Emerson sits low in the Pascack Valley, and a hard August storm shows you exactly where the water wants to go. RK Environmental Services reads a lawn that way — the wet corner, the bald patch under the downspout, the strip along the drive that never quite fills in. The work is mowing, trimming and edging on a regular week, mulch in the beds, cleanups at both ends of the year, all of it aimed at turf that can take a soaking and come back. Grass grown thick is its own kind of drainage. When the sky finally clears over the borough, the lawn should look like nothing happened.