Karst Feature Calculator

Karst landscapes form where groundwater slowly dissolves soluble bedrock like limestone, and this calculator models both the dissolution rate and the resulting sinkhole risk. The dissolution rate is built from a simplified version of the Dreybrodt (1988) framework: a CO2-partial-pressure factor that rises with both temperature and rainfall (more biological activity and more water means more carbonic acid reaching the rock), multiplied by a base rate scaled to annual rainfall and a temperature factor, yielding a rate in millimeters of rock lowered per thousand years. From that rate, the calculator derives a very rough "time to dissolve through the whole limestone thickness," which is a useful relative indicator but not a literal prediction, since real dissolution concentrates along fractures and bedding planes rather than lowering the whole surface uniformly.

The sinkhole susceptibility index (0–100) combines three weighted factors: how thin the overburden is above the limestone (thinner soil cover means a collapse reaches the surface more easily and violently), how close the water table sits to the bedrock surface (a water table already within the limestone scores maximum risk, since water-table fluctuation is what triggers cover-collapse sinkholes), and the dissolution rate itself. That composite maps to a four-tier risk category from Low to Very High. The key limitation to keep in mind is that this is a screening-level index built from general empirical relationships, not a substitute for a site-specific geotechnical or geophysical survey — actual sinkhole formation also depends on local fracture density, cave/void geometry, and human factors like groundwater pumping that this model doesn't capture.