Local planning context
What the regional setting changes—and what it does not
Routes may shift from residual clay, saprolite, and weathered rock to sandier Coastal Plain material, with Congaree-area alluvium and urban fill in lower corridors.
That context helps a Columbia project team choose samples, route segments, material zones, and moisture conditions. It does not establish a design thermal rho. The reported value belongs to the tested material and preparation.
