BTO is probably the best surf feature in the Cache la Poudre Canyon. It’s found river left (the far side of the river) at the standard Bridges run take out. It’s easier to handle for kayakers than it is for surfers, since it’s on the far side of the river and, depending on flows, swims can rake you over a couple of downstream rocks, so it’s not the most user-friendly feature in the world. On the bright side, it’s a decent wave or wave/hole, depending on flows, and the river often stays within its surfable flows for quite a while (though note below that you won’t have a working USGS gauge for this one).
No accurate gauge exists for most runnable sections of the Cache la Poudre River. The only thing close to this stretch of the river is a USGS gauge placed below a big series of diversion dams, and the dams siphon off so much water so unpredictably that the USGS gauge doesn’t tell you much about what’s happening in the canyon. Fortunately, the Poudre Rock Report exists. There is a painted gauge at the top of Pineview Falls, a major feature in the canyon, on the downstream side of a river-right house-sized rock that has a cute little pine tree growing on it. Most sections of river in the canyon are calibrated to the foot markers on the Pineview Gauge. For many runs, 1′ is the minimum, and anything over 3.5′ is high. The Rock Report commonly updates the internet on the status of the rock gauge, and you can even sign up for emails on their page. They’re on facebook too. For BTO, keep an eye out for something between 2.2 and 3.5 to 4 on the gauge.
BTO has a decent-sized pull-off a mile or so upstream of the last diversion dam in the canyon on the east side of the road. You’ll probably see quite a bit of rafting and kayaking traffic in the area if flows are up.