Photographer Andrew Parke shot this video on Sunday at the third of three "obstacles" along the San Fernando Valley stretch of the river now open to permitted trips.
Insiders call it Rock Rapids.
"The Rock" is perhaps the most challenging obstacle along the tour route between Balboa Boulevard and the Sepulveda Dam--and it is hardly that.
The others are called Cattail Chute and Lake Balboa Ledge.
Paddle the L.A. River, one of two groups offering tours, kicked off trips last Saturday.
L.A. River Expeditions begins their tours on Sunday.
though a few seats could open up on "group" trips being offered to youth and other organizations.
L.A. River Expeditions is also conducting an online fundraising campaign to run a youth program during the school year.
And check back at the site for more of Andrew Parke's photos.