Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-36 - REGULATION NO. 36 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR RIO GRANDE BASIN
Section 5 CCR 1002-36.24 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JULY, 2002 RULEMAKING

A. Resegmentation

Some renumbering and/or creation of new segments was made in the basin due to information which showed that:

B. Outstanding Waters Designations

The following segments, which already included wilderness areas in their description, were designated outstanding waters (OW). The water quality of the following segments met the 12 parameter test and other requirements of 31.8(2)(a):

Rio Grande segment 1

Alamosa segment 1

Closed Basin segment 1

C. Recreation Classifications/Fecal Coliform and E. Coli Standards

The biological standards were updated to include the dual standards for E. coli and fecal coliform, which were adopted by the Commission in the 2000 revisions to the Basic Standards. As stated in the statement of basis for the Basic Standards revisions, the Commission intends that dischargers will have the option of either parameter being used in establishing effluent limitations in discharge permits. In making section 303(d) listing decisions, in the event of a conflict between fecal coliform and E. coli data, the E. coli data will govern. The Commission believes that these provisions will help ease the transition from fecal coliform to E. coli standards.

In a continuation of the Commission's efforts to comply with the requirements contained in the federal Clean Water Act that all waters of the nation should be suitable for recreation in and on the water (known as the "swimmable" goal), the Commission reviewed all Recreation Class 2 segments. In Colorado, the "swimmable" goal translates into Recreation Class 1a, with the 200/100 ml fecal coliform and 126/100 ml E. Coli standard, and Class 1b with the 325/100 ml fecal coliform and 205/100 ml E. coli standard. Class 1a indicates waters where primary contact uses have been documented or are presumed to be present. Class 1b indicates waters where no use attainability analysis has been performed demonstrating that a recreation class 2 classification is appropriate. To maintain the existing Recreation Class 2 with the 2000/100 ml standard on a segment, it must be shown that there is minimal chance that a Recreation Class 1 activity could exist (e.g. ephemeral or small streams that have insufficient depth to support any type of Recreation Class 1 use or very restricted access).

A recreation class 1a classification of a segment is not intended to imply that the owner or operator of a property surrounding a waterbody in a segment would allow access for primary contact recreation. The application of recreation classifications to state waters pursuant to these provisions does not create any rights of access on or across private property for the purposes of recreation in or on such waters. A recreation class 1a classification is intended to only affect the use classification and water quality standards of a segment, and does not imply public or recreational access to waters with restricted access within a segment.

For segments changing to recreation Class 1a because no information was available about actual recreational uses, the last paragraph of section 31.6 will apply to future changes to the recreation classification where a proper showing is made through a use attainability analysis that a recreation Class 2 classification is appropriate, without application of the other downgrading criteria in this section. Moreover, the Commission is relying in part on the testimony from EPA that completion of a use attainability analysis showing that a lower recreation classification is appropriate satisfies applicable downgrading criteria. Based on these factors, the Commission intends that in a future rulemaking hearing, the test for adopting a recreation Class 2 classification would be the same as if it had been considered in this hearing

The following segments with existing Recreation Class 1 classifications were changed to Class 1a:

Rio Grande segments 1, 2, 4, 5, 8, 9, 10, 11, 12, 13, 19, 21, 23, 25, 27, 28, and 30

Alamosa segments 11, 14, 15, 17, and 19

Closed Basin segments 1, 2, 4, 6, 11, 12

Based on the information received that showed Recreation Class 1a uses are in place or are presumed to be present in at least a portion of the segment, the Commission changed the following segments from Class 2 to Class 1a with a 200/100 ml fecal coliform and 126/100 ml E. coli standard:

Rio Grande segments 3, 6, 7, 14, 16, 17, 18, 20, 22, 24, 26, and 29

Alamosa segments 1, 2, 3a, 3b, 3c, 4a, 4b, 5, 6, 7, 8, 9, 10, 12, 13, 16, 18, 20 and 22

Closed Basin segments 3, 5, 7, 8. 9a, 9b, 10, 13, and 14

The following segments retained their Recreation Class 2 classification with 2,000/100mL fecal coliform and 630/100 ml E. coli standard after sufficient evidence was received that a Recreation Class 1a or 1b use was unattainable.

