A car tunnel and railroad tunnel are located between the stack hill and the arsenic kitchen area. Some dense vegetation exists on steep slopes and along the bluffs above Commencement Bay. Its primary surface features are the Tacoma Yacht Club building, a paved access road, and paved parking areas. An estimated 15 million tons of slag exist at the smelter property and slag peninsula. Surface water features on the smelter property include surface water in the cooling pond and south and west stack hill areas and a number of springs and seeps around the stack hill and arsenic kitchen areas.
Surface water drains into one of four drain systems and then into outfalls at the site.
A complex pattern of groundwater flows through or beneath the smelter property, including through the slag, into Commencement Bay. Three primary groundwater aquifers have been identified. A thick slit barrier exists between the shallow and deep aquifers throughout much of the site. Because of the high degree of fractures in and porous nature of the slag, the tides bring seawater inland several hundred feet where it mixes with groundwater. The groundwater within each of the three aquifers is designated as either potential drinking water or as non-potable water.