11-18-020 Definitions.
   For the purposes of this chapter, unless the context requires otherwise, the following terms, regardless of whether or not they are capitalized, shall have the definitions set forth below:
   Applicant. A person applying for a Stormwater Management Plan approval or an amendment thereto or variance therefrom. An Applicant must be the Owner or Developer of the Regulated Development specified in the Plan.
   Average Dry-Weather Flow. Non-stormwater flow that consists of either (a) sanitary flow as quantified in 35 Ill. Admin. Code, Subtitle C, Chapter II, Part 370, Appendix B ("Table Number 2 – Commonly Used Quantities of Sewage Flows From Miscellaneous Type Facilities"), as amended, or (b) industrial process water flow as quantified by determining the cubic feet per second released during the average of seven consecutive 24-hour periods.
   Best Management Practice (BMP). A measure approved by the commissioner and used to control the adverse stormwater-related effects of development.
   Building commissioner. The commissioner of buildings or his designee.
   Commissioner. The commissioner of water management or his designee.
   Developer. Any person who manages, organizes, oversees, plans or supervises the creation of a Regulated Development.
   Drainage Area. Any location from which or through which stormwater moves to a drainage system.
   Existing Conditions. The condition of a site in the ten years prior to the date of a Plan submission, as shown on historical aerial photographs or other verifiable documentation. If a site has been demolished and/or cleared within such ten-year period, its conditions prior to such demolition and/or clearing may be used as a basis for existing conditions.
   Impervious Surface. A surface which substantially precludes the infiltration of water, such as concrete, asphalt, tile or compacted gravel.
   Infiltration. The passage, movement or percolation of water into and through soil surfaces, including soil surfaces on roofs and in landscaped areas.
   Maintenance Activity. In-kind replacement, restoration, or repair of existing infrastructure, pavement, or facilities including, but not limited to, roadways, parking lots and overhead utilities, provided they will perform the same function for which they were originally designed and constructed.
   Owner. The owner, manager, agent or other person in charge, possession or control of a Regulated Development or any part thereof.
   Plan. The Stormwater Management Plan required by this chapter.
   Regulated Development or Development. Any construction activity, excavation or grading, commencing on or after January 1, 2008, that:
      (a)   disturbs a land area or substantially contiguous land areas of 15,000 or more square feet in the aggregate. Land areas separated by public right-of- way at the conclusion of development shall not be deemed "substantially contiguous" to each other for purposes of this definition. For purposes of calculating square footage pursuant to this paragraph (a), "land area" shall include twenty-five percent of the square footage of the sidewalls of a building that directly connects to the sewer system via side gutters, and shall also include any average dry-weather flow based on a conversion rate of 1.0 cfs (cubic feet per second) into one acre (43,560 square feet), or
      (b)   creates an at-grade impervious surface of 7,500 or more substantially contiguous square feet, or
      (c)   results in any discharges of stormwater into any waters or separate sewer system.
   For purposes of this definition, square footage shall be calculated based upon the project as a whole, regardless of whether construction proceeds in phases. A Regulated Development shall not include projects located entirely within the public right-of-way at the conclusion of development. With respect to a project located both on the public right-of-way and on private property at the conclusion of development, that portion of the project located on the public right-of-way will not be included in calculating the square footage thresholds of subparagraphs (a) and (b) of this definition. If a project includes Residential Development, the Residential Development will not be included in calculating the square footage thresholds of subparagraphs (a) and (b) of this definition.
   Residential Development. A Regulated Development, or portion thereof, which upon completion will result in the subdivision of land into detached single-family or two-family dwellings.
   Runoff. The water derived from precipitation falling onto a Regulated Development which is in excess of the infiltration capacity of the soils of that Development, which flows over the surface of the ground or is collected in any watercourse.
   Stormwater. Water derived from any form of precipitation.
   Stormwater Drainage System. Any and all natural and artificial means used in combination to conduct stormwater to, through, or from a Drainage Area to the point of infiltration or final outlet from a Regulated Development. A Stormwater Drainage System includes, but is not limited to, any of the following: conduits and appurtenance features, canals, channels, ditches, streams, culverts, streets, storm sewers, detention basins, swales, vegetated areas and pumping stations.
   Stormwater Management Plan. A detailed formulation of a program of action which describes a proposed or existing Stormwater Drainage System and environmental features applicable to a Regulated Development. The Plan shall include programs for grading and drainage, operations and maintenance, and soil, sediment and erosion control. These programs shall consist of written documentation, scaled maps and drawings with supporting engineering calculations.
   Watercourse. Any channel, natural or artificial, lined or unlined, through which water flows or may flow.
   Waters. All watercourses and all lakes, ponds, wetlands and other bodies of water, whether natural or artificial, that are located wholly or partly within or adjoining the territorial boundaries of the City.
(Added Coun. J. 12-13-06, p. 95586, § 1; Amend Coun. J. 11-8-12, p. 38872, § 208; Amend Coun. J. 12-14-22, p. 58278, Art. VII, § 6)