“Basin” shall mean an area from which surface runoff is concentrated, usually to a single point such as the mouth of a stream.

“Best management practice” or “BMP” shall mean the schedules of activities, prohibitions of practices, maintenance procedures, and structural and/or management practices approved by Ecology that, when used singly or in combination, prevent or reduce the release of pollutants and other adverse impacts to waters of Washington. BMPs are listed and described in the Gig Harbor stormwater management and site development manual, most recent version.

“Development” shall mean any manmade change to improved or unimproved real estate including, but not limited to, buildings or other structures, placement of manufactured home/mobile home, mining, dredging, clearing, filling, grading, paving, excavation, drilling operations, or the subdivision of property. See also the definitions for redevelopment and land disturbing activity.

“Erosion” shall mean the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep. Also, detachment and movement of soil or rock fragments by water, wind, ice, or gravity.

“Land disturbing activity” shall mean any activity that results in a movement of earth or a change in the existing soil cover (both vegetative and nonvegetative) and/or the existing soil topography. Land disturbing activities include but are not limited to clearing, grading, filling, and excavation. Compaction that is associated with stabilization of structures and road construction shall also be considered a land disturbing activity. Vegetation maintenance practices are not considered land disturbing activity. Stormwater facility maintenance is not considered land disturbing activity if conducted according to established standards and procedures.

“Municipal separate storm sewer system (MS4)” or “stormwater drainage system” means the system of conveyances including sidewalks, roads with drainage systems, municipal streets, catchbasins, curbs, gutters, ditches, manmade channels, or storm drains owned and operated by the city and designed or used for collecting or conveying stormwater.

“Redevelopment” shall mean, where a site that is already substantially developed (i.e., has 35 percent or more of existing impermeable surface coverage), the creation or addition of impermeable surfaces; the expansion of a building footprint or addition or replacement of a structure; structural development including construction, installation or expansion of a building or other structure; replacement of impermeable surface that is not part of a routine maintenance activity; and land disturbing activities.

“Stormwater” shall mean that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes and other features of a stormwater drainage system into a defined surface water body, or a constructed infiltration facility.

“Stormwater facility” shall mean a constructed component of a stormwater drainage system, designed or constructed to perform a particular function, or multiple functions. Stormwater facilities include, but are not limited to, pipes, swales, ditches, culverts, street gutters, detention ponds, retention ponds, constructed wetlands, infiltration devices, catch basins, oil/water separators, and biofiltration swales. (Ord. 1347 § 1, 2016; Ord. 1169 § 2, 2009).