SinkholeOdds

Sinkhole risk in Richardson County, NE: 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
1%
At or near the surface
0%
Buried under cover
1%

The next step for one property

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

That works out to roughly 7 of Richardson County's 552 square miles on soluble rock. With about 7,666 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 324 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Richardson County

The nearest county rated sinkhole country is Johnson County, KS, about 98 miles southeast. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Richardson County is built on

The largest mapped soluble unit here is the Shawnee Group (limestone), Late Pennsylvanian- Virgilian in age, covering about under 1% of the county. Next is the Chase Group at under 1%.

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 Nebraska

Richardson County ranks 79 of 93 in Nebraska for soluble rock at the surface, and sits above 0% of US counties on that measure.