Commerce ledges (a series of three ledges, named after the small community on the north bank) provides surfing possibilities near Des Moines.
UPDATE: (2008-04-11)
The DNR did some work along the access to provide more adequate parking and a trail that leads to two easy put-ins. Large stone steps lead down to the water for easy access to all of the features. The improvements make it much easier to take advantage of the play without having to deal with the muddy banks that were previously a big deterant for boaters.
James Weeks contributes (2006-07-20)
_The eddyline, river left, below the main wave is very strong and provides a great opportunity to peel-out, stern squirt, or surf the more consistent waves at around 1500 to 4000 cfs. Much lower and the real honey is at the top ledge. There is also a recirculating current along the river left bordering the wave train that will take you nearly all the way back to the top if you catch it before getting too far downstream._
_From the furthest upriver put-in, you can paddle out to a large boulder, which should be clearly visible in the center of the river. The rock creates a 9ft. wide eddy about 20ft long. A weak eddy on surfer's left of the rock will carry you to the ledge. Nice defined zig-zag wave on 2/3rds of the river at a level of 900 to 1500 cfs. Lots of play here before floating down into the waves._
_I haven't explored the 3rd ledge much. Very shallow there, though surfable above 2000 cfs._
_Thursday nights in the summer, some locals gather to paddle from 6pm to 9pm (dark)._
Thanks, James, for that contribution!