Chapter 24.08
STORMWATER MANAGEMENT
Sections:
24.08.050 Abrogation and greater restrictions.
24.08.080 Regulated activities.
24.08.100 Stormwater management manuals adopted.
24.08.110 Stormwater best management practices (BMPs).
24.08.130 Conditional discharges.
24.08.140 Allowable discharges.
24.08.150 – 24.08.190 Repealed.
24.08.200 Minimum requirement No. 1 – Preparation of stormwater site plans.
24.08.210 Minimum requirement No. 2 – Construction stormwater pollution prevention plan (SWPPP).
24.08.220 Minimum requirement No. 3 – Source control of pollution.
24.08.230 Minimum requirement No. 4 – Preservation of natural drainage systems and outfalls.
24.08.240 Minimum requirement No. 5 – On-site stormwater management.
24.08.250 Minimum requirement No. 6 – Runoff treatment.
24.08.260 Minimum requirement No. 7 – Flow control.
24.08.270 Minimum requirement No. 8 – Wetlands protection.
24.08.280 Minimum requirement No. 9 – Operation and maintenance.
24.08.420 Duration of exception.
24.08.010 Findings of fact.
A. The city council of the city of Pacific hereby finds that:
1. Stormwater pollution is a problem associated with land utilization and development and the common occurrence of potential pollutants such as pesticides, fertilizers, petroleum products, pet wastes, and numerous others.
2. Land utilization and development is also known to increase both the volume and duration of peak flows. The resulting erosion, scouring, and deposition of sediment affect the ecological balance in the stream.
3. Sedimentation and stormwater pollution cause diversity of species to decrease and allows more tolerant (and usually less desirable) species to remain.
4. Stormwater pollution can cause or contribute to restrictions on public use of the waters within the city.
B. An expanding population and increased development of land have led to:
1. Water quality degradation through discharge of nutrients, metals, oil and grease, toxic materials, and other detrimental substances including, without limitation, insect and weed control compounds;
2. Drainage and storm- and surface-water runoff problems within the city; and
3. Safety hazards to both lives and property posed by uncontrolled water runoff on streets and highways.
C. Continuation of present stormwater management practices, to the extent that they exist, will lead to water quality degradation, erosion, property damage, and will endanger the health and safety of the inhabitants of the city of Pacific.
D. In the future such problems and dangers will be reduced or avoided if existing properties and future developers, both private and public, provide for stormwater quality and quantity controls.
E. Stormwater quality and quantity controls can be achieved when land is developed or redeveloped by implementing appropriate best management practices (BMPs).
F. Best management practices can be expected to perform as intended only when properly designed, constructed and maintained. (Ord. 1482 § 1, 2000).
24.08.020 Need.
The city council finds that this chapter is necessary in order to:
A. Minimize or eliminate water quality degradation;
B. Prevent erosion and sedimentation in creeks, streams, ponds, lakes and other water bodies;
C. Protect property owners adjacent to existing and developing lands from increased runoff rates which could cause erosion of abutting property;
D. Preserve and enhance the suitability of waters for contact recreation, fishing, and other beneficial uses;
E. Preserve and enhance the aesthetic quality of the water;
F. Promote sound development policies which respect and preserve city surface water, ground water and sediment;
G. Ensure the safety of city roads and rights-of-way;
H. Decrease stormwater-related damage to public and private property from existing and future runoff; and
I. Protect the health, safety and welfare of the inhabitants of the city of Pacific. (Ord. 1482 § 1, 2000).
24.08.030 Purpose.
A. The provisions of this chapter are intended to guide and advise all who conduct new development or redevelopment within the city of Pacific. The provisions of this chapter establish the minimum level of compliance that must be met to permit a property to be developed or redeveloped within the city.
