From CBS4Denver.com (Ericka Lewis):
“Is there trash that continues to happen in the river? Yes, there is just like there is everywhere and anywhere but that amount has reduced to where we can bring in more volunteers and do more things than just pick up trash,” said Jeff Shoemaker, Greenway Foundation. Volunteers also painted the barrier walls of the Platte River and fences along the bike path and over bridges. The River Sweep is held the last Saturday in September every year.
More South Platte River basin coverage here.