Rio Grande segment 15

Alamosa segment 21

D. Ambient Quality-Based Standards

There are several segments in the Rio Grande Basin that contain ambient standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher than table value standards. EPA had requested that the Commission review the information that is the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped.

The Division reviewed the information about ambient water quality levels and provided testimony that justified retaining or revising the following ambient standards:

Alamosa segment 3a: Fe, pH

Alamosa segment 3b: Cu, Fe

Alamosa segments 3c and 3d: Fe

Alamosa segment 7: Ag, Cd, Cu, Fe, Mn, Ni, Pb, and Zn

Ambient standards were replaced by TVS in the following segment, due to new data and/or changes to the basic standards which indicated ambient standards were no longer appropriate:

Closed Basin segment 7: Cu(ac/ch)

E. Temporary Modifications

There were several segments where temporary modifications that reflect current ambient conditions were adopted. Temporary modifications were set to expire on 12/31/07 to coincide with the next triennial review. The segments are:

Rio Grande segment 7

Closed Basin segments 9a and 9b

F. Organic Standards

The organic standards were updated to include changes adopted by the Commission in the 2000 revisions to the Basic Standards (see 31.11 in Regulation No. 31). "Water + Fish" organic standards are presumptively applied to all Aquatic Life Class 1 streams which also have a Water Supply classification, and are applied to Aquatic Life Class 2 streams which also have a Water Supply classification, on a case-by-case basis. The "Fish Ingestion" organic standards are presumptively applied to all Aquatic Life Class 1 streams which do not have a Water Supply classification, and are applied to aquatic life class 2 streams which do not have a Water Supply classification, on a case-by-case basis.

Information was reviewed regarding Aquatic Life Class 2 segments that have fish that are presently being taken for human consumption or have fisheries that would indicate the potential for human consumption, along with the segments water supply classification. The following segments were changed from Water + Fish to Fish Ingestion:

Rio Grande segments 3 and 18 Alamosa segments 12, 15, 17 and 18

G. Water Supply Classification

Water Supply classification and associated water supply standards were added to Closed Basin segment 3.

H. Modification of Water Supply Standards

Water supply standards were modified to conform to changes made by the Commission in the 2000 revisions to the Basic Standards (see Regulation No. 31 at 31.11(6)). The Commission modified the water supply standards for iron, manganese, and sulfate that are based on secondary drinking water standards (based on esthetics as opposed to human-health risks). The numeric values in the tables were changed to: Fe(ch) = WS (dis), Mn(ch) = WS (dis), and SO4 = WS. These abbreviations mean that for all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as discussed in the Basic Standards and Methodologies at 31.11(6): either (i) existing quality as of January 1 2000; or (ii) Iron = 300 (g/L (dissolved); Manganese = 50 (g/L (dissolved); Sulfate = 250 mg/L (dissolved). For all surface waters with a "Water Supply" classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determined as the result of a site-specific rulemaking hearing that such standards are appropriate.

I. Agriculture Standards

Numeric Standards to protect Agricultural Uses were adopted for the following segments:

Rio Grande segments 15 and 20

Alamosa segment 21

Closed Basin segment 3

J. Other Site-Specific Revisions

The Commission corrected several typographical and spelling errors, and clarified segment descriptions. In addition, the following site-specific revisions were made:

Rio Grande segment 6: The Use Protected designation was removed from this aquatic life class 1 water.

Closed Basin segment 9a: The site-specific standard for Cd was changed to the value to protect the water supply use; the secondary drinking water standards for iron, manganese and sulfate were changed to read WS.

Closed Basin segment 9b: The secondary drinking water standards for iron, manganese and sulfate were changed to read WS.

PARTIES/MAILING LIST STATUS FOR THE JULY, 2002 RULEMAKING HEARING