SinkholeOdds

Sinkhole risk in Nemaha County, KS: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock
6%
At or near the surface
0%
Buried under cover
6%

What to do about a house in Nemaha County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 45 of Nemaha County's 717 square miles on soluble rock. With about 10,062 residents (14 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 400 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and why the 6% under cover still counts.

Counties around Nemaha County

The nearest county rated sinkhole country is Dickinson County, KS, about 89 miles southwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Which formation it is

The largest mapped soluble unit here is the Council Grove Group (limestone), Early Permian Gearyan in age, covering about 6% of the county.

The county also lies over the Northern Anadarko Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Kansas

Nemaha County ranks 102 of 105 in Kansas for soluble rock at the surface, and sits above 0% of US counties on that measure.