B. It is the purpose of this chapter to:
1. Minimize water quality degradation and sedimentation in streams, ponds, lakes, wetlands and other water bodies;
2. Minimize the impact of increased runoff, erosion and sedimentation caused by land development and maintenance practices;
3. Maintain and protect groundwater resources;
4. Minimize adverse impacts of alterations on ground and surface water quantities, locations and flow patterns;
5. Decrease potential landslide, flood and erosion damage to public and private property;
6. Promote site planning and construction practices that are consistent with natural topographical, vegetational and hydrological conditions;
7. Maintain and protect the city stormwater management infrastructure and those downstream;
8. Provide a means of regulating clearing and grading of private and public land while minimizing water quality impacts in order to protect public health and safety; and
9. Provide minimum development regulations and construction procedures which will preserve, replace or enhance, to the maximum extent practicable, existing vegetation to preserve and enhance the natural qualities of lands, wetlands and water bodies. (Ord. 1482 § 1, 2000).
24.08.040 Definitions.
For the purposes of this chapter, the definitions below apply, provided unless otherwise defined in this chapter the definitions provided in the Manuals adopted by reference in PMC 24.08.100 shall apply. If there is a conflict, the definitions in this section shall govern.
“Approval” means the proposed work or completed work conforms to this chapter in the opinion of the director.
“As-graded” means the extent of surface conditions on completion of grading.
“Authorized enforcement agency” means employees or designees of the public works director of the city of Pacific designated to enforce this code.
“Best management practice” or “BMP” means physical, structural, and/or managerial practices that, when used singly or in combination, prevent or reduce pollution of water, and have been approved by Ecology. BMPs are listed and described in the Manual.
“Bioretention” means a flow control best management practice consisting of a shallow landscaped depression designed to temporarily store and promote infiltration of stormwater runoff. Standards for bioretention design, including soil mix, plants, storage volume and feasibility criteria, are specified in the Manual.
“Clean Water Act” means the federal Water Pollution Control Act (33 U.S.C. Section 1251 et seq.), and any subsequent amendments thereto.
“Commercial agriculture” means those activities conducted on lands defined in RCW 84.34.020(2), and activities involved in the production of crops or livestock for wholesale 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.
“Compaction” means densification of a fill by mechanical means.
“Ecology” means the Washington State Department of Ecology.
“Excavation” means the mechanical removal of earth material.
“Fill” means a deposit of earth material placed by artificial means.
“Flow control BMP” means BMPs that control the volume rate, frequency, and flow duration of stormwater surface runoff.
“Illegal discharge” means any direct or indirect nonstormwater discharge to the storm drain system, except as exempted in PMC 24.10.050.
“Illicit connections” means either of the following:
A. Any drain or conveyance, whether on the surface or subsurface, which allows an illegal 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 an authorized enforcement agency; or
B. Any drain or conveyance connected from a commercial or industrial land use to the storm drain system which has not been documented in plans, maps, or equivalent records and approved by an authorized enforcement agency.
“Illicit discharge” means all nonstormwater discharges to stormwater drainage systems that cause or contribute to a violation of state water quality, sediment quality or groundwater quality standards, including but not limited to sanitary sewer connections, industrial process water, interior floor drains, car washing and greywater systems.
“Industrial activity” means activities subject to NPDES industrial permits as defined in 40 CFR 122.26(b)(14).
“LID best management practices” means distributed stormwater management practices, integrated into a project design, that emphasize predisturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration. LID BMPs are referred to as flow control BMPs and include, but are not limited to, bioretention, permeable pavements, limited infiltration systems, roof downspout controls, dispersion, soil quality and depth, and minimal excavation foundations.
“LID principles” means 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.
“Low impact development” or “LID” means a stormwater and land use management strategy that strives to mimic predisturbance hydraulic 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.
“Manual” or “Stormwater Management Manual” means the manual or manuals adopted by reference in PMC 24.08.100.
“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; and
E. Compensation for the impact by replacing, enhancing, or providing substitute resources or environments.
“MS4” means municipal separate storm sewer system.
“Nonstormwater discharge” means any discharge to the storm drain system that is not composed entirely of stormwater.
“Person” means any individual, partnership, corporation, association, organization, cooperative, public or municipal corporation, agency of the state, or local government unit, however designated.
