This culvert is a portal...

to the eponymously named Culvert Canyon, found along the Potash Road near the Gold Bar campground on the Colorado River, and the focus of today's backcountry sojourn (click images to enlarge):

There are no maintained trails in the branching canyon system, and route finding is not trivial, but here's a reasonably accurate description that can guide you on your own adventure.  This sandstone spire stands as a prominent landmark in the upper part of the basin, and serves as a natural guidepost:

Climbing higher and through the pass containing the sandstone sentinel the ultimate goal of today's exploration is found a short distance beyond, Gold Bar Arch:

The opening is about 40 ft high and 50 ft wide, and provides a fantastic stony frame to the distant La Sal Mountains:

Here's a view after passing through the arch, towards the west:

Critical stats:  1.75 miles from the trail head with 1,100 feet of elevation gain.  One large rockfall heard.  Zero humans encountered.  Priceless.