Code of Massachusetts Regulations › 302 CMR - DEPARTMENT OF CONSERVATION AND RECREATION › Title 302 CMR 10.00 - Dam Safety › Section 10.03 - Definitions

Current through Register 1525, July 5, 2024
In addition to M.G.L. c. 253, § 44 as used in
				302 CMR
				10.00, the following terms shall have the following
				meanings:
(1)
Undefined Terms
. As used in
				302 CMR
				10.00 any term not defined in accordance with 302 CMR
				10.03 shall have the meaning given to the term by any statutes, regulations,
				executive orders or policy directives governing the subject matter of the term.
				Examples include terms pertaining to:
(a) Wetlands, which is defined by the Wetlands Protection Act,
				M.G.L. c. 131, § 40, and its implementing regulations,
				310 CMR
				10.00:
Wetlands Protection,
and
				33
				USC 1341 and
				314 CMR 9.00:
401
				Water Quality Certification for Discharge of Dredged or Fill Material,
				Dredging, and Dredged Material Disposal in Waters of the United States Within
				the Commonwealth
regarding Water Quality Certification, as well as
				other statutes, regulations, executive orders, or policy directives that govern
				wetlands issues; and
(b) Roadways or traffic, which are defined by the Massachusetts
				Highway Department's Highway Access Policy (adopted September 17,1991), its
				Standard Operating Procedure for Review of State Highway Access permits
				(adopted September 17,1991), and the Guidelines for EIR/EIS Traffic Impact
				Assessment (1989, as amended) by the Massachusetts Department of Transportation
				and the Executive Office of Energy and Environmental Affairs, as well as other
				statutes, regulations, executive orders or policy directives that govern
				roadway and traffic issues.
(2)
Defined Terms
. As used in
				302 CMR
				10.00, the following terms shall have the following
				meanings:
Abutment
. That part of a valley side
				against which a dam is constructed. An artificial abutment is sometimes
				constructed as a concrete gravity section, to take the thrust of an arch dam
				where there is no suitable natural abutment. Right and left abutments are those
				on respective sides of an observer looking downstream.
Acre-foot
. A unit of volumetric
				measure that would cover one acre to a depth of one foot. It is equal to 43,560
				cubic feet. One million U.S. gallons = 3.068 acre foot.
Applicant
. Any person making
				application for a dam safety permit.
Appurtenant Works
. Structures, either
				in dams or separate therefrom, including, but not limited to, spillways;
				reservoirs and their rims; low level outlet works; and water conduits,
				including tunnels, pipelines or penstocks, either through the dams or their
				abutments.
Artificial Impoundment
. As applied to
				dam safety, a reservoir created by a dam.
As-builts
. Plans, drawings and all
				other descriptive and factual information that depict how a dam was actually
				constructed or repaired. As-builts are required to be submitted to the
				Commissioner at dam completion.
Axis of Dam
. A plane or curved
				surface, arbitrarily chosen by a designer, appearing as a line in a plan or
				cross section to which the horizontal dimensions of the dam can be
				referred.
Baffle Block
. A block, usually of
				concrete, constructed in a channel or stilling basin to dissipate the energy of
				water flowing at high velocity.
Base Width (Base Thickness)
. The
				maximum width or thickness of a dam measured horizontally between upstream and
				downstream faces and normal to the axis of the dam but excluding projections
				for outlets,
etc.
Beaver Dams
. Dams that are constructed
				by beavers and not subject to
				302 CMR
				10.00. Control of beaver population and removal of
				beaver dams is regulated by M.G.L. c. 131,
				321 CMR 2.00:
Miscellaneous Regulations Relating to Fisheries and Wildlife
,
				and also by the Local Boards of Health and Conservation Commissions.
Berm
. A horizontal step or bench in
				the sloping profile of an embankment dam.
Boil
. A disturbance in the surface
				layer of soil caused by water escaping under pressure from behind a water
				retaining structure such as dam or a dike. The boil may be accompanied by the
				deposit of soil particles (usually sand) in the form of a ring (miniature
				volcano) around the area where the water escapes.
