“Abandoned construction site” means a lot or group of lots, including subdivisions, building or buildings, or other development where work has ceased for any reason for a period of 90 days. Circumstances indicating abandonment of a construction site include, but are not limited to, failure to call for inspections, absence of workers, or removal of equipment and supplies. A valid permit or approval issued by the city does not alter the status of a construction site deemed abandoned.

“Applicant” means the individual, partnership, association, or corporation applying for a permit to do work under this chapter, including the property owner, and any employee, agent, consultant or contractor acting on behalf of the applicant, and any successor in interest.

“Best management practices (BMPs)” are the schedules of activities, prohibitions of practices, maintenance procedures, and structural and/or managerial practices that, when used singly or in combination, prevent or reduce the release of pollutants and other adverse impacts to the city’s storm and surface water system or receiving waters.

“Building site” shall have the meaning set forth in Chapter 20.50 LUC, now or as hereafter amended.

“Certified erosion and sediment control lead (CESCL)” means an individual who has current certification through an approved erosion and sediment control training program that meets the minimum training standards established by Ecology (see BMP C160 in the Ecology Manual). A CESCL is knowledgeable in the principles and practices of erosion and sediment control. The CESCL must have the skills to assess site conditions and construction activities that could impact the quality of stormwater and the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. Certification is obtained through Ecology’s approved erosion and sediment control course. Course listings are provided online at Ecology’s website.

“Clearing” means the act of destroying or removing the existing soil cover (both vegetative and nonvegetative).

“Clearing and grading development standards” means city of Bellevue clearing and grading development standards that contain appropriate engineering standards and include relevant provisions of Chapters 3 and 4 of Volume II of the Ecology Manual.

“Clearing and grading permit” means the written permission of the director to the permittee to proceed with the act of clearing and grading within the provisions of this chapter. The clearing and grading permit includes the associated approved plans and any conditions of approval as well as the permit form itself.

“Construction stormwater pollution prevention plan (CSWPPP)” means a written plan to implement measures to identify, prevent, and control the contamination of point source discharge of stormwater. The CSWPPP explains and illustrates the measures, usually in the form of best management practices (BMPs), to take on a construction site to control potential pollution problems.

“Critical area” shall have the same meaning set forth in Chapter 20.50 LUC, now or as hereafter amended.

“CSWPPP” means Construction Stormwater Pollution Prevention Plan.

“Director” means the director of the development services department or his/her designee or other person designated by the city manager.

“Discharge” means the addition of stormwater, runoff, or pollutants into either the storm and surface water system or receiving waters.

“Ecology” means the Washington State Department of Ecology.

“Ecology Manual” means the 2012 Stormwater Management Manual for Western Washington, as amended in December 2014.

“Engineered fill” means soil fill which is wetted or dried to near its optimum moisture content, placed in lifts of 12 inches or less and each lift compacted to a minimum percent compaction as specified by a geotechnical engineer.

“Excavation” means the removal of material such as earth, soil, sand, peat, gravel, rock, asphalt, or concrete.

“Fill” means earth, soil, sand, peat, gravel, rock, asphalt, concrete, or other solid material used above or below the ordinary high water mark to increase the ground surface elevation or to replace excavated material.

“Filling” means any act by which fill is deposited or placed.

“Geotechnical engineer” means a professional engineer currently registered in the state of Washington, qualified by reason of experience and education in the practice of geotechnical engineering, and designated by the owner as the geotechnical engineer of record for the project.

“Grading” means any excavating or filling or combination thereof.

“Ground water” means water in a saturated zone or stratum beneath the surface of the land or below a surface water body.

“Hard surface” means an impervious surface, a permeable pavement, or a vegetated roof.

“Heavy rain” means rainfall at a rate greater than or equal to 0.03 inches per six minutes or 0.30 inches per hour.

“Impervious surface” means a nonvegetated surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development. It is also a nonvegetated 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, rooftops, 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 for purposes of determining whether the thresholds for application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered impervious surfaces for purposes of runoff modeling.

“Land disturbing activity” 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, clearing, grading, filling, and excavation. Compaction that is associated with stabilization of structures and road construction shall also be considered a land disturbing activity. Maintenance of existing landscape, as described in LUC 20.25H.055(C), is not considered a land disturbing activity.

“Landscaping” or “landscaped areas” means land that has been modified by altering soil levels and/or vegetation for aesthetic or practical purposes.

“Landslide” means the movement of a mass of rocks and/or earth down a slope.

“Landslide deposit” means a large mass of earth and/or rock that has moved physically downslope by gravity and broken into discrete fragments.

“LID” means low impact development.

“Low impact development (LID)” means a stormwater and land use management strategy that strives to mimic pre-disturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration by emphasizing conservation, use of on-site natural features, the planning, and distributed stormwater management practices that are integrated into a project design.

“Low impact development (LID) best management practices” means distributed stormwater management practices, integrated into a project design, that emphasize pre-disturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration. LID BMPs include, but are not limited to, bioretention/rain gardens, permeable pavements, roof downspout controls, dispersion, soil quality and depth, vegetated roofs, minimum excavation foundations, and water re-use.

“Minimum requirements (MRs)” refer to the regulations contained in BCC 23.76.090 and 24.06.065, now or as hereafter amended, and applicable development and engineering standards, which describe requirements for stormwater management for development and redevelopment as required by the NPDES permit.

“Modular block wall” means a wall constructed of manufactured modular wall units acting as a protective facing for an exposed soil face or as a gravity retaining wall.

