Iowa Criteria Development Progress
This page provides information about the progress Iowa has made towards the development of numeric criteria and shows what statewide and site-specific criteria are currently in effect.
Note: The information on the tabs below reflects the information available on EPA’s
Water Quality Standards Repository. The criteria presented here will be updated as new water quality standards documents are posted to the Repository.
Numeric Criteria Development
The information presented below gives a summary of state progress towards the development of numeric criteria. The information comes from EPA’s “State Adoption of Numeric Nutrient Standards (1998-2008)” report, current water quality standards, program activity measures, and nutrient criteria development plans. Links to the Iowa’s Nutrient Criteria Plan and state water quality standards are also provided.
Existing Numeric Criteria
| Waterbody Type | N | P | Chl-a | Clarity |
|---|---|---|---|---|
| Lakes & Reservoirs | ||||
| Rivers & Streams | ||||
| Estuaries | N ⁄ A | N ⁄ A | N ⁄ A | N ⁄ A |
| Wetlands |
S = Statewide W = For selected waterbody N ⁄ A=Not Applicable
Note: See Statewide Criteria and Site-specific Criteria tabs for more information.
Links to Numeric Nutrient Criteria Plan and Existing Nutrient Criteria
Plan:
WQS: Iowa Water Quality Standards
Iowa DNR Water Quality Standards Exit
Milestone Information
Milestone information updated July 2012.
Milestone |
Rivers and Streams | Lakes and Reservoirs | Estuaries and Coastal Waters | |||
|---|---|---|---|---|---|---|
| TN | TP | TN | TP | TN | TP | |
| Planning for criteria development | No date provided | No date provided | No date provided | No date provided | Not applicable | Not applicable |
| Collection of information and data | No date provided | No date provided | No date provided | No date provided | Not applicable | Not applicable |
| Analysis of information and data | No date provided | No date provided | No date provided | No date provided | Not applicable | Not applicable |
| Proposal of criteria | No date provided | No date provided | No date provided | No date provided | Not applicable | Not applicable |
| Adoption of criteria | No date provided | No date provided | No date provided | No date provided | Not applicable | Not applicable |
TN: Total Nitrogen; TP: Total Phosphorus
Statewide Criteria
The information on this tab shows EPA-approved nutrient criteria for Iowa’s waterbodies. The language presented below comes directly from state water quality standards and applies to all waterbodies within the state (unless a waterbody type or designated use is noted). Criteria applicable to specific waterbodies within the state can be found on the “Site-specific Criteria” tab. For more information, refer to the Iowa water quality standards.
The following information reflects Iowa’s water quality standards posted to the Water Quality Standards Repository as of November 2010 (EPA-approved November 2009).
567—61.3(455B) Surface Water Quality Criteria.
61.3(2) General water quality criteria. The following criteria are applicable to all surface waters including general use and designated use waters, at all places and at all times for the uses described in 61.3(1)“a.” *
c. Such waters shall be free from materials attributable to wastewater discharges or agricultural practices producing objectionable color, odor or other aesthetically objectionable conditions.
e. Such waters shall be free from substances, attributable to wastewater discharges or agricultural practices, in quantities which would produce undesirable or nuisance aquatic life.
Table 1. Criteria for Chemical Constituents
(all values as micrograms per liter as total recoverable unless noted otherwise)
Human health criteria for carcinogenic parameters noted below were based on the prevention of an incremental cancer risk of 1 in 100,000. For parameters not having a noted human health criterion, the U.S. Environmental Protection Agency has not developed final national human health guideline values. For non-carcinogenic parameters, the recommended EPA criterion was selected. For Class C waters, the EPA criteria for fish and water consumption were selected using the same considerations for carcinogenic and non-carcinogenic parameters as noted above. For Class C waters for which no EPA human health criteria were available, the EPA MCL value was selected.
| Use Designations** | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Parameter | B(CW1) | B(CW2) | B(WW-1) | B(WW-2) | B(WW-3) | B(LW) | C | HH | |
| Nitrate as N | MCL | — | — | — | — | — | — | 10* | — |
| Nitrate + Nitrite as N | MCL | — | — | — | — | — | — | 10* | — |
| Nitrite as N | MCL | — | — | — | — | — | — | 1* | — |
* Units expressed as milligrams/liter
**Surface Water Classification
B. Water use designation abbreviations.
"B" means wildlife and aquatic life uses. "WW-1" means warm water - type 1, "WW-2 means warm water - type 2, and "WW-3" means warm water type 3. "LW" means lakes and wetlands warm water. "CWI" means cold water - type 1, and "CW2 means cold water - type 2.
"C” means raw water source of potable water supply.
"HH" means human health
Site-specific Criteria
The information on this tab shows EPA-approved site-specific nutrient criteria for Iowa’s waterbodies. Criteria on this page apply only to the waterbodies listed below. Criteria applicable to all waterbodies within the state are found on the “Statewide Criteria” tab. For more information, refer to the Iowa water quality standards.
The following information reflects Iowa’s water quality standards posted to the Water Quality Standards Repository as of November 2010 (EPA-approved November 2009).
None.