Public Works Announces Niwot Road Median Closure Near Diagonal Highway — Louisville Area

Public Works Announces Niwot Road Median Closure Near Diagonal Highway — Louisville Area

Boulder County Public Works announces a temporary median closure on Niwot Road near the CO-119 Diagonal Highway intersection for utility infrastructure improvements. The closure will affect left turns from Niwot Road onto the Diagonal Highway for approximately six weeks. A signed detour route will be in place.

Water quality monitoring at 13 stations along Boulder Creek, St. Vrain Creek, and Left Hand Creek showed all parameters within acceptable ranges for 2025. The Public Health publishes quarterly water quality reports on the Boulder County website.

Environmental review of the project area near Flagstaff Road found 11 sensitive species and 3 wetland areas requiring mitigation. The Public Health worked with Colorado Parks and Wildlife to develop a habitat conservation plan.

Eligibility

The Board of County Commissioners will review progress on this initiative at their June 3 business meeting. Agenda items and supporting documents are posted on the Boulder County website 72 hours before each meeting.

Data from the 2025 Boulder County Community Survey shows that 54% of respondents rated this service as “important” or “very important.” The survey, conducted every two years, received 6,729 responses from residents across the county.