“Best management practice (BMP)” means schedules of activities, prohibitions of practices, maintenance procedures, and other physical, structural, and/or managerial practices that prevent or reduce the release of pollutants and other adverse impacts to waters of Washington State. BMPs can be used singularly or in combination. BMPs have been approved by Ecology. BMPs are listed and described in the DOE Manual, current edition.

“BMC” means Bellingham Municipal Code.

“Building footprint” means the exterior perimeter of the outermost vertical faces of a building foundation or exterior wall where it meets the ground.

“Clearing” means the removal or destruction, by any means, of vegetation, including trees, shrubs, and/or ground cover, which may include root removal or damage to critical root zones, and disruption/compaction of soil.

“Common ownership” means property that is held in common by an owner or group of owners. For purposes of this chapter underlying ownership by a common party, parties or related individuals may be construed by the city as a common ownership. Proof of separate and unrelated property ownership is the duty of the owner or applicant.

“Critical root zone” means the area occupied by the root system of a tree and considered a zone of high sensitivity to disturbance such that damage from excavation, soil compaction or other means will likely lead to declining health and/or stability of the tree. The critical root zone is measured as seven times the root flare diameter.

“Director” means the director of the planning and community development department.

“Disturbed soil” means native soil which is subjected to activity which reduces the inherent soil structure and density, results in compaction, or which relocates soil through excavation or transport.

“Ecology Manual” means the Washington State Department of Ecology “Stormwater Management Manual for Western Washington” as currently adopted or hereafter modified. The LID Guidance Manual shall be considered a portion of this manual.

“Exempt gardening” means those gardening and landscape practices that are contained within one or more areas of a property. The total square footage of all areas together shall not exceed five percent of the property or 500 square feet, whichever is the greater. Exempt gardens shall be maintained and located to prevent runoff resultant from direct precipitation, runoff and irrigation. Exempt garden areas are not exempt from the prohibition on the use of phosphorus containing products including fertilizers, pesticides or other deleterious materials. Landscape or gardening areas beyond the limit provided herein are considered to be partially pervious surfaces and subject to the limitations and requirements of Chapters 15.42 and 16.80 BMC regarding those areas. Exempt gardens that are not in active use for gardening or landscaping purposes for more than 30 days shall provide for the stabilization of the exempt garden by the use of a Type I mulch or other approved method.

“Grading” means the movement of soil and other earth materials in the form of excavation and/or placement of fill.

“Gross lot area” means all of the land area within the surveyed perimeter of an individual lot or parcel, including any pipestem or joint-access easement area. No portion of any abutting right-of-way may be included, unless vacated by city ordinance to the abutting property. No portion of any lot that has been previously constrained by a conservation easement or deed restriction for the purpose of earning and/or transferring impervious credits as described in BMC 16.80.100 may be included in the gross lot area calculation. For properties within the jurisdiction of the shoreline management program (Chapter 16.40 BMC), submerged lands and/or tidelands within the boundaries of any waterfront parcel that are located waterward of the ordinary high water mark shall not be used in impervious/pervious surface calculations.

“Healthy soils” means soils that have all of the following qualities: good structure to absorb water and nutrients and favorable for root development; active microorganisms to break down organic matter and thereby provide good structure for drainage and water retention; adequate organic matter to feed the microorganisms that maintain the soil structure; and adequate decomposition of organic matter by the microorganisms.

“Impervious area credit” means additional impervious area allocated to a lot or parcel as provided in Ordinance No. 2001-01-001.

“Impervious surface” means a hard surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development. 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, packed gravel surfaces, packed earthen materials, and oiled, macadam or other surfaces which similarly impede the natural infiltration of stormwater.

“ISA-certified arborist” means an arborist who has a current certification with the International Society of Arboriculture (ISA).

“Lake Whatcom Watershed Basin One” means those lands within the Lake Whatcom watershed that drain into Basin One of Lake Whatcom via natural topography or through manmade conveyance systems. The boundaries of Basin One are shown on Map 16.80.040. Where in conflict, the definition of the watershed boundaries provided herein shall supersede the map.

