Water quality standards (WQS) adopted and submitted since May 30, 2000 are not effective for Clean Water Act (CWA) purposes until EPA approves them (see 40 CFR 131.21).  This is known as the Alaska Rule.  Idaho has several sections of its water quality standards undergoing EPA review, and until these are acted upon, their use in CWA programs, such as National Pollutant Discharge Elimination System (NPDES) permits or Total Maximum Daily Loads (TMDL), will not be approved by EPA.

Instead, prior rules remain in effect for CWA programs.  For state adopted rules awaiting EPA action, the information presented below provides the previous rule language that is currently effective for CWA purposes.  The rule section and date of publication is included in parenthesis.

> Link to current rule language.

In 2006, Idaho adopted statewide site-specific aquatic life criteria for cadmium, revising the hardness dependent criteria equations for cadmium in section 210.02 of the rules.  Until EPA acts on this change to state WQS, the effective water column criteria for dissolved cadmium at 100 mg/L hardness are summarized in the table below (IDAPA 58.01.02.210.01, 2005). 

     CMC (acute criterion) = WER * EXP^{(1.0166 * LN(hardness) - 3.924)} * ACF

     CCC (chronic criterion) = WER * EXP^{(0.7852 * LN(hardness) - 3.490)} * CCF

          Where:

          WER = water effects ratio

          EXP = base e exponential function

          ACF = acute conversion factor = 1.136672 * In(hardness)*0.041838

          CCF = chronic conversion factor = 1.101672 * In(hardness)*0.041838

Idaho first adopted temperature criteria for the seasonal cold beneficial use (IDAPA 58.01.02.250.3) in April 2000. In 2002, Idaho revised its temperature criteria for the seasonal cold beneficial use.  These revised criteria are undergoing review at EPA.  Although the criteria adopted in 2000 have not been acted on by EPA, they were adopted by Idaho and submitted to EPA prior to May 30; therefore, these criteria are effective for CWA purposes per the Alaska Rule.  The effective temperature criteria for seasonal cold are:

Water temperatures of twenty-seven (27) degrees C or less as a daily maximum with a daily average of no greater than twenty-four (24) degrees C.

Idaho adopted bull trout temperature criteria in 1998. These criteria were revised in 2003 and the revisions are currently undergoing EPA review.  At the present time, the bull trout temperature criterion effective for CWA purposes is the federally promulgated temperature criterion of 10ºC (7-day average of maximum daily temperatures) for waters specified in 40CFR 131.33.  For waters not listed in 40 CFR 131.33, the following 1998 criteria (IDAPA 58.01.02.250.02.f) are effective:

Although these criteria were not acted on by EPA, they were adopted prior to May 30, 2000, thus, they are effective for CWA purposes but only for a few water bodies not included in the federal rule. 

> Link to list of water bodies not included in federal rule (still under development).