Union Chutes is an artificial whitewater park in a somewhat industrial area of Denver, with a number of somewhat unusual features.
The first feature is a wing dam, and it’s generally too weak to surf at low flows and can get chundery at higher flows; it’s also universally pretty shallow.
U2, the second feature, comes in around 1200 cfs and is surfable at any flows above that. Immediately below it is the Hollywood Hole, a somewhat infamous feature that creates big swirling/boiling eddylines behind it. Hollywood has the potential of sending you deep if you swim through it, so be prepared for some down time. And leave the leashes at home; the force shoving things around in Davy Jones’ Locker could prevent just about anyone from releasing if they get snagged. At lower flows, Hollywood can form a difficult-to-surf wave.
Next is Hawaii 5-0, a high-speed wedge-style wave that starts to come in around 1,000, but cleans up significantly around 1500, and picks up more of a pile around 2,000. Watch for strong eddylines and rocks below.
The bottom wave/hole of the main stretch is also surfable; it’s shallow and probably not worth it around 1500, and by 2,000 it’s a big wave hole you can get some time in on.
Low flows are also possible at Union, but for the most part better low flow options can be found downstream. Note that high flows can bring about some exciting swims; be careful out there.
The South Platte Below Union gives an accurate read of this stretch. You’ll want to look for something over 250 cfs if you’re low-water groveling, and over 750 for the good stuff.
For photos of the waves at specific flows, check out the River Surf Report.
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Park on the edge of Centennial Park, to the right of the baseball fields near the river. You’ll be in front of the first drop; the rest are all downstream from you.