(A) Although not all of the abbreviations and definitions listed below are used in this chapter, the additional terminology is provided to assist ordinance administrators, other community officials, residents and permit applicants in understanding technical terminology associated with the subject matter of this chapter.
(B) For the purpose of this chapter, the following abbreviations shall apply unless the context clearly indicates or requires a different meaning.
AC-FT. Acre-feet.
CFS. Cubic feet per second.
COE. United States Army Corps of Engineers.
FEMA. Federal Emergency Management Agency.
FPS. Feet per second.
HERPICC. Highway Extension and Research Project for Indiana Counties and Cities.
IDEM. Indiana Department of Environmental Management.
IDNR. Indiana Department of Natural Resources.
INDOT. Indiana Department of Transportation.
NRCS. National Resources Conservation Service.
SWCD. Soil and Water Conservation District.
(C) For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
APPARENT RIGHT-OF-WAY.
(a) All that area lying adjacent to, and including, the public road which is being used and occupied by the public and public utilities, and the area of maintenance by county or city government.
(b) The limits of the apparent right-of-way shall be defined as the greater of any of the following:
1. Existing fence of long standing;
2. Edge of existing utilities;
3. Field occupation lines (plowed or tilled ground);
4. Existing woody vegetation (may signify evidence of prior fence location);
5. Or if none of the above exists, edge of traveled road surface, and the adjacent area of maintenance by a county or city road development.
(c) The APPARENT RIGHT-OF-WAY is subordinate to dedicated rights-of-way of record.
BACKFLOW PREVENTER. A device that allows liquids to flow in only 1 direction in a pipe. BACKFLOW PREVENTERS are used on sewer pipes to prevent a reverse flow during flooding situations.
BACKWATER. The rise in water surface elevation caused by some obstruction such as a narrow bridge opening, buildings or fill material that limits the area through which the water shall flow.
BASE FLOOD. See REGULATORY FLOOD.
BASE FLOOD ELEVATION (BFE). The water surface elevation corresponding to a flood having 1% probability of being equaled or exceeded in a given year.
BASEMENT. Any area of the building having its floor subgrade on all sides.
BENCHMARK. A marked point of known elevation from which other elevations may be established.
BEST MANAGEMENT PRACTICES. Design, construction and maintenance practices and criteria for stormwater facilities that minimize the impact of stormwater runoff rates and volumes, prevent erosion and capture pollutants.
BUILDING. See STRUCTURES.
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.
CENTERLINE OF CHANNEL. The middle point or baseline of a channel.
CHANNEL. A natural or artificial watercourse which periodically or continuously contains moving water, or which forms a connecting link between 2 bodies of water. It has a defined bed and banks which serve to confine the water.
CONTIGUOUS. Adjoining or in actual contact with.
CONTOUR. Imaginary line on the earth's surface which connects points of equal elevation.
CONTOUR LINE. Line on a map which represents a contour or points of equal elevation.
CONTROL STRUCTURE. A structure designed to control the rate of flow that passes through the structure, given a specific upstream and downstream water surface elevation.
CROSS WALKWAY. A strip of land dedicated to public use, which is reserved across a block to provide pedestrian access to adjacent areas.
CROWN OF PIPE. The elevation of the top or highest point of the internal surface of the transverse cross section of a pipe.
CROSS- SECTION. A graph or plot of ground elevation across a stream valley, or a portion of it, usually along a line perpendicular to the stream or direction of flow.
CUBIC FEET PER SECOND (CFS). Used to describe the amount of flow passing a given point in a stream channel. One cubic foot per second is equivalent to approximately 7.5 gallons per second.
CULVERT. A closed conduit used for the conveyance of surface drainage water under a roadway, railroad, canal or other impediment.
CURVE NUMBER (CN). The NRCS index that represents the combined hydrologic effect of soil, land use, land cover, hydrologic condition and antecedent runoff condition.
DAM. All obstructions, wall embankments or barriers, together with any abutments and appurtenant works, constructed to store, direct water or create a pool (not including underground water storage tanks).
DATUM. Any level surface to which elevations are referred, usually using mean sea level.
DEPRESSIONAL STORAGE AREAS. Non-riverain depressions in the earth where stormwater collects. The volumes are often referred to in units of acre-feet.
