Chapter 15.20
SURFACE WATER AND STORMWATER MANAGEMENT1
Sections:
15.20.040 Regulated activities and allowed activities.
15.20.050 General requirements.
15.20.010 Purpose.
The provisions of this chapter are intended to establish regulation for all new development, redevelopment or construction activities within the city that will or may impact surface water, groundwater or stormwater. The provisions of this chapter establish the minimum requirements that must be met to permit a property to be developed, redeveloped or proceed with construction activities within the city. The purpose of this chapter is to:
A. Preserve and enhance the suitability of waters for contact recreation, fishing, and other beneficial uses;
B. Minimize water quality degradation and sedimentation in streams, ponds, lakes, wetlands and other water bodies;
C. Minimize the impact of increased runoff, erosion and sedimentation caused by land development and poor maintenance practices;
D. Maintain and protect groundwater resources;
E. Minimize adverse impacts from projects on ground and surface water quantities, locations and flow patterns;
F. Decrease potential landslide, flood and erosion damage to public and private property;
G. Establish site planning and construction practices that are consistent with natural topographical, vegetational and hydrological conditions and that limit the extent of land disturbing activities;
H. Maintain and protect the city stormwater management infrastructure and downstream systems and properties. (Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 1, 2009: Ord. 98-31 § 1, 1999)
15.20.020 Definitions.
1. “Approval” means the proposed work or completed work conforms to this chapter in the opinion of the director.
2. “Best management practice (BMP)” means physical, structural, and/or managerial practices that, when used singly or in combination, prevent and reduce the release of pollutants and other adverse impacts to waters of Washington State.
3. “City” means the city of Bainbridge Island.
4. “Clearing” means the destruction and removal of vegetation by manual, mechanical, or chemical methods.
5. “Compaction” means densification, settlement, or packing of soil in such a way that permeability of the soil is reduced.
6. “Detention” means the release of stormwater runoff from a specific site at a slower rate than it is collected by the stormwater facility system, the difference being held in temporary storage.
7. “Detention facility” means an above or below ground facility, such as a pond or tank, that temporarily stores stormwater runoff and subsequently releases it at a slower rate than it is collected by the drainage facility system. There may be little or no infiltration of stored stormwater.
8. “Development” means new development, redevelopment, or both.
9. “Earth material” means any rock, natural soil or fill and/or any combination thereof.
10. “Erosion” means the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep, or the detachment and movement of soil or rock fragments by water, wind, ice, or gravity.
11. “Excavation” means the mechanical removal of earth material.
12. “Exotic species” means an introduced or nonindigenous species living outside its native distributional range which has arrived there by human activity, either deliberate or unintentional.
13. “Fill” means a deposit of earth material placed by artificial means.
14. “Forest practice” means any activity conducted on or directly pertaining to forest land and relating to growing, harvesting, or processing timber, as defined by RCW 76.09.050.
15. “Geologically hazardous areas” means areas susceptible to significant erosion, sliding, earthquake, or other geological events. They pose a threat to public health and safety when used as sites for incompatible commercial, residential or industrial development. Geologically hazardous areas include erosion hazard areas, landslide hazard areas, and seismic hazard areas. Refer to Chapter 16.20 BIMC.
16. “Groundwater” means water in a saturated zone or stratum beneath the surface of land or a surface water body.
17. “Hard surface” means an impervious surface, a permeable pavement, or a vegetated roof.
18. “Illegal discharge” and “illegal connections” are as defined in BIMC 15.22.020.
19. “Impervious surface” means a nonvegetated surface area which either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development and/or a hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to, roof tops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled macadam or other surfaces which similarly impede the natural infiltration of stormwater. Open, uncovered retention/detention facilities shall not be considered as impervious surfaces for purposes of determining whether the thresholds for application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered impervious surfaces for purposes of runoff modeling.
20. “Interflow” means that portion of rainfall that infiltrates into the soil and moves laterally through the upper soil horizons until intercepted by a stream channel or until it returns to the surface; for example, in a wetland, spring or seep.
21. “Invasive plant species” means opportunistic plant species (either native or nonnative) that colonize disturbed ecosystems and come to dominate the plant community in ways that are seen by us as reducing the values provided by the previous plant community.