“Premises” means any building, lot, parcel of land, or portion of land whether improved or unimproved including adjacent sidewalks and parking strips.
“Public works director” means the person holding the position of the public works manager of the city of Pacific, or his or her designee.
“Rain garden” means a 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 to allow stormwater to pass through the amended soil profile.
“Stormwater drainage facility” means a constructed component of a stormwater drainage system, designed or constructed to perform a particular function, or multiple functions. Stormwater facilities include, but are not limited to, pipes, swales, ditches, culverts, street gutters, detention basins, retention basins, constructed wetlands, infiltration devices, catchbasins, oil/water separators, sediment basins and modular pavement.
“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.
“Toe of slope” means a point or line of slope in an excavation or cut where the lower surface changes to horizontal or meets the existing ground slope.
“Top of slope” means a point or line on the upper surface of a slope where it changes to horizontal or meets the original surface.
“Unstable slopes” means those sloping areas of land which have in the past exhibited, are currently exhibiting, or will likely in the future exhibit mass movement of earth.
“Vegetation” means all organic plant life growing on the surface of the earth.
“Wastewater” means any water or other liquid, other than uncontaminated stormwater, discharged from a facility.
“Water body” means surface waters including rivers, streams, lakes, marine waters, estuaries, and wetlands. (Ord. 2058 § 4, 2022; Ord. 1949 § 11, 2017; Ord. 1816 § 3, 2012; Ord. 1726 § 1, 2009; Ord. 1482 § 1, 2000).
24.08.050 Abrogation and greater restrictions.
It is not intended that this chapter repeal, abrogate, or impair any existing regulations, easements, covenants, or deed restrictions. However, where this chapter imposes greater restrictions, the provisions of this chapter shall prevail. (Ord. 1482 § 1, 2000).
24.08.060 Interpretation.
The provisions of this chapter shall be held to be minimum requirements in their interpretation and application and shall be liberally construed to serve the purposes of this chapter. (Ord. 1482 § 1, 2000).
24.08.070 Applicability.
A. When any provision of any other chapter of the municipal code of the city of Pacific conflicts with this chapter, that which provides more environmental protection shall apply unless specifically provided otherwise in this chapter.
B. The city of Pacific 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 city shall not grant any approval or permission to conduct a regulated activity including, but not limited to, the following:
1. Building permit, commercial or residential.
2. Binding site plan.
3. Conditional use permit.
4. Franchise right-of-way construction permit.
5. Grading and clearing permit.
6. Master plan development.
7. Planned unit development.
8. Right-of-way permit.
9. Shoreline substantial development permit.
10. Shoreline variance.
11. Shoreline conditional use permit.
12. Shoreline environmental redesignation.
13. Unclassified use permit.
14. Variance.
15. Zone reclassification.
16. Subdivision.
17. Short subdivision.
18. Special use permit.
19. Utility and other use permit.
20. Zone reclassification.
21. Any subsequently adopted permit or required approval not expressly exempted by this chapter.
C. Regulated activities shall be conducted only after the city of Pacific approves a stormwater site plan that includes one or more of the following as required by this chapter:
1. Small parcel erosion and sediment control site drainage plan;
2. Large parcel erosion and sediment control plan engineering plans with erosion/sediment control and a technical information report; or
3. Permanent stormwater quality control (PSQC) plan master drainage plan. (Ord. 1482 § 1, 2000).
24.08.080 Regulated activities.
Consistent with the minimum requirements contained in this chapter, the city of Pacific shall approve or disapprove the following activities, unless exempted under PMC 24.08.090:
A. New development, including, but not limited to:
1. Land disturbing activities;
2. Structural development, including construction; installation or expansion of a building or other structure;
3. Creation of impervious surfaces;
4. Class IV general forest practices that are conversions from timber land to other uses; and
5. Subdivision, short subdivision and binding site plans, as defined in RCW 58.17.020.
B. Redevelopment. On an already developed site, the creation or addition of impervious surfaces, structural development including construction, installation or expansion of a building or other structure, land disturbing activity, and/or replacement of impervious surface that is not part of a routine maintenance activity, and land disturbing activities associated with structural or impervious redevelopment.
