Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 21, § 65

(a) As used in this section and section 66, the following words shall, unless the context clearly require otherwise, have the following meanings:--

“High hazard dam”, a dam located where structural failure will likely cause loss of life and serious damage to homes, industrial or commercial facilities, essential public utilities, main highways or railroads.

“Low hazard dam”, a dam located where structural failure may cause minimal property damage and loss of life is not expected.

“Significant hazard dam”, a dam located where structural failure may cause loss of life and damage to homes, industrial and commercial facilities, secondary highways or railroads or interruption of use of service of relatively important facilities.

(b) The department shall ensure that emergency action plans shall be developed for all high hazard dams and significant hazard dams. The department shall establish and make available to dam owners an emergency action plan template. The department shall ensure that necessary local and state dam safety officials have immediate access to such plans in the event of a potential dam failure.

(c) The department shall develop an inspection schedule to ensure that all high hazard dams are inspected at least every 2 years, all significant hazard dams are inspected at least every 5 years and all low hazard dams are inspected at least every 10 years.

(d) The department shall review the hazard classifications of dams at least every 10 years to ensure the accuracy of the dam classification. Requests for review of the hazard classification of a dam shall be made at the expense of the owner of the dam.