Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-34 - REGULATION NO. 34 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR SAN JUAN AND DOLORES RIVER BASINS
Section 5 CCR 1002-34.18 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE; AUGUST, 1989 HEARING ON MULTIPLE SEGMENTS

A. Jurisdiction on Tribal Lands

On the issue of classifying and setting standards on tribal lands, the Commission was advised to classify and set standards as they would for waters on non-tribal lands with the understanding that the Commission is not attempting to assert jurisdiction or to usurp the authority of the tribe to classify and set standards for waters within the boundaries of the reservation.

B. Table Value Standards for Metals

San Juan, Segment 7;

Los Pinos, Segment 4;

Animas, Segment 5;

Dolores, Segments 5 and 7.

Numerical standards for metals for these segments have in most instances previously been based on table values contained in Table III of the Basic Standards and Methodologies for Surface Water. Table III has been substantially revised, effective September 30, 1988. A few of these segments had no new data to indicate that new table value standards are not appropriate. There are also some of these segments whose previous standards were based in part on ambient quality, since their quality did not meet old table values based on alkalinity ranges. However, these segments generally have much higher hardness than alkalinity, and the new table values (based on hardness-dependent equations) are now appropriate as standards.

C. New High Quality 2 Designations

San Juan, Segments 1, 5, and 9;

Piedra, Segments 3 and 5;

Los Pinos, Segment 2a;

Animas, Segments 8a, 10, 11, 12a, 12b, and 14;

La Plata, Segments 1 and 4;

Dolores, Segments 4 and 10.

From the information available, it appears that the existing quality of these segments meets or exceeds the quality specified by the revised criteria in Table III, and new acute and chronic table value standards based thereon have therefore been adopted.

Second, in addition to these standards changes, the use classifications have been revised where necessary so that each of these segments has the following classifications:

Recreation - Class 1

Cold Water Aquatic Life - Class 1

Water Supply

Agriculture

D. Existing High Quality 2 Segments; New Classifications and Standards

San Juan, Segment 4;

Piedra, Segments 1 and 2;

Los Pinos, Segment 1;

Animas and Florida, Segment 1;

Dolores, Segment 1.

These segments were already described as High Quality Class 2, as all are wilderness and wild and scenic rivers. Available information indicates that the parallel new High Quality 2 designation continues to be appropriate for each, along with new table value numeric standards and equations for cold water aquatic life classifications, i.e., acute (trout) for cadmium and zinc and chronic (trout) for silver.

The following use classifications, and associated table value standards, have been adopted for these segments:

Recreation - Class 1

Cold Water Aquatic Life - Class 1

Water Supply

Agriculture

E. Existing High Quality 2 Segments; New Classifications and Standards

San Juan, Segments 3, 10, and 11;

Piedra, Segment 6; Los Pinos, Segment 6;

Animas and Florida, Segments 3, 4, 9, 13b, and 15;

La Plata, Mancos, McElmo, and San Juan, Segments 2, 3, 5, 6, 7, and 8;

Dolores, Segment 9 and 11.

These segments all qualify for a Use-Protected designation based either on their present classifications or the existing standards contain three or more of the following metals parameters whose concentrations, based on total recoverable metals, indicate they may be worse than that specified in Table III for the protection of aquatic life class 1 use: cadmium, copper, iron, lead, or zinc.

F. New Use-Protected Designation; Table Value Standards

Piedra, Segment 7;

Animas and Florida, Segment 13a.

These segments qualify for a Use-Protected designation based upon their classification. Previous standards were based on table values and no new data was presented to indicate new table value standards are not appropriate.

For these segments, acute and chronic table value standards have been adopted for arsenic, cadmium, chromium (III and IV), copper, iron, lead, manganese, mercury, nickel, selenium, silver, and zinc.

G. Revised Recreation Classification

San Juan, Segments 2 and 6;

Piedra, Segment 4;

Los Pinos, Segment 2b;

La Plata, Segment 9

The recreation classification on these segments has been upgraded from Class 2 to Class 1 (whole body immersion is likely) because the stream sampling data indicate that the fecal coliform standard 200/100 ml is not being exceeded, and conditions are normally considered suitable for swimming or intentional whole body contact. This action was taken in response to a concern raised by the EPA regarding segments not attaining "fishable/swimmable" uses.

H. Other Revisions