Code of Vermont Rules › Agency 12 - AGENCY OF NATURAL RESOURCES › Sub-Agency 030 - DEPARTMENT OF ENVIRONMENTAL CONSERVATION › Chapter 037 - VERMONT DAM SAFETY RULE › Section 12 030 037 - VERMONT DAM SAFETY RULE

Current through June, 2024
Section 101 Authority
This rule is adopted by the Vermont Agency of Natural
				  Resources pursuant to 10 V.S.A. Chapter 43, in particular § 1110.
Section 102 Purpose
The purpose of this rule is to provide guidance on the
				  implementation of 10 V.S.A. Chapter 43 regarding the inventory, inspection, and
				  evaluation of dams in Vermont. This includes guidance regarding the regulation
				  and Agency oversight of dams under the jurisdiction of the Department of
				  Environmental Conservation, including dams the failure of which may result in
				  loss of human life, economic loss including property damage, lifeline
				  disruption, and environmental damage. This rule also provides guidance
				  regarding measures intended to protect public safety and provide for the public
				  good through the proper planning, design, construction, reconstruction,
				  enlargement, repair, alteration, breach, removal, inspection, operation,
				  maintenance, monitoring, and supervision of dams and to provide for adequate
				  margins of safety.
Section
				103 Definitions
Any terms not defined in this section shall have the meaning
				  given to the term by any Vermont statutes, rules, or policies governing the
				  subject matter.
Agency means the Vermont Agency of Natural Resources
Appurtenant works means structures belonging to the dam and
				  related to the dam's operation, including but not limited to, spillways, either
				  in the dam or separate therefrom; the reservoir and its rim; low-level outlet
				  works; and water conduits such as tunnels, pipelines or penstocks, either
				  through the dam or its abutments.
Auxiliary Spillway means the secondary spillway not in use
				  under normal conditions but used when needed to pass flood flows that exceed
				  the capacity of the principal spillway.
Breached Dam means a dam that does not retain water or liquid
				  but may or may not retain sediment under mean annual flow conditions with a
				  hydraulic height of zero due to a partial dam failure or construction of a
				  channel through or around a dam (i.e. dam maintains the reservoir drained under
				  normal conditions).
Dam means any artificial barrier, including its appurtenant
				  works, that is capable of impounding water, other liquids, or accumulated
				  sediments.
A dam includes an artificial barrier that meets all the
				  following:
1. previously was capable
				of impounding water, other liquids, or accumulated sediments;
2. was partially breached; and
3. has not been properly removed or
				mitigated.
A dam shall not mean:
1. barriers or structures created by beaver
				or any other wild animal as that term is defined in Section 4001 of this
				title;
2. transportation
				infrastructure that has no normal water storage capacity and that impounds
				water only during storm events;
3.
				an artificial barrier at a stormwater management structure that is regulated by
				the Agency of Natural
Resources under Chapter 47 of this title;
4. an underground or elevated tank to store
				water otherwise regulated by the Agency of Natural Resources or an agricultural
				waste storage facility regulated by the Agency of Agriculture, Food and Markets
				under 6 V.S.A. Chapter 215;
5.
				above or below grade tanks, vessels, or storage chambers of steel or concrete
				construction used to store wastewater;
6. dug ponds created by excavating below
				grade and constructed without artificial barriers or outlet structures, which
				pose no threat to life, property, lifelines, or the environment downstream from
				the pond;
7. any structure related
				to a wastewater treatment facility permitted by the Agency pursuant to
				10 V.S.A. §
											1263, excluding wastewater ponds and lagoons
				impounded by a dam;
8. levees,
				meaning any earthen embankment, floodwall, or structure along a water course
				whose purpose is flood risk reduction or water conveyance.
Dam Breach Analysis means the analytical process of computing
				  the flood hydrograph, resulting flood levels, and inundation area resulting
				  from a simulated dam breach or failure.
Dam Crest means the top of the nonoverflow portion of the
				  dam.
Dam Failure means a collapse of a dam resulting in the
				  uncontrolled release of all or a portion of the reservoir contents.
Department means the Department of Environmental
				  Conservation.
Dike means any appurtenant artificial barrier located on the
				  same reservoir or waterbody as the dam that together with the dam impounds or
				  is capable of impounding the reservoir. Typically, dikes are at saddle (low)
				  points around a reservoir rim and do not include appurtenances such as
				  spillways or low-level outlets. A dike is a dam.
Drainage Area means the total area that drains to a
				  particular point on a river, stream, or reservoir.
Drained refers to the condition of a reservoir or impoundment
				  where the water level is intentionally lowered below normal levels using
				  appurtenant works such as a low-level outlet or temporary controls such as
				  pumps or siphons. The dam remains in place and has not been partially breached,
				  breached, or removed. Reservoirs can be drained permanently such as during dam
				  removal, or temporarily, such as during dam rehabilitation.
