The following performance criteria shall be applicable to all stormwater management plans, unless otherwise provided for in this chapter:
(a) Water Quality. All stormwater runoff generated from a site shall be adequately treated before discharge. It will be presumed that a stormwater management system complies with this requirement if:
(1) It is sized to treat the prescribed water quality treatment volume from the site;
(2) Appropriate structural stormwater controls or nonstructural practices are selected, designed, constructed or preserved, and maintained; and,
(3) Runoff from hotspot land uses and activities identified by the City of Urbana are adequately treated and addressed through the use of appropriate structural stormwater controls, nonstructural practices and pollution prevention practices.
(b) Structural Stormwater Controls. All structural stormwater controls must be designed appropriately to meet their intended function. All structural stormwater controls must be documented through prior studies, literature reviews, or other means and receive approval from the City of Urbana before being included in the design of a stormwater management system. In addition, if hydrologic or
topographic conditions, or land use activities warrant greater control than that provided by the minimum control requirements, the City of Urbana may impose additional requirements deemed necessary to protect upstream and downstream properties and aquatic resources from damage due to increased volume, frequency, and rate of storm water runoff or increased nonpoint source pollution loads created on the site in question.
(c) Drainage System Guidelines. Stormwater conveyance facilities, which may include but are not limited to culverts, stormwater drainage pipes, catch basins, drop inlets, junction boxes, headwalls, gutter, swales, channels, ditches, and energy dissipaters shall be provided when necessary for the protection of public right-of-way and private properties adjoining project sites and/or public right-of-ways. Stormwater conveyance facilities that are designed to carry runoff from more that one parcel, existing or proposed, shall meet the following requirements:
(1) Methods to calculate stormwater flows shall be in accordance with Chapter 1163 Design Standards of the City of Urbana Codified Ordinances.
(2) All development items including culverts, pipe systems and open channel flow systems, etc. shall be designed in accordance with the Chapter 1167 Construction Standards and Drawings of the City of Urbana Codified Ordinances. (Ord. 4382. Passed 3-13-12.)