Marion Yohn, in Reisterstown, is among thousands of commuters who cross an arm of Liberty Reservoir on Route 140 at the Carroll/Baltimore county line. "We hear ... that our water situation is good," Yohn says. Yet "there is only a narrow river going through that large expanse." Liberty has recovered to 84 percent of capacity. Liberty Gulch looks dry because it's at the reservoir's highest elevation, so it's the last stretch to fill. Things are greening up, and hot weather's coming. Use water wisely.