It all starts with a snowflake—or rather, billions of them. Once spring yields to summer and the powder trove that drew more than a million skiers and riders to Aspen’s four mountains over the winter has melted away, the trickle-down theory applies, quite literally, to summer adventure. Practical needs of irrigation aside, the bounty of water released from winter’s grip roils rivers, fills reservoirs, and fuels outdoor recreation—and lots of it, affording play in many different ways, at least for a few months. You may be a rafter or kayaker seeking the thrill of peak-runoff whitewater on the aptly named Roaring Fork. You may relish the solitude of dawn on a paddleboard at Ruedi Reservoir before the wakeboarders wake and make waves. Or you may find liquid bliss in the mountains sipping a cold one while lounging poolside on a rooftop terrace in downtown Aspen. Whatever your leisure pleasure, this insider’s guide to the valley’s water-based activities was written for you.