Storm water runoff is generated when precipitation from rain and snow-melt events flows over land or impervious surfaces and does not percolate into the ground. As the runoff flows over the land or impervious surfaces (paved streets, parking lots, and building rooftops), it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff is discharged untreated. You can help reduce pollution by removing trash and debris from streets, wetponds, culverts and inlets. Recycle used motor oil. Scoop the poop from your pooch, picking up after your dog will prevent waste from polluting our water facilities. Bag or compost grass clippings and yard waste.