Port Orchard City Zoning Code
Subtitle VII
STORMWATER DRAINAGE
§ 20.150.010 Purpose and objectives – Liability.
(1)
Purpose. The purpose of this chapter is to regulate storm and surface water discharges from all new development and redevelopment to prevent and control adverse impacts of drainage and storm and surface water on the public health, safety, and general welfare, consistent with the provisions of the Federal Clean Water Act (33 U.S.C. § 1251 et seq.) as administered by the Washington State Department of Ecology through issuance of the National Pollutant Discharge Elimination System (NPDES) Phase II Municipal Stormwater Permit (permit), in accordance with Chapter 90.48 RCW. The provisions of this subtitle shall be liberally construed to accomplish the purposes of the chapters herein and the protection and preservation of the public health, safety, and general welfare.
(2)
Objectives. The objectives of this subtitle are to:
(a)
Establish a water quality restoration and storm and surface water management program for the city of Port Orchard to be administered by the city of Port Orchard's department of public works;
(b)
Promote sound, practical, and economical development practices and construction procedures that prevent or minimize impacts to the city's waters;
(c)
Prevent or minimize degradation of water quality and to control the sedimentation of streams, rivers, lakes, wetlands, marine waters, and other waters to the maximum extent practicable by all known and reasonable methods of prevention, control, and treatment;
(d)
Control stormwater runoff originating from new development or redevelopment;
(e)
Preserve the quality of water for recreation and fish and wildlife habitat;
(f)
Maintain aquatic habitat;
(g)
Maintain the quality of the city's water resources;
(h)
Prevent or minimize adverse effects caused by degradation of surface water quality flow patterns or quantities, locations, and changes to hydrologic flow patterns;
(i)
Prevent groundwater degradation from surface water flows;
(j)
Preserve and protect the city's wetlands by maintaining hydrologic continuity with other aquatic resources;
(k)
Maintain the safety of city roads and rights-of-way;
(l)
Protect public safety by reducing soil erosion, slope instability, and landslides;
(m)
Promote nonstructural preventative and source control activities and actions; and
(n)
Require the use of low impact development (LID) best management practices (BMPs) where feasible, as defined in the city's stormwater manual.
(3)
Liability. Administration of this chapter shall not be construed to create the basis for any liability on the part of the city, its appointed and elected officials, and/or employees while working within the scope of their duties for any action or inaction thereof authorized or done in connection with the implementation of this chapter.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.020 Definitions.
Definitions provided below apply only to this chapter, unless otherwise indicated. In the application of this chapter, where a definition in this chapter conflicts with a definition in the stormwater manuals, as adopted herein, the most restrictive definition shall control. Where a term used in the stormwater manuals is not defined in this chapter, the definition in the stormwater manuals shall control. The following definitions of terms shall apply to this chapter:
(1) "Accepted performance of construction" "Arterial"
"A"
shall mean the written acknowledgment from the director of the satisfactory completion of all work accepted by the city, including all work shown on the accepted plans, accepted revisions to the plans, and accepted field changes.
shall mean a road or street primarily for through traffic. A major arterial connects an interstate highway to cities and counties. A minor arterial connects major arterials to collectors. A collector connects an arterial to a neighborhood. A collector is not an arterial. A local access road connects individual homes to a collector.
(2) "Basin plan" "Best management practices (BMPs)" "Biofiltration/biofilter facilities" "Bioretention"
"B"
shall mean a plan and all implementing regulations and procedures including, but not limited to, land use management adopted by ordinance for managing stormwater quality and quantity management facilities and drainage features within individual sub-basins.
shall mean the schedule 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 waters of Washington and have been approved by the city as accepted BMPs.
shall mean vegetative BMPs that treat stormwater by filtration through vegetation. Biofiltration facilities include, but are not limited to, grassed or vegetated swales and filter strips.
shall mean an engineered facility that treats stormwater by passing it through a specific soil profile and either retaining or detaining the treated stormwater for flow attenuation. Refer to the currently adopted Stormwater Management Manual for bioretention BMP types and design specifications.
(3) "Certified erosion and sediment control lead (CESCL)" "City" "Civil engineer" "Closed depressions" "Commercial agriculture" "Comprehensive drainage plan" "Contiguous land" "Converted vegetation (areas)" "Critical drainage area"
"C"
shall mean an individual who has current certification through an approved erosion and sediment control training program that meets the minimum training standards established by the Department of Ecology (see the currently adopted Stormwater Management Manual).
shall mean the city of Port Orchard, Washington, or as indicated by the context, the public works director, or other authorized representative of the governmental authority of the city of Port Orchard.
shall mean a professional engineer currently registered in the state of Washington to practice in the field of civil engineering.
shall mean low-lying areas that have no surface outlet, or such a limited surface outlet that in most storm events the area acts as a retention basin, holding water for infiltration, evaporation, or transpiration.
shall mean those activities conducted on lands defined under RCW 84.34.020(2) and activities involved in the production of crops or livestock for commercial 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.
shall mean a detailed analysis, adopted by the city, for a drainage basin which assesses the capabilities and needs for runoff accommodation due to various combinations of development, land use, structural and nonstructural management alternatives. The plan recommends the form, location and extent of stormwater quantity and quality control measures that would satisfy legal constraints, water quality standards, and community standards, and identifies the institutional and funding requirements for plan implementation.
shall mean land adjoining and touching other land regardless of whether or not portions of the parcels have separate assessor's tax numbers or were purchased at different times, lie in different sections, are in different government lots, or are separated from each other by private road or private rights-of-way.
shall mean surfaces on a project site where native vegetation, pasture, scrub/shrub, or unmaintained nonnative vegetation (e.g., Himalayan blackberry, scotch broom) are converted to lawn or landscaped areas, or where native vegetation is converted to pasture.
shall refer to those areas designated in POMC § 20.150.070, Special stormwater drainage improvements, which have a high potential for stormwater quantity or quality problems.
(4) "Design storm event" "Developed site" "Development proposal" "Director" "Discharge point" "Diversion" "Drainage feature" "Drainage plan"
"D"
shall mean a theoretical storm event, of a given frequency, interval, and duration, used in the analysis and design of a stormwater facility.
shall mean the condition of the development site following completion of construction of the development including all approved phases of construction.
shall mean any activity requiring a permit or other approval from the city of Port Orchard relative to the use or development of land.
shall mean the public works director or designee(s).
shall mean the location where a discharge leaves the city's (permittee's) municipal separate storm sewer system (MS4) through the permittee's MS4 facilities/BMPs designed to infiltrate.
shall mean the routing of stormwater to other than its natural discharge location.
shall mean any natural or manmade structure, facility, conveyance, or topographic feature which has the potential to concentrate, convey, detain, retain, infiltrate, or affect the flow rate of stormwater runoff.
shall mean a plan for the collection, transport, treatment, and discharge of runoff, and may include both the plan and profile views of the site as well as construction details and notes.
(5) "Easement" "Effective impervious surface" "Erodible or leachable materials" "Erosion control design storm" "Existing stormwater facilities"
"E"
shall mean an acquired privilege or right of use or enjoyment that a person, party, firm, corporation, municipality, or other legal entity has in the land of another.
shall mean impervious surfaces that are connected via sheet flow or discrete conveyance to a drainage system. Impervious surfaces on residential development sites are considered ineffective if the runoff is dispersed through at least 100 feet of native vegetation in accordance with the currently adopted Stormwater Management Manual, is residential roof runoff infiltrated in accordance with Downspout Full Infiltration Systems in the currently adopted Stormwater Management Manual, or approved continuous runoff modeling methods indicate that the entire runoff file is infiltrated.
shall mean wastes, chemicals, or other substances that measurably alter the physical or chemical characteristics of runoff when exposed to rainfall. Examples include erodible soils that are stockpiled, uncovered process wastes, manure, fertilizers, oily substances, ashes, kiln dust, and garbage dumpster leakage.
shall mean the six-month frequency, 24-hour duration storm event used for analysis and design of sedimentation and erosion control facilities.
shall mean those facilities constructed or under permitted construction prior to the effective date of the ordinance codified in this chapter.
(6) "Forested land"
"F"
shall mean as defined in RCW 76.09.020, and shall include all land which is capable of supporting a merchantable stand of timber and is not being actively used in a manner incompatible with timber growing.
(7) "Geotechnical engineer" "Geotechnical report" "Grading"
"G"
shall mean a practicing professional engineer licensed as a professional civil engineer by the state of Washington who has at least four years of professional employment as a geotechnical engineer.
shall mean a study of the effects of drainage and drainage facilities on soil characteristics, geology and ground water. The geotechnical analysis shall be prepared by a geotechnical engineer.
shall mean any excavating, filling, or embanking of earth materials.