22. “Land disturbing activity” means any activity that results in a change in the existing soil cover (both vegetative and nonvegetative) and/or the existing soil topography. Land disturbing activities include, but are not limited to, clearing, grading, filling and excavation. Compaction that is associated with stabilization of structures and road construction shall also be considered a land disturbing activity. Vegetation maintenance practices are not considered land disturbing activity. Stormwater facility maintenance is not considered land disturbing activity if conducted according to established standards and procedures.
23. “List No. 1” means on-site stormwater management BMPs for lawn and landscaped areas, roofs, and other hard surfaces included in the stormwater manual adopted in BIMC 15.20.050 for projects triggering Minimum Requirements No. 1 through 5.
24. “List No. 2” means on-site stormwater management BMPs for lawn and landscaped areas, roofs, and other hard surfaces included in the stormwater manual adopted in BIMC 15.20.050 for projects triggering Minimum Requirements No. 1 through 9.
25. “Low impact development (LID)” means a stormwater and land use management strategy that strives to mimic predisturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration by emphasizing conservation, use of on-site natural features, site planning, and distributed stormwater management practices that are integrated into a project design.
26. “Low impact development best management practices (LID BMPs)” mean distributed stormwater management practices, integrated into a project design, that emphasize predisturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration. LID BMPs include, but are not limited to: bioretention, rain gardens, permeable pavements, roof downspout controls, dispersion, soil quality and depth, minimal excavation foundations, vegetated roofs, and water reuse.
27. “LID performance standard” means matching developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from eight percent of the two-year peak flow to 50 percent of the two-year peak flow.
28. “LID principles” are land use management strategies that emphasize conservation, use of on-site natural features, and site planning to minimize impervious surfaces, native vegetation loss, and stormwater runoff.
29. “Minimum requirement” means one of nine minimum requirements for stormwater management that are applicable to new development and redevelopment projects as defined in the stormwater manual adopted in BIMC 15.20.050.
30. “Mitigation” means, in the following order of preference:
a. Avoiding the impact altogether by not taking a certain action or part of an action;
b. Minimizing impacts by limiting the degree or magnitude of the action and its implementation, by using appropriate technology, or by taking affirmative steps to avoid or reduce impacts;
c. Rectifying the impact by repairing, rehabilitating or restoring the affected environment;
d. Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.
31. “Native vegetation” means plant species that are indigenous to the coastal region of the Pacific Northwest and which reasonably could have been expected to naturally occur on the site. Invasive species and exotic species are not considered to be native species.
32. “New development” means land disturbing activities, including Class IV – general forest practices that are conversions from timber land to other uses; structural development, including construction or installation of a building or other structure; creation of hard surfaces; and subdivision, short subdivision and binding site plans, as defined and applied in Chapter 58.17 RCW. Projects meeting the definition of redevelopment shall not be considered new development.
33. “Pervious surface” means any surface material that allows stormwater to infiltrate into the ground. Examples include lawn, landscape, pasture, native vegetation areas, and permeable pavement.
34. “Pollution” means such contamination or other alteration of the physical, chemical, or biological properties of waters of the state, including change in temperature, taste, color, turbidity, or odor of the waters, or such discharge of any liquids, gaseous, solid, radioactive or other substance into any waters of the state as will or is likely to create a nuisance or render such waters harmful, detrimental or injurious to the public health, safety or welfare, or to domestic, commercial, industrial, agricultural, recreational, or other legitimate beneficial uses, or to livestock, wild animals, birds, fish or other aquatic life; as defined in RCW 90.48.020 as now existing or hereafter amended.
35. “Pollution-generating hard surface (PGHS)” means hard surfaces considered to be a significant source of pollutants in stormwater runoff. See the listing of surfaces under “pollution-generating impervious surface (PGIS).”
36. “Pollution-generating impervious surface (PGIS)” means impervious surfaces considered to be a significant source of pollutants in stormwater runoff. Such surfaces include those which are subject to vehicular use; industrial activities (as further defined in the glossary of the stormwater manual adopted in BIMC 15.20.050); storage of erodible or leachable materials, wastes, or chemicals, and which receive direct rainfall or the run-on or blow-in of rainfall; metal roofs unless they are coated with an inert, nonleachable material (e.g., baked-on enamel coating); or roofs that are subject to venting significant amounts of dusts, mists, or fumes from manufacturing, commercial, or other indoor activities.