Certificate of Completion
. A document
				signed and stamped by a registered professional engineer with contractor's
				signature and supporting as-builts, upon completion of the work, attesting that
				the work has been performed in accordance with the design plans and
				specifications and permit conditions.
Certificate of Compliance
. When a dam
				has been evaluated, constructed, repaired, altered or removed to the
				satisfaction of the Commissioner under a properly issued permit, the
				Commissioner shall issue a certificate of compliance, on a form prescribed by
				the Commissioner, to the owner certifying that the permitted construction
				project has been completed in accordance with the plans and specifications and
				any requirement set forth by the Commissioner. Such certificate shall be
				recorded by the owner in the registry of deeds in the county where the dam
				lies. Issuance of such Certificate of Compliance shall release the dam owner
				from the requirements of the Certificate of Non-compliance.
Certificate of Non-compliance
. A
				certificate issued by the Commissioner when a dam or appurtenant features are
				in poor or unsafe condition with identified structural deficiencies. Such
				certificate shall be recorded by the Commissioner in the registry of deeds in
				the county where the dam lies.
Cofferdam
. A temporary structure
				enclosing all or part of a construction area so that construction can proceed
				in a dry area. A "diversion cofferdam" diverts a river into a pipe, channel or
				tunnel.
Commissioner
. The Commissioner of the
				Department of Conservation and Recreation or his or her authorized
				designee.
Conduit
. A closed channel for
				conveying discharge through or under a dam.
Crib Dam
. A gravity dam built up of
				boxes, cribs, crossed timbers, or gabions and filled with earth or rock.
Culvert
. A drain or waterway built
				transversely under a road, railway, or embankment, usually consisting of a pipe
				or covered channel of box section. It includes a gallery or waterway
				constructed through any type of dam, which is normally dry but is used
				occasionally for discharging water, hence the terms "scour culvert", "draw-off
				culvert", and "spillway culvert". A roadway or railway culvert may not be
				considered a dam if its invert is at the natural bed of the water course, it
				has adequate discharge capacity, and it does not impound water under normal
				circumstances. A culvert with an installed man made water control device which
				impounds, releases, or diverts water may be designated by the Commissioner as a
				dam.
Cutoff Wall
. An impervious
				construction or material which reduces seepage or prevents it from passing
				through foundation material.
Dam
Any artificial barrier, including
				appurtenant works, which impounds or diverts water, and which:
(a) is 25 feet or more in height from the natural bed of the
				stream or watercourse measured at the downstream toe of the barrier, or from
				the lowest elevation of the outside limit of the barrier, if it is not across a
				stream channel or watercourse, to the maximum water storage elevation;
				or
(b) has an impounding capacity at maximum water storage
				elevation of 50 acre feet or more. Any other artificial barrier, including
				appurtenant works, the breaching of which could endanger property or safety,
				may be designated by the Commissioner as a dam, and shall be subject to M.G.L.
				c. 21, § 65 and c. 253, §§ 44 through 48.
Dam
shall not mean any of the
				following:
1. any appurtenant works which temporarily impounds or diverts
				water used on land in agricultural use as defined pursuant to M.G.L. c. 131,
				§ 40;
2. any barrier or appurtenant works which has a size
				classification of small or low hazard potential classification that is used on
				land in agricultural use as defined in M.G.L. c. 131, §40; and
3. any barrier which is not in excess of six feet in height,
				regardless of storage capacity, or which has a storage capacity at maximum
				water storage elevation not in excess of 15 acre feet, regardless of height.
The Commissioner shall make such determination by taking into
				consideration factors such as height, type of structure, condition of
				structure, volume of the impoundment, extent of development downstream, and
				other factors deemed appropriate by the Commissioner.
Dam Breach
. An eroded or failed
				section opening through a dam which drains the impoundment. A controlled breach
				is a design and constructed opening. An uncontrolled breach is an unintentional
				opening which allows uncontrolled discharge from the impoundment.