(8) "Highway" "Hydrograph" "Hydrograph method"
"H"
shall mean a public road connecting towns and cities.
shall mean a graph of runoff rate, inflow rate, or discharge rate, past a specific point over time.
shall mean a method of estimating a hydrograph using a mathematical simulation. Commonly accepted hydrograph methods include the Soil Conservation Service TR-55 Method and the Santa Barbara Urban Hydrograph Method.
(9) "Illicit connection" "Illicit discharge" "Impervious surface"
"I"
means (a) any drain or conveyance, whether on the surface or subsurface, which allows an illicit discharge to enter the storm drain system including, but not limited to, any conveyances which allow any nonstormwater discharge including sewage, process wastewater, and wash water to enter the storm drain system and any connections to the storm drain system from indoor drains and sinks, regardless of whether said drain or connection had been previously allowed, permitted, or approved by the city; or (b) any drain or conveyance connected from a residential, commercial or industrial land use to the storm drain system which has not been documented in plans, maps, or equivalent records and approved by the city.
shall mean any discharge to a municipal separate storm sewer or to surface or ground water that is not composed entirely of stormwater, except discharges pursuant to an NPDES permit (other than the NPDES permit for discharges from the municipal separate storm sewer), discharges resulting from fire fighting activities, and those discharges expressly allowed conditionally by Chapter 15.30 POMC, Illicit Discharge Detection and Elimination.
shall mean a nonvegetated surface area that either (a) prevents or retards the entry of water into the soil mantle as under natural conditions prior to development, or (b) 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 the 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.
(10) "Land disturbing activity" "Land use permits and approvals"
"L"
shall mean 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, including the creation and/or replacement of impervious surfaces. Land disturbing activities include, but are not limited to, demolition, construction, paving, clearing, grading, filling, excavation, and grubbing. 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. The cutting of trees less than 18 inches DBH, not located within any potential critical areas nor part of required landscape or stormwater infrastructure, is not considered a land disturbing activity.
shall mean any use or development of land that requires city action in legislation, administration, or approval.
(11) "Maintenance" "Maintenance covenant" "Maintenance schedule" "Major development" "Minor development" "Municipal separate storm sewer system (MS4)"
"M"
shall mean any activity that is conducted on currently serviceable stormwater structures, facilities, and equipment in good working order so as to function as designed without expansion or use beyond that previously existing and results in no significant adverse hydrologic impact. Maintenance shall include activities taken to prevent decline, lapse or cessation in use of the systems or structures, including complete reconstruction of a dysfunctional stormwater facility, including cases where environmental permits require replacing an existing structure with a different type structure, as long as the functioning characteristics of the original structure are not changed. Maintenance of stormwater facilities shall include assessment to ensure ongoing proper operation, removal of built up pollutants (i.e., sediments), replacement of failed or failing treatment media, and the correction of any problem on the site property that may directly impair the functions of the stormwater facilities as identified in the maintenance standards of the currently adopted Stormwater Management Manual.
shall mean a binding agreement between the city of Port Orchard and the person or persons holding title to a property served by a stormwater facility whereby the property owner promises to maintain certain stormwater facilities, grants the city the right to enter the subject property to inspect and to make certain repairs or perform certain maintenance procedures on the stormwater control facilities when such repairs or maintenance have not been performed by the property owner, and promises to reimburse the city for the cost should the city perform such repairs or maintenance.
shall mean a document detailing required stormwater facility maintenance activities to be performed at specified intervals.
shall mean any new development or any redevelopment activity that (a) includes the creation or cumulative addition of 5,000 square feet or greater of impervious surface area from the predevelopment conditions, or (b) includes land disturbing activity of one acre or greater, or (c) includes grading involving the movement of 5,000 cubic yards or more of material.
shall mean any new development or redevelopment activity that (a) includes the creation or addition of less than 5,000 square feet of new impervious surface area, and (b) includes land disturbing activity of less than one acre, and (c) includes grading involving the movement of less than 5,000 cubic yards of material.
means a conveyance or system of conveyances which is intended to convey only stormwater (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains) and which are: (a) owned or operated by the city of Port Orchard; (b) designed or used for collecting or conveying stormwater; (c) are not part of a publicly owned treatment works (any device or system used in treatment of municipal sewage or industrial wastes of a liquid nature which is publicly owned); and (d) are not a combined sewer (a system that collects sanitary sewage and stormwater in a single sewer system).
(12) "National Pollutant Discharge Elimination System (NPDES) permit" "Native vegetation" "New development" "Nonforestry use"
"N"
shall mean a permit issued by the Environmental Protection Agency (EPA) or by the Washington State Department of Ecology that authorizes the discharge of pollutants to waters of the United States from point sources, whether the permit is applicable to an individual, group, or general area-wide basis.
shall mean vegetation comprised of plant species, other than noxious weeds, that are indigenous to the coastal region of the Pacific Northwest and which reasonably could have been expected to naturally occur on the site. Examples include trees such as Douglas Fir, western hemlock, western red cedar, alder, big-leaf maple, and vine maple; shrubs such as willow, elderberry, salmonberry, and salal; and herbaceous plants such as sword fern, foam flower, and fireweed.
shall mean 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 impervious 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.
shall mean an active use of land that is incompatible with timber growing.
(13) "Off-site drainage analysis" "Oil/water separator" "On-site stormwater BMPs" "Operation and maintenance manual" "Operator"(a) (b) "Outfall" "Owner"
"O"
shall mean a study of those land areas contributing surface runoff to a development site as well as a study of the existing and predicted impacts of surface runoff from the development site on properties and drainage features that have the potential to receive stormwater from the development site.
shall mean a structure or device used to remove suspended oil and greasy solids from water.
shall mean a synonym for low impact development BMPs.
shall mean a written manual, prepared by a qualified civil engineer, which provides a description of operation and maintenance procedures for specific stormwater control facilities, for use by operation and maintenance personnel.
shall mean any party associated with a construction project that meets either of the following two criteria:
The party has operational control over construction plans and specifications, including the ability to make modifications to those plans and specifications; or
The party has day-to-day operational control of those activities at a project which are necessary to ensure compliance with a SWPPP for the site or other permit conditions (e.g., they are authorized to direct workers at a site to carry out activities required by the SWPPP or comply with other permit conditions).
shall mean a point source as defined by 40 CFR 122.2 at the point where a discharge leaves the permittee's MS4 and enters a surface receiving waterbody or surface receiving waters. Outfall does not include pipes, tunnels, or other conveyances which connect segments of the same stream or other surface waters and are used to convey primarily surface waters (i.e., culverts).
shall mean any person or persons having a legal or equitable property right or interest, whether or not said right is legal or equitable in character, including a fee owner, contract purchaser or seller, mortgagor or mortgagee, optionor or optionee, and beneficiary or grantor of a trust or deed of trust.
(14) "Permeable pavement" "Pollution" "Pollution-generating hard surface (PGHS)" "Pollution-generating impervious surface (PGIS)" "Pollution-generating pervious surface (PGPS)" "Predevelopment condition" "Professional engineer" "Project engineer" "Project site"
"P"
shall mean 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.
shall mean contamination or other alteration of the physical, chemical, or biological properties of any waters of the city, state, or United States, 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 as will or is likely to create a nuisance or render such waters harmful, or is otherwise 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.
shall mean those hard surfaces considered to be a significant source of pollutants in stormwater runoff. See listing of surfaces under pollution-generating impervious surface.
shall mean those 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 Management Manual for Western Washington); 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 (i.e., baked-on enamel coating); or roofs that are subject to venting significant amounts of dust, mists, or fumes from manufacturing, commercial, or other indoor activities.
shall mean any nonimpervious surface subject to vehicular use, industrial activities (as further defined in the glossary of the Stormwater Management Manual for Western Washington); or storage of erodible or leachable materials, wastes, or chemicals, and which receive direct rainfall or the 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, landscaped areas including: golf courses, parks, cemeteries, and sports fields (natural and artificial turf).
shall mean native vegetation and soils that existed prior to the influence of Euro-American settlement. Predeveloped condition shall be assumed to be forested land cover unless reasonable, historic information is provided that indicates the site was prairie prior to settlement.
shall mean a person who, by reason of their special knowledge of the mathematical and physical sciences and the principles and methods of engineering analysis and design, acquired by professional education and practical experience, is qualified to practice engineering as attested by their legal registration as a professional engineer in the state of Washington.
shall mean the professional engineer responsible for the design of the project, who will affix their seal on the project drainage plans and drainage analysis. The project engineer shall be licensed in the state of Washington and qualified by experience or examination.
shall mean that portion of a property, properties, or right-of-way subject to land disturbing activities, new hard surfaces, or replaced hard surfaces.