“Lake Whatcom watershed reservoir” means all areas which, due to topography, hydrologically drain directly or indirectly into Lake Whatcom, as determined by the city.

“Land-disturbing activity” means any activity that results in 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 or gardening are not generally considered land-disturbing activity with the noted exception of the placement of phosphorus containing materials within the Lake Whatcom watershed.

“Low impact development (LID)” means a group of BMPs and land use practices that are aimed at lessening the hydrologic and water quality impacts to the environment from development. LID practices include but are not limited to, reduction in impervious surfaces, infiltration of flow, dispersion of flow, soil remediation and cluster development.

“Native vegetation” means plant species that originated in the lowlands ecoregion of Whatcom and Skagit Counties, and were not introduced, either intentionally or unintentionally, by humans. Plants native to the county are listed by the Washington Native Plant Society.

“Native vegetation protection area (NVPA)” means that area on a site that is in a natural forested condition, with a forest canopy and a multiple understory of plants, all comprised of native vegetation, or that same area restored to the natural forested condition.

“Natural forested condition” means a vegetated condition mimicking well-established forests and supporting soils found in the lowlands of Whatcom County prior to European settlement. The pre-European-settlement condition is characterized by an extensive canopy cover dominated by native coniferous trees, a significant duff layer, and all distinct plant layers present (tree, shrub, ground cover). The natural forested condition shall function and perform as the “forested condition” in the Department of Ecology Stormwater Manual, current edition.

“Natural grade” means the existing ground, level prior to development, on all sides of a building footprint, at and within the exterior perimeter foundation.

“Partially pervious surfaces” means nonexempt surfaces per Chapter 15.42 BMC that cause an increase in stormwater runoff from a natural forested condition but that are not clearly a defined impervious surface. Common surfaces in this category are lawns, landscaping areas, gardens, areas that have been cleared of native vegetation, and nonengineered pervious driveways that have not been proven through engineering analysis as being capable of fully infiltrating the water from a 10-year developed condition storm.

“Pervious surface” means those areas or surfaces that are not impervious or partially pervious, as defined herein. Forested land is pervious along with other soil areas that either naturally or through application or best management practices can infiltrate water to avoid downstream impacts.

“Pervious system” means a constructed surface or system that allows or causes water to infiltrate into the underlying soil as would occur in a naturally forested condition. Approval of pervious system designs shall be as provided for in Chapter 15.42 BMC and shall be approved by the public works department.

“Phosphorus” means a nutrient required by all organisms for the basic processes of life, and as a natural element, is found in rocks, soils, and organic material.

“Pollution-generating pervious surfaces (PGPS)” means any nonimpervious surface subject to the use of pesticides and fertilizers or loss of soil. Typical PGPS include, by way of example, lawns, landscaped areas, golf courses, parks, cemeteries, and sports fields.

“Public land” means land owned by the city of Bellingham, Whatcom County or other public entity.

“Qualified professional” means a person with expertise in the pertinent scientific discipline. The qualified professional shall have a minimum of a B.S. or B.A., or equivalent certification, and a minimum of five years of directly related work experience.

“Redevelopment” means, on a site that is already developed (which means 10 percent or more of existing impervious surface coverage), 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. For Basin One of the Lake Whatcom watershed redevelopment also means the creation of or expansion of partially pervious surfaces.

“SEPA” means State Environmental Policy Act as adopted by the city of Bellingham.

“Total maximum daily load (TMDL),” as identified in Section 303(d) of the federal Clean Water Act, are the types and amounts of pollutant loading that a given water body (river, marine water, wetland, stream, or lake) can receive and still meet water quality standards.

“Undisturbed grade” means natural grade which remains in predevelopment configuration during and after development.

“Undisturbed soil” means native soil which remains in predevelopment condition. [Ord. 2017-03-009 § 12; Ord. 2009-06-040; Ord. 2001-01-001].