PERMFILE48500 - Laserfiche WebLink

Home Browse Search

' 31.7 PROCESS FOR ASSIGNING STANDARDS AND GRANTING. EXTENDING OR REMOVING TEMPORARY MODIFICATIONS ' (1) Assigning Standards The Commission is responsible for promulgating water quality standards as set forth in section 25-8-204, C.R.S. Standards may be narrative and/or numeric and include the following: ' (a) Basic Standards The basic standards in section 31.11 shall apply to all state surface waters at the ' effective date of the regulation. (b) Numeric Standards A numeric standard may be assigned by the Commission either to apply on a statewide basis or to specific state surface waters. A numeric standard will be ' assigned by the Commission when it is presented with evidence that a particular numeric level for a parameter is the suitable limit for protecting the classified use. A numeric standard consists of a numeric level and may include a description as to how that numeric level is to be measured. Numeric standards will include appropriate averaging periods and appropriate frequencies of allowed excursions. A numeric standard may be exceeded due to temporary natural conditions such as unusual precipitation patterns, spring runoff or drought. Such uncontrollable ' conditions are not cause for changing the numeric standard. A temporary modification of a numeric standard may be granted by the ' Commission if the numeric standard is not being met at the present time, but such numeric standard is necessary to allow the full attainment of the classified use. ' Numeric standards will be assigned based on the evidence presented at the classification and numeric-standard-setting hearings. Numeric standards may not necessarily be assigned for all constituents listed in the tables. In making this ' determination, the Commission will consider the likelihood of such constituents being present in the waters in question naturally or due to point or nonpoint sources, and shall consider the significance of the constituents with respect to protection of the classified uses. Entities having specific water quality data for the ' waters being classified, such as 208 agencies, local municipalities and industries, and citizens' groups, the Water Quality Control Division, state and federal agencies, environmental organizations, and other interested persons are ' encouraged to present such information. The Commission may use any of the following approaches to establish site-specific ' numeric standards, as it determines appropriate with respect to specific state surface waters. Existing site-specific standards shall remain in effect until superceded by revised standards promulgated pursuant to this section: 10