All development proposal activities in the city shall comply with the standards, specifications, and requirements contained in this code and Manual. When best management practices (BMPs) are required by this chapter or any other chapter of this code, they shall be implemented in compliance with the manual and the property owner or responsible party shall be required to maintain in perpetuity such BMPs consistent with the Manual.
Where there are differences and/or conflicts between the Manual and/or Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit, the most restrictive criteria shall apply. (Ord. 2058 § 5, 2022; Ord. 1482 § 1, 2000).
24.08.090 Exemptions.
A. Commercial agriculture, and forest practices regulated under WAC Title 222, except for Class IV-General forest practices that are conversions from timber land to other uses, are exempt from the provisions of this chapter.
B. Development undertaken by the Washington State Department of Transportation in state highway rights-of-way is regulated by Chapter 173-270 WAC, the Puget Sound Highway Runoff Program.
C. All other new development and redevelopment is subject to the minimum requirements of this chapter. (Ord. 1482 § 1, 2000).
24.08.100 Stormwater management manuals adopted.
The 2021 Edition of King County’s Surface Water Design Manual, the 2021 Edition of the King County Stormwater Pollution Prevention Manual, and Appendices 1 and 8 of the Western Washington Phase II Municipal Stormwater Permit are hereby adopted by reference and are collectively referred to as the Manual. If there is any conflict between this chapter and the requirements of the Manual, this chapter shall prevail. (Ord. 2058 § 6, 2022; Ord. 1949 § 12, 2017; Ord. 1816 § 3, 2012; Ord. 1482 § 1, 2000).
24.08.110 Stormwater best management practices (BMPs).
A. General. BMPs shall be used to control pollution from stormwater. BMPs shall be used to comply with the standards in this chapter.
B. Source Control BMP Requirements. The Manual provides information on source control pollution prevention best management practices (BMPs) for commercial, industrial, multifamily residential, single-family residential, and public sites that shall be implemented in accordance with this chapter to reduce the contamination of stormwater, surface water, and groundwater. The source control requirements shall also be applicable to pollutant generating sources associated with existing land uses and activities included in Appendix 8 of the Western Washington Phase II Municipal Stormwater Permit, as amended, which includes the following businesses and activities: activities for animal production, construction of buildings, heavy and civil engineering construction, specialty trade contractors, beverage, food, and tobacco manufacturing, wood product manufacturing, paper manufacturing, printing and related support activities, chemical manufacturing, petroleum and coal products manufacturing, plastics and rubber product manufacturing, leather and allied product manufacturing, nonmetallic mineral product manufacturing, primary metal manufacturing, fabricated metal product manufacturing, machinery, computer, and electronic product manufacturing, electrical equipment, appliance, and component manufacturing, transportation equipment manufacturing, rail transportation and ground passenger transportation, truck transportation and warehousing, support activities for transportation, utilities, wholesale trade – durable goods, wholesale trade – nondurable goods, building materials, hardware, garden supplies dealers, food and beverage stores, automotive dealers and gasoline service stations, food services and drinking places, rental and leasing services, repair and maintenance, ambulatory health care services and hospitals, educational services, museums, and historical sites, and similar institutions.
All proposals for new development and redevelopment shall include source control pollution prevention BMPs as required by the Manual.
In applying the Manual to prohibited discharges from normal single-family residential activities, the director shall use public education and technical assistance as the primary method of gaining compliance with this chapter. Enforcement action will be used if the director determines:
1. The discharge from a normal single-family residential activity, whether singly or in combination with other discharges, is causing a significant contribution of contaminants to surface and stormwater or groundwater; or
2. The discharge from a normal single-family residential activity poses a hazard to the public health, safety or welfare, endangers any property or adversely affects the safety and operation of city rights-of-way, utilities, or other city-owned or maintained property.
