State official says culvert work in California Gulch should be straightforward; county must file request

Kyle Sandor of the Colorado Department of Public Health and Environment told Lake County officials June 10 that installing a culvert in the California Gulch area (Operable Unit 8) should be a straightforward approval from the state, but requires written notice and attention to institutional controls covering the site.

Sandor said institutional controls covering Operable Unit 8 require county or city approval from CDPHE for excavation, grading or building that disturbs the operable unit. “It'll be a very straightforward process,” he said. He recommended the county submit a written request to CDPHE describing the project; in many cases the agency can respond by email granting approval. Sandor added that the county could, if it prefers, prepare a materials management plan describing how it would limit dust, control truck traffic and manage any metal-impacted soil, but said that document is not required by the institutional-control language.

Sandor reviewed historical remedial work in the gulch and said he did not find evidence that the earlier remedial excavation and tailings consolidation extended to the specific reach under consideration near the tubing area. He said Newmont (or Resurrection) holds environmental covenants in parts of Operable Unit 8, but not in the specific stretch under discussion. “If you can manage the material in place to the extent you know possible, that's what I recommend for this project,” Sandor said on the record.

County staff and commissioners pressed on logistics, sampling and timing. Sandor said excavated soils could be used on-site if they are placed below grade or in a manner that does not cause exposure, but noted the county typically must provide analytical data to move material into the county’s sitewide repository. He also suggested sampling a small number of test borings or samples prior to large redistribution if the county plans to use excavated soils at ground level. “If...you do think it's gonna be used in an area that you could lead to exposure, it might be worth even grabbing a sample just to see what the concentrations are,” Sandor said.

Participants discussed potential wetlands jurisdiction and whether the Army Corps of Engineers or the Colorado Water Quality Control Division should be consulted. Sandor recommended contacting the state water quality control division and, if warranted, the U.S. Army Corps, but said in his experience the Corps typically does not intervene for relatively minor projects unless there is a major wetland or jurisdictional concern.

Regarding design capacity, county staff estimated three 5-foot culverts would provide more capacity than the existing downstream 36-inch pipes. Sandor added that the discharge from the nearby water-treatment plant keeps flows relatively steady but urged the county to consider debris and long-term hydrology in the culvert design.

Next steps agreed at the meeting: county staff will prepare and submit a written request to CDPHE; Sandor said he would review the submission and respond. Staff also agreed to contact the state water quality division about marsh/wetland questions and, if necessary, the Army Corps. County staff planned a follow-up meeting to coordinate paperwork and schedule a shorter review.

The commissioners and staff closed the item after confirming the county’s next steps and likely contacts at CDPHE and water-quality authorities.