Dam Break Analysis
. A determination of
				a flood hydrograph, resulting flood levels and inundation area resulting from a
				dam breach.
Dam Certificate of Registration
. A
				certificate to be issued by the Commissioner to the dam owner following
				completion and submittal by the dam owner of the dam registration form.
Dam Failure
. A collapse of an
				impounding structure resulting in an uncontrolled release of impounded water
				from a dam.
Dam Inspection Form or Format
. A form
				or forms prescribed by the Commissioner containing information relative to the
				present condition, safety and adequacy of the dam and such other information as
				the Commissioner may require by regulation, signed by a registered professional
				engineer and filed with the Department.
Dams Not Regulated by M.G.L. c. 253, §§
				44 through 48
. Dams constructed by beavers, created by ice,
				debris,
etc.
and any other non-man-made structures.
Dam Registration Form
. A form or forms
				to be provided by the Commissioner to be prepared by the owner and filed with
				the Commissioner containing the name of the owner, the location and the
				dimensions of the dam and such other information as the Commissioner may
				require by regulation.
Dam Safety Engineer
. A person who is
				employed by the department who meets the requirements established by the
				Department of Personnel Administration.
Database
. An electronic database of
				detailed information about dams. The database is owned, compiled, maintained
				and distributed by the Commissioner. Requests for database information are
				subject to M.G.L. c. 4, § 7, clause twenty-sixth (n) (Public Records)
				until suspended.
DEP
. The Department of Environmental
				Protection.
Department or DCR
. The Department of
				Conservation and Recreation, as established in M.G.L. c. 21 § 1.
Drainage Area
. The area which drains
				to a particular point on a river or stream.
Drawdown
. The lowering of water
				surface level due to loss of water from a reservoir.
Embankment
. The fill material, usually
				earth or rock, placed with sloping sides which provide a permanent barrier
				which impounds water.
Emergency Condition
. Unsafe dams with
				highest risk of failure, requiring immediate attention and a predetermined plan
				of action to reduce the highest level of risk, for the protection of public
				safety.
Emergency Action Plan
. A predetermined
				plan of action to be taken to reduce the potential for property damage and/or
				loss of life in an area affected by an impending dam break.
Engineer/Design Engineer
.
See
Registered Professional Engineer.
Factor of Safety
. As applied to dam
				safety, the ratio of the forces or moments resisting mass movement to the
				forces or moments tending to produce mass movement.
Fees
. As applied to dam safety, the
				cost of services listed under
				801 CMR
				4.02:
Fees for Licenses, Permits, and
				Services to be Charged by State Agencies
(302 CMR: Department of
				Conservation and Recreation) and provided by the Department.
Flashboards
. A length of timber,
				concrete, or steel placed on the crest of a spillway or other hydraulic control
				structure to raise the retention water level but that may be quickly removed in
				the event of a flood either by a tripping device or by a deliberately designed
				failure of the flashboard or its supports.
Flood Hydrograph
. A graphical
				representation of the flood discharge and/or stage with respect to time for a
				particular point on a stream or river.
Flow Net
. A graphical representation
				of families of streamlines and equipotential lines, used in groundwater studies
				to determine quantities, rate, and directions of flow.
Freeboard
. The vertical distance
				between a stated water level and the top of a dam. Net freeboard, dry
				freeboard, flood freeboard or residual freeboard are measured by the vertical
				distance between the spillway design flood water level and the top of a
				dam.
Gravity Dam
. A dam constructed of
				concrete and/or masonry that relies on its weight for stability.
Great Pond
. A pond containing in its
				natural state more than ten acres of land, as defined in
				310 CMR 9.02:
Definitions.
Great Pond/Enlarged
. As applied to dam
				safety, any change in or addition to an existing Great Pond which raises, or
				may raise, the normal water level of the water impounded by a Great Pond, by
				construction of a dam.
