Land use in our society is generally an "either-or" proposition. Any given site is zoned for industry or housing or open space, but rarely more than one use at a time. And we compartmentalize one land use from another by drawing thick black lines on our land-use maps, often in a completely arbitrary way. That thick black line has grown a little thinner on 471 acres of land, nearly half of which lie underwater, owned by Dow Chemical in the city of Pittsburg.
