True Level

I stepped down from the outfall ledge onto the dry stone floor of the retention culvert. Near the base of a stepped concrete weir, a heavy steel ball bearing sat half-buried in dry silt. I dislodged it with two fingers, wiping away the chalky residue against my palm. The solid weight was balanced and true. Kneeling at the crest of the sloped concrete apron, I set the steel sphere down along the seam. It began an even, silent roll down the incline, cutting a clean thread through the fine dust before coming to rest squarely against the lower expansion joint. The gradient is uniform. I retrieved the bearing and slipped it into my pocket.