DESIGN STORM. A selected storm event, described in terms of the probability of occurring once within a given number of years, for which stormwater or flood control improvements are designed and built.
DETENTION FACILITY. A facility designed to detain a specified amount of stormwater runoff assuming a specified release rate. The volumes are often referred to in units of acre-feet. Examples include on rooftops, in streets, parking lots, school yards, parks, open spaces or other areas under predetermined and controlled conditions.
DETENTION STORAGE. The temporary storage of stormwater in a detention facility, with the rate of release regulated by appropriately installed devices.
DEVELOPMENT. Any human-made change to improved or unimproved real estate a quarter-acre or larger including but not limited to:
(a) Construction, reconstruction or placement of a building or any addition to an existing building that adds over 1/4 acre or more of impermeable surface (ie: rooftop, parking lot, driveway and the like);
(b) All subdivisions requiring approval under the current Chapter 157, effective after the adoption of this Drainage Chapter;
(c) Installing utilities, construction or reconstruction of roads or similar projects;
(d) Construction of flood control structures such as levees, dikes, dams, channel improvements and the like;
(e) Mining, dredging, filling, grading, excavation;
(f) Construction and/or reconstruction of bridges or culverts; and
(g) Any other activity that might change the direction, height or velocity of flood or surface waters.
(h) DEVELOPMENT does not include activities such as the maintenance of existing buildings and facilities such as painting or re-roofing, resurfacing roads or gardening, plowing and similar agricultural practices. In addition, DEVELOPMENT does not include the reconstruction or maintenance of regulated drains or replacement of existing stream crossing by the City of Brazil.
DISCHARGE. Normally, the rate of flow into or out of a sewer, stormwater storage facility or from a land surface. DISCHARGES are customarily measured in cubic feet per second (cfs).
DRAINAGE AREA. The area from which water is carried off by a drainage system; a watershed or catchment area.
DRAINAGE EASEMENT. An authorized grant made by a property owner for use by another of any designated part of his or her property, and legally recorded, for the purpose of ensuring satisfactory present and future drainage of the property and the area surrounding the property.
DROP MANHOLE. 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 FACILITY. A facility designed to be completely dewatered after having provided its planned detention or runoff during a storm event.
DURATION. The time period of a rainfall event.
EASEMENT. A grant by a property owner for the use of a strip of land by the general public, a corporation or a certain person or persons for a specific purpose or purposes.
ENGINEER. See PROFESSIONAL ENGINEER.
EROSION. Wearing away of the land by running water and waves, abrasion, temperature changes, ice and wind.
EXTRATERRITORIAL JURISDICTION. Any area(s) outside of civil boundaries where a specified governmental body has the right to interpret and apply the law.
FARM or FIELD TILE. A subsurface pipe installed in an agricultural area to allow drainage of farmland.
FLOOD or FLOOD WATERS. A general and temporary condition of a partial or complete inundation of normally dry land areas from the overflow, the unusual and rapid accumulation or the runoff of surface waters from any source.
FLOOD BOUNDARY AND FLOODWAY MAP (FBFM). A map prepared by Federal Emergency Management Agency (FEMA) that depicts the FEMA designated floodways within a community. This map also includes the delineation of the 100-year and 500-year floodplain boundaries and the location of the flood insurance study cross-sections.
FLOOD CREST. The maximum stage or elevation reached or expected to be reached by the waters of a specified flood at a given location.
FLOOD DURATION. The length of time a stream is above flood stage or overflowing its banks.
FLOOD EASEMENT. Easement granted to identify areas inundated by the 100-year flood.
FLOOD ELEVATION. The elevation at all locations delineating the maximum level of high waters for a flood of given return period.
FLOOD FREQUENCY. A statistical expression of the average time period between floods equaling or exceeding a given magnitude. For example, a 100-year flood has a magnitude expected to be equaled or exceeded on the average once every 100 years; this flood has a 1% chance of being equaled or exceeded in any given year. Often used interchangeably with RECURRENCE INTERVAL.
FLOOD HAZARD BOUNDARY MAP (FHBM). A map prepared by the FEMA that depicts special flood hazard areas as a Zone A within a community. There are no study texts, base flood elevations or floodways associated with this map.