(15) "Rain garden" "Receiving waters" "Redevelopment" "Replaced hard surface" "Replaced impervious surface"
"R"
shall mean 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 allow stormwater to pass through the amended soil profile.
shall mean 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 MS4 discharges.
shall mean any land disturbing activity occurring on existing substantially developed property (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.
shall mean 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.
shall mean 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.
(16) "SEPA" "Shorelines of the state" "Site" "Site development activity" "Soils engineer" "Soils investigation report" "Source control BMP" "Stormwater" "Stormwater facility" "Stormwater pollution prevention plan (SWPPP)" "Stormwater quality control" "Stormwater quantity control"
"S"
shall mean the Washington State Environmental Policy Act.
shall mean the total of all "shorelines" and "shorelines of state-wide significance" within the state, as defined in RCW 90.58.030, also known as the Shoreline Management Act.
shall mean 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.
shall mean the alteration of topography, clearing, paving, grading, construction, alteration of stormwater systems, site preparation, or other activity commonly associated with site development.
shall mean a practicing civil engineer licensed as a professional civil engineer in the state of Washington who has at least four years of professional employment as a civil engineer dealing with soil descriptions and characterizations.
shall mean a study of soils on a subject property with the primary purpose of characterizing and describing the soils. The soils investigation report shall be prepared by a qualified soils engineer, who shall be directly involved in the soil characterization either by performing the investigation or by directly supervising employees.
shall mean a best management practice (BMP), either a structure or operation that is intended to prevent pollutants from coming into contact with stormwater through physical separation of areas or careful management of activities that are sources of pollutants. The currently adopted Stormwater Management Manual separates source control BMPs into two types. Structural source control BMPs are physical, structural, or mechanical devices, or facilities that are intended to prevent pollutants from entering stormwater. Operational BMPs are nonstructural practices that prevent or reduce pollutants from entering stormwater. See the currently adopted Stormwater Management Manual for details.
shall mean the surface flow, runoff, and drainage consisting entirely of water from any form of natural precipitation, including snowmelt, during and following precipitation, and resulting from such precipitation that meets the nonpollutant requirements.
shall mean a component of a manmade drainage feature, or features, 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, wetponds, constructed wetlands, infiltration devices, catch basins, oil/water separators, and sediment basins. Stormwater facilities shall not include building gutters, downspouts, and drains serving one single-family residence.
shall mean a documented plan to implement measures to identify, prevent, and control the contamination of point source discharges of stormwater.
shall mean the control of the introduction of pollutants into stormwater and the process of separating pollutants from stormwater. Stormwater quality control facilities include, but are not limited to, source controls, biofiltration/biofilter facilities, wet ponds, wetland forebays, oil/water separators, constructed wetlands and erosion and sedimentation control facilities.
shall mean the control of the rate and/or volume of stormwater released from a development site. Stormwater quantity control facilities include, but are not limited to, detention and retention facilities.
(17) "Technical deviation" "Threshold discharge area"
"T"
shall mean permission granted by the director to deviate from the provisions of this chapter.
shall mean an on-site area draining to a single natural discharge location or multiple natural discharge locations that combine within one-quarter mile downstream (as determined by the shortest flowpath).
(18) "Variance" "Vehicular use"
"V"
shall mean permission granted by the city council to deviate from the provisions of this chapter.
shall mean regular use of an impervious or pervious surface by motor vehicles. The following are subject to regular vehicular use: roads, unvegetated road shoulders, bike lanes within the traveled lane of a roadway, driveways, parking lots, unrestricted access fire lanes, vehicular equipment storage yards, and airport runways. The following are not considered subject to regular vehicular use: paved bicycle pathways separated from and not subject to drainage from roads for motor vehicles, restricted access fire lanes, and infrequently used maintenance access roads.
(19) "Water quality design storm event" "Waters of the state"
"W"
shall mean a design storm event selected by the director for the purpose of establishing design performance criteria for water quality BMPs. Under most conditions, the term applies to the runoff rate and volume resulting from 64 percent of the precipitation of the two-year frequency, 24-hour duration storm event.
shall include 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 include lakes, rivers, ponds, streams, inland waters, underground waters, salt waters and all other surface waters and watercourses within the jurisdiction of the state of Washington.
(Ord. 019-17 § 18 (Exh. 1); Ord. 029-19 § 6; Ord. 023-22 § 2; Ord. 017-23 § 1 (Exh. A))
§ 20.150.030 Administration.
(1)
Authority. The director shall have the authority to develop and implement procedures to administer and enforce this chapter.
(2)
Inspections. All activities regulated by this chapter shall be inspected by the department. The director shall inspect projects at various stages of the work requiring approval to determine that adequate control is being exercised. Stages of work requiring inspection include, but are not limited to, preconstruction, installation of BMPs, land disturbing activities, installation of utilities, permanent stormwater control facilities, landscaping, retaining walls, and completion of project. When required by the director, a special inspection and/or testing shall be performed.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.040 Applicability.
(1)
The provisions of this chapter shall apply to all development proposals within the bounds of incorporated Port Orchard.
(2)
Any land development which is required by operation of any city of Port Orchard ordinance, state law, or federal law to construct, install, or modify any natural or manmade drainage features, either public or private, within, abutting, or serving the development shall do so in accordance with this chapter.
(3)
The provisions of POMC § 20.150.260, Facilities – Operation and maintenance, shall also apply to existing stormwater facilities in incorporated Port Orchard.
(4)
The requirements of this chapter are in addition to other city codes, standards, and regulations. Where conflicts exist between the provisions of this chapter and other codes and standards, the most restrictive shall apply. Where the provisions of this chapter directly conflict with any other state law, federal law, or comprehensive drainage plan, the more stringent provisions shall apply to the extent permissible by law.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.050 Exemptions.
The following activities are exempt from the provisions of this chapter:
(2)
Development that is undertaken by the Washington State Department of Transportation in state highway rights-of-way and is regulated by Chapter 173-270 WAC, the Puget Sound Highway Runoff Program; and
(3)
Pavement maintenance. Pavement maintenance practices which are exempt include potholes and square cut patching, overlaying existing asphalt or concrete pavement with asphalt or concrete without expanding the area of coverage, shoulder grading, reshaping/regrading drainage systems, crack sealing, resurfacing with in-kind material without expanding the road prism, pavement restoration activities that do not expand the road prism, and vegetation maintenance. See Appendix 1 of Municipal NPDES Permit for practices which are not categorically exempt.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.060 Regulations and guidelines – Adopted manuals.
(1)
The provisions of this chapter together with those manuals and standards described herein shall constitute the city's stormwater regulations.
(3)
The following state and local regulations and guidelines pertaining to surface and stormwater design and management are adopted by reference and shall be collectively referred to as the "Port Orchard stormwater manuals" or the "stormwater manuals":
(a)
The 2019 Edition of the Washington State Department of Ecology Stormwater Manual for Western Washington (Stormwater Management Manual);
(b)
The 2012 Edition of the Puget Sound Partnership Low Impact Development Technical Guidance Manual for Puget Sound;
(c)
The city of Port Orchard design and construction standards; and
(d)
The definitions, minimum requirements, adjustment, and variance criteria found in Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit, except that the erosivity waiver is not adopted.
(e)
All references to this chapter shall include the Port Orchard stormwater manuals adopted herein.
(4)
All development proposal activities in the city shall comply with the standards, specifications, and requirements contained in the city's stormwater regulations and stormwater manuals. When best management practices (BMPs) are required by this chapter or any other chapter of the POMC, they shall comply with the stormwater manuals.
(5)
Where there are differences and/or conflicts between the stormwater manuals and/or Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit, the most stringent criteria shall apply.
(6)
The adopted regulations and guidelines in the stormwater manuals may be modified for projects located within specific areas for which a specialized stormwater drainage plan has been approved by the city and the Washington State Department of Ecology.
(7)
The director may amend the Port Orchard stormwater manuals as necessary, by ordinance passed by a majority of the Port Orchard city council, to reflect changing conditions and technology.
(8)
Compliance with the regulations in this chapter and the stormwater manuals does not necessarily mitigate all probable and significant environmental impacts to aquatic biota. Fishery resources and other living components of aquatic systems are affected by a complex set of factors. While employing a specific flow control standard may prevent stream channel erosion or instability, other factors affecting fish and other biotic resources (such as increases in stream flow velocities) are not directly addressed by the stormwater manuals. Thus, compliance with the stormwater manuals should not be construed as mitigating all probable and significant stormwater impacts, and additional mitigation, beyond what is required in the stormwater manuals, may be required to protect aquatic biota in streams and wetlands.
(Ord. 019-17 § 18 (Exh. 1); Ord. 023-22 § 1)
§ 20.150.070 Special stormwater drainage improvements.
