From The Crested Butte News (Mike Horn):
The majority of the revisions to Regulation No. 31 are being proposed by the Water Quality Control Division, with the Colorado Mining Association and the Colorado Wastewater Utility Council submitting additional proposals. The proposed revisions include changes to criteria for, among others, dissolved oxygen, E. coli, and molybdenum. Temporary modifications of standards and anti-degradation to protect high-quality waters are also on the docket, as is adoption of new provisions authorizing variances to water quality standards in limited circumstances.
More Colorado Water Quality Control Commission coverage here.