FLOOD INSURANCE RATE MAP (FIRM). A map prepared by FEMA that depicts special flood hazard areas within a community. This map also includes the 100-year or base flood elevation at various locations along the watercourses. More recent versions of the FIRM may also show the FEMA designated floodway boundaries and the location on the flood insurance study cross-sections.
FLOOD INSURANCE STUDY (FIS). A study prepared by FEMA to assist a community participating in the National Flood Insurance Program in its application of the program regulations. The STUDY consists of a text which contains community background information with respect to flooding, a floodway data table, summary of flood discharges, flood profiles, a flood insurance rate map and a flood boundary and floodway map.
FLOODPLAIN. The channel proper and the areas adjoining the channel which have been or hereafter may be covered by the regulatory or 100-year flood. Any normally dry land areas that is suspectable to being inundated by water from any natural source. The FLOODPLAIN includes both the floodway and the floodway fringe districts.
FLOODPLAIN MANAGEMENT. The operation of a program of corrective and preventive measures for reducing flood damage, including but not limited to flood control projects, floodplain land use regulations, floodproofing of buildings and emergency preparedness plans.
FLOODPLAIN REGULATIONS. General term applied to the full range of codes, ordinances and other regulations relating to the use of land and construction within floodplain limits. The term encompasses zoning ordinances, subdivision regulations, building and housing codes, encroachment laws and open area (space) regulations.
FLOOD PROFILE. A graph showing the relationship of water surface elevation to a specific location, the latter generally expressed as distance above the mouth of the stream of water flowing in an open channel. It is generally drawn to show surface elevation for the crest of a specific magnitude of flooding, but may be prepared for conditions at any given time or stage.
FLOOD PROTECTION GRADE (FPG). The elevation of the regulatory or 100-year flood plus 2 feet at any given location in the special flood hazard area or 100-year floodplain.
FLOODWAY. The channel of a river or stream and those portions of the floodplains adjoining the channel which are reasonably required to efficiently carry and discharge the peak flow of the regulatory flood of any river or stream.
FLOODWAY FRINGE. That portion of the floodplain 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 ground water elevation.
FREEBOARD. An increment of height added to the base flood elevation to provide a factor of safety for uncertainties in calculations, unknown local conditions, wave actions and unpredictable efforts such as those caused by ice or debris jams. See FLOOD PROTECTION GRADE.
FRENCH DRAIN. A drainage trench backfilled with a coarse, water-transmitting material; may contain a perforated pipe.
GABION. An erosion control structure usually consisting of wire cage filled with rocks.
GRADE. The inclination or slope of a channel, canal, conduit or the like or natural ground surface usually expressed in terms of the percentage the vertical rise (or fall) bears to the corresponding horizontal distance.
HYDRAULIC GRADE LINE (HGL). The open channel flow, the HGL is equal to the water surface elevation, whereas for pressure flow it is the level to which water will rise in a pipe due to its own pressure.
HYDRODYNAMIC LOADS. Forces imposed on structures by floodwaters due to the impact of moving water on the upstream side of the structures, drag along its sides and eddies or negative pressure on its downstream side.
HYDROGRAPH. For a given point on a stream, drainage basin or a lake, a graph showing either the discharge, stage (depth), velocity or volume of water with respect to time.
HYDROLOGY. The science of the behavior of water, its dynamics, composition and distribution in the atmosphere, on the surface of the earth and underground. A typical hydrologic study is undertaken to compute flow rates associated with specified flood events.
IMPERVIOUS SURFACE. Any hard-surfaced, human-made area that does not readily absorb or retain water, including but not limited to building roofs, parking and driveway areas, compacted graveled areas, sidewalks and paved recreation areas.
INFILTRATION. Passage or movement of water into the soil.
INFILTRATION SWALES. A depressed earthen area that is designed to promote infiltration.
INLET. An opening into a storm sewer system for the entrance of surface stormwater runoff, more completely described as a storm sewer inlet.
INVERT ELEVATION. The elevation at the inside bottom of a culvert or other conduit.
JUNCTION CHAMBER. A converging section of conduit, usually large enough for a person to enter, used to facilitate the flow from 1 or more conduits into a main conduit.
LAND SURVEYOR. A person licensed under the laws of the State of Indiana to practice land surveying.
