We have gravel alleys for the most part. We have residents that want their alley paved, and we are exploring paving 2 "wheel paths" rather than paving the whole width of the alley. The 2 paths would slightly pitch toward the middle of the alley to minimize runoff due to the new impermeable surface (either asphalt or concrete). I am proposing that grass be planted between these two paved paths to help absorb the runoff. I think this is responsible, economical design. It should cost about half as much as paving the full width of the alley. Also it will (nearly) eliminate the need for costly structures like catch basins or manholes or storm sewers for that matter. I would anticipate minimal runoff to the adjacent properties rear yards, unless the "trench" overfills. Has anyone done/seen this, and what are your experiences/feelings/thoughts about it???