Saturday, February 28, 2009

Iowa - IDNR Draft Antidegradation Policy

The Iowa Department of Natural Resources (IDNR) is proposing changes to its “Antidegradation Policy”. The changes can impact any wastewater discharger in Iowa, but especially new permittees or existing permittees that may wish to increase their discharge in the future. The changes being proposed include:

  • Incorporate by reference the document entitled “Iowa Antidegradation Implementation
    Procedure,” which proposes an approach to assessing and minimizing degradation of Iowa’s surface waters,
  • Update antidegradation policy language with four tier approach,
  • Remove High Quality (Class HQ) and High Quality Resource (Class HQR) designated uses and add several waters to the newly proposed Outstanding Iowa Water (OIW) category.

The purpose of the antidegradation policy is to set minimum requirements to conserve, maintain, and protect existing uses and water quality for water bodies that currently meet their water quality standards. The department is required by Clean Water Act to develop and adopt a statewide antidegradation policy and to identify procedures for implementing the policy. Comments on the draft policy are being accepted through January 29, 2009.


Caltha LLP provides expert consulting services to public and private sector clients nationwide to address water quality standards, wastewater permitting and assessing potential impacts of chemicals in the aquatic environment.

Caltha LLP Aquatic Toxicology / WQ Standards Services Website