For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
BOARD. The Drainage Board of the county and any subordinate person to whom they shall specifically delegate a responsibility authorized by this chapter.
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/standing 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.
COMPENSATORY STORAGE. An artificial volume of storage within a floodplain used to offset loss of natural flood storage capacity when artificial fill or structures are placed within the floodplain.
CONDUIT. A device to convey water runoff or drainage flow.
CONTIGUOUS. Adjoining or in actual contact with.
COUNTY SURVEYOR. The County Surveyor of Knox County, IN and any person to whom he/she shall specifically delegate a responsibility authorized by this section.
CULVERT. A closed conduit used for the passage of surface drainage water under a roadway, railroad, canal or other impediment.
DETENTION BASIN. A storm water control facility constructed or modified to restrict the flow of storm water to a prescribed maximum rate, and to concurrently detain the excess waters resulting from development. This facility has no permanent water pool during inter-storm periods.
DETENTION STORAGE. The temporary detaining or storage of storm water in storage basins, underground chambers, streets, parking lots, school yards, parks, open spaces or other areas under predetermined and controlled conditions, with the rate of drainage released therefrom regulated by appropriately installed devices.
DEVELOPMENT OR DEVELOPED LANDS. The activities that result in a change of land use, or an area where a change to a more intensive land use has occurred, or migration from a less intense to more intense land use. This activity commonly results in increased runoff and peak discharge.
DRAINAGE AREA. The area that contributes runoff to a point of interest, or design point, during a rainfall event (i.e., a watershed or catchment area).
DURATION. The time period of a rainfall event.
EROSION. Wearing away of the land by running water, waves, weather cycles, ice or wind.
FLOOD ELEVATION. The elevation delineating the maximum level of high waters for a flood of given return period and rainfall duration.
FOOTING DRAIN. A drain pipe installed around the exterior of a building or basement wall foundation to relieve water pressure caused by high ground water elevation.
GRADE/SLOPE. The inclination, or slope, of a channel, canal, conduit and the like or natural ground surface usually expressed in terms of the percentage of the vertical rise (or fall) to the corresponding horizontal distance.
HIGHWAY DEPARTMENT. The Highway Department of Knox County, IN and any person to whom they shall specifically delegate a responsibility authorized by this section.
IMPACT AREAS. Areas defined, listed and/or 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 with no adequate drainage outlet, a floodway or flood plain, land within 75 feet of the top of each bank of any regulated drain or within 75 feet from the center line of any regulated storm sewer or tile drain.
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 water runoff, more appropriately described as a storm sewer inlet.
LATERAL STORM SEWER. A sewer that has inlets connected to it, but has no other upstream storm sewer connected. LATERAL STORM SEWERS connect to a main storm sewer outlet.
MAJOR DRAINAGE SYSTEM. Drainage systems carrying runoff from a watershed area of one or more square miles.
MANHOLE. Storm sewer junction and maintenance structure through which a person or equipment may enter to gain access to an underground storm sewer or enclosed structure.
MINOR DRAINAGE SYSTEMS. Drainage systems having a watershed area of less than one square mile.
OFF-SITE. Considered to be not on-site. Typically not under the direct control or influence of the developer.
ON-SITE. Located within the controlled area of development.
OUTFALL. The point or location where storm runoff discharges from a storm sewer or drain; also applies to the outfall sewer or channel which carries the storm runoff to its point of outfall.
PEAK FLOW. The maximum rate of flow of stormwater at a given point in a channel or conduit resulting from a particular storm or flood, commonly recorded in cubic feet per second.
RADIUS OF CURVATURE. Length of radius of circle used to define a curve.
RAINFALL INTENSITY. The cumulative depth of rainfall occurring over a given time period, normally expressed in inches per hour.
REACH. Any selected length of river, channel or storm sewer.
REDEVELOPMENT. Alterations of a property that change a site or building in such a way that a more intensive land use has occurred. This activity commonly results in increased runoff and peak discharge. The term does not include such activities as exterior remodeling.
RELEASE RATE. The amount of stormwater released from a stormwater control facility (typically a detention basin or retention pond) per unit of time. This term is normally expressed in cubic feet per second.
RETENTION POND. A stormwater control facility designed to retain a permanent pool of water after having provided its planned detention of runoff during a storm event, or one that has no outlet and discharges into the soil with time.
RETURN PERIOD. The average interval of time within which a given rainfall event will be equaled or exceeded one time. 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% of the rain falling on a given surface appears as stormwater runoff.
SEDIMENT. Material of soil and rock origin transported, carried and deposited by water.
SPILLWAY. A waterway in or about a hydraulic structure for the passage or flow of water. A portion of a stormwater control facility designed for the passage or flow of water.
STILLING BASIN. A water-filled basin used to dissipate energy of flowing water.
STORAGE DURATION. The length of time that water may be stored in any storm water control facility, measured from the time water first begins to be stored until the end of the storage need.
STORM SEWER. A closed conduit for conveying collected storm water.
STORM WATER DRAINAGE SYSTEM. All means, natural or human-made, used for conducting storm water 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.
STORM WATER RUNOFF. The water derived from rains falling within a watershed, flowing over the surface of the ground or collected in channels or conduits.
TRIBUTARY. Contributing storm water from upstream land areas.
URBANIZATION. The development, re-development, change or improvement of any parcel of land consisting of one or more lots for residential, commercial, industrial, institutional, recreational, municipal or public utility purposes.
WATERCOURSE. Any natural or man-made drainage way, river, stream, creek, brook, branch and the like into which storm water runoff or flood waters flow either regularly or intermittently.
WATERSHED. See DRAINAGE AREA.
(Ord. 8-2014, passed 7-21-2014)