Approximately 350 volunteers collected more than 40 tons of debris and garbage today along the banks of rivers and waterways in Allegheny, Armstrong, Beaver, Washington and Westmoreland counties.

The annual River Sweep cleanup is organized by the Ohio River Valley Water Sanitation Commission to pick up trash and debris along more than 3,000 miles of the Ohio River and other waterways stretching across six states.

The event, which is annually held on the third Saturday of June, saw volunteers along the banks of the Ohio, Allegheny, Beaver, Kanawha, and Kentucky rivers and other tributaries.

In Pittsburgh, volunteers assembled this morning in the South Side's Riverfront Park and along a North Side trail to pick up debris and other trash from the Monongahela and Ohio rivers.

The Ohio River Valley Water Sanitation Commission is a collaboration of environmentalists in Pennsylvania, West Virginia, Ohio, Kentucky, Indiana and Illinois.

Betsy Mallison, the commission's coordinator for Pennsylvania, said today's cleanup -- the 19th for Western Pennsylvania -- was particularly necessary because of recent rainstorms that raised water levels and washed up debris along all three Pittsburgh rivers.

"The river is a natural resource and we need to take care of it," she said.