Illinois Administrative Code › Title 17 - CONSERVATION › Part 3706 - REGULATION OF CONSTRUCTION WITHIN FLOOD PLAINS › Subpart L - DEFINITIONS › Section 3706.1210 - Definitions

Current through Register Vol. 48, No. 28, July 12, 2024
Unless specifically defined below, words or phrases used in
				  this Part shall be interpreted so as to give them the meaning they have in
				  common usage and to give this Part its most reasonable application.
"Authorized Flood Control Project" - A project which all
				  authorizations required by law for construction, including any required for
				  expenditure of construction funds, have been secured.
"Channel" - A natural or artificial watercourse of
				  perceptible extent, with definite bed and banks to confine and conduct
				  continuously or periodically flowing water. The top of the banks form dividing
				  lines between the channel and the overbank portion of the flood plain.
"Construction" - The placement or erection of structures or
				  earthworks; land filling, excavation or other non-agricultural alternation of
				  the ground surface; installation of public utilities; channel modification;
				  storage of materials or any other activity undertaken to modify the existing
				  physical features of a flood plain with respect to the storage and conveyance
				  of flood waters.
"Conveyance" - Capacity of the valley cross section to
				  discharge flood flows at the regulatory flood stage.
"Encroachment Limit" - A smoothed line based on hydraulic
				  analysis indicating the maximum channelward encroachment which may be
				  undertaken without significantly increasing flood stage. The encroachment limit
				  forms the common boundary of the flood fringe and regulatory floodway. On small
				  streams and steepwalled valleys, the encroachment limit may coincide with the
				  boundary of the regulatory flood plain.
"Equal Degree of Encroachment" - A method of determining the
				  location of encroachment limits so that flood plain lands on both sides of a
				  stream are capable of conveying a proportionate share of flood flows. This is
				  determined by considering the effect of encroachment on the hydraulic
				  efficiency of the flood plain along both sides of a stream for a significant
				  reach.
"Flood" - A temporary rise in stream level that results in
				  inundation of areas not ordinarily covered by water.
"Flood Damage Potential" - Susceptibility to economic loss
				  caused by flooding, such as inundation and damage to contents, structural
				  damage, loss of occupancy or use, or interruption of normal services. Threats
				  to health and safety such as contamination of public water supplies, danger of
				  drowning or electrocution, interruption of emergency services caused by
				  flooding, failure of on-site waste disposal, and blighting of structures.
				  Nuisances to adjacent lands caused by sediment or erosion, or the flotation of
				  materials which may jam bridges or litter other lands.
"Flood Fringe" - Those portions of the regulatory flood plain
				  outside the regulatory floodway. Structures and fill placed within the flood
				  fringe will not significantly increase flood stages. The flood fringe could be
				  quite wide on large streams, quite small or nonexistent on small
				  streams.
"Flood Plain" - That land adjacent to a body of water which
				  has been or may be hereafter covered by flood water including but not limited
				  to the regulatory flood.
"Pollution" - Pollution shall be as defined in the
				  Environmental Protection Act [415 ILCS 5 ] or the Rules and Regulations enacted
				  under that Act (35 Ill. Adm. Code).
"Regulatory Flood Plain" - That land adjacent to a body of
				  water with ground surface elevation at and below the regulatory flood
				  elevation.
"Regulatory Flood Profile" - A graph showing the relationship
				  of water surface elevation of the regulatory flood to location along the
				  stream.
Regulatory Flood Protection Elevation" - An elevation of one
				  foot above the regulatory flood elevation which provides freeboard protection
				  against ice jams, waves, and debris.
"Regulatory Flood Stage" - The water surface elevation to be
				  expected during discharge of the regulatory flood.
"Regulatory Floodway" - That portion of the regulatory flood
				  plain required to store and convey the flood water of the regulatory flood with
				  no significant increase in stage.
"Storage" - The volume between the regulatory flood stage and
				  the ground surface. The area measured on a valley cross section is a
				  representation of the storage at that section.