April in Littleton is a sound before it is a sight — water moving again in the ditches, heads ticking awake across a lawn that has been brown since November. Arrowhead Sprinklers lives inside that turn of the year, waking systems up in spring, keeping the grass cut and even through the long bright summer, then blowing the lines out in October before the first hard freeze finds them. The Front Range hands this town a stingy, dazzling climate: thin air, relentless sun, and rain that arrives all at once or not at all, so every drop has to be aimed. When the cold comes for good, the same crew returns to push snow off the drives and open the walks. It is one long conversation with a yard, carried from thaw to thaw.