"Adjustments"are changes to the minimum requirements which provide substantially equivalent environmental protection, are based on sound engineering practices, and meet the objectives of safety, function, and facility maintenance.
"Basin plan"means a plan that assesses, evaluates, and proposes solutions to existing and potential future impacts to the beneficial uses of, and the physical, chemical, and biological properties of, waters of the state within a basin. The plan will include but not be limited to recommendations for: stormwater requirements for new development and redevelopment; capital improvement projects; land use management through identification and protection of critical areas, comprehensive land use and transportation plans, zoning regulations, site development standards, and conservation areas; source control activities including public education and involvement, and business programs; other targeted stormwater programs and activities, such as maintenance, inspections and enforcement; monitoring; and an implementation schedule and funding strategy. A plan that is "adopted and implemented" has the following characteristics: it has been adopted by legislative or regulatory action of jurisdictions with responsibilities under the plan; ordinances, regulations, programs, and procedures recommended by the plan are in effect or on schedule to be in effect; and an implementation schedule and funding strategy are in progress.
"Best management practice (BMP)"means schedules of activities, prohibition of practices, 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 waters of Washington State.
"Comprehensive drainage plan"refers to a detailed analysis for each drainage basin which compares the capabilities and needs for runoff accommodation due to various combinations of development, land use, structural and nonstructural management alternatives.
"Computations"means calculations, including coefficients and other pertinent data, made to determine the drainage plan with rates of flow of water given in cubic feet per second and cubic meters per second (CMS).
"Construction stormwater pollution prevention plan (SWPPP)"is a document that describes the potential for pollution problems on a construction project (defined as any exterior renovation that disturbs the ground) and explains and illustrates the measures to be taken on the construction site to control those problems.
"Critical areas"means those areas identified in accordance with Chapter
16.15 MTMC as wetlands, geologically hazardous areas, frequently flooded areas, and fish and wildlife habitat.
means a facility for which even a slight chance of flooding might be too great. Critical facilities include, but are not limited to, schools, nursing homes, hospitals, police, fire and emergency response installations, and installations which produce, use or store hazardous materials or hazardous waste.
"Department"means the Public Works Department or its assigns.
"Design storm"means a rainfall (or other precipitation) event or pattern of events for use in analyzing and designing drainage facilities, specifying both the return period in years and the duration in hours.
"Detention facilities"means facilities designed to hold runoff while gradually releasing it at a predetermined maximum rate.
"Developer"means the individual(s) or corporation(s) applying for the permits or approvals described in MTMC §
16.20.060(A).
means any manmade change to improved or unimproved real estate including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment and materials located within the area of special flood hazard.
"Director"means the City of Mountlake Terrace Public Works Director or his/her designee.
"Erosion and sedimentation control"means any temporary or permanent measures taken to reduce erosion, control siltation and sedimentation and ensure that sediment-laden water does not leave a site.
"Flood" or "flooding"means a general and temporary condition of partial or complete inundation of normally dry land areas from:
1. The overflow of inland or tidal waters; and/or
The unusual and rapid accumulation of runoff of surface waters from any source.
"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.
"Impervious surface"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 may 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 storm and surface water.
"Land-disturbing activity"is 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, including landscape maintenance and gardening, are not considered land-disturbing activity. Stormwater facility maintenance is not considered land-disturbing activity if conducted according to established standards and procedures.
"Low impact development"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, site planning, and distributed stormwater management practices that are integrated into a project design.
"Natural location of drainage systems"refers to the location of those channels, swales, and other nonmanmade conveyance systems as defined by the first documented topographic contours existing for the subject property, either from maps or photographs, or such other means as appropriate.
"New development"means land-disturbing activities; structural development, including construction, installation or expansion of a building or other structure; creation of impervious surfaces; and subdivision or short subdivision, and binding site plans as defined in Chapter
58.17 RCW.
means the maximum surface water runoff rate (cubic feet per second and cubic meters per second) determined for the design storm.
"Pollutant"means any substance which, when added to water, would contaminate or alter the chemical, physical, or biological properties of any waters of the City's drainage system or of the state. This includes a 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 City's drainage system or of the state as will or is likely to create a nuisance. It also includes any substance which renders 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.
"Project"means any proposed action to alter or develop a site or area which may also require drainage review.
"Receiving bodies of water"means creeks, streams, lakes, and other bodies of water into which waters are directed, either naturally, in manmade ditches, or in closed conduit systems.
"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; and land-disturbing activities.
"Retention facilities"means facilities designed to hold water for a considerable length of time and then consume it by evaporation, plant transpiration, or infiltration into the soil.
"Runoff"means water originating from rainfall and other precipitation that is found in drainage facilities, rivers, streams, springs, seeps, ponds, lakes and wetlands as well as shallow ground water.
"Stormwater"means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, channels or pipes into a defined surface water channel, or a constructed infiltration facility.
"Stormwater Manual"means the 2019 Stormwater Management Manual for Western Washington as prepared by, and as on file with, the Washington State Department of Ecology. The Stormwater Manual contains BMPs to prevent, control or treat pollution in stormwater and reduce other stormwater-related impacts to waters of the state. The Stormwater Manual is intended to provide guidance on measures necessary in western Washington to control the quantity and quality of stormwater runoff from new development and redevelopment.
"Stormwater site plan"is the comprehensive report containing all of the technical information and analysis necessary for regulatory agencies to evaluate a proposed new development or redevelopment project for compliance with stormwater requirements. Contents of the stormwater site plan will vary with the type and size of the project, and individual site characteristics. It includes a construction stormwater pollution prevention plan (construction SWPPP) and a permanent stormwater control plan (PSC plan).
"Subject property"means the tract of land which is the subject of the permit and/or approval action, and is defined by the full legal description of all parcels involved in the proposed development.
"Technical guidance manual"means the latest version of the Low Impact Development Technical Guidance Manual for Puget Sound (Puget Sound Action Team and Washington State University, Pierce County Extension).
"Variances"are exemptions from the obligation to follow minimum requirements on a project.
"Wetland" or "wetlands"means areas that are inundated or saturated by surface water 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. Wetlands do not include those artificial wetlands intentionally created from nonwetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street or highway. Wetlands may include those artificial wetlands intentionally created from nonwetland areas to mitigate conversion of wetlands.
(Ord. 2549 § 1, 2010; Ord. 2611 § 1, 2013; Ord. 2700 § 2, 2016; Ord. 2729 § 4, 2018; Ord. 2798 § 2, 2021)