For years, the South Platte was the Rodney Dangerfield of rivers. It got no respect -- just a lot of trash. But all that changed with the River Sweep, an annual event combining the organizational skills of REI, Trout Unlimited and Denver Water with the litter-picking talents of hundreds of volunteers. The 2007 event, set for September 29, will mark the fifteenth time that the Greenway Foundation has teamed with Denver to clean the banks of the South Platte along all fifteen miles that run through the city.