Embankment means an artificially constructed feature usually
				  consisting of earth and rock with sloping sides and a flat crest, intended to
				  provide a permanent barrier that impounds or is capable of impounding
				  water.
Emergency includes, but is not limited to, dam failures and
				  all conditions leading to or causing a dam failure, including overtopping, or
				  any other condition of a dam and its appurtenant structures that may be
				  construed by the Department as hazardous or threatening to life or
				  property.
Emergency Action Plan means a written plan that identifies
				  the area that would likely be inundated by the failure of a dam, and identifies
				  the actions that should be taken by the Owner to protect life, property,
				  lifelines, and the environment in the event of a dam failure or threatening
				  condition at the dam. The plan is usually implemented in cooperation with the
				  local, regional, and state emergency personnel.
Engineer means a professional engineer licensed under Title
				  26 who has experience in the design and investigation of dams.
Environmental Loss means damage to the natural environment
				  resulting from the failure or mis-operation of a dam, including damage to
				  aquatic biota and habitat. Only the incremental damage caused by dam failure or
				  mis-operation is considered. Environmental losses are considered "reversible"
				  if they are expected to self-remediate within five years.
Federal dam means a dam owned by the United States or a dam
				  subject to Federal Energy Regulatory Commission license or exemption.
Flashboard means a section (board) of timber, concrete,
				  metal, inflatable bladder, etc. placed on the crest of a spillway to raise the
				  water level, but that is designed to either be quickly removed in the event of
				  a storm or deliberately designed to fail under storm loading.
Freeboard means the vertical distance between the dam crest
				  and the reservoir water surface.
Hazard creep means the increase in hazard potential due
				  primarily to new development downstream of existing dams that was not present
				  during original design and construction or has increased since the dam's hazard
				  classification was last evaluated.
Hazard Potential means the potential for incremental damages
				  that could result from the release of water or stored contents due to failure
				  of the dam or mis-operation of the dam or its appurtenances. The hazard
				  potential classification of a dam is based on the potential loss of life, and
				  damage to property, lifelines, and the environment resulting from dam failure,
				  and does not reflect in any way on the current condition of the dam and its
				  appurtenant structures.
HIGH Hazard Potential Dam mean dams where failure or
				  mis-operation will probably cause loss of human life.
Hydraulic Height-of-dam means the vertical distance from the
				  lowest point in the stream bed or native ground surface at the downstream toe
				  of the dam to the elevation of the normal pool or water level in the
				  reservoir.
Hydrologic and Hydraulic Analysis or "H&H" means the
				  analytical process of computing the inflow to a reservoir and outflow from a
				  dam under normal and storm conditions. This also includes the analyses of
				  intermediary flood events and the means of managing flows during the
				  construction, rehabilitation, or removal of a dam. Such analyses are used to
				  determine normal and maximum reservoir pools, dam crest, spillway, and
				  low-level outlet design requirements.
In-Service Dam means a dam that is currently retaining water,
				  liquid, or sediment as originally designed.
Incremental damage means under the same conditions (e.g.,
				  flood, earthquake, or other event), the difference in impacts that would occur
				  due to failure or mis-operation of the dam as opposed to those that would have
				  occurred without failure or mis-operation of the dam and appurtenances
Inspection means the examination of a dam to determine its
				  condition and need for improved operation, maintenance, study and analyses,
				  repairs, rehabilitation, and or removal.
Instrumentation means an arrangement of devices (e.g.
				  piezometers, inclinometers, weirs, etc.) installed into or near a dam which
				  provide for measurements that can be used to evaluate the structural behavior
				  and performance of a dam.
Intake structure means a dam that is constructed and operated
				  for the primary purposes of minimally impounding water for the measurement and
				  withdrawal of streamflow to ensure use of the withdrawn water for snowmaking,
				  potable water, irrigation, or other purposes approved by the Department.
Interested person means, in relation to any dam, a person:
				  who has riparian rights affected by that dam; who has a substantial interest in
				  economic or recreational activity affected by the dam; or whose safety would be
				  endangered by a failure of the dam.
Inundation Map means a map delineating the area that could be
				  flooded by a particular flood event and dam failure condition.
Invert means the base level of a weir, pipe, tunnel, or
				  penetration.
Lifeline means a structure or service indispensable for
				  maintaining or protecting life, including but not limited to key transportation
				  links such as bridges or highways; power supply lines; potable water connection
				  or supply; or sanitary sewer connection.
LOW Hazard Potential Dam means dams where failure or
				  mis-operation results in no probable loss of human life and low economic and
				  environmental losses
Low-level outlet or "LLO" means an installed pipe and
				  operable gate or valve typically located in or near the foundation of a dam
				  that can be used to alter water levels, drain the reservoir, or otherwise meet
				  operational or safety needs. Also called a pond drain.