In order to mitigate or eliminate potential drainage-related impacts on critical drainage areas, the director may require drainage improvements in excess of those required in this chapter and the stormwater manuals. For particularly sensitive drainage areas, the director may specify the general type of drainage improvement required. Accordingly, the following are designated as critical drainage areas:
(2)
Geologic hazardous area and historically documented unstable slopes;
(3)
All lands within 200 feet of the ordinary high water mark of bodies of water possessing fish spawning and rearing habitat for anadromous and resident fish species, as designated by the State Department of Fish and Wildlife;
(4)
All lands designated critical areas in any comprehensive drainage plan, or defined as critical areas by separate ordinance;
(5)
All lands that are classified as wetlands as defined by any separate city ordinance or policy;
(6)
Any lands that have existing local requirements for the management or protection of ground water, aquifers, or sole source aquifers;
(7)
Any lands that drain to a closed depression;
(8)
Any lands that have existing local or state requirements for the protection of particular fish or wildlife habitats;
(9)
Any lands that are established by law as shellfish protection areas; and
(10)
Any lands determined by the director to have a high potential for drainage and water quality problems, and/or are sensitive to the effects of construction or development.
In the event of conflict between maps or other available information resources regarding the above designations, the final determination of whether or not certain lands are critical drainage areas shall be made by the director. In making such a final determination, the director may use detailed site surveys and/or other topographic data that the director may require the applicant to furnish at the applicant's expense.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.080 Permit – Form.
(1)
Permit Required. A stormwater drainage permit is required for all development proposals, except as exempt under Chapter 20.140 POMC, Land Disturbing Activity, or as may be otherwise exempt herein. No construction or development activity shall occur until a stormwater drainage permit has been issued, nor shall said activity continue without an approved stormwater drainage permit in force.
(2)
Application Form. The stormwater drainage permit shall be submitted pursuant to forms provided by the city. As required by this chapter and the permit submittal requirements in POMC § 20.150.090, supporting documents submitted with the application shall address the applicable minimum requirements for surface and stormwater control pursuant to the stormwater manuals and include the proposed BMPs to mitigate such stormwater impacts.
(3)
Fees. Stormwater drainage permits shall be subject to fees for application review and inspections during construction. Fees for stormwater drainage permits shall be set forth in the city's current fee schedule.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.090 Permit – Submittal requirements.
The following submittal requirements apply to all stormwater drainage permit applications:
(1)
Low Impact Development Site Analysis Required. All development proposals shall conduct a low impact development (LID) site analysis in accordance with the minimum requirements outlined in the stormwater manuals. LID site assessment findings shall be a required component of the stormwater drainage permit submittal.
(2)
Drainage Report – When Required. Development proposals that include any of the following activities shall submit a drainage report, as prescribed by this chapter and the stormwater manuals, together with the required calculations, plans, and details, as a component of the stormwater drainage permit; the drainage report and supporting plan documents shall address the applicable minimum stormwater management requirements and include the proposed BMPs to mitigate stormwater impacts:
(a)
Development or redevelopment activities that qualify as a major development as defined herein; or
(b)
Grading activities that result in the movement of 150 cubic yards or more of earth; or
(c)
Grading activities that will result in a temporary or permanent slope having a steepness exceeding three to one (3:1) (three feet horizontal to one foot vertical) and having a total slope height, measured vertically from toe of slope to top of slope, exceeding five feet; or
(d)
Grading activities that include the construction of embankment berms that will result in the impoundment of water to a depth exceeding 18 inches and/or with a maximum volume exceeding 2,500 cubic feet of water; or
(e)
Grading activities that will result in the diversion of existing drainage courses, both natural and manmade, from their natural point of entry or exit from the grading site;
(f)
Any land clearing or grading on slopes steeper than 30 percent, or within the mandatory setback of a wetland, stream, lake, or Puget Sound, as established by separate ordinance or by the public works department.
(3)
BMP Plans, Only – When Required. Minor development, as defined herein, or projects that do not require a drainage report pursuant to subsection (2) of this section, shall submit plans that document the proposed BMPs to mitigate stormwater impacts as a component of the stormwater drainage permit. The proposed BMPs shall address the applicable minimum requirements pursuant to the stormwater manuals.
(4)
Off-Site Analysis. All development proposals that require a drainage report pursuant to subsection (2) of this section shall also include an off-site drainage analysis as defined in this chapter, prepared by a qualified professional engineer, and based on a field investigation of the development's off-site contributing and receiving drainage areas as a required component of the stormwater drainage permit submittal.
(5)
Soils Analysis. All development proposals that require a drainage report pursuant to subsection (2) of this section and where the soils underlying the proposed project have not been mapped, or where existing soils maps of the project site are inconsistent, or where the director deems that existing soils maps of the project site are not of sufficient resolution to allow proper engineering analysis, shall include a soils investigation report as a required component of the stormwater drainage permit submittal.
(6)
Geotechnical Analysis. All development proposals where grading or the construction of stormwater retention facilities, detention facilities, LID BMPs, or other stormwater facilities is proposed within 200 feet of slopes steeper than 30 percent, or where the director deems that the proposed construction poses a potential hazard due to its proximity to a slope, shall, when required by the director, include a geotechnical analysis prepared by a qualified geotechnical engineer as a required component of the stormwater drainage permit submittal. Said geotechnical analysis shall address the effects of ground water interception and infiltration, seepage, potential slip planes, and changes in soil bearing strength.
(7)
When a Professional Engineer Is Required. Unless otherwise required in this chapter, documents submitted in support of a stormwater drainage permit application must be prepared by a qualified professional engineer when one of the following conditions exists:
(a)
Any land use or building or development proposal on real property which meets the definition of a major development; or
(b)
Any improvements within the boundaries of city rights-of-way for which Port Orchard will ultimately assume responsibility for maintenance; or
(c)
Any development proposal that the director deems to be in the public's best interest to require that certain stormwater drainage permit application submittal documents be prepared by a professional civil engineer.
(8)
Engineering and Drainage Plans. All engineering plans shall be submitted to the department for review in accordance with the stormwater manuals. All drainage plans, if required, shall be submitted to the department for review in accordance with the stormwater manuals and in accordance with the requirements of any associated permit applications or development approvals.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.100 Permit – Decision type – Review criteria.
A stormwater drainage permit shall be issued as an administrative decision of the director, appealable to the Port Orchard hearing examiner in a closed record hearing.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.110 Permit – Review criteria.
(1)
Every stormwater drainage permit, or approval application with storm drainage review, must meet the design and submittal requirements of this chapter and the adopted stormwater manuals.
(a)
The required review for any submitted stormwater drainage permit shall be scaled by the director to the scope of the project's size, type of development, and potential for impacts to the regional surface water system to facilitate preparation and review of project applications. The director shall determine which drainage reviews apply to a stormwater drainage permit application, as specified in the stormwater manuals.
(b)
Stormwater generated on site from all new impervious surfaces shall be managed through a combination of LID BMPs in accordance with this chapter and the stormwater manuals, or any other LID BMPs approved by the city through the design deviation process in POMC § 20.150.120, unless site and soil conditions make LID infeasible as determined by the director.
(2)
Low Impact Development BMPs – Additional Conditions. The following LID BMPs utilized as part of a stormwater drainage permit submittal shall be subject to additional review and conditions for implementation by the director as part of the stormwater drainage permit review and issuance:
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.120 Permit – Technical deviations.
The director may grant technical deviations from requirements contained in the stormwater manuals pursuant to the requirements in the stormwater manuals; and provided, that all of the following criteria are met:
(1)
The technical deviation will not otherwise result in noncompliance with this chapter;
(2)
The granting of the technical deviation will not result in noncompliance with the development conditions imposed upon the project by the city;
(3)
The granting of the technical deviation will produce a compensating or comparable result that is in the public interest; and
(4)
The granting of the technical deviation will meet the objectives of safety, function, appearance, environmental protection, and maintainability based on sound engineering judgment.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.130 Permit – Variances.
(1)
Eligibility.
(a)
Requests for a variance from the minimum requirements under this chapter and the stormwater manuals may be considered for stormwater drainage permits pending approval. The permit application review time will be extended by the director as required for the review.
(b)
Requests for a variance from the minimum requirements under this chapter and the stormwater manuals may be considered for stormwater drainage permits that have not yet expired; provided, that the variance request must be submitted a minimum of 90 calendar days prior to the stormwater drainage permit expiration date. The 90-day requirement may be increased by the director depending on the complexity of the variance.
(2)
Submittal Requirements.
(a)
Applicants requesting a variance from the minimum requirements under this chapter and the stormwater manuals shall provide all necessary justification and supporting documentation in accordance with Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit. Additional information shall be submitted if required by the director.
(b)
The permit applicant shall be responsible for all costs associated with analyses, documentation, and additional review time of the variance, in accordance with the process established by the director.