LATERAL STORM SEWER. A storm sewer that has an inlet at its upstream end and empties into another storm sewer or facility.
LETTER OF MAP AMENDMENT (LOMA). A letter from FEMA removing an existing structure or a legally defined parcel of land unaltered by fill from a special flood hazard area.
LETTER OF MAP REVISION (LOMR). A letter from FEMA officially revising the current National Flood Insurance Program map to show changes to floodplains, floodways or flood elevations. LOMR's typically depict decreased flood hazards.
LOW ENTRY ELEVATION. The elevation in a structure where overbank flooding can enter the structure.
LOWEST ADJACENT GRADE. The absolute lowest grade around the outside of a structure, taking into account patios and support posts for decks or porches.
LOWEST FLOOR. Refers to the lowest of the following:
(a) The top of the basement floor;
(b) The top of the garage floor, if the garage is the lowest level of the building;
(c) The top of the first floor of buildings construction on a slab or of buildings elevated on pilings or construction on a crawl space with permanent openings; or
(d) The top of the floor level of any enclosure below an elevated building where the walls of the enclosure provide any resistance to the flow or flood waters unless:
1. The walls are designed to automatically equalize the hydrostatic flood forces on the walls by allowing for the entry and exit of flood waters, by providing a minimum of 2 openings (in addition to doorways and windows) having a total area of 1 square foot for every 2 square feet of enclosed area subject to flooding. The bottom of all openings shall be no higher than 1 foot above grade; or
2. The enclosed space shall be usable only for the parking of vehicles or building access.
MAJOR DRAINAGE SYSTEM. Drainage system carrying runoff from drainage area of 1 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.
MANNING ROUGHNESS COEFFICIENT or MANNING'S "N" VALUE. A dimension less coefficient ("n") used in the Manning's equation to account for channel wall frictional losses in steady uniform flow.
MINOR DRAINAGE SYSTEM. Drainage system carrying runoff from a drainage area less than 1 square mile.
NATIONAL FLOOD INSURANCE PROGRAM (NFIP). A federal program enabling property owners to purchase flood insurance. FEMA administers the NFIP in communities throughout the United States. The NFIP is based on an agreement between local communities and the federal government which states that if a community will implement floodplain management measures to reduce future flood hazard areas, the federal government will make flood insurance available within the community as a financial protection against flood losses that do occur.
NATIONAL GEODETIC VERTICAL DATUM OF 1929 (NGVD 1929). A nationwide federal elevation datum used to reference topographic elevations to a known value.
OFF-SITE. Everything not located at or within a particular site.
ON-SITE. Located within the developing property where runoff originates.
100-YEAR FREQUENCY FLOOD. The flood having a 1% probability of being equaled or exceeded in any given year.
OPEN CHANNEL. A conveyance in which the liquid stream is not completely enclosed by solid boundaries.
ORIFICE. A device which controls the rate of flow from a detention basin.
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.
OVERLAND FLOW. Consists of sheet flow, shallow concentrated flow and open channel flow.
PEAK FLOW. The maximum rate of flow of water at a given point in a channel or conduit resulting from a predetermined storm or flood.
PLANIMETRIC DATA. Horizontal measurements involving distances or dimensions on a diagram, map, plat of survey or topographic map. Normally given in units of feet or meters.
PLAT OF SURVEY. A scaled diagram showing boundaries of a tract of land or subdivision. This may constitute a legal description of the land and be used in lieu of a written description.
PRIVATE DRIVE. A private drive serves as the means of vehicular access to the public road or street system for not more than 1 residence or business.
PROFESSIONAL ENGINEER. A person licensed under the laws of the State of Indiana to practice professional engineering.
RAINFALL INTENSITY. The cumulative depth of rainfall occurring over a given duration, normally expressed in inches per hour. In the rational formula, this represents the average rainfall intensity over a duration equal to the time of concentration for the catchment.
REACH. Any length of stream, channel or storm sewer.
RECURRENCE INTERVAL. A statistical expression of the average time between floods equaling or exceeding a given magnitude.
REDEVELOPMENT. See the definition of DEVELOPMENT.
REGULATED AREA. All of the City of Brazil under the control of the Common Council.