Maximum Pool means the highest water elevation, reservoir
				  surface area, and reservoir storage capacity that could be impounded by the
				  dam, including accumulated sediments, with the water or liquid level at the top
				  of the lowest nonoverflow part of the structure or dam crest.
MINIMAL Hazard Potential Dam means dams that impound or are
				  capable of impounding less than 500,000 cubic feet (11.48 acre-feet) of water,
				  other liquid, and/or sediment and meet the LOW hazard potential dam definition
				  above.
Non-federal dam means a dam that is not a federal dam.
Non-power dam means any dam that is not a power dam.
Normal Pool means the water elevation, reservoir surface
				  area, and reservoir storage capacity that is prevalent at the site or typical
				  under normal, non-storm conditions. Typically, this level is controlled by the
				  principal spillway.
Order means an official document prepared by the Department
				  authorizing a dam owner to construct, enlarge, raise, lower, remodel, remove,
				  reconstruct, or otherwise alter any nonfederal dam, pond, or impoundment or
				  other structure that is or will be capable of impounding more than 500,000
				  cubic feet of water or other liquid after construction or alteration, pursuant
				  to
				  10 V.S.A. §
												1082.
Owner means a person owning legal title to a dam or the owner
				  of the land on which a dam is located.
Operation and Maintenance Plan or "O&M" means a plan that
				  provides guidelines for the necessary, regular operation and maintenance
				  activities at a dam.
Parti ally Breached Dam means a dam that is no longer capable
				  of impounding its normal pool under normal conditions but may still partially
				  impound the reservoir, and has a hydraulic height greater than zero under mean
				  annual flows (i.e. normally maintains a partially filled reservoir). A portion
				  of the dam structure that impacts flow remains in place.
Person means any individual; partnership; company;
				  corporation; association; joint venture; trust; municipality; the State of
				  Vermont or any agency, department, or subdivision of the State; any federal
				  agency; or any other legal or commercial entity.
Potential Failure Mode Analysis means the development and
				  evaluation of possible modes of partial or full failure at a dam.
Power dam means a dam that relates to or is incident to the
				  generation of electrical energy for public use or as part of a public utility
				  system.
Principal spillway means a structure that maintains normal
				  pool conditions and over which daily non- storm related and flood flows are
				  discharged. Also called a primary or service spillway.
Probably/probable means more likely than not to occur;
				  expected; realistic.
Property Loss means direct and indirect economic losses due
				  to flood-damaged property or infrastructure located downstream of a dam, as a
				  result of dam failure.
Removed Dam means the location where a dam once existed but
				  is now a free-flowing stream with no remaining remnants of the dam in place
				  that could impound water.
Reservoir means any area which contains or will contain
				  impounded water, wastewater, or liquid-borne materials by virtue of its having
				  been impounded by a dam. Also referred to as impoundment.
SIGNIFICANT Hazard Potential Dam means dams where failure or
				  mis-operation results in no probable loss of human life but can cause economic
				  loss, environmental damage, disruption of lifeline facilities, or impact other
				  concerns. Significant hazard potential classification dams are often located in
				  predominantly rural or agricultural areas but could be located in areas with
				  population and significant infrastructure.
Spillway Crest means the invert elevation of the subject
				  spillway.
Spillway Design Flood or "SDF " means the storm event which
				  the hydraulic capacity of the spillway structure and dam is designed and
				  required to safely pass.
Stoplog means a section of timber, concrete or steel placed
				  in a slot or channel to maintain normal pool conditions but that can be removed
				  to alter water levels, drain the reservoir, or otherwise meet operational or
				  safety needs.
Structural Height-of-dam means the vertical distance from the
				  lowest point in the stream bed or native ground surface at the downstream toe
				  of the dam to the elevation of the lowest nonoverflow section of the dam
				  crest.
Toe-of-dam means the junction of the downstream slope or face
				  of a dam with the native ground surface or the invert out of the low-level
				  outlet, whichever occurs at the lowest point.
Unsafe Dam means a dam that has been determined to be unsafe
				  via Unsafe Dam Proceedings.
Unsafe Dam Order means an order issued by the Department as a
				  result of an Unsafe Dam Proceeding, directing reconstruction, repair, removal,
				  breaching, draining, or other action the Department considers necessary to
				  improve the safety of the dam sufficiently to protect life and property.
Unsafe Dam Proceedings means dam safety proceedings carried
				  out pursuant to
				  10 V.S.A.
				  §
												1095.
Wastewater means sanitary waste or used water from any
				  building or structure or campground, including, but not limited to, carriage
				  water, toilet water, shower and wash water, food processing wastewater, and
				  process wastewater. Wastewater does not include stormwater.