(3)
Review and Approval. The hearing examiner may grant a variance from the provisions of this chapter; provided, that all of the following criteria and requirements are met:
(a)
The applicant has provided all necessary justification and supporting documentation to meet the requirements of Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit;
(b)
The granting of the variance will produce a compensating or comparable result that is in the public interest; and
(c)
The granting of the variance will meet the objectives of safety, function, appearance, environmental protection, and maintainability based on sound engineering judgment.
(4)
Denial – Appeal.
(a)
The permit applicant is responsible for fully meeting the minimum requirements of this chapter and the stormwater manuals if the variance is not approved prior to the stormwater drainage permit expiration.
(b)
The decision of the hearing examiner to grant or deny a variance pursuant to this section may be appealed to the city council in a closed record appeal. The decision of the city council upon a closed record appeal is final.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.140 Permit – Construction timing and final approval.
(1)
No work related to permanent or temporary storm drainage control for a permitted development may proceed without the approval of the director pursuant to this chapter.
(2)
Erosion and sediment control measures associated with both the interim and permanent drainage systems shall be approved and constructed pursuant to the requirements in Chapter 20.140 POMC, Land Disturbing Activity.
(3)
Prior to the construction of any improvements or buildings on the site, or to final recording of a plat or short plat, those portions of the stormwater drainage facilities required pursuant to the applicable issued stormwater drainage permit(s) shall be constructed and in operation as approved by the city; but, after receipt of a written request, the director may authorize recording prior to final approval to minimize impacts that may result from construction of said stormwater drainage facilities during inappropriate times of the year.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.150 Permit – Expiration – Extension.
(1)
Expiration. A stormwater drainage permit issued pursuant to this chapter shall expire three years from the date of issuance if the permitted work has not yet commenced. In the event that a stormwater drainage permit, and any renewal thereof pursuant to subsection (2) of this section, expires prior to the completion of construction, all construction activity must cease, a new stormwater drainage permit application must be submitted, and the issuance of a new stormwater drainage permit shall be at the discretion of the director, subject to city development standards in force at the time of the new permit application.
(2)
Permit Extension.
(a)
If construction pursuant to an issued stormwater drainage permit has begun, been documented, and is continuing prior to the expiration of said permit, the property owner or stormwater drainage permit applicant may request a permit extension, submitted in writing to the director, prior to the expiration date of the permit. Having the required inspections performed and approved within every 360 days is evidence that work has commenced and is continuing.
(b)
The director may grant a one-time extension not to exceed two additional years. The director shall not grant more than one permit extension for a stormwater drainage permit.
(c)
The director's decision whether to grant an extension pursuant to this subsection shall be final.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.160 Standards – Minimum site development requirements.
The following minimum site development requirements apply to all new development, redevelopment, and construction site activities that result in land disturbance of equal or greater than one acre, including projects less than one acre that are part of a larger common plan of development or sale, regardless of whether a permit under this chapter or Chapter 20.140 POMC, Land Disturbing Activity, is required:
(1)
Plans and Reports (Minimum Requirement No. 1). All development and redevelopment meeting the thresholds contained in this section shall submit plans and reports in accordance with the criteria stipulated in the manual.
(2)
Construction Stormwater Pollution Prevention Plan (SWPPP) (Minimum Requirement No. 2). All new development and redevelopment is responsible for preventing erosion and discharge of sediment and other pollutants into receiving waters by preparing a SWPPP. The SWPPP shall include a narrative and drawings. All BMPs shall be clearly referenced in the narrative and marked on the drawings. The SWPPP narrative shall include documentation to explain and justify the pollution prevention decisions made for the project and shall be available to the director upon request. The SWPPP shall include each of the 12 elements below and shall be fully implemented, from initial soil disturbance until final stabilization, unless site conditions render the element unnecessary and the exemption from that element is clearly justified in the SWPPP.
(a)
Preservation of vegetation/marking clearing limits;
(b)
Construction access;
(c)
Controlling flow rates;
(d)
Installing sediment controls;
(e)
Stabilizing soils;
(f)
Protecting slopes;
(g)
Protecting drain inlets;
(h)
Stabilizing channels and outlets;
(i)
Controlling pollutants;
(j)
Controlling dewatering;
(k)
Maintaining best management practices; and
(l)
Management of the project.
(3)
Source Control of Pollution (Minimum Requirement No. 3). Source control best management practices (operational and/or structural) are required for all projects. Those practices listed in the source control chapter of the currently adopted Stormwater Management Manual as applicable operational or structural source controls for a particular pollutant source are required under this minimum requirement.
(4)
Preservation of Natural Drainage Systems and Outfalls (Minimum Requirement No. 4).
(a)
Natural drainage patterns shall be maintained, and discharges from the project site shall occur at the natural location, to the maximum extent practicable. The manner by which runoff is discharged from the project site must not cause a significant adverse impact to downstream receiving waters and down gradient properties. All outfalls require energy dissipation.
(b)
Downstream Analysis. The following projects shall conduct an analysis of downstream water quality impacts resulting from the project and shall provide mitigation of these impacts:
The analysis shall extend a minimum of one-quarter of a mile downstream from the project site. The existing or potential impacts to be evaluated and mitigated shall include excessive sedimentation, erosion, discharges to ground water contributing to recharge zones, violations of water quality standards, and spills and discharges of priority pollutants.
(5)
On-Site Stormwater Management (Minimum Requirement No. 5). All projects shall maintain the average annual volume of water that infiltrates on a site (ground water plus interflow) at or above predevelopment levels as predicted by an approved hydrologic model. Project proponents may use prescriptive predesigned best management practices contained in the manual to fulfill this requirement.
(6)
Runoff Treatment (Minimum Requirement No. 6). The following require construction of stormwater treatment facilities designed in accordance with the manual:
(a)
Projects in which the total pollution-generating impervious surface (PGIS) is 5,000 square feet or more; or
(b)
Projects in which the total of pollution-generating pervious surface (PGPS) is three-quarters of an acre or more, and from which there is a surface discharge in a natural or manmade conveyance system from the site.
(7)
Oil Control Treatment Requirements.
(a)
Treatment to achieve oil control applies to projects that have "high-use sites." High-use sites are those that typically generate high concentrations of oil due to high traffic turnover or frequent transfer of oil. High-use sites include:
(i)
An area of a commercial or industrial site subject to an expected average daily traffic (ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross building area;
(ii)
An area of a commercial or industrial site subject to petroleum storage and transfer in excess of 1,500 gallons per year, not including routinely delivered heating oil;
(iii)
An area of a commercial or industrial site subject to parking, storage or maintenance of 25 or more vehicles over 10 tons gross weight (trucks, buses, trains, heavy equipment, etc.);
(iv)
A road intersection with a measured ADT count of 25,000 vehicles or more on the main roadway and 15,000 vehicles or more on any intersecting roadway, excluding projects proposing primarily pedestrian and bicycle use improvements.
(b)
Oil/Water Separators. All stormwater from impervious areas at high-use sites subject to motor vehicle traffic shall flow through a spill-containment type oil/water separator prior to surface discharge off site.
(8)
Phosphorus Treatment Requirements. Phosphorus treatment as described in the manual is required for the following:
(9)
Enhancement Treatment Requirements. Enhanced treatment for reduction in dissolved metals (primarily copper and zinc) is required for the following project sites that discharge to fish-bearing streams, lakes, or to waters or conveyance systems tributary to fish-bearing streams or lakes:
(10)
Basic Treatment Requirements. Basic treatment applies to:
(a)
Project sites that discharge to the ground, unless:
(i)
The soil suitability criteria for infiltration treatment are met (see the manual for soil suitability criteria); or
(ii)
The project uses infiltration strictly for flow control and not treatment and the discharge is within one-quarter mile of a phosphorus sensitive lake (use a phosphorus treatment facility), or within one-quarter mile of a fish-bearing stream or a lake (use an enhanced treatment facility);
(b)
Residential projects not otherwise needing phosphorus control as designated by U.S. EPA, the Department of Ecology, or by the city of Port Orchard;
(c)
Project sites discharging directly to salt waters, river segments, and lakes listed in the currently adopted Stormwater Management Manual;
(d)
Project sites that drain to streams that are not fish-bearing, or to waters not tributary to fish-bearing streams; and
(e)
Landscaped areas of industrial, commercial, and multifamily project sites, and parking lots of industrial and commercial project sites that do not involve pollution-generating sources (e.g., industrial activities, customer parking, storage of erodible or leachable material, wastes or chemicals) other than parking of employees' private vehicles. For developments with a mix of land use types, the basic treatment requirement shall apply when the runoff from the areas subject to the basic treatment requirement comprise 50 percent or more of the total runoff.
