US-50 in Reno County, KS east of Hutchinson has undergone active deformation from ground subsidence. Subsurface karsting from salt dissolution is the main cause for this phenomenon. Two prominent sinkhole features occur in close proximity to one another and to the regionally mapped dissolution front of the Hutchinson Salt Member. Brandy Lake, which is a lake forming sinkhole, has undergone active subsidence along its western margin whereas the sinkhole at the Victory Road/US-50 intersection has had subsidence occur within the last 12 years. Using a Terrestrial Laser Scanning (TLS) approach, this study analyzes the geometry, magnitude and temporal nature of the active subsidence over these two sinkholes. Results show that the Brandy Lake sinkhole has an asymmetric subsidence geometry along the western margin of the lake with a deformed road area of 358 m and a magnitude of subsidence of 1.15 m. The Victory Road sinkhole is characterized by a symmetric bowl-shaped depression that is 125 m wide from west to east and 117 m wide from north to south with a magnitude of subsidence of 1.20 m. Both of the sinkholes exhibit no active change over the course of the study indicating that subsidence has temporarily ceased. These observations agree with the fact that subsidence is transient on the local scale but regionally controlled by the main dissolution front and subsurface structural lineaments.
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