Hazard Potential Classification
. The
				rating for a dam based on the potential consequences of failure. The rating is
				based on potential for loss of life and damage to property that failure of that
				dam could cause downstream of the dam. The hazard potential classification for
				a dam has no relationship to the current structural integrity, operational
				status, flood routing capability, or safety condition of the dam or its
				appurtenances.
Height of Dam
. The vertical distance
				from the elevation of the dam crest to the lowest point of natural ground,
				including any stream channel, along the downstream toe of the dam.
Hydraulic and Hydrologic (H&H)
				Analyses
. The analytical process of computing the inflow and
				outflow from the dam under normal and flood conditions. Such analysis
				determines normal and maximum reservoir levels, outflows and spillway design
				and freeboard requirements.
Hydraulic Height
. The height to which
				water is normally retained behind a dam above the lowest point of natural
				ground, including any stream channel along the downstream toe of the
				dam.
Inspections
.
(a)
Additional Required Inspection
means an additional inspection by a registered professional engineer of the
				dam, in accordance with the inspection frequency established by the
				Commissioner, to detect apparent signs and changes of deterioration in
				material, developing weaknesses or unsafe hydraulic and/or structural behavior
				or any other deficiencies of the dam structure or function since the initial
				Phase I or poor/unsatisfactory condition was determined. The additional
				inspection report shall follow a form as established by the
				Commissioner.
(b)
Follow-up Inspection
means an
				inspection of dams determined to be in poor or unsafe condition with structural
				deficiencies performed on a frequency determined by the Commissioner, or as
				otherwise required for any dam at any time. The Follow-up Inspection report
				shall follow a form as established by the Commissioner.
(c)
Phase I Formal Inspection
means
				the formal visual inspection of the dam, in accordance with the inspection
				frequency established by, at a minimum, M.G.L. c. 21, § 65, or by the
				Commissioner, by a registered professional civil engineer to evaluate or
				reevaluate the safety and integrity of the dam and appurtenant structures to
				determine if the structure appears to meet current design criteria. Formal
				inspection includes field observations to detect any signs of deterioration in
				material, seepage, developing weaknesses or unsafe hydraulic and/or structural
				conditions and a review of the records on project design, construction and
				performance. The Phase I Formal Inspection shall determine the overall dam
				condition. The final Phase I Formal Inspection report shall follow a form or
				format as established by the Commissioner and shall be filed with the Office of
				Dam Safety.
(d)
Phase II Detailed Inspection
means
				all studies, investigations and analyses ordered by the Commissioner to
				evaluate the structural stability and hydraulic capacity of a dam or reservoir
				and appurtenant works. This inspection may include, but is not limited to,
				updated visual inspection, structural stability analyses, detailed
				hydrologic/hydraulic assessment, dam breach analyses, subsurface investigation,
				soil and materials testing, foundation explorations, conclusions, conceptual
				alternatives, cost estimate and recommendations. This inspection shall be
				performed by a registered professional civil engineer.
(e)
VIF (Verification In Field) Jurisdictional
				Determination Inspection
means an inspection to collect pertinent
				and sufficient information pertaining to a dam to determine if the Commissioner
				has a basis for claiming statutory and regulatory jurisdiction of a dam.
Instrumentation
. An arrangement of
				devices installed into or near dams
(i.e.
piezometers,
				inclinometers, strain gages, measurement points, seepage measuring devices,
etc.)
which provide for measurements that can be used to
				evaluate the structural behavior and performance parameters of the
				structure.
Inundation Map
. A map delineating the
				area that would be flooded by a particular flood event or dam failure.
Liability
. Legal liability associated
				with the ownership, operation, maintenance, repair and failure of a dam.
Lien
. A notice for the payment by the
				owner of a dam to the Commonwealth of the costs and expenses incurred by the
				Commonwealth for any actions taken in accordance with M.G.L. c. 253, § 47
				and shall be effective upon mailing to the owner at the address shown in the
				Certificate of Registration and recorded at the Registry of Deeds in the county
				where the dam lies.
Low Level Outlet (Pond Drain)
. An
				installed pipe and operable gate or valve that can be utilized to alter water
				levels, empty an impoundment, or otherwise meet operational or safety
				needs.
