For the purpose of these standards, the following definitions shall apply:
"BASE FLOOD ELEVATION." The elevation delineating the level of flooding from the 100-year frequency flood.
"BOARD." The town of Pendleton, Indiana, and any subordinate employee 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 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.
"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.
"DETENTION BASIN." A facility constructed or modified to restrict the flow of stormwater to a prescribed maximum rate, and to temporarily detain concurrently the excess waters that accumulate behind the outlet.
"DETENTION STORAGE." The temporary storage of stormwater in detention basins which could include rooftops, streets, parking lots, school yards, parks, open spaces, or other areas under predetermined and controlled conditions. The release rate from the detention storage area is regulated by designed and installed devices.
"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 completely drain after providing detention of excess runoff during a storm event.
"DURATION." The time period of a rainfall event.
"FLOOD PROTECTION ELEVATION." The base flood elevation (100 year flood) plus two feet.
"FLOODWAY." The channel of a river or stream and those portions of the floodplain adjacent to the channel which are reasonably required to convey the 100-year flood discharge without increasing the water surface elevation of the 100-year flood more than 0.1 feet at any point.
"FLOODWAY FRINGE." The area between the floodway and the boundary of the 100-year 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, or natural ground surface usually expressed in terms of the percentage the vertical rise (or fall) bears to the corresponding horizontal distance.
"IMPERVIOUS AREA." A hard surface area that does not readily absorb water. Impervious surfaces would include pavement, parking lots, driveways, rooftops and other hard surfaces that do not absorb water.
"INLET." An opening into a storm sewer system for the entrance of surface stormwater runoff, more completely described as a storm sewer inlet.
"LATERAL STORM SEWER." A sewer that has inlets connected to it and empties into another storm sewer or channel.
"MAJOR DRAINAGE SYSTEM." A 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 SYSTEM." A drainage system having an area of less than one square mile.
"OFF-SITE." Everything outside the developing right-of-way.
"ON-SITE." Located within the developing right-of-way 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.
"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 town of Pendleton, Indiana.
"REGULATORY FLOOD." That flood having a peak discharge that has a one percent probability of being equaled or exceeded in any given year, as calculated using a method that is acceptable to the Indiana Department of Natural Resources.
"RELEASE RATE." The amount of stormwater released 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 of a conduit which lying 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.
"STORAGE DURATION." The length of time that water may be stored in any storm water control facility, computed from the time water first begins to be stored.
"STORM SEWER." A closed conduit for conveying collected stormwater.
"STORMWATER DRAINAGE FACILITY." All means, natural or man-made, including conduits and appurtenant features, canals, channels, ditches, streams and culverts, used for conveying stormwater runoff.
"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." Any watercourse that flows into a larger watercourse.
"WATERCOURSE." Any river, stream, creek, brook, branch, natural or manmade drainageway in or into which stormwater runoff or floodwaters flow.
"WATERSHED." A geographic area from which water drains to a specific concentration point at the furthest downstream (lowest elevation) point.
"WET BOTTOM RETENTION BASIN." A basin designed to retain a permanent pool of water after having provided its planned temporary detention of runoff during a storm event.
(Ord. 1999-05, passed 6-8-99)