According to KRDO on August 25th:

The Colorado Department of Transportation said Santa Fe Ave. was closed under I-25 Tuesday because of a water main break.

CDOT says crews working on the I-25 reconstruction project between City Center Drive and Ilex Street hit the line, causing the break.

Water service to homes and businesses was not disrupted.

A detour was in place for today’s work and will remain in place until road and water line repairs are completed and drilling operations conclude.

All traffic is reduced to a single lane and in a head-to-head configuration on northbound Santa Fe Avenue. The current estimate for repairs is up to three days.