5 Colo. Code Regs. § 1002-34.18
The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; 25-8-207 and 25-8-402 C.R.S. provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4), C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE:
First, the Commission has adopted new introductory language for the tables, in section 3.4.6 . The purpose of this language is to explain the new references to "table value standards"(TVS) that are contained in the Tables. The other changes considered and adopted are addressed below.
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.
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.
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
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
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.
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.
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.
Based on stream sampling data for Segment 3, table value standards were established as were ambient standards for cadmium and lead. For Segment 5, ambient standards for cadmium and lead were added; table value standards were added for the remaining metals.
Table Value Standards for metals have been adopted for this segment with the exception of total recoverable iron whose 50 percentile value is 2200 ug/l. In addition, the recreation classification has been changed from Class 2 to Class 1 with a fecal coliform standard of 200/100 ml.
5 CCR 1002-34.18