For the purpose of this chapter, the following definitions shall apply.
“BOARD.” The Drainage Board of Huntington County, Huntington Indiana.
“CAPACITY OF A STORM DRAINAGE FACILITY.” The maximum flow that can be conveyed or stored by a storm drainage facility without causing damage to public or private property.
“CHANNEL.” A natural or artificial watercourse which periodically or continuously contains moving water, or which forms a connecting link between two bodies of water. It has a defined bed and banks which serve to confine the water.
“COMMISSION.” The City of Huntington Advisory Plan Commission.
“COMPENSATORY STORAGE.” An artificial volume of storage within a floodplain used to balance the loss of natural flood storage capacity when artificial fill or structures are placed within the floodplain.
“CONTIGUOUS.” Adjoining or in actual contact with.
“CULVERT.” A closed conduit used for the passage of surface drainage water under a roadway, railroad, canal, or other impediment.
“DEPARTMENT.” The Community Development and Redevelopment Department.
“DETENTION BASIN.” A facility constructed or modified to restrict the flow of stormwater to a prescribed maximum rate, and to detain concurrently the excess waters that accumulate behind the outlet.
“DETENTION STORAGE.” The temporary detaining or storage of stormwater in storage basins, on rooftops, in streets, parking lots, school yards, parks, open spaces, or other areas under predetermined and controlled conditions, with the rate of drainage therefrom regulated by appropriately installed devices.
“DEVELOPMENT.” The construction, reconstruction, conversion, structural alteration, relocation or enlargement of any buildings; or any clearing, grading or other movement of land.
“DRAINAGE AREA.” The area from which water is carried off by a drainage system; a watershed or catchment area.
“DROP MANHOLE.” A manhole having a vertical drop pipe connecting the inlet pipe to the outlet pipe. The vertical drop pipe shall be located immediately outside the manhole.
“DRY BOTTOM DETENTION BASIN.” A basin designed to be completely dewatered after having provided its planned detention of runoff during a storm event.
“DURATION.” The time period of a rainfall event.
“EROSION.” Wearing away of the land by running water, waves, temperature changes, ice or wind.
“FLOOD ELEVATION.” The elevation at all locations delineating the maximum level of high waters for a flood of given return period and rainfall duration.
“FLOOD HAZARD AREA.” Any flood plain, floodway, floodway fringe, or any combination thereof, which is subject to inundation by the regulatory flood; or any flood plain as delineated by Zone A on a Flood Hazard Boundary Map.
“FLOOD OR FLOOD WATERS.” The water of any watercourse which is above the banks of the watercourse. It also means the water of any lake which is above and outside the banks thereof.
“FLOOD PLAIN.” The area adjoining the river or stream which has been or may hereafter be covered by floodwater.
“FLOOD PROTECTION GRADE.” The elevation of the lowest floor of a building. If a basement is included, the basement floor is considered the lowest floor.
“FLOODWAY.” See “REGULATORY FLOODWAY.”
“FLOODWAY FRINGE.” That portion of the flood plain lying outside the floodway, which is inundated by the regulatory flood.
“FOOTING DRAIN.” A drain pipe installed around the exterior of a basement wall foundation to relieve water pressure caused by high groundwater elevation.
“GRADE.” The inclination or slope of a channel, canal, conduit, etc., or natural ground surface, usually expressed in terms of the percentage the vertical rise (or fall) bears to the corresponding horizontal distance.
“IMPACT AREAS.” Areas defined and mapped by the Board which are unlikely to be easily drained because of one or more factors, including but not limited to, any of the following: soil type, topography, land where there is not adequate outlet, a floodway or floodplain, land within 75 feet of each bank of any regulated drain or within 75 feet from the centerline of any regulated tile ditch.
“IMPERVIOUS.” A term applied to material through which water cannot pass, or through which water passes with difficulty.
“INLET.” An opening into a storm sewer system for the entrance of surface stormwater runoff, more completely described as a storm sewer inlet.
“JUNCTION CHAMBER.” A converging section of conduit, usually large enough for a person to enter, used to facilitate the flow from one or more conduits into a main conduit.
“LATERAL STORM SEWER.” A sewer that has inlets connected to it but has no other storm sewer connected.
