The Great American River Clean-Up is 9 a.m. to Noon Saturday in Sacramento County.
It is one of the largest inland events in the annual statewide effort to clean California waterways.
The nonprofit American River Parkway Foundation organizes and conducts the event.
More than 1,500 volunteers are expected to clean up trash from 23 locations along the 23-mile stretch of the American River Parkway from Discovery Park to Folsom.
Low water levels, because of the drought, may mean volunteers collect more trash and debris from the riverbed than in past years.
"You can visually see the bottom of the rivers now," says American River Parkway Foundation Executive Director Dianna Poggetto. "If you walk over the bridge between William Pond and River Bend, you can see glasses, bottles, blankets. So I believe the tonnage that we pull out of the river, as well as along the river banks, will be greater than the years previous."
She says in past events, volunteers have collected between 15,000 and 20,000 pounds of garbage.
Poggetto says there is a special emphasis this year on picking up cigarette butts because of the threat they pose to wildlife.
"We've had a campaign over the past year and a half called 'Kick Butt' to pick up cigarette butts," says Poggetto. "It's a great campaign for schools, because they can incorporate math and science components in conjunction with students collecting the butts."
"We've had classes of 20 kids, in a 15 minute period, pick up almost 1,500 cigarette butts," says Poggetto.