REGULATED DRAIN. A drain, either open channel or closed tile/sewer, subject to the provisions of the Indiana Drainage Code, I.C. 36-9-27.
REGULATORY FLOOD. The discharge or elevation associated with the 100-year flood as calculated by a method and procedure which is acceptable to and approved by the IDNR and FEMA. The REGULATORY FLOOD is also known as the BASE FLOOD.
RELEASE RATE. The amount of stormwater released from a stormwater control facility per unit of time.
RESERVOIR. A natural or artificially created pond, lake or other space used for storage, regulation or control of water. The reservoir may be either permanent or temporary. The term is also used in the hydrologic modeling of storage facilities.
RETENTION FACILITY. A facility designed to completely retain a specified amount of stormwater runoff without release except by means of evaporation, infiltration or pumping. Volumes are often referred to in units of acre-feet.
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 1% probability of being equaled or exceeded in any 1 year.
RIGHT-OF-WAY. A strip of land appropriated for public use as a street, highway, driveway, alley or walkway or for any drainage or public utility purpose of other similar uses.
RIPRAP. Large rock that when installed along an erodible surface reduces the erosion and scour potential.
RIVERINE. Relating to, formed by or resembling a stream (including creeks and rivers).
RUNOFF. The waters derived from melting snow or rain falling within a tributary drainage basin that exceed the infiltration capacity of the soils of that basin, flow over the surface of the ground or are collected in channels or conduits.
RUNOFF COEFFICIENT. A decimal fraction relating the amount of rain which appears as runoff and reaches the storm sewer 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.
SANITARY BACKUP. The condition where a sanitary sewer reaches capacity and surcharges into the lowest available area.
SCOUR. The clearing and digging action of flowing water.
SEDIMENT. Material of soil and rock origin, transported, carried or deposited by water.
SEDIMENTATION. The process that deposits soil, debris and other materials either on the ground surfaces or in bodies or water or watercourses.
SEEPAGE. The passage of water or other fluid through a porous medium, such as the passage of water through an earth embankment or masonry wall.
SILT SCREEN FENCE. A fence constructed of wood or steel supports and either natural (e.g. burlap) or synthetic fabric stretched across area of flow during site development to trap and retain on-site sediment due to rainfall runoff.
SIPHON. A closed conduit or portion of 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 affect 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.
SPECIAL FLOOD HAZARD AREA (SFHA). Those lands within the jurisdiction of a community which are subject to inundation by the regulatory or 100-year flood. SPECIAL FLOOD HAZARD AREAS are usually designated on a flood hazard boundary map as Zone A. After detailed evaluation of local flooding characteristics, the flood insurance rate map will refine this categorization into Zones A, AE, AH, AO and A1-30.
SPILLWAY. A waterway in or about a hydraulic structure designed for the escape of excess water.
STORM 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 DURATION may also refer to the length of a qualified rainfall event (1/2-hour, 1-hour or 24-hour storms, for example).
STORM SEWER. A closed conduit for conveying collected stormwaters.
STORMWATER FACILITY. All ditches, channels, conduits, levees, ponds, natural or human-made impoundments, wetlands, tiles, swales, sewers and other natural or artificial means of draining surface and subsurface water from land.
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.
STREET. The space or area between the lot lines, abutting upon a right-of-way and designed as a way for vehicular traffic whether designated as an alley, street, highway, throughway, freeway, expressway, road, avenue, boulevard, lane, place or however otherwise designated and which shall include but not be limited to those illustrated in the comprehensive plan for the City of Brazil. For the purpose of this subchapter, STREET shall be classified as follows.
ALLEY. A minor way which is used primarily for vehicular service access to the back or side of properties otherwise abutting on a street.
ARTERIALS. Those federal, state and county roads of regional importance. These are high capacity highways moving traffic at fast rates of speed. They provide good continuity between distant points and are constructed to high standards. ARTERIAL HIGHWAYS provide 2 to 4 traffic lanes and should have a median strip wherever possible. Crossing traffic from other roads and access to abutting properties are often controlled, or partially so.
CUL-DE-SAC STREET. A local road with only 1 outlet, having a paved, circular, turn-around at the closed end.
FREEWAYS. Limited-access highways which carry large volumes of interstate traffic and have more importance regionally than locally. They often contain 4 or more moving lanes and permit a continuous high speed traffic flow. These highways have a high order of design and construction requirements.