(11)
Flow Control (Minimum Requirement No. 7). Except as provided in subsection (12) of this section, the following require construction of flow control facilities and/or land use management BMPs that result in stormwater discharges that match developed condition discharge durations to predeveloped condition durations for the range of predeveloped discharge rates from 50 percent of the two-year peak flow up to the full 50-year peak flow:
(a)
Projects in which the total of effective impervious surfaces is 10,000 square feet or more;
(b)
Projects that convert three-quarter acre or more of native vegetation to lawn or landscape, or convert two and one-half acres or more of native vegetation to pasture, and from which there is a surface discharge in a natural or manmade conveyance system from the site; or
(c)
Projects that through a combination of effective impervious surfaces and converted pervious surfaces cause a one-tenth cubic foot per second increase in the 100-year flow frequency as estimated using the Western Washington Hydrology Model or other approved model.
(12)
Flow Control Exemption. Flow control is not required for projects that discharge directly to Puget Sound if all the following are satisfied:
(a)
Direct discharge to the exempt receiving water does not result in the diversion of drainage from any perennial stream classified as Types 1, 2, 3, or 4 in the State of Washington Interim Water Typing System, or Types "S," "F," or "Np" in the Permanent Water Typing System, or from any Category I, II, or III wetland;
(b)
Flow splitting devices or drainage BMPs are applied to route natural runoff volumes from the project site to any downstream Type 5 stream or Category IV wetland:
(i)
Design of flow splitting devices or drainage BMPs will be based on continuous hydrologic modeling analysis. The design will assure that flows delivered to Type 5 stream reaches will approximate, but in no case exceed, durations ranging from 50 percent of the two-year to the 50-year peak flow; and
(ii)
Flow splitting devices or drainage BMPs that deliver flow to Category IV wetlands will also be designed using continuous hydrologic modeling to preserve preproject wetland hydrologic conditions unless specifically waived or exempted by regulatory agencies with permitting jurisdiction;
(c)
The project site must be drained by a conveyance system that is comprised entirely of manmade conveyance elements (e.g., pipes, ditches, outfall protection, etc.) and extends to the ordinary high water line of the exempt receiving water;
(d)
The conveyance system between the project site and the exempt receiving water shall have sufficient hydraulic capacity to convey discharges from future build-out conditions (under current zoning) of the site, and the existing condition from nonproject areas from which runoff is or will be collected;
(e)
Any erodible elements of the manmade conveyance system must be adequately stabilized to prevent erosion; and
(f)
Shoreline erosion is avoided through the use of appropriate energy dissipation or other protective measures.
(13)
Wetlands Protection (Minimum Requirement No. 8).
(a)
Discharges to wetlands shall maintain the hydrologic conditions, hydrophytic vegetation, and substrate characteristics necessary to support existing and designated uses. The hydrologic analysis shall use the existing land cover condition to determine the existing hydrologic conditions unless directed otherwise by a regulatory agency with jurisdiction.
(b)
Stormwater treatment and flow control facilities shall not be built within a natural vegetated buffer, except for:
(c)
An adopted and implemented basin plan prepared in accordance with the provisions of POMC § 20.150.230 may be used to develop requirements for wetlands that are tailored to a specific basin.
(14)
Operation and Maintenance (Minimum Requirement No. 9). All stormwater facilities shall be operated and maintained in accordance with POMC § 20.150.260.
(Ord. 019-17 § 18 (Exh. 1); Ord. 023-22 § 3)
§ 20.150.170 Standards – Redevelopment activities.
(1)
Where redevelopment activities meet the definition of a major development, the requirements of this section shall apply to that portion of the site that is being redeveloped. In addition, where one or more of the following conditions exist, the requirements of this section shall apply, to the maximum extent practicable, for the entire site, including adjoining parcels, if they are part of the project:
(2)
Approved Hydrological Methods for Design. Estimation of peak stormwater runoff rates used in the design of stormwater quantity control facilities shall utilize hydrograph methods of analysis approved by the director. The design of storage facilities that are a part of stormwater quantity control facilities shall be designed using methods approved by the director.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.180 Standards – Stormwater quantity control.
The following minimum requirements for stormwater quantity control shall apply to all development proposals that meet the definition of a major development:
(1)
All surface water and stormwater entering the development site in its predevelopment state shall be received at the naturally occurring or otherwise legally existing locations. All surface water and stormwater leaving the development site shall be discharged at all times during and after development at the naturally occurring or otherwise legally existing locations so as not to be diverted onto or away from adjacent downstream properties, except diversion which will correct an existing manmade downstream problem may be permitted by the director. For the purposes of this chapter, "naturally occurring location" shall mean the location of those channels, swales, and preexisting and established systems as defined by the first documented topographic contours existing for the subject property, either from maps or photographs, site inspections, decisions of a court of law, or other means determined appropriate by the director.
(2)
The post-development peak stormwater discharge rates from the development site for the two-, 10-, and 100-year, 24-hour duration storm events and the 100-year, seven-day duration storm event shall at no time exceed the predevelopment peak stormwater runoff rates for the same design storm events, except as expressly permitted by this chapter. Also, where stormwater directly or indirectly discharges to open channels or streams, streambank erosion protection is required; the post-development peak stormwater discharge rate from the development site for the two-year, 24-hour duration storm event shall not exceed 50 percent of the predevelopment peak stormwater runoff rate for the same design storm event. The director may require that runoff from a development site be controlled for additional design storm events.
(3)
Closed depressions shall be analyzed using hydrograph routing methods. Infiltration shall be addressed where appropriate. If a proposed project will discharge runoff to an existing closed depression that has greater than 5,000 square feet of water surface area at overflow elevation, the following requirements must be met:
(a)
Case 1. The predevelopment 100-year, seven-day and 24-hour duration design storms from the drainage basin tributary to the closed depression are routed into the closed depression using only infiltration as outflow. If the design storms do not overflow the closed depression, no runoff may leave the site for the same storm events following development of a proposed project. This may be accomplished by excavating additional volume in the closed depression subject to all applicable requirements. If a portion of the depression is located off of the project site, impacts to adjacent properties shall be evaluated.
(b)
Case 2. The predevelopment 100-year, seven-day and 24-hour duration design storm events from the drainage basin tributary to the closed depression are routed to the closed depression using only infiltration as outflow, and overflow occurs. The closed depression shall then be analyzed as a detention/infiltration pond. The required performance, therefore, shall not exceed the predevelopment runoff rates for 50 percent of the two-year and 100 percent of the 10-year and 100-year, 24-hour duration and 100-year, seven-day duration design storms. This will require that a control structure, emergency overflow spillway, access road, and other applicable design criteria be met. If the facility will be maintained by the city, the closed depression shall be placed in a dedicated tract. If the facility will be privately maintained, the tract shall be located within a drainage easement. If a portion of the depression is located off of the project site, impacts to adjacent properties shall be evaluated.
(c)
Case 3. When a proposed project is contributory to a closed depression located off site, the volume of runoff discharged may not be increased for the two-, 10-, and 100-year, 24-hour duration, and the 100-year, seven-day duration storm events. The exception to this requirement is in the case where discharge would not result in an increase in water surface elevation of greater than one-one-hundredth foot for the 100-year storm events.
(4)
Land developments shall provide stormwater quantity control facilities designed to meet, as a minimum performance standard, the requirements of this section, except in the following circumstances:
(a)
The development site discharges directly into Puget Sound, or directly into the tidally influenced areas of rivers and streams discharging into Puget Sound, where runoff quantity control is not required by other governmental agencies.
(b)
The development site discharges to a regional stormwater facility approved by the director to receive the developed site runoff.
(c)
The development site discharges to a receiving body of water (lake, wetland, etc.) where it can be demonstrated by the applicant, to the satisfaction of the director, that stormwater quantity control is not warranted.
(5)
In the event that conditions downstream from a proposed development site are determined by the director to be exceptionally sensitive to potential stormwater discharges from the subject site, the director may require a factor of safety be applied to the total retention/detention storage volume and/or a reduction of allowable stormwater release rates.
(6)
Submittals for all proposed development projects shall include an analysis of downstream water quantity impacts resulting from the project and shall provide for mitigation of these impacts. The analysis shall extend a minimum of one-quarter of a mile downstream from the project. The existing or potential impacts to be evaluated and mitigated shall include, but not be limited to, excessive streambank erosion, flooding, surcharging of existing closed drainage conveyance facilities, discharge to closed depressions, and discharge to existing off-site runoff control facilities.
(7)
Retention facilities and open stormwater quantity control facilities shall not be located in dedicated public road rights-of-way.
(8)
Reasonable access for maintenance, as determined by the director, shall be provided to all stormwater facilities.
