1. “Approval” means the proposed work or completed work conforms to this chapter in the opinion of the director.
2. “Best management practice (BMP)” means physical, structural, and/or managerial practices that, when used singly or in combination, prevent and reduce the release of pollutants and other adverse impacts to waters of Washington State.
3. “City” means the city of Bainbridge Island.
4. “Clearing” means the destruction and removal of vegetation by manual, mechanical, or chemical methods.
5. “Compaction” means densification, settlement, or packing of soil in such a way that permeability of the soil is reduced.
6. “Detention” means the release of stormwater runoff from a specific site at a slower rate than it is collected by the stormwater facility system, the difference being held in temporary storage.
7. “Detention facility” 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 may be little or no infiltration of stored stormwater.
8. “Development” means new development, redevelopment, or both.
9. “Earth material” means any rock, natural soil or fill and/or any combination thereof.
10. “Erosion” means the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep, or the detachment and movement of soil or rock fragments by water, wind, ice, or gravity.
11. “Excavation” means the mechanical removal of earth material.
12. “Exotic species” means an introduced or nonindigenous species living outside its native distributional range which has arrived there by human activity, either deliberate or unintentional.
13. “Fill” means a deposit of earth material placed by artificial means.
14. “Forest practice” means any activity conducted on or directly pertaining to forest land and relating to growing, harvesting, or processing timber, as defined by RCW 76.09.050.
15. “Geologically hazardous areas” means areas susceptible to significant erosion, sliding, earthquake, or other geological events. They pose a threat to public health and safety when used as sites for incompatible commercial, residential or industrial development. Geologically hazardous areas include erosion hazard areas, landslide hazard areas, and seismic hazard areas. Refer to Chapter 16.20 BIMC.
16. “Groundwater” means water in a saturated zone or stratum beneath the surface of land or a surface water body.
17. “Hard surface” means an impervious surface, a permeable pavement, or a vegetated roof.
18. “Illegal discharge” and “illegal connections” are as defined in BIMC 15.22.020.
19. “Impervious surface” means a nonvegetated 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 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.
20. “Interflow” means that portion of rainfall 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; for example, in a wetland, spring or seep.
21. “Invasive plant species” means opportunistic plant species (either native or nonnative) that colonize disturbed ecosystems and come to dominate the plant community in ways that are seen by us as reducing the values provided by the previous plant community.
22. “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. 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.
23. “List No. 1” means on-site stormwater management BMPs for lawn and landscaped areas, roofs, and other hard surfaces included in the stormwater manual adopted in BIMC 15.20.050 for projects triggering Minimum Requirements No. 1 through 5.
24. “List No. 2” means on-site stormwater management BMPs for lawn and landscaped areas, roofs, and other hard surfaces included in the stormwater manual adopted in BIMC 15.20.050 for projects triggering Minimum Requirements No. 1 through 9.
25. “Low impact development (LID)” means a stormwater and land use management strategy that strives to mimic predisturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration by emphasizing conservation, use of on-site natural features, site planning, and distributed stormwater management practices that are integrated into a project design.
26. “Low impact development best management practices (LID BMPs)” mean distributed stormwater management practices, integrated into a project design, that emphasize predisturbance 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, minimal excavation foundations, vegetated roofs, and water reuse.
27. “LID performance standard” means matching developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from eight percent of the two-year peak flow to 50 percent of the two-year peak flow.
28. “LID principles” are land use management strategies that emphasize conservation, use of on-site natural features, and site planning to minimize impervious surfaces, native vegetation loss, and stormwater runoff.
29. “Minimum requirement” means one of nine minimum requirements for stormwater management that are applicable to new development and redevelopment projects as defined in the stormwater manual adopted in BIMC 15.20.050.
30. “Mitigation” means, in the following order of preference:
a. Avoiding the impact altogether by not taking a certain action or part of an action;
b. Minimizing 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;
c. Rectifying the impact by repairing, rehabilitating or restoring the affected environment;
d. Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.
