Bethlehem sits at roughly 360 feet where the Lehigh River cuts through the Lehigh Valley, and that river corridor shapes almost every yard in town. Properties on the South Side climb steep pitches toward South Mountain, so beds there shed material fast and need heavier stone or coarse hardwood mulch to hold a slope. North Side neighborhoods like Rosemont and West Bethlehem sit on flatter silt loam that packs tight and holds water after the 46 inches of rain this area gets each year. Older streets near the historic Moravian district and the SteelStacks furnaces often hide fill, cinder, and slag just below the topsoil, which means new beds usually need imported screened soil rather than amendments alone. Homeowners in nearby Freemansburg, Hellertown, and Fountain Hill run into the same mix of clay dense subsoil and river bottom silt.