For the purposes of this chapter, the following definitions shall apply:
means proposed or completed work conforms to this chapter in the opinion of the director.
means a physical, structural, and/or managerial practice that, when used singly or in combination, prevents or reduces pollution of water. BMPs are listed and described in the manual.
means destruction or removal of vegetation by manual, mechanical or chemical methods.
means activities conducted on lands defined in RCW 84.34.020(2) and activities involved in the production of crops or livestock for wholesale trade. An activity ceases to be considered commercial agriculture when the area on which it is conducted is proposed for conversion to a nonagricultural use or has lain idle for more than five years, unless the idle land is registered in a federal or state soils conservation program, or unless the activity is maintenance of irrigation ditches, laterals, canals, or drainage ditches related to an existing and ongoing agricultural activity.
means the release of stormwater runoff from the site at a slower rate than it is collected by the stormwater facility system, the difference being held in temporary storage.
means an above or below ground facility, such as a pond or tank, that temporarily stores stormwater runoff and subsequently releases it at a slower rate than it is collected by the drainage facility system. There is little or no infiltration of stored stormwater.
means the city public works director or his or her designee.
means any rock, natural soil or fill and/or any combination thereof.
means the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep. Detachment and movement of soil or rock fragments by water, wind, ice, or gravity.
means the mechanical removal of earth material.
means a BMP that has not been approved through a process of using an approved testing protocol.
means a deposit of earth material placed by artificial means.
means any activity conducted on or directly pertaining to forest land and relating to growing, harvesting or processing timber, including but not limited to road and trail construction; harvesting, final and intermediate; precommercial thinning; reforestation; fertilization; prevention and suppression of diseases and insects; salvage of trees and brush control.
means water in a saturated zone or stratum beneath the surface of land or a water body.
means all nonstormwater discharges to stormwater drainage systems that cause or contribute to a violation of state water quality, sediment quality or groundwater quality standards, including but not limited to sanitary sewer connections, industrial process water, interior floor drains and gray water systems.
means a hard surface area which either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development, and/or a hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to, roof tops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled, macadam or other surfaces which similarly impede the natural infiltration of stormwater. Open, uncovered retention/detention facilities shall not be considered as impervious surfaces.
means that portion of precipitation that infiltrates into the soil and moves laterally through the upper soil horizons until intercepted by a stream channel or until it returns to the surface via a wetland, spring or seep.
means any activity that results in 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, demolition, construction, clearing, grading, filling and excavation.
means a plan to implement BMPs to control pollution generated during land disturbing activity. Guidance for preparing a large parcel ESC plan is contained in the manual.
means the current edition of the King County Surface Water Design Manual, as adopted or hereafter amended by King County.
From first to last:
Avoid the impact altogether by not taking a certain action or part of an action;
Minimize impacts by limiting the degree or magnitude of the action and its implementation, by using appropriate technology, or by taking affirmative steps to avoid or reduce impacts;
Rectify the impact by repairing, rehabilitating or restoring the affected environment;
Reduce or eliminate the impact over time by preservation and maintenance operations during the life of the action; and
Compensate for the impact by replacing, enhancing, or providing substitute resources or environments.
means land disturbing activities; structural development, including construction, installation or expansion of a building or other structure; creation of impervious surfaces; Class IV – general forest practices that are conversions from timber land to other uses; and subdivision and short subdivision of land as defined in RCW 58.17.020. All other forest practices and commercial agriculture are not considered new development.
means any individual, partnership, corporation, association, organization, cooperative, public or municipal corporation, agency of the state, or local government unit, however designated.
means contamination or other alteration of the physical, chemical, or biological properties of waters of the state, including change in temperature, taste, color, turbidity, or odor of the waters, or such discharge of any liquid, gaseous, solid, radioactive or other substance into any waters of the state as will or is likely to create a nuisance or render such waters harmful, detrimental or injurious to the public health, safety or welfare, or to domestic, commercial, industrial, agricultural, recreational, or other legitimate beneficial uses, or to livestock, wild animals, birds, fish or other aquatic life.
means, on an already developed site, the creation or addition of impervious surfaces, structural development including construction, installation or expansion of a building or other structure, and/or replacement of impervious surface that is not part of a routine maintenance activity, and land disturbing activities associated with structural or impervious redevelopment.
means a portion of property that is directly subject to development.
means a plan for small sites to implement temporary BMPs to control pollution generated during the construction phase only, primarily erosion and sediment. Guidance for preparing a small parcel ESC plan is contained in the manual.
means unconsolidated mineral and organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants.
means a BMP that is intended to prevent pollutants from entering stormwater. Examples include erosion control practices, maintenance of stormwater facilities, roofing storage and working areas, and directing wash water and similar discharges to the sanitary sewer or a dead end sump.
means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows overland, via interflow, or through channels or pipes into a defined surface water channel or constructed infiltration facility.
means constructed and natural features which function together as a system to collect, convey, channel, hold, inhibit, retain, detain, infiltrate, divert, treat or filter stormwater.
means 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 basins, retention basins, constructed wetlands, infiltration devices, catch basins, oil/water separators, sediment basins and modular pavement.
means all organic plant life growing on the surface of the earth.
means surface waters including rivers, streams, lakes, marine waters, estuaries and wetlands.
means a geographic region within which water drains to a particular river, stream or body of water as identified and numbered by the State of Washington Water Resource Inventory Areas (WRIAs) as defined in Chapter 173-500 WAC.
means areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas, and areas created, restored or enhanced as part of a mitigation procedure. Constructed wetlands or the following surface waters of the state intentionally constructed from sites that are not wetlands are not included: irrigation and drainage ditches, grass-lined swales, canals, agricultural detention facilities, farm ponds, and landscape amenities.
(Ord. 1118 § 2, 2001; Ord. 1577 § 1, 2016; Ord. 1666 § 14, 2018; Ord. 1809 § 4, 2024)