31. “Native vegetation” means plant species that are indigenous to the coastal region of the Pacific Northwest and which reasonably could have been expected to naturally occur on the site. Invasive species and exotic species are not considered to be native species.
32. “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. Projects meeting the definition of redevelopment shall not be considered new development.
33. “Pervious surface” means any surface material that allows stormwater to infiltrate into the ground. Examples include lawn, landscape, pasture, native vegetation areas, and permeable pavement.
34. “Pollution” means such 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 liquids, 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; as defined in RCW 90.48.020 as now existing or hereafter amended.
35. “Pollution-generating hard surface (PGHS)” means hard surfaces considered to be a significant source of pollutants in stormwater runoff. See the listing of surfaces under “pollution-generating impervious surface (PGIS).”
36. “Pollution-generating impervious surface (PGIS)” means impervious surfaces considered to be a significant source of pollutants in stormwater runoff. Such surfaces include those which are subject to vehicular use; industrial activities (as further defined in the glossary of the stormwater manual adopted in BIMC 15.20.050); storage of erodible or leachable materials, wastes, or chemicals, and which receive direct rainfall or the run-on or blow-in of rainfall; metal roofs unless they are coated with an inert, nonleachable material (e.g., baked-on enamel coating); or roofs that are subject to venting significant amounts of dusts, mists, or fumes from manufacturing, commercial, or other indoor activities.
37. “Pollution-generating pervious surfaces (PGPS)” means any pervious surface subject to vehicular use; industrial activities (as further defined in the glossary of the stormwater manual adopted in BIMC 15.20.050); storage of erodible or leachable materials, wastes, or chemicals, and that receive direct rainfall or run-on or blow-in of rainfall; use of pesticides and fertilizers; or loss of soil. Typical PGPS include permeable pavement subject to vehicular use, lawns, and landscaped areas including golf courses, parks, cemeteries, and sports fields (natural and artificial turf).
38. “Redevelopment” means, on a site that is already substantially developed (i.e., has 35 percent or more of existing impervious surface coverage) or which legally existed prior to February 10, 1999, the creation or addition of impervious 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 impervious surface that is not part of a routine maintenance activity; and land disturbing activities.
39. “Replaced hard surface” means, for structures, the removal and replacement of hard surfaces down to the foundation. For other hard surfaces, the removal down to bare soil or base course and replacement.
40. “Replaced impervious surface” means, for structures, the removal and replacement of impervious surfaces down to the foundation. For other impervious surfaces, the removal down to bare soil or base course and replacement.
41. “Site” means the area defined by the legal boundaries of a parcel or parcels of land that is (are) subject to new development or redevelopment. For road projects, the length of the project site and the right-of-way boundaries define the site.
42. “Stormwater” means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland, interflow, channels or pipes into a defined surface water channel, or a constructed infiltration facility.
43. “Stormwater drainage system” 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.
44. “Stormwater facility” means a constructed component of a stormwater drainage system, designed or constructed to perform a particular function, or multiple functions, including but 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.
45. “Stormwater manual” means the Stormwater Management Manual for Western Washington adopted by reference in BIMC 15.20.050.
46. “Vegetation” means any plant life growing on the Island’s surfaces, including ponds, wetlands, and marshes.
47. “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 which includes lakes, rivers, ponds, streams, inland waters, groundwater, salt waters and all other surface waters and water courses within the jurisdiction of the state of Washington.
48. “Wetlands” means those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support (and under normal circumstances do support) a prevalence of vegetation typically adapted for life in saturated soil conditions, such as swamps, marshes, bogs, and other similar areas. This definition includes wetlands created, restored or enhanced as part of a mitigation procedure; it does not include constructed wetlands or the following surface waters of the state intentionally constructed from sites that are not wetlands: irrigation and drainage ditches, grass-lined swales, canals, agricultural detention facilities, farm ponds, and landscape amenities. Refer to Chapter 16.20 BIMC. (Ord. 2017-03 § 2, 2017; Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 2, 2009: Ord. 2005-10 § 1, 2005; Ord. 2003-22 § 22, 2003; Ord. 2001-49 § 1, 2001; Ord. 98-31 § 1, 1999)