IN HB1159

Dam regulations apply only to structures meeting at least two of three conditions: exceeding 20 feet in height, having a drainage area above the dam of more than one square mile, or impounding more than 100 acre-feet of water.

Department of Natural Resources must establish a classification system for dams based on structural height, water volume impounded, water force, and likely consequences from uncontrolled release due to failure or misoperation.

Classification categories change from "high hazard, significant hazard, and low hazard" to "high capacity, significant capacity, and low capacity," with the failure standard changing from "may cause" to "likely to cause."

Department may raise a dam's classification to high capacity upon written request from a downstream property owner, representative, or resident who believes the structure poses risk to life or serious property damage.

Prior inspections conducted before the July 1, 2018 effective date are not affected; structures previously inspected are exempt from reinspection requirements for two to five years depending on their previous classification.