Under a blue moon at the confluence of the Green and Colorado rivers, I was exhausted but exhilarated: I’d just completed the first swim of the Colorado River through Utah’s Canyonlands, starting at Moab and ending at this merging of two rivers, a distance of 47.5 miles. Time: 13 hours and 56 minutes.

The swim was an attempt to raise awareness about the plight of the Colorado River and the important work of the nonprofit American Rivers, which advocates for free-flowing rivers everywhere.

The swim wasn’t easy. It was cold, with the water about 68 degrees. The support crew in their touring sea kayaks didn’t have it easy, either; their main job was keeping me in the fastest currents, finding the channel that is a river within a river. The Colorado River can be wide and shallow in spots, and I hit a few rocks and branches along the way. Sometimes I had to crawl through the sand and mud on my belly.

Our team followed English Channel Rules/World Open Water Swimming guidelines: No flotation, no wetsuit, no touching the boat or another person, and no stopping.