Street Sweeping provides two primary benefits to the City. The more obvious benefit is the collection and removal of paper, leaves, and other visible debris that collect in the gutters. This debris can block storm drains, causing localized flooding during heavy rains. An equally important, but less visible benefit is the removal of metal particles and other hazardous waste products left by passing vehicles. Although they are virtually invisible, these particles can be extremely harmful to fish and other wildlife. Street sweeping is an effective method of removing both the large and microscopic pollutants that collect on City streets.