Sinkhole risk in Bamberg County, SC: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 100%
At or near the surface: 84%
Buried under cover: 15%

What to do about a house in Bamberg County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 391 of Bamberg County's 393 square miles on soluble rock, 331 of them with the rock at or near the surface. With about 12,870 residents (33 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 585 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 15% under cover still counts, and the signs to look for and how an inspection works.

Counties around Bamberg County

The closest county with no soluble rock mapped is Saluda County, SC, about 68 miles northwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Orangeburg County, SC 22 mi northeast · 72% at surface
Barnwell County, SC 22 mi west · 45% at surface
Allendale County, SC 24 mi southwest · 76% at surface
Hampton County, SC 30 mi south · 70% at surface
Colleton County, SC 34 mi southeast · 48% at surface
Calhoun County, SC 36 mi northeast · 62% at surface

Which formation it is

The largest mapped soluble unit here is the Duplin Formation (sand), Pliocene in age, covering about 61% of the county. Next is the Huber/Lisbon/Barnwell Formations, undivided at 32%.

Against the rest of South Carolina

Bamberg County ranks 3 of 46 in South Carolina for soluble rock at the surface, and sits above 95% of US counties on that measure.