A. “Development” means any alteration by grading or filling of the ground surface, or by construction of any improvement or other impervious surface area that affects the hydraulic properties of any parcel of land.

B. “Impervious surface unit” means a configuration or conglomeration of impervious surface estimated to contribute an amount of runoff to the city’s storm water management system which is approximately equal to that created by the average single-family residential parcel. One impervious surface unit (ISU) is equivalent to 2,000 square feet of impervious surface area. For purposes of computation of the charges provided for in this chapter, impervious units are truncated (rounded down) to the nearest tenth.

C. “New impervious surface” means the creation of a nonvegetated surface such as roofs, pavement, gravel or dirt or the addition of a more compacted surface such as the paving of existing dirt or gravel.

D. “Regional storm water facilities” or “regional system” means public conveyance, detention, infiltration, and/or water quality facilities designed to manage storm water runoff from specific areas of the city to meet the city’s water quality goals, and to support new development in a cost effective manner. Properties being developed may have the option to or be required to participate in the financing of the facilities, and in return requirements for on-site controls are eliminated or reduced. Proposed facilities are shown on the proposed regional storm water facilities map in the clearing, grading, and storm water management technical notebook.

E. “Replaced impervious surface” means: (1) for structures, the removal and replacement of any exterior impervious surfaces or foundations; and (2) for other impervious surfaces, the removal down to bare soil or base course and replacement. (Ord. 2200 § 2 (Exh. B), 2016; Ord. 2082 § 1, 2011).