Ohio Administrative Code › Title 1501:21 - Division of Soil and Water Resources - Dam Safety › Chapter 1501:21-3 - Definitions; Registered Professional Engineer Requirement › Section 1501:21-3-01 - Definitions

Current through all regulations passed and filed through July 1, 2024
The following definitions  apply to the terms used in division 1501:21
				of the Administrative Code:
(A)
			 "Applicant" means the individual, corporation, partnership, proprietor, or
			 public agency which is making an application for a construction
			 permit.
(B) "Appurtenant works"
			 means interrelated elements or components of the dam including but not limited
			 to outlet works and spillway channels.
(C) "Breach" is defined as an opening in a
			 dam that prevents the dam from impounding a significant amount of
			 water.
(D) "Bulkhead" means a
			 structure or partition to reduce pressure and shut off water from entering a
			 valve or gate chamber to allow for repair and maintenance of the valve or
			 gate.
(E) "Chief" means the chief
			 of the division of water resources of the department of natural resources,
			 state of Ohio.
(F) "Conveyance" is
			 the hydraulic term applied to the measurement of the carrying capacities of
			 stream channels and overbank areas. Conveyance is directly proportional to
			 discharge.
(G) "Critical flood"
			 means the flood that would result in no additional loss of life, health or
			 property along a critical routing reach downstream of the dam from overtopping
			 failure of the dam when compared to the potential for loss of life, health or
			 property caused by the flood in the absence of a dam overtopping
			 failure.
(H) "Critical routing
			 reach" means the entire floodplain area downstream of the dam where life,
			 health, or property is potentially affected by failure of a dam.
(I) "Dam" means any artificial barrier
			 together with any appurtenant works, which either does or may impound water or
			 other liquefied material. Upground reservoirs and lagoons are considered to be
			 dams. A fill or structure intended solely for highway or railroad use that does
			 not permanently impound water or other liquefied material as determined by the
			 chief is not considered a dam.
(J)
			 "Design flood" is the runoff from the design storm taking into account the
			 physiographic, topographic, hydrologic, and hydraulic characteristics of the
			 drainage area.
(K) "Division" means
			 the division of water resources of the department of natural resources, state
			 of Ohio.
(L) "Emergency spill way"
			 means a discharge system designed to operate at an elevation above the
			 principal spill way to safely convey discharges that exceed the principal spill
			 way's capacity without jeopardizing the safety of the dam.
(M) "Enlargement" means increasing the
			 elevation of the top of an existing dam for the purpose of increasing the
			 elevation of the normal pool level of the impoundment, or increasing the
			 elevation of the top of an existing levee.
(N) "Flood" means a general and temporary
			 condition of partial or complete inundation of normally dry land
			 area.
(O) "Flood profile" means a
			 graph or longitudinal plot of maximum water surface elevations of a flood event
			 versus measured distance along a stream from a fixed point of
			 reference.
(P) "Floodplain" means
			 the land area adjoining a watercourse which may be inundated during a
			 flood.
(Q) "Freeboard" means the
			 vertical dimension between the top of the dam or levee (without camber) and the
			 reservoir at normal pool level, maximum operating pool, or stream water
			 surface.
(R) "Height-of-dam" means
			 the vertical dimension as measured from the elevation of the natural stream
			 bed, watercourse, or lowest ground elevation at the downstream or outside toe
			 of a dam to the elevation of the top of the dam.
(S) "Length-of-dam" means the horizontal
			 dimension as measured along the crest of the dam from natural abutment to
			 natural abutment. Spillway systems over the dam but not in the abutment area
			 are included in the length determination. For upground reservoirs the length is
			 the continuous distance around the crest of the dam.
(T) "Levee" means any artificial barrier
			 together with any appurtenant works that will divert or restrain the flow of a
			 stream or other body of water for the purpose of protecting an area from
			 inundation by flood waters.
(U)
			 "One-hundred-year flood" means the flood having a one per cent probability of
			 being equaled or exceeded in any given year.
(V) "Overtopping" means an event that occurs
			 when the pool or stream elevation exceeds the elevation of the top of a dam or
			 levee.
(W) "Owner" means those who
			 own, or propose to construct a dam or levee.
(X) "Pipe conduit" means any tube or hollow
			 channel which conveys water to or from a reservoir, or through a
			 levee.
(Y) "Primary or principal
			 spillway" means the first discharge system designed to begin operation after
			 the normal design storage capacity has been exceeded.
(Z) "Probable maximum flood" or "PMF" means
			 the flood that may be expected from the most severe combination of critical
			 meteorologic and hydrologic conditions that are reasonably possible in the
			 drainage basin under study. The "PMF" is derived from the probable maximum
			 precipitation and is determined by using a hydrologic model to simulate the
			 drainage basin's response to those critical conditions which produce the most
			 severe flood runoff.
(AA) "Probable
			 maximum precipitation" or "PMP" means theoretically, the greatest depth of
			 precipitation for a given duration that is physically possible over a given
			 size storm area at a particular geographic location. The "PMP" is determined on
			 the basis of data obtained by the national oceanic and atmospheric
			 administration or other sources accepted by the chief.
(BB) "Reservoir" means any impoundment, or
			 any potential impoundment, that will be created by a dam.
(CC) "Spillway level" means the elevation of
			 the primary (principal) spillway or the elevation of the top of the dam if
			 there is no spillway.
(DD) "Storage
			 volume" or "storage capacity" means the volume of water or other liquefied
			 material, which is or may be impounded by a dam at a given elevation above the
			 natural stream bed or above the natural grade for upground reservoirs.
			 Impounded material that can be shown to the satisfaction of the chief to be
			 non-liquefied can be excluded from the storage volume.
(EE) "Total storage volume" means the total
			 volume of water or other liquefied material impounded when the pool level is at
			 the top of the dam immediately before it is overtopped. Impounded material that
			 can be shown to the satisfaction of the chief to be non-liquefied can be
			 excluded from the total storage volume.
(FF) "Upground reservoir" means a reservoir
			 formed by artificial barriers on two or more sides and which impounds water or
			 liquefied material pumped or otherwise imported from an exterior source.
			 Lagoons are considered upground reservoirs.