37. “Pollution-generating pervious surfaces (PGPS)” means any pervious surface subject to vehicular use; industrial activities (as further defined in the glossary of the stormwater manual adopted in BIMC 15.20.050); storage of erodible or leachable materials, wastes, or chemicals, and that receive direct rainfall or run-on or blow-in of rainfall; use of pesticides and fertilizers; or loss of soil. Typical PGPS include permeable pavement subject to vehicular use, lawns, and landscaped areas including golf courses, parks, cemeteries, and sports fields (natural and artificial turf).
38. “Redevelopment” means, on a site that is already substantially developed (i.e., has 35 percent or more of existing impervious surface coverage) or which legally existed prior to February 10, 1999, the creation or addition of impervious surfaces; the expansion of a building footprint or addition or replacement of a structure; structural development including construction, installation or expansion of a building or other structure; replacement of impervious surface that is not part of a routine maintenance activity; and land disturbing activities.
39. “Replaced hard surface” means, for structures, the removal and replacement of hard surfaces down to the foundation. For other hard surfaces, the removal down to bare soil or base course and replacement.
40. “Replaced impervious surface” means, for structures, the removal and replacement of impervious surfaces down to the foundation. For other impervious surfaces, the removal down to bare soil or base course and replacement.
41. “Site” means the area defined by the legal boundaries of a parcel or parcels of land that is (are) subject to new development or redevelopment. For road projects, the length of the project site and the right-of-way boundaries define the site.
42. “Stormwater” means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland, interflow, channels or pipes into a defined surface water channel, or a constructed infiltration facility.
43. “Stormwater drainage system” means constructed and natural features which function together as a system to collect, convey, channel, hold, inhibit, retain, detain, infiltrate, divert, treat or filter stormwater.
44. “Stormwater facility” means a constructed component of a stormwater drainage system, designed or constructed to perform a particular function, or multiple functions, including but not limited to pipes, swales, ditches, culverts, street gutters, detention basins, retention basins, constructed wetlands, infiltration devices, catch basins, oil/water separators, sediment basins and modular pavement.
45. “Stormwater manual” means the Stormwater Management Manual for Western Washington adopted by reference in BIMC 15.20.050.
46. “Vegetation” means any plant life growing on the Island’s surfaces, including ponds, wetlands, and marshes.
47. “Waters of the state” includes those waters as defined as “waters of the United States” in 40 CFR Subpart 122.2 within the geographic boundaries of Washington State and “waters of the state” as defined in Chapter 90.48 RCW which includes lakes, rivers, ponds, streams, inland waters, groundwater, salt waters and all other surface waters and water courses within the jurisdiction of the state of Washington.
48. “Wetlands” means those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support (and under normal circumstances do support) a prevalence of vegetation typically adapted for life in saturated soil conditions, such as swamps, marshes, bogs, and other similar areas. This definition includes wetlands created, restored or enhanced as part of a mitigation procedure; it does not include constructed wetlands or the following surface waters of the state intentionally constructed from sites that are not wetlands: irrigation and drainage ditches, grass-lined swales, canals, agricultural detention facilities, farm ponds, and landscape amenities. Refer to Chapter 16.20 BIMC. (Ord. 2017-03 § 2, 2017; Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 2, 2009: Ord. 2005-10 § 1, 2005; Ord. 2003-22 § 22, 2003; Ord. 2001-49 § 1, 2001; Ord. 98-31 § 1, 1999)
15.20.030 General provisions.
A. Procedures. The department of public works/engineering department is authorized to adopt written procedures for the purpose of carrying out the provisions of this chapter. Prior to fulfilling the requirements of this chapter, the administrator or assigns shall not grant any approval or permission to conduct a regulated activity, including but not limited to the following:
1. Building permits, commercial or residential;
2. Comprehensive plan amendments;
3. Conditional use permits;
4. Final plats (short/long/large lot);
5. Forest practices;
6. Grading or clearing permits;
7. Planned unit developments;
8. Plats;
a. Subdivide, preliminary and final (short/long/large lot);
9. Preliminary plats (short, long, large lot);
10. Reasonable use exceptions;
11. Right-of-way permits;
12. Shoreline substantial development permits;
13. Shoreline variance/shoreline conditional use permits;
14. Site plan reviews;
15. Variances;
16. Zone reclassification (rezones); or
17. Any subsequently adopted permit or required approval not expressly exempted by this chapter.
B. The following agencies may also require a drainage review to assess the impact of development on a site. Any requirements imposed by these agencies are separate from the city mandates. It is the applicant’s sole responsibility to resolve any conflicting issues that may arise from submittal reviews.
