chapter 61: Water Quality Standards. This review includes, but is not necessarily limited to: designated uses, criteria, and antidegradation.

DNR contact: Marie Todey (515) 204-7569 marie.todey@dnr.iowa.gov

Use Attainability Analysis (UAA)

Under Iowa's water quality standards, it is presumed that all perennial streams and rivers on the 1:100,000 DLG hydrography data map (published July 1993) are attaining the highest level of recreational (A1) and aquatic life (BWW1) uses and should be protected for activities such as fishing and swimming. A use attainability analysis (UAA) is a process of gathering field data and assessing the available information to determine if a stream is capable of supporting the highest level of recreation and aquatic life uses, and, if not, assign more accurate recreational and aquatic life uses.

Assessment Protocols:

Surface Water Classification Document - Rule referenced document containing a list of designated water bodies in Iowa and their designated uses.

Use Attainability Analysis Database - the UAA database contains all the information on UAAs prior to 2022. Moving forward, new UAAs that are put out on public notice will be posted to this webpage under the UAA public notices tab. Once the UAAS are adopted into rule, they will be posted to ADBNet.

Water Quality Standards: Surface Water Classifications Fact Sheet - Fact sheet describing how water bodies are classified in Iowa.

Water Quality Standards: Use Attainability Analysis (UAA) Fact Sheet - Fact sheet explaining UAAs in Iowa.

DNR contact: Marie Todey (515) 204-7569 marie.todey@dnr.iowa.gov