Materially Alter
. Any change to a dam
				or reservoir which affects the physical parameters and/or safety of the dam or
				reservoir which may include, but is not limited to, changing the height of a
				dam, increasing the normal pool or spillway elevation or changing the elevation
				or physical dimensions of an emergency spillway.
Maximum Impoundment Elevation
. The
				maximum water surface elevation which can be contained by the dam without
				overtopping the embankment section.
Maximum Water Storage Elevation
. The
				water surface elevation reached during the spillway design flood, which could
				be below the top of the dam or above the top of the dam.
Normal Water Level
. The water surface
				elevation that is maintained by the dam owner under normal operating
				conditions.
Office of Dam Safety (OPS)
. The office
				of the Department of Conservation and Recreation, composed of technical and
				administrative staff responsible for administering the Commonwealth's Dam
				Safety Law and Regulations.
One-hundred-year Storm Event
. A storm
				which is estimated to have a 1% chance of occurrence in any year, or a one in
				100 chance of being equaled or exceeded in one year.
Operation and Maintenance Manual
				(O&MM)
. A document identifying routine maintenance and
				operational procedures under routine and storm conditions.
Order
. A written document prepared and
				issued by the Commissioner which mandates specific actions to be accomplished
				by a dam owner within a specified time frame. Failure to comply with an order
				shall make the owner subject to fines as provided for in
				302 CMR 10.15.
Orientation
.
(a)
Upstream
means the side of the dam
				that borders the reservoir;
(b)
Downstream
means the side opposite
				the upstream side;
(c)
Right
means the area to the right
				when the viewer is looking downstream; and
(d)
Left
means the area to the left
				when the viewer is looking downstream.
Owner
. The person or persons,
				including any individual, firm, partnership, association, syndicate, company,
				trust corporation, municipality, agency, political or administrative
				subdivision of the commonwealth or any other legal entity of any kind holding
				legal title to a dam, but excluding the United States, its agencies or any
				person who operates a dam owned by the United States.
Permit or Chapter 253 Dam Safety
				Permit
. A written approval, pursuant to M.G.L. c. 253,
				§§ 44 through 48, to construct, repair, alter, breach or remove a
				dam. The technical aspect of the Permit must be reviewed and confirmed complete
				by an Office of Dam Safety Engineer.
Phreatic Surface
. The free surface of
				groundwater at atmospheric pressure.
Piezometer
. As applied to dam safety,
				an instrument used for measuring water pressure within soil, rock or
				concrete.
Piping
. The progressive development of
				internal erosion by seepage, appearing downstream as a hole or seam discharging
				water that contains soil particles.
Poor Condition Dam
. A dam whose
				condition, as determined by the Commissioner, presents a significant risk to
				public safety located downstream from the dam. Among the deficiencies that may
				result in this determination are: significant seepage or piping, significant
				woody vegetation and tree growth on embankments and areas immediately adjacent
				to the dam and appurtenances, significant erosion or subsidence conditions,
				significant sink holes, significant sloughing of embankment, significant
				deficient flood routing spillway capacity and/or condition of outlet(s),
				significant movement or cracking of structural elements and other significant
				structural deficiencies.
Probable Maximum Flood (PMF)
. The most
				severe flood that is considered reasonably possible at a site as a result of
				the most severe combination of critical meteorological and hydrologic
				conditions possible in the region. PMFs are based on National Oceanic and
				Atmospheric Administration (NOAA) Probable Maximum Precipitation Estimates
				published in
Hydrometerological Report No. 51
and applicable
				NOAA guidance documents.
Registered Professional Engineer
. In
				the context of dam engineering, means a civil engineer licensed and registered
				in the Commonwealth of Massachusetts with experience in dam safety inspections
				and engineering.
Removal
. The physical removal or
				engineered breaching of a dam to the extent that no water can be impounded by
				the dam.
