1. Connected Drain Spouts - Water runs directly from the roof to the storm sewer.
2. Thin top soil - Once saturated, allows water to flow directly to the street. A small amount of water is able to soak deeper into the ground before the topsoil dries out.
3. Storm sewers efficiently collect all runoff directing it to the outfall.
4. Flow rates at outfalls may be high causing local erosion.Total runoff may not cause increased flows in creeks. Short duration flooding may occur.