Littoral marine organisms colonized shorelines as ocean water replaced glacial meltwater. Glacial drift includes unsorted material called till and layers deposited by meltwater streams called outwash. During the summer glacial meltwater dominates the streamflow, turning the Puyallup River turbid. The landscape is very rocky from glacial meltwater deposits. Cwmafan in Port Talbot is built upon alluvial and glaciofluvial deposits, formed from glacial meltwater. Below the equilibrium line, glacial meltwater is concentrated in stream channels. Lakes may form in basins where there is sufficient precipitation or meltwater from glaciers above. Summer meltwater from the glaciers provides the primary source of soil nutrients. Erosion by glacial meltwater formed many of the park's characteristic features. The Teays River was dissected and largely wiped away by advancing glaciers and their meltwater. Some kames form when meltwater deposits sediments through openings in the interior of the ice. Meanwhile, meltwater within and beneath the ice leaves stratified alluvial deposits. Sewerage is the infrastructure that conveys sewage or surface runoff (stormwater, meltwater, rainwater) using sewers. Rivers are shallow, non-navigable and fed by meltwater and often underground sources. There is evidence that meltwater discharges are episodic.