(9)
As the first priority, streambank erosion control BMPs shall utilize infiltration to the fullest extent practicable, only if site conditions are appropriate and ground water quality is protected. Streambank erosion control BMPs shall be selected, designed, and maintained according to the manual. Streambank erosion control BMPs shall not be built within a natural vegetated buffer, except for necessary conveyance systems as approved by the department of public works.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.190 Standards – Water quality BMPs.
(1)
Water quality best management practices (BMPs) shall be used to the maximum extent practicable to control pollution in stormwater. Water quality BMPs shall be used to comply with the standards of this chapter, including those contained in the stormwater manual. Construction and post-development water quality BMPs shall be utilized for all developments. Said water quality BMPs shall provide runoff water quality treatment for all storm events with intensities less than or equal to the water quality design storm event, as defined in this chapter.
(2)
Illicit Discharges. Illicit discharges or illicit connections to a stormwater drainage system, pursuant to Chapter 15.30 POMC are prohibited.
(3)
Experimental Best Management Practices. In those instances where appropriate best management practices are not in the stormwater manual, experimental BMPs should be considered. In an effort to improve stormwater quality technology, experimental BMPs are encouraged as a means of solving problems in a manner not addressed by the stormwater manual. Experimental BMPs must be approved by the director. The director may require that the performance of experimental BMPs be monitored to document their effectiveness for future use.
(4)
Incorporation into Stormwater Quantity Control Facilities. Water quality BMPs may be incorporated into the design of stormwater quantity control facilities where appropriate.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.200 Standards – Stormwater conveyance facilities.
(1)
All proposed developments must provide on-site stormwater conveyance facilities having sufficient capacity to convey, without flooding or otherwise damaging existing or proposed structures, the post-development peak stormwater runoff rate resulting from a 100-year storm event, plus any existing upstream runoff that will be conveyed through the development site.
(2)
Estimation of peak stormwater runoff rates used in the design of water conveyance facilities shall use either the rational method or a hydrograph method of analysis accepted by the director.
(3)
Existing drainage ways and/or other conveyance facilities downstream from proposed developments that are identified within the scope of the downstream portion of the off-site drainage analysis shall have sufficient capacity to convey, without flooding or otherwise damaging existing or proposed structures, the post-development peak stormwater discharge for the 25-year storm event. All newly constructed downstream drainage ways and/or conveyance facilities shall have sufficient capacity to convey the post-development peak stormwater discharge for the 100-year storm event. Downstream improvements or additional on-site stormwater quantity control measures shall be provided to eliminate any potential downstream flooding or other damage that may occur following completion of the proposed development. The director has the authority to waive the requirement for downstream improvements.
(4)
Drainage through closed conveyance structures such as pipes shall not discharge directly onto the surface of a public road.
(5)
Easements, Tracts, and Covenants.
(a)
Drainage easements shall be provided in a proposed development for all stormwater conveyance systems that are not located in public rights-of-way or tracts. Said drainage easements shall be granted to the parties responsible for providing ongoing maintenance of the systems.
(b)
Stormwater facilities that are to be maintained by the city, together with maintenance access roads to said facilities, shall be located in public right-of-way, separate tracts dedicated to the city, or drainage easements located in designated open space. The exception is for stormwater conveyance pipes that may be located within easements on private property; provided, that all catch basins can be accessed without entering private property.
(c)
All runoff from impervious surfaces, roof drains, and yard drains shall be directed so as not to adversely affect adjacent properties. Wording to this effect shall appear on the face of all final plats/PUDs, and shall be contained in any covenants required for a development.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.210 Standards – Wetlands.
The following requirements apply only to situations where stormwater discharges directly or indirectly into a wetland and must be met in addition to meeting the requirements of Volume V and Volume I Appendix 1-D:
(1)
Stormwater discharges to wetlands must be controlled and treated to the same extent as all other discharges, with the goal of meeting state water quality and ground water quality standards.
(2)
Discharges to wetlands shall maintain the hydroperiod and flows of predevelopment site conditions to the extent necessary to protect the characteristic functions of the wetland. Prior to discharging to a wetland, alternative discharge locations shall be evaluated, and natural water storage and infiltration opportunities outside the wetland shall be maximized.
(3)
Created wetlands that are intended to mitigate for loss of wetland acreage, function and value shall not be designed to also treat stormwater.
(4)
In order for constructed wetlands to be considered treatment systems, they must be constructed in areas which are not designated as wetland or wetland buffer or in other areas which are in conflict with designated critical areas and associated buffers, and they must be managed for stormwater treatment. If these systems are not managed and maintained in accordance with the manual for a period exceeding three years, these systems may no longer be considered constructed wetlands.
(5)
Wetland BMPs shall not be built within a natural vegetated buffer, except for necessary conveyance systems as approved by the department of public works.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.220 Standards – Regional facilities.
When the director has determined that the public would benefit by the establishment of a regional stormwater facility which would serve as an alternative to the construction of separate on-site drainage facilities, the director may recommend to the city council that a regional stormwater facility be constructed which would serve more than one development in providing stormwater quantity and/or quality control. The associated owner(s) shall meet currently adopted stormwater regulations at the time of development. In the event that a regional stormwater facility is required by the city council, such a regional stormwater facility shall be located outside of fish-bearing streams, unless otherwise accepted by the Washington State Department of Fish and Wildlife. All future developments constructed on lands designated by the city council to be served by the regional facility shall, at the time of issuance of a stormwater management permit for a development, be required to contribute a fair share to the cost of land purchase, design, and construction of said regional facility. In the event that a proposed regional stormwater facility is not yet in operation at the time of completion of construction of a development that is to be served by said regional facility, the applicant for said development shall be required to provide temporary stormwater quantity and quality controls. Temporary quantity and quality controls may be constructed in temporary easements, rather than in separate tracts.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.230 Standards – Basin planning.
An adopted and implemented basin plan may be used to develop requirements for source control, stormwater treatment, streambank erosion control, wetlands, and water quality sensitive areas that are tailored to a specific basin. Adopted and implemented watershed-based basin plans may be used to modify any or all of the minimum requirements for stormwater quantity or quality control addressed in this chapter; provided, that the level of protection for surface or ground water achieved by the basin plan will equal or exceed that which would otherwise be achieved by implementation of the provisions of this chapter in the absence of a basin plan. Basin plans shall evaluate and include, as necessary, retrofitting of BMPs for existing development and/or redevelopment in order to achieve watershed-wide pollutant reduction goals. Standards developed from basin plans shall not modify any of the above requirements until the basin plan is formally adopted and fully implemented by the city.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.240 Standards – Exemptions.
Residential lots one acre or larger shall be exempt from the provisions of POMC § 20.150.170 through § 20.150.230, or as otherwise determined by the director. Cases where this exemption does not apply include, but are not limited to, sites within or adjacent to critical areas or watersheds, steep or unstable slopes, or where the cumulative impacts of development warrant compliance with these provisions. Site development activities taking place on individual lots of one acre or larger, which meet the definition of a major development, are not exempt from the requirements of POMC § 20.150.160. Proposed access roadways serving residential lots larger than two and one-half acres, which meet the definition of a major development, are not exempt from the requirements of POMC § 20.150.170.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.250 Facilities – Covenants, sureties, and liability insurance.
(1)
Site Stabilization Surety.
(a)
Prior to the issuance of a stormwater drainage permit and prior to beginning any construction activity on a project site, the owner of the project will be required to record a performance covenant or post a performance surety for site stabilization and erosion and sedimentation control. In addition, the owner may be required to provide a certificate of commercial liability insurance as outlined in subsection (5) of this section.
(b)
This performance requirement for stabilization and erosion control should not be confused with the performance bond accepted at the time of final plat recording as a surety for construction items not yet completed. When a performance bond is accepted for a final plat in lieu of construction completion, the surety or covenant for stabilization and erosion control will be released, and the new performance bond shall cover site stabilization and erosion control along with the other incomplete construction items.
(2)
Performance Covenant for Site Stabilization. For project sites with less than five acres of land disturbing activity, a performance covenant may be recorded in lieu of performance surety for site stabilization prior to issuance of the stormwater drainage permit to guarantee the city that temporary erosion and sedimentation control and permanent site stabilization measures will perform in accordance with this chapter. This covenant shall be recorded with the Kitsap County auditor and shall run with the land until such a time as the city issues final acceptance of the permitted activities, or until a separate performance bond is posted prior to final plat approval. Upon issuance of final project approval, the department of public works will record a document that extinguishes the performance covenant.
(3)
Performance Surety for Site Stabilization.