“MAJOR DRAINAGE SYSTEM.” Drainage system carrying runoff from an area of one or more square miles.
“MANHOLE.” Storm sewer structure through which a person may enter to gain access to an underground storm sewer or enclosed structure.
“MINOR DRAINAGE SYSTEMS.” Drainage systems having an area of less than one square mile.
“OFF-SITE.” Everything not on site.
“ON-SITE.” Located within the controlled area where runoff originates.
“OUTFALL.” The point or location where storm runoff discharges from a sewer or drain. Also applies to the “OUTFALL” sewer or channel which carries the storm runoff to the point of “OUTFALL.”
“PEAK FLOW.” The maximum rate of flow of water at a given point in a channel or conduit resulting from a particular storm or flood.
“RADIUS OF CURVATURE.” Length of radius of a circle used to define a curve.
“RAINFALL INTENSITY.” The cumulative depth of rainfall occurring over a given duration, normally expressed in inches per hour.
“REACH.” Any length of river, channel or storm sewer.
“REGULATED AREA.” All of the land under the jurisdiction of the City of Huntington Plan Commission.
“REGULATORY FLOOD.” That flood having a peak discharge which can be equaled or exceeded on the average of once in a 100-year period, as calculated by a method and procedure which is acceptable to the Commission. If a permit from the National Resources Commission for construction in the floodway is required (see § 55.05), then the regulatory flood peak discharge should be calculated by a method acceptable to the Commission and the Natural Resources Commission. This regulatory flood is equivalent to a flood having a probability of occurrence of one percent in any given year.
“REGULATORY FLOODWAY.” The channel of a river or stream and those portions of the floodplains adjoining the channel which are reasonably required to carry and discharge the peak flow of the regulatory flood of any river or stream.
“RELEASE RATE.” The amount of stormwater release from a stormwater control facility per unit of time.
“RETURN PERIOD.” The average interval of time within which a given rainfall event will be equaled or exceeded once. A flood having a return period of 100 years has a one percent probability of being equaled or exceeded in any one year.
“RUNOFF COEFFICIENT.” A decimal fraction relating the amount of rain which appears as runoff and reaches the storm drainage system to the total amount of rain falling. A coefficient of 0.5 implies that 50 percent of the rain falling on a given surface appears as stormwater runoff.
“SEDIMENT.” Material of soil and rock origin, transported, carried or deposited by water.
“SIPHON.” A closed conduit, or portion thereof, which lies above the hydraulic grade line, resulting in a pressure less than atmospheric and requiring a vacuum within the conduit to start flow. A siphon utilizes atmospheric pressure to effect or increase the flow of water through a conduit. An inverted siphon is used to carry stormwater flow under an obstruction such as a sanitary sewer.
“SPILLWAY.” A waterway in or about a hydraulic structure, for the escape of excess water.
“STILLING BASIN.” A basin used to slow water down or dissipate its energy.
“STORAGE DURATION.” The length of time that water may be stored in any stormwater control facility, computed from the time water first begins to be stored.
“STORM SEWER.” A closed conduit for conveying collected stormwater.
“STORMWATER DRAINAGE SYSTEM.” All means, natural or manmade, used for conducting stormwater to, through or from a drainage area to any of the following: conduits and appurtenant features, canals, channels, ditches, streams, culverts, streets and pumping stations.
“STORMWATER RUNOFF.” The water derived from rains falling within a tributary basin, flowing over the surface of the ground or collected in channels or conduits.
“TRIBUTARY.” Contributing stormwater from upstream land areas.
“URBANIZATION.” The development, change or improvement of any parcel of land consisting of one or more lots for residential, commercial, industrial, institutional, recreational or public utility purposes.
“WATERCOURSE.” Any river, stream, creek, brook, branch, natural or manmade drainage way, in or into which stormwater runoff or floodwater either regularly or intermittently flows.
“WATERSHED.” See “DRAINAGE AREA.”
“WET BOTTOM DETENTION BASIN (RETENTION BASIN).” A basin designed to retain a permanent pool of water after having provided its planned detention of runoff during a storm event.
(Ord. 16-C-98, passed 6-9-98; Am. Ord. 22-C-98, passed 8-11-98; Am. Ord. 22-C-04, passed 11-9-04; Am. Ord. 20-C-14, passed 7-29-14)