1. U.S. Army Corps of Engineers;
2. Washington State Department of Natural Resources;
3. Bremerton-Kitsap County Health District;
4. Washington State Department of Ecology: general permit is required for development that disturbs one acre or more;
5. Washington State Department of Fish and Wildlife;
6. Washington State Department of Transportation. (Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2005-10 § 2, 2005: Ord. 98-31 § 1, 1999)
15.20.040 Regulated activities and allowed activities.
A. Regulated Activities. Consistent with the minimum requirements contained in the stormwater manual, the administrator shall approve or disapprove the following activities and may require the following permits:
1. New development may require a site assessment and development permit, building permit, land use permit, and/or zoning permit for the following:
a. Land disturbing activities;
b. Structural development, including construction, installation or expansion of an existing building or other structure;
c. Creation of 800 square feet or more of new hard surfaces;
d. Class IV general forest practices that are conversions from timber land to other uses; and
e. Subdivision, short subdivision and binding site plans, as defined in RCW 58.17.020.
2. Redevelopment may require a site assessment and development permit, building permit, land use permit, and/or zoning permit. On an already developed site, the creation or addition of 800 square feet or more of hard surfaces; structural development including construction, installation or expansion of a building or other structure; any land disturbing activity, and/or replacement of hard surface (that is not part of a routine maintenance activity); and land disturbing activities associated with structural or hard surface redevelopment. (Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 3, 2009: Ord. 2005-10 § 3, 2005: Ord. 98-31 § 1, 1999)
15.20.050 General requirements.
A. Stormwater Management Manual Adopted. The Washington State Department of Ecology’s 2019 Stormwater Management Manual for Western Washington, as amended, is hereby adopted by reference and is hereinafter referred to as the stormwater manual; provided, that certain provisions of the stormwater manual are amended as stated in BIMC 15.20.060.
B. Illegal discharges and illegal connections to the stormwater drainage system are prohibited by Chapter 15.22 BIMC.
C. Low Impact Development Manual Adopted. The 2012 Low Impact Development (LID) Technical Guidance Manual for Puget Sound is hereby adopted by reference and is hereinafter referred to as the LID manual. (Ord. 2022-11 § 3, 2022; Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 4, 2009: Ord. 2005-10 § 4, 2005: Ord. 98-31 § 1, 1999)
15.20.060 Approval standards.
A. City-Specific Standards. The city amends the standards adopted as part of the stormwater manual as follows:
1. Instead of following the Better Site Design BMP (BMP T5.41) in Volume V, Section V-2 of the stormwater manual, conduct a site assessment following the guidance in the LID manual adopted in BIMC 15.20.050. Comply with the city of Bainbridge Island design and construction standards for streets and roadways unless an exception is granted in writing by the administrator.
2. The hard surface threshold for triggering Minimum Requirements No. 1 through 5 for new development and redevelopment (Volume I, Section I-3.3) is reduced from 2,000 square feet to 800 square feet or greater of new plus replaced hard surface area.
3. Volume I, Section 3.5.2, Additional Protective Measure (“APM”) 1, Financial Liability, is not adopted.
4. Volume I, Section 3.5.1, APM No. 2, Off-Site Analysis and Mitigation, and Volume III, Section 3.2.3, Perform an Off-Site Analysis, is required for new development and redevelopment projects creating 5,000 square feet or more of hard surface area.
5. Volume I, Section 3.6.1, Adjustments to the MRs, is not adopted.
6. Volume V, BMP D.1, Detention Ponds, Signage section under Design Criteria, is amended to include the following language:
City of Bainbridge Island specific signage for constructed ponds is required to be provided by the developer as a part of the project. Contact the City Stormwater Management Program Coordinator to obtain approved sign specifications for a permanent surface water control pond, which will include the pond name, pond number, and telephone number to include on the sign.
7. Volume V, Section 1.2, Setbacks, Slopes, and Embankments, is amended to add the following language after the first paragraph in the Setbacks section:
Chapter 16.20 BIMC defines “Zone of Influence” as it relates to moderate and steep slopes. A Geotechnical Engineer is required to evaluate a project stormwater site plan that proposes land disturbance, changes in land use, or changes in site hydrology within the zone of influence of any geologically hazardous area as defined in Chapter 16.20 BIMC.