“New development” means land disturbing activities, including Class IV – general forest practices that are conversions from timber land to other uses; structural development, including construction or installation of a building or other structure; creation of hard surfaces; and subdivision, short subdivision and binding site plans, as defined and applied in Chapter 58.17 RCW, now or as hereafter amended. Projects meeting the definition of redevelopment shall not be considered new development.

“NPDES” means National Pollutant Discharge Elimination System.

“NPDES permit” means an authorization, license, or equivalent control document issued by either the United States Environmental Protection Agency or authorized state authority, which in Washington is the Department of Ecology, to authorize point source discharges to surface waters and implement the provisions of 33 U.S.C. 1342 (Section 402) of the federal Clean Water Act.

“Peak volumetric stream flow” means the maximum instantaneous rate of flow, expressed in terms of volume per unit of time, during a storm.

“Permanent erosion control” means permanent improvements, such as landscaping or drainage control structures, that cover the soil such that erosion is minimized or eliminated.

“Permeable pavement” means pervious concrete, porous asphalt, permeable pavers or other forms of pervious or porous paving material intended to allow passage of water through the pavement section. It often includes an aggregate base that provides structural support and acts as a stormwater reservoir.

“Permit,” unless noted otherwise, refers to the clearing and grading permit; see “clearing and grading permit.”

“Permittee” means the property owner to whom the clearing and grading permit is issued. The property owner may be a person(s), partnership, association, or corporation. Both the property owner and its agent are considered the permittee and are responsible for ensuring compliance with this chapter.

“Potential slide block (failure envelope)” means the area near the surface of a slope between the toe of the slope and a line drawn upward at two feet horizontal to one foot vertical from the toe to the surface of the ground above the slope, or as otherwise determined by a geotechnical engineer.

“Rain garden” means a nonengineered shallow landscaped depression with compost-amended native soils and adapted plants. The depression is designed to pond and temporarily store stormwater runoff from adjacent areas, and to allow stormwater to pass through the amended soil profile.

“Rainy season” means that period from October 1st through April 30th unless the director modifies these dates based on weather patterns and forecasts.

“Receiving waters” means naturally and/or reconstructed naturally occurring surface water bodies, such as creeks, streams, rivers, lakes, wetlands, estuaries, and marine waters or ground water to which a municipal separate storm sewer system (MS4) discharges.

“Redevelopment” means on a site that is already substantially developed (i.e., has 35 percent or more of existing hard surface coverage), the creation or addition of hard 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 hard surface that is not part of a routine maintenance activity; or land disturbing practices.

“Reinforced fill” or “reinforced soil” means soil fill designed by an engineer, which includes reinforcement consisting of metal or synthetic materials in bars, trips, grids or sheets.

“Retaining wall” means a wall designed to resist the lateral displacement of soil or other materials.

“Rockery” or “rock wall” means one or more courses of rocks stacked against an exposed soil face to protect the soil face from erosion and sloughing. The bottom course of rocks bears on the foundation soils and the upper rocks bear partially or entirely on the rocks below. The face of inclination of a rockery varies from near vertical to about 1H:4V. A rockery or rock wall is not considered a retaining wall.

“Runoff” is water that travels across the land surface and discharges to water bodies either directly or through a collection and conveyance system. See also “stormwater.”

“Significant tree” shall have the meaning set forth in Chapter 20.50 LUC, now or as hereafter amended.

“Site” shall have the meaning set forth in Chapter 20.50 LUC, now or as hereafter amended.

“Slide” means the movement of a mass of rocks and/or earth down a slope.

“Soil” means unaggregated or uncemented deposits of mineral and/or organic particles or fragments derived from the breakdown of massive rocks or decay of living matter.

“Storm and surface water system” also means the entire system within the city, both public and private, naturally existing and manmade, for the drainage, conveyance, detention, treatment or storage of storm and surface waters. Facilities directly associated with buildings or structures such as foundation drains, rockery/retaining wall drains, gutters and downspouts or groundwater are not considered parts of the storm and surface water system.

“Stormwater” means runoff during and following precipitation and snowmelt events, including surface runoff and drainage. See also “runoff.”

“Structure” means a combination of materials constructed and erected permanently on or under the ground or attached to something having permanent location on or under the ground. Not included are residential fences, retaining walls less than 30 inches in height, rockeries less than 30 inches in height and similar improvements of a minor character.

“Uncontrolled fill” means fill which has been placed under unknown conditions or without any controls such as geotechnical inspection or monitoring.

“Unstable slopes” means those sloping areas of land which have in the past exhibited, are currently exhibiting, or will likely exhibit mass movement of earth.

“Vegetated roof” means thin layers of engineered soil and vegetation constructed on top of a conventional flat or sloped roof. All vegetated roofs consist of four basic components: a waterproof membrane, a drainage layer, a lightweight growth medium, and vegetation.

“Wall drain” means a drainage system behind retaining walls, rockeries, rock walls or modular block walls used to collect water moving through the soil or rock behind the wall or rockery.

“Water quality standards” means the Surface Water Quality Standards, Chapter 173-201A WAC, Ground Water Quality Standards, Chapter 173-200 WAC, and Sediment Management Standards, Chapter 173-204 WAC, now or as hereafter amended.

“Waters of the state” includes those waters as defined as “waters of the United States” in 40 CFR Subpart 122.2 within the geographic boundaries of Washington State and “waters of the state” as defined in Chapter 90.48 RCW, now or as hereafter amended, which includes lakes, rivers, ponds, streams, inland waters, underground waters, salt waters and all other surface water and water courses within the jurisdiction of the state of Washington.