Code of Vermont Rules › Agency 30 - PUBLIC UTILITY COMMISSION › Sub-Agency 000 - GENERAL › Chapter 4500 - SAFETY OF HYDROELECTRIC DAMS › Section 30 000 4500 - SAFETY OF HYDROELECTRIC DAMS

Current through June, 2024
Section 4.510 Size and
			 Hazard Classifications
(A) Dams
			 shall be categorized by size. The size category shall be determined
			 by height or storage, whichever gives the larger size category. The
			 height of a dam and its storage shall both be established with
			 respect to its maximum storage potential, measured from the natural
			 bed of the water course to the maximum water storage elevation. For
			 the purpose of determining size category, the maximum water storage
			 elevation shall be considered to be the height above streambed as
			 defined in section 4.521(B).
Category
Storage (ac-ft)
Height (ft)
Small
<1,000
<40
Medium
=/> $ 1,000 and
						  <50,000
=/>$ 40 and <100
Large
=/> $ 50,000
=/>$ 100
(B) Dams shall also be classified
			 by hazard potential. The hazard potential classification of a dam
			 pertains to potential loss of human life or property damage in the
			 area downstream of the dam in the event of failure of the dam.
Hazard Class
Potential Loss of
						  Life
Potential Economic
						  Loss
Minimal
None expected
None expected
Low
None expected (no permanent structures for
						  human habitation)
Minimal (undeveloped to occaisional
						  structures or agriculture)
Significant
Few (no urban development and no more than a
						  small number of inhabitable structures)
Appreciable (notable agriculture, industry,
						  or structures)
High
More than a few
Excessive (extensive community, industry, or
						  agriculture)
(C) At the request of its owner or
			 operator, a dam which both impounds less than fifty acre-feet and is
			 less than twenty-five feet tall may be placed in the 'Minimal' hazard
			 class for purposes of this rule. A dam which is less than six feet
			 tall or which has a maximum storage potential of less than fifteen
			 acre-feet shall be classified in the 'Mnimal' hazard class, unless
			 reclassified pursuant to paragraph (D).
(D) Any dam may be reclassified to
			 another hazard class by means of a petition brought by the owner or
			 operator of the dam, the Department of Public Service, on the
			 Commission's own motion, or by a petition brought pursuant to section
			 1095
			 of Title 10 of the Vermont Statutes Annotated. A proceeding based
			 upon such a petition shall be a contested case for purposes of
			 Chapter 25 of Title 3 of the Vermont Statutes Annotated.
(E) Unless classified or
			 reclassified pursuant to paragraphs (C) or (D), a dam shall be
			 classed in the same hazard class to which it is assigned by the U.S.
			 Army Corps of Engineers on its inventory made pursuant to the
			 National Dam Inspection Act,
			 Public Law
			 92-367. If a dam is not included in the
			 inventory, it shall be placed in the Low hazard class if it is of
			 Small size, in the Significant hazard class if it is of Medium size,
			 and in the High hazard class if it is of Large size. Classifications
			 of such non-inventoried dams shall be reviewed by the Commission as
			 soon as practicable.