8. The city utilizes the Rain Garden Handbook for Western Washington: A Guide for Design, Installation and Maintenance (Hinman et al., 2013). Volume V, Section V-11 of the stormwater manual, BMP T5.14, Rain Gardens, is modified to add the following text to the end of the first paragraph of the Design Guidelines section:
Use the “Good (80%)” performance level for Rainfall Region 3 in the Rain Garden Sizing Chart at a minimum. “Better (95%)” performance level is preferred.
(Ord. 2022-11 § 4, 2022; Ord. 2017-03 § 3, 2017; Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 5, 2009: Ord. 2005-10 § 5, 2005: Ord. 2001-49 § 2, 2001; Ord. 98-31 § 1, 1999)
15.20.070 Administration.
A. Administrator. The public works director or a designee shall administer this chapter and shall be referred to as the administrator. The administrator shall have the authority to develop and implement administrative procedures to administer and enforce this chapter.
B. Review and Approval. The administrator may approve, conditionally approve or deny an application for activities regulated by this chapter.
C. Enforcement Authority. The administrator shall enforce this chapter.
D. Inspection. All activities regulated by this chapter shall be inspected by the administrator. The administrator 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:
1. Prior to clearing and construction (preconstruction) to ensure that clearing limits, sensitive areas and their buffers, and trees that are to be preserved have been clearly marked;
2. During construction to verify proper installation and maintenance of erosion and sediment control BMPs, maintenance of clearing limits, and protection of trees that are to be preserved;
3. Every six months during construction for new residential development until 90 percent of the lots are constructed (or when construction has stopped and the site is fully stabilized) to identify maintenance needs for permanent stormwater facilities;
4. Upon completion of construction and prior to final approval or occupancy to ensure proper installation of permanent stormwater facilities; and
5. Ongoing annual inspections of permanent stormwater facilities designed to meet Minimum Requirement No. 6 (Runoff Treatment) and/or Minimum Requirement No. 7 (Flow Control) per Chapter 15.21 BIMC.
When required by the administrator, a special inspection and/or testing shall be performed. (Ord. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 6, 2009: Ord. 2005-10 § 6, 2005: Ord. 98-31 § 1, 1999)
15.20.080 Enforcement.
A. Failure to Comply. It is unlawful for any person to violate any provision or fail to comply with any of the requirements of this chapter.
B. Emergency Access and Reparation. In the event the violation constitutes an immediate danger to public health or safety, the administrator 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.
C. Civil Infraction. Except as provided in subsection D of this section, conduct made unlawful by this chapter shall constitute a civil infraction and is subject to enforcement and fines as provided in BIMC 1.26.035. A civil infraction under this section shall be processed in the manner set forth in Chapter 1.26 BIMC.
D. Misdemeanor. Any person who, having been found in violation of this chapter, fails once again to abide by its regulations, commits a misdemeanor and is subject to the penalties provided in BIMC 1.24.010.A.
E. Civil Penalty. In addition to any civil infraction fine, criminal penalty, and/or other available sanction or remedial procedure, any person engaging in conduct made unlawful by this chapter shall be subject to a cumulative civil penalty in the amount of $1,000 per day for each violation from the date set for compliance until the date of compliance. Any such civil penalty shall be collected in accordance with BIMC 1.26.090.
F. Additional Remedies.
1. In addition to any other remedy provided by this chapter or under the Bainbridge Island Municipal Code, the city may initiate injunction or abatement proceedings or any other appropriate action in courts against any person who violates or fails to comply with any provision of this chapter to prevent, enjoin, abate, and/or terminate violations of this chapter and/or to restore a condition which existed prior to the violation. In any such proceeding, the person violating and/or failing to comply with any provisions of this chapter shall be liable for the costs and reasonable attorneys’ fees incurred by the city in bringing, maintaining and/or prosecuting such action.
2. 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 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. 2016-28 § 8 (Exh. C), 2016: Ord. 2009-13 § 7, 2009: Ord. 2005-10 § 7, 2005: Ord. 98-31 § 1, 1999)
15.20.090 Exceptions and appeals.
Repealed by Ord. 2009-13. (Ord. 2005-10 § 8, 2005: Ord. 2003-25 § 6, 2003; Ord. 98-31 § 1, 1999)
15.20.100 Severability.
Repealed by Ord. 2003-24. (Ord. 98-31 § 1, 1999)
Prior legislation: Ords. 85-13, 86-02, 88-16 and 94-29.