The Saint Vrain River contains several sections of quality whitewater for varying skill levels. The north and south fork converge in the town of Lyons. On the north fork above Buttonrock reservoir is a challenging but rewarding class V+ section (Upper NSV). Below Buttonrock is a short V- section (Proving Grounds), followed by a III+ section (CR80 to Apple Valley bridge) , and a class II section (Apple Valley bridge to town), which also contains a small playpark. The south branch (SSV) contains a stretch of low volume class V whitewater.
Below the confluence in town are three playholes, Black Bear hole, A-hole (across from the Black Bear In), and October Hole (1/2 mile downstream below a diverison dam).
The south branch (SSV) no longer has an active online gauge, however the flow can be reasonably accurately measured by subtracing the flow of the north branch from the Lyons gauge. SSV does have a foot gauge on it (visual only) and there's a Facebook page (South Saint Vrain SSV Gauge) where people report the current reading.