(a)
The term "bond" as defined in this chapter shall mean a surety bond, assignment of funds, or irrevocable bank letter of credit. For project sites with five or more acres of land disturbing activity, a performance bond shall be posted prior to issuance of a stormwater drainage permit to guarantee the city that temporary erosion and sedimentation control and permanent site stabilization measures will perform in accordance with this chapter. The amount of the performance bond shall be as follows:
(i)
One hundred fifty percent of the estimated cost of performing minor grading and installing temporary erosion and sedimentation control, and permanent site stabilization measures to bring the construction site into compliance with this chapter. A cost estimate shall be submitted by the project engineer subject to the approval of the director. The minimum amount of the bond shall be $5,000; or
(ii)
One thousand dollars per acre of land disturbing activity. No engineer's estimate is required.
(b)
If the site work is determined by the director to be in violation of this chapter, the city may use the performance bond to provide temporary and permanent site stabilization.
(c)
All performance bonds shall run continuously until released by the city, and shall not be subject to an expiration or cancellation date.
(4)
Performance Bond for Uncompleted Site Improvements.
(a)
For single-family residential developments, a performance bond shall be provided prior to the final recording of the plat/PUD, guaranteeing completion of all site improvements not yet completed. The amount of the performance bond shall be 150 percent of the estimated cost of said improvements. The estimated cost of the construction shall be determined by a civil engineer subject to the approval of the director.
(b)
All performance bonds shall run continuously until released by the city, and shall not be subject to an expiration or cancellation date.
(5)
Commercial Liability Insurance. The owner of any project must provide a certificate of liability insurance to the department of public works prior to issuance of a stormwater drainage permit. The liability insurance shall remain in force until final project approval is issued by the city. The commercial liability insurance shall be in the amount of not less than $1,000,000 combined single limit bodily injury and property damage, with a $2,000,000 aggregate. Such insurance shall include the city of Port Orchard, its officers, and employees as additional insureds, with respect to the terms and conditions of the policy.
(6)
Maintenance Bonds. A maintenance bond is required for all subdivisions and commercial projects for which stormwater facilities and/or roads are required pursuant to the following:
(a)
Prior to the final approval of construction and release of any performance sureties, a maintenance bond must be posted and maintained by the project owner for a period of two years.
(b)
The maintenance bond shall guarantee the stormwater facilities and roads constructed under permit against design defects and/or failures in workmanship and shall guarantee that the facilities constructed under the permit will be regularly and adequately maintained throughout the maintenance period. At the end of this time, the city will inspect the system and, when the facility is acceptable and 80 percent of the lots in that phase have been improved, the city will release the maintenance bond. In the event that 80 percent of the lots in a residential development have not been improved by the end of the two-year maintenance period, the maintenance bond may be extended, subject to the approval of the director, for one additional year.
(c)
The amount of the maintenance bond shall be 10 percent of the estimated construction cost of the stormwater facilities and roads requiring maintenance, or $5,000, whichever is greater. The construction cost of the stormwater facilities requiring maintenance shall be estimated by the project engineer, subject to the approval of the director.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.260 Facilities – Operation and maintenance.
(1)
Maintenance of Stormwater Facilities by Owners.
(a)
Any person or persons holding title to a nonresidential property for which stormwater facilities and BMPs have been required by the city shall be responsible for the continual operation, maintenance, and repair of said stormwater facilities and BMPs in accordance with the provisions of this chapter.
(b)
For privately maintained stormwater facilities, the maintenance requirements specified in this chapter, including the stormwater manuals, shall be enforced against the owner(s) of the subject property served by the stormwater facility.
(2)
Maintenance Covenant Required for Privately Maintained Drainage Facilities.
(a)
Prior to the beneficial use of a development constructed under a city permit, the owner shall record a maintenance covenant that guarantees Port Orchard that the owner shall properly operate, maintain, and inspect the stormwater facilities, and that also gives the city the authority to enter and inspect the facility. The restrictions set forth in such covenant shall be included in any instrument of conveyance of the subject property and shall be recorded with the Kitsap County auditor.
(b)
The director may require the owners of existing stormwater facilities for which the city has not previously accepted operation and maintenance responsibility to record a maintenance covenant, or to request that the city accept operation and maintenance responsibility for the stormwater facilities subject to the requirements of this chapter.
(c)
Maintenance covenants shall remain in force for the life of the development, or until the responsibility for the operation and maintenance of the subject stormwater facilities is accepted by the city.
(3)
City Acceptance of New Stormwater Facilities. The city may accept for maintenance those new residential stormwater facilities constructed under an accepted stormwater drainage permit that meet the following conditions:
(a)
Improvements in residential plats/PRDs have been completed on at least 80 percent of the lots, unless waived by the director;
(b)
All drainage facilities have been inspected and accepted by the director and said drainage facilities have been in satisfactory operation for at least two years;
(c)
All drainage facilities reconstructed during the maintenance period have been accepted by the director;
(d)
The stormwater facility, as designed and constructed, conforms to the provisions of this chapter;
(e)
All easements required under this chapter, entitling the city to properly operate and maintain the subject drainage facility, have been conveyed to the city and have been recorded with the Kitsap County auditor;
(f)
For nonstandard drainage facilities, an operation and maintenance manual, including a maintenance schedule, has been submitted to and accepted by the city; and
(g)
A complete and accurate set of reproducible Mylar as-built drawings and a CD containing an acceptable electronic set of as-built drawings have been provided to the city. A professional engineer shall certify that both the vertical and horizontal alignment meet the design objectives.
(h)
The director may terminate the city's assumption of maintenance responsibilities under this section in writing after determining that continued maintenance will not significantly contribute to protecting or improving the health, safety and welfare of the community.
(4)
City Acceptance of Existing Stormwater Facilities. The city may accept for maintenance those stormwater facilities for residential developments existing prior to the effective date of the ordinance codified in this chapter that meet the following conditions:
(a)
Improvements in residential plats/PRDs have been completed on at least 80 percent of the lots; and
(b)
An inspection by the director has determined that the stormwater facilities are functioning as designed; and
(c)
The stormwater facilities have had at least two years of satisfactory operation and maintenance, unless otherwise waived by the director; and
(d)
The person or persons holding title to the properties served by the stormwater facilities submit a petition containing the signatures of the title holders of more than 50 percent of the lots served by the stormwater facilities requesting that the city maintain the stormwater facilities; and
(e)
All easements required under this chapter, entitling the city to properly operate and maintain the subject stormwater facilities, have been conveyed to the city and have been recorded with the Kitsap County auditor; and
(f)
The person or persons holding title to the properties served by the stormwater facilities show proof of the correction of any defects in the drainage facilities, as required by the director.
(g)
The director may terminate the city's assumption of maintenance responsibilities under this section in writing after determining that continued maintenance will not significantly contribute to protecting or improving the health, safety and welfare of the community.
(5)
City Inspections of Privately Maintained Stormwater Facilities.
(a)
The director is authorized to develop an inspection program for privately owned and maintained stormwater facilities in the city. The purpose of this inspection program shall be to determine if said stormwater facilities, conveyance structures, and water quality facilities are in good working order and are properly maintained and to ensure that stormwater quality BMPs are in place and that nonpoint source pollution control is being implemented.
(b)
Whenever the provisions of the inspection program are being implemented, or whenever there is cause to believe that a violation of this chapter has been or is being committed, the inspector is authorized to inspect during regular working hours and at other reasonable times any and all stormwater drainage facilities within the city to determine compliance with the provisions of this chapter.
(6)
Inspection Schedule. The director is authorized to establish a master inspection and maintenance schedule to inspect appropriate stormwater facilities that are not owned and operated by the city. The party (or parties) responsible for maintenance and operation shall be identified. Critical stormwater facilities, as so deemed by the director, may require a more frequent inspection schedule.
(Ord. 019-17 § 18 (Exh. 1))
§ 20.150.270 Enforcement.
(1)
Violations of This Chapter. It is unlawful for any person to violate any provision or fail to comply with any of the requirements of this chapter or of any notice or lawful order issued hereunder. The city may enforce any such violation, at the city's discretion, through the enforcement and penalty provisions of Chapter 20.02 POMC, Administration and Enforcement, and/or Chapter 15.30 POMC.
(2)
Emergency Access and Reparation. In the event the violation constitutes an immediate danger to public health or safety, the director is authorized to enter upon the subject private property, without giving prior notice, to take any and all measures necessary to abate the violation and/or restore the property. Any expense related to such remediation undertaken by the city shall be fully reimbursed by the property owner and/or responsible party. Any relief obtained under this section shall not prevent the city from seeking further relief or applying other penalties as provided in this chapter.
(3)
Violation of Additional Laws. Any person who violates any provision of this chapter may also be in violation of the Federal Clean Water Act, NPDES Phase II permit, and/or Chapter 90.48 RCW and may be subject to sanctions associated with each, including civil and criminal penalties. Any enforcement action authorized under this chapter shall also include written notice to the violator of such potential liability.
(Ord. 019-17 § 18 (Exh. 1); Ord. 024-19 § 1 (Exh. 1); Ord. 043-22 § 2 (Exh. B))