Environment Department Requests Public Comment
on a Report Supporting Water Quality Standards Changes
to Smelter Tailings Soils Investigation Unit Drainages
within the Chino Mine Investigation Area, Grant County, New Mexico
The Department is requesting public comment on a report that may be used to support amendments to surface water quality standards for five drainages within the Chino Mine Investigation Area, Grant County, New Mexico. The amendments would change the drainages to unclassified ephemeral waters subject to §220.127.116.11 NMAC, from their current status as default unclassified nonperennial waters subject to §18.104.22.168 NMAC.
Unclassified nonperennial waters are by default subject to §22.214.171.124 NMAC, with designated uses of marginal warmwater aquatic life, primary contact, wildlife habitat, and livestock watering. In November, 2012, Chino Mines Company provided a report to the Department, Application of the Hydrology Protocol to Smelter Tailings Soils Investigation Unit (STSIU) Drainages. The Department has reviewed the report, which includes a Use Attainability Analysis (UAA) based on the Department’s “Hydrology Protocol”, and finds it demonstrates that that Clean Water Act §101(a)(2) uses of primary contact and marginal warmwater aquatic life are not attainable in five STSIU drainages, and that the highest attainable uses are limited aquatic life and secondary contact.
In accordance with 126.96.36.199.C, the Department is releasing this report for a 30-day public review which will end at 5 PM on February 14, 2013. After consideration of public comments, the Department may proceed by submitting the report and response to comments to EPA Region 6 for technical approval. If EPA grants approval, the waters will be considered unclassified ephemeral waters subject to §188.8.131.52 NMAC. The report and UAA, the technical approval, and the applicability of§ 184.108.40.206 NMAC to the waters will be posted on the Department’s water quality standards website. The Department will periodically petition the Water Quality Control Commission to list ephemeral waters under Subsection C of 220.127.116.11 NMAC and to incorporate changes to classified segments in the water quality standards regulations as appropriate.