Sinkhole risk in Lyman County, SD: No soluble rock mapped
No soluble rock mapped
No soluble bedrock mapped.
- On soluble rock
- under 1%
- At or near the surface
- 0%
- Buried under cover
- under 1%
What to do about a house in Lyman County
No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.
That works out to roughly 13 of Lyman County's 1,642 square miles on soluble rock. With about 3,721 residents (2 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 260 map points about 2.5 miles apart, so a pocket smaller than that can be missed or overstated.
Read next: how these percentages are measured, and the warning signs that apply anywhere.
Counties around Lyman County
The nearest county rated sinkhole country is Boyd County, NE, about 88 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.
- Buffalo County, SD 33 mi east · 3% at surface
- Hughes County, SD 34 mi north · 0% at surface
- Tripp County, SD 38 mi south · 3% at surface
- Brule County, SD 39 mi east · under 1% at surface
- Jones County, SD 42 mi west · 0% at surface
- Hyde County, SD 48 mi north · 0% at surface
What Lyman County is built on
The largest mapped soluble unit here is the Niobrara Formation (limestone), Late Cretaceous in age, covering about under 1% of the county.
Against the rest of South Dakota
Lyman County ranks 46 of 66 in South Dakota for soluble rock at the surface, and sits above 0% of US counties on that measure.
- Lawrence County 42%
- Fall River County 37%
- Custer County 30%
- Gregory County 17%
- Pennington County 13%