For the purpose of this chapter certain terms and words shall be used, interpreted and defined as set forth in this section. Unless the context clearly indicates to the contrary, words used in the present tense include the future tense; words used in the singular shall include the plural, and vice-versa; the words, "these regulations", means "this chapter"; the word, "person", includes corporation, partnership, and unincorporated association of persons; and the word "shall" is always mandatory.
(1) "100 year storm" means rainstorms of a specific duration having a one percent (1%) chance of occurrence in any given year.
(2) "10 year storm" means that the calculated flows will occur on the average of no more than once every ten years. Since this is an average occurrence, it may be possible that higher flows occur several times in any ten-year period and then not occur again for many years.
(3) "Base flood" means the flood having a one percent (1%) chance of being equalled or exceeded in any given year, that is the 100 year flood.
(4) "By-pass channel" means a channel formed in the topography of the earth's surface to carry stormwater runoff through a specific area.
(5) "Channel" means a water course of perceptible extent which periodically or continuously contains moving water, or which forms a connecting link between two bodies of water, and which has a definite bed and banks.
(6) "Common use" means a storm sewer or ditch or swale which has been in use for over twenty-one years or is located in a street right of way or is encumbered by a recent easement for stormwater purposes.
(7) "Culvert" means any transverse drain under a road, driveway, bridge or other means of access to the travelled portion of a highway.
(8) "Control structure" means a structure designed to control the volume of stormwater runoff that passes through it during a specific length of time.
(9) "Detention basins" means any man-made area which serves as a means of controlling and temporarily storing stormwater runoff.
(10) "Detention storage" means the temporary detaining or storage of stormwater in reservoirs, on rooftops, on parking lots and other areas under predetermined and controlled conditions.
(11) "Development" means any change of land use or improvement of any parcel of land.
(12) "Differential runoff" means the volume and rate of flow of drainage area which is or will be greater than that volume and rate which pertained prior to proposed development or redevelopment.
(13) "Downhill" means drainage to a lower area.
(14) "Drainage system" means a network consisting of any combination of type of open channels, holding basins and enclosed facilities employed to convey the runoff of natural waters.
(15) "Dry bottom stormwater storage area" means a facility that is designed to be normally dry and contains water only when excess stormwater runoff occurs.
(16) "Easement" means authorization by a property owner for use by another party or parties of all or any portion of his/her land for a specified purpose.
A. "Easement for mutual benefit" means a storm sewer easement maintained by the property owner for flow of stormwater over owner's property to the benefit of uphill property owners.
(17) "Enclosed drainage system" means a network of artificial conduits and pipe constructed to convey the runoff of natural waters.
(18) "Encroachment limit" means the boundary of a maintenance way easement adjacent to a drainage channel within which no building or structure shall be erected or trees, bushes or other plantings planted which shall interfere with the maintenance of the drainage channel.
(19) "Excess stormwater" means that portion of stormwater runoff which exceeds the transportation capacity of storm sewers or natural drainage channels serving a specific watershed.
(20) "Factor of one" means a calculation to indicate that the stormwater runoff before a project development is to remain the same after development.
(21) "Floodplain" mean a land area adjoining a river, stream, watercourse, or lake which is likely to be flooded.
(22) "Floodway" means the channel of a river or other watercourse and the adjacent land areas that shall be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
(23) "Freeboard" means a factor of safety expressed as the difference in elevation between the top of the detention basin dam and the design surface water flow elevation.
(24) "Grade" means the slope of land around a building.
(25) "Habitable dwelling unit" means a dwelling unit intended for suitable human habitation.
(26) "Natural drainage" means channels formed by the existing surface topography of the earth prior to changes made by unnatural causes.
(27) "100 year peak flow" means the peak rate of flow of water at a given point in a channel, watercourse or conduit resulting from the base flood.
(28) "Open drainage system" means a network of natural streams, constructed channels, ditches and detention-retention areas employed to convey and control the runoff of natural waters.
(29) "Plat" means a legally recorded plan of a parcel of land subdivided into lots with streets, alleys and other land lines drawn to scale.
(30) "Positive gravity outlet" means a term used to described the drainage of an area by means of natural gravity so that it lowers the free water surface to a point below the existing grade or invert of storm drains within the area.
(31) "Project" means any development involving the construction, reconstruction or improvement of structures and/or grounds.
(32) "Public right of way" means any public passage, street, boulevard, road or alley.
(33) "Person" means any individual, firm, partnership, association, corporation, company or organization of any kind.
(34) "Public ditch or storm sewer" means a storm sewer or ditch which has been in use for the general public for over twenty-one years or is within a public street right of way or is encumbered by a recent easement for stormwater purpose.
(35) "Rational method" means an empirical formula for calculating peak rates of runoff resulting from rainfall.
(36) "Recognized agency" means an agency or governmental unit that has statistically and consistently examined local, climatic and geologic conditions and maintained records as they apply to stormwater runoff.
(37) "Safe storm drainage capacity" means the quantity of stormwater runoff that can be transported by a channel or conduit without having the water surface rise above the level of the earth's surface over the conduit or adjacent to the waterway.
(38) "Site" means a parcel of land under one ownership.
(39) "Slope" means the grade of the land around a building over which water will flow.
(40) "Stormwater runoff" means water that results from precipitation which is not absorbed by the soil, evaporated into the atmosphere, or entrapped by ground surface depressions and vegetation, and which flows over the ground surface.
(41) "Stormwater runoff release rate" means the rate at which stormwater runoff is released from dominant to servient land.
(42) "Stormwater storage area" means areas designated to store excess stormwater.
(43) "Structure" means any object constructed above or below ground.
(44) "Tributary area" means all of the area that contributes stormwater runoff to a given point.
(45) "The primary system" means the system composed of the regulatory floodplain as shown on the National Flood Insurance Program maps.
(46) "The secondary system" means the system composed of all watercourses and drainage structures, both public and private, that are not mapped as part of the primary system.
(47) "Uphill" means drainage from a higher area.
(48) "Wet bottom basin" means a detention basin intended to have a permanent pool.
(49) "Watercourse" means any surface stream, creek, brook, branch, depression, reservoir, lake, pond or drainageway in or into which stormwater runoff flows.
(50) "Yard" means the area around a building; front, side and rear.