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 States 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.
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 below.
Copper Criteria
Waterbody
|
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
|
Chapter 61 Rule Making: Aquatic Life Water Quality Criteria for Metals
The Environmental Protection Commission (EPC) has amended Chapter 61 to update aquatic life water quality criteria for selected metals. The final rule will be effective November 11, 2020. Public comments were addressed in a public participation responsiveness summary.
View the Chapter 61 Amendments
Questions regarding the new water quality criteria can be directed to Katie Greenstein at 515-490-2095 or katie.greenstein@dnr.iowa.gov.