In forests and meadows, about 80-percent of rain and melted snow soaks into the ground, where roots, soil, and rocks filter impurities before the water joins underground reservoirs, and only heavy rains or rapid snow melts send water across the surface to streams or rivers. In urban environments, hard surfaces such as parking lots, roads, sidewalks, and roofs prevent water from soaking in, so gutters and storm drains carry it directly to streams without slowing or filtering it, increasing flooding, erosion, and pollution that rivers then carry downstream. Plans that slow drainage with plantings let water soak into the ground instead of being channeled straight to streams, filtering it through soil and roots, replenishing groundwater, and allowing it to enter streams gradually. In downtown Harrisonburg, groundwater feeds springs such as the one marked by the Spring House at the southwest corner of Court Square, and Liberty Park was transformed from a parking lot that created an impervious surface into a pocket park with grass, pollinator flowers, shrubs, and trees.