Repairs
means any work done at a dam
				which affects the integrity of the dam. This includes, but is not limited to,
				work requiring excavation into the embankment fill or foundation of a dam or
				work requiring removal or replacement of major structural components of a
				dam.
Reservoir
. The area which contains or
				will contain the body of water impounded by a dam.
Riprap
. A layer or layers of
				sufficiently large uncoursed stones, broken rock, or pre-cast blocks placed in
				random fashion on the upstream or downstream slope of an embankment dam, on a
				reservoir shore, on the sides of a channel or other elements of a dam to
				provide protection from erosion expected to be caused by wave action, freeze
				thaw cycles, flowing water or other erosive forces.
Riprap
is sometimes referred to as armoring.
Risk
. A measure of the likelihood and
				severity of adverse consequences. In dam safety applications, life-safety risk
				is expressed in units of loss-of-lives per year; economic, societal and
				environmental risks are expressed in units of dollars per year. The risk may be
				associated with an individual failure mode or it may be total risk,
				representing the cumulative risk associated with all failure modes.
Risk Assessment
. As applied to dam
				safety, the process of identifying the likelihood and consequences of dam
				failure to provide the basis for informed decisions on a course of
				action.
Roll Dams
. Low head dams usually
				run-of-the-river overflow weir or spillway structures that produce vertical
				water surface drops of one to 15 feet and change river flows from
				super-critical to sub-critical.
Run-of-the-river-dam
. A dam situated
				on a river or stream whose spillway length and width of impoundment is nearly
				equal to the width of the original river or stream bank to bank and likely
				having minimal storage available for flood attenuation.
Safety Evaluation
. As applied to dam
				safety, the process of determining the ability of a dam and its appurtenances
				to pass a given flood.
Seepage
. The interstitial movement of
				water that may take place through a dam, its foundation, or its
				abutments.
Siphon/Inverted
. A conduit or culvert
				to permit water to pass under an intersecting roadway, stream or other
				obstruction.
Spillway
. A structure over or through
				which non-storm related and flood flows are discharged. If the flow is
				controlled by gates or other works of control, it is a controlled spillway; if
				the elevation of the spillway crest is the only control, it is an uncontrolled
				spillway.
Spillway/Auxiliary or Emergency
				Spillway
. A secondary spillway designed to operate only during
				flood events that exceed the principal spillway capacity or operate in tandem
				with the principal spillway.
Spillway(s) Design Flood (SDF)
. The
				flood used in the design of a dam and its appurtenant works particularly for
				sizing the spillway(s) and outlet works, and for determining maximum temporary
				storage and height of dam requirements.
Stoplogs
. Logs, timbers, steel or
				alloy beams placed on top of each other with their ends held in guides on each
				side of a channel or conduit to control water level in reservoir.
Tailwater Level
. As applied to dam
				safety, the level of water in the discharge channel immediately downstream of
				the dam. Tailwater levels can be those levels that result from normal to flood
				flow (SDF) conditions.
Toe of Dam
. The junction of the
				downstream face of a dam with the ground surface, also referred to as
				downstream toe. For an embankment dam, the junction of the upstream face with
				ground surface is called the upstream toe.
Unsafe Condition Dam
. A dam whose
				condition, as determined by the Commissioner, is such that a high risk of
				failure exists and the dam condition presents a high risk to public safety
				located downstream from the dam. Among the deficiencies that may result in this
				determination are: severe seepage or piping, severe woody vegetation and tree
				growth on embankments and areas immediately adjacent to the dam and
				appurtenances, severe erosion or subsidence conditions, severe sink holes,
				severe sloughing of embankment, severely deficient flood routing spillway
				capacity and/or condition of outlet(s), severe movement and/or severe cracking
				of structural elements and other severe structural deficiencies.
Uplift
. As applied to dam safety, the
				upward pressure in the pores of a material (interstitial pressure) or on the
				base of a structure.
Weir
. A barrier installed in an open
				channel stream or constructed waterway used for measuring and/or controlling
				the flow of water. Types of weir include broad crested weir, sharp-crested
				weir, ogee weir, and V-notched weir.