Antidegradation refers to federal regulations designed to maintain and protect high quality waters and existing water quality in other waters from unnecessary pollution.

Background and Additional Reference
Introduction to Antidegradation  
Iowa Antidegradation Implementation Procedure (2-17-10)  
List of Scenarios  
Frequently Asked Questions  
EPA Interim Economic Guidance for Water Quality Standards  

Additional Antidegradation Resources
Forms and Information
Exhibit 9A - Preliminary Review of Antidegradation Alternatives Analysis
PDF File Format
Financial Worksheet - Blank Form
DOC File Format
PDF File Format
Sample Public Notice
DOC File Format
PDF File Format
Public and Interagency Contact List  
PDF File Format
Example Alternative Analysis for a Municipal Wastewater Facility
DOC File Format
PDF File Format
Financial Worksheet - Completed Example
DOC File Format
PDF File Format
Example Alternative Analysis for Cooling Tower Chemical Switch  
PDF File Format
Example Alternative Analysis for a New Industrial Contributor to a Municipal WWTP  
PDF File Format
Exhibit 3 - Waste Load Allocation Request Form and Instructions
DOC File Format
PDF File Format
Iowa Surface Water Classifications
DOC File Format
PDF File Format
Outstanding Iowa Waters (OIW) Maps - See document library at bottom of this page

 Process Charts
- Antidegradation Process when Construction is Needed 
- Antidegradation Process for a New Discharger without Construction 
- Antidegradation Process for an Amendment to an NPDES Permit 
- Antidegradation Process for NPDES Permit Renewals 
- Antidegradation Process for Wastewater Construction Projects 
Antidegradation Training Presentations - June 28, 2010
Antidegradation Workshop - Chuck Corell 
Background & Scenarios - Adam Schnieders 
Role of WES - Satya Chennupati 
Waste Load Allocation Form - Connie Dou 
Alternatives Analysis - Larry Bryant 
Affordability Analysis - Terry Kirschenman 
Exhibit 9b - Terry Kirschenman 
Antidegradation Flow Chart - Lori McDaniel 

Antidegradation Rulemaking Documents
Antidegradation Final Rule - Published 1/13/10  
Antidegradation Fiscal Impact Statement - Updated November 2008  
Regulatory Analysis for OIW - IAB published 10/21/09  
Antidegradation Public Comment Responsiveness Summary  
EPA Approval 9/30/10 

Questions? Contact:
Larry Bryant,; 515-725-8426
Connie Dou,; 515-725-8400

Outstanding Iowa Waters Map Iowa's Outstanding Waters
Download a printable map of overall locations of Iowa’s Outstanding Iowa Waters (OIW). For more detailed information about each specific stream, click on the individual OIW Maps shown below in the following table.

Outstanding Iowa Waters