LOCAL ROADS. Low capacity and low speed roads whose function is to provide direct access to homes and property. Through traffic and heavy use of these roads should be discouraged. To the extent possible, residence driveways and ingress and egress points to other uses or structures should be oriented to the local roads rather than to the arterials or collectors.
LOCAL SUBDIVISION STREETS. Low capacity and low speed streets within major subdivisions whose function is to provide direct access to homes and property. Through traffic and heavy use of these streets should be discouraged.
MAJOR COLLECTOR HIGHWAYS. Have less regional importance than the arterial highways and more county or inter-county significance. They are medium-capacity highways moving traffic at relatively fast rates of speed. They include both state designated routes and county roads. MAJOR COLLECTOR HIGHWAYS provide 2 traffic lanes.
MARGINAL ACCESS STREETS. Local roads which are parallel to and adjacent to arterial streets and highways, and which provide access to abutting properties and protection from through traffic.
MINOR COLLECTOR ROADS. Moderate capacity thoroughfares designed to accommodate relatively low speed traffic. They should, however, provide a smooth flow of traffic. Two moving lanes, unseparated, but wider than local road lanes are required.
STRUCTURE. Refers to a structure that is principally above ground and is enclosed by walls and a roof. The term includes a gas or liquid storage tank, a manufactured home or a prefabricated building. The term also includes recreational vehicles to be installed on a site for more than 180 days.
STRUCTURAL ENGINEER. A person licensed under the laws of the State of Indiana to engage in the designing or supervising of construction, enlargement or alteration of structures or any part thereof, for others, to be constructed by persons other than himself or herself.
STRUCTURAL FLOODPLAIN MANAGEMENT MEASURES. Those physically or engineering measures employed to modify the ways floods behave, e.g. dams, dikes, levees, channel enlargements or diversions.
SUBAREA/SUBBASIN. Portion of a watershed divided into homogenous drainage units which can be modeled for purposes of determining runoff rates. The SUBAREAS/SUBBASINS have distinct boundaries, as defined by the topography of the area.
SUMP PUMP. A small pump that discharges seepage from foundation footing drains.
SURCHARGE. Backup of water sanitary or storm sewer system in excess of the design capacity of the system.
TAILWATER. The water surface elevation at the downstream side of a hydraulic structure (ie. culvert, bridge, weir, dam or the like).
THALWEG. The deepest point of an open channel.
TIME OF CONCENTRATION (TC). The travel time of a particle of water from the most hydraulically remote point in the contributing area to the point under study. This can be considered the sum of an overland flow time and times of travel in street gutters, storm sewers, drainage channels and all other drainage ways.
TOPOGRAPHIC MAP. Graphical portrayal of the topographic features of a land area, showing both the horizontal distances between the features and their elevations above a given datum.
TOPOGRAPHY. The representation of a portion of the earth's surface showing natural and human-made features of a given locality such as rivers, streams, ditches, lakes, roads, buildings and most importantly, variations in ground elevations for the terrain of the area.
TRIBUTARY. Based on the size of the contributing drainage area, a smaller watercourse which flows into a larger watercourse.
UNDERDRAIN. A small-diameter perforated pipe that allows the bottom of a detention basin, channel, swale or street to drain.
WATERCOURSE. Any river, stream, creek, brook, branch, natural or human-made drainage way in or into which stormwater runoff or floodwaters flow.
WATERSHED. The land area drained by contributing water to a specific point that could be along a stream, lake or other stormwater facilities. Watersheds are often broken down into subareas for the purpose of hydrologic modeling.
WATERSHED AREA. The total area from which surface runoff is carried away by a drainage system.
WEIR. A device which is used to restrict the flow of water thereby limiting the discharge rates. A WEIR can also facilitate calculation of measurement of the discharge rates. These are often used to control the rate of flow out of stormwater storage facilities.
WET- BOTTOM RETENTION FACILITY. A facility designed to retain a permanent pool of water after having provided its planned detention of runoff during a storm event.
WETLANDS. Areas that are inundated or saturated by surface water or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions and/or those wetland areas that are under the COE jurisdiction.
(Ord. 01-2000, passed 7-18-2000)