In applying the source control BMPs to prohibited discharges from existing commercial, industrial, multifamily and public sites, the city may require the application of operational or structural source control BMPs at any time through formal code enforcement for pollutant generating sources associated with existing land uses and activities where necessary to prevent illicit discharges. Failure to comply shall result in enforcement action in accordance with this chapter.
C. Experimental BMPs. In those instances where appropriate BMPs are not in the Manual, experimental BMPs should be considered. Experimental BMPs are encouraged as a means of solving problems in a manner not addressed by the Manual in an effort to improve stormwater quality technology. Experimental BMPs must be approved in accordance with the approval process outlined in the Manual.
D. Exemptions.
1. Persons implementing BMPs through another approved federal, state, or local program will not be required to implement the BMPs prescribed in the Manual, unless the director determines that the other program’s BMPs are ineffective at minimizing the discharge of contaminants. If the other program requires the development of a stormwater pollution prevention plan, the person shall make their plan available to the city upon request. Persons who qualify for exemptions include, but are not limited to, persons who:
a. Have obtained and are complying with a general or individual permit under the NPDES Stormwater Permit Program from the Washington State Department of Ecology;
b. Are a public facility implementing BMPs in compliance with the stormwater management program of an NPDES municipal stormwater permit;
c. Are voluntarily implementing other BMPs, which are equivalent measures, methods, or practices to the BMPs in the Manual. (Ord. 2058 § 7, 2022; Ord. 1482 § 1, 2000).
24.08.120 Illicit discharges.
Illicit discharges or illicit connections to a stormwater drainage system are prohibited, as set out in Chapter 24.10 PMC. (Ord. 2058 § 8, 2022).
24.08.130 Conditional discharges.
A. The following types of discharges shall not be considered illicit discharges for the purpose of this title if they meet the stated conditions, or unless the director and/or designee determines that the type of discharge, whether singly or in combination with others, is causing or is likely to cause pollution of surface water or groundwater:
1. Potable water, including water from water line flushing, hyperchlorinated water line flushing, fire hydrant system flushing, and pipeline hydrostatic test water. Planned discharges shall be dechlorinated to a concentration of 0.1 mg/L (ppm) or less, pH adjusted, if necessary and in volumes and velocities controlled to prevent resuspension of sediments in the stormwater system.
2. Lawn watering and other irrigation runoff are permitted but shall be minimized.
3. Dechlorinated swimming pool, spa and hot tub discharges. These discharges are allowed only if no other option, such as discharging to a sanitary sewer, is available. These discharges shall be dechlorinated to a total residual chlorine concentration of 0.1 mg/L (ppm) or less, pH adjusted, and deoxygenized if necessary and in volumes and velocities controlled to prevent resuspension of sediments in the stormwater system. Discharges shall be thermally controlled to prevent an increase in temperature of the receiving water. Swimming pool cleaning wastewater and filter backwash shall not be discharged to the stormwater system.
4. Street and sidewalk wash water, water used to control dust, and routine external building washdown that does not use detergents or chemicals of any kind. Wash water is required to be kept at a minimum. Pressure washing that results in paint or other building materials in wash water is prohibited from entering the stormwater drainage system. Street flushing at construction sites is prohibited in Pacific.
5. Fire Sprinkler System Flushing. These discharges are allowed only if no other option, such as discharging to a sanitary sewer, is available. Sprinkler system flushing water with any chemicals added is prohibited in the stormwater drainage system. Sprinkler system flushing water discharges shall be dechlorinated to a concentration of 0.1 mg/L (ppm) or less, pH adjusted, if necessary and discharged in volumes and velocities controlled to prevent resuspension of sediments in the stormwater system.
6. Nonstormwater discharges covered by an individual or general NPDES permit; provided, that the discharge is in full compliance with all requirements of the permit, waiver, or order and other applicable laws and regulations.
7. Other nonstormwater discharges. The discharges shall be in compliance with requirements of a stormwater pollution prevention plan (SWPPP) reviewed and approved by the city of Pacific, which addresses control of such discharges by applying all known and reasonable technologies (AKART) to prevent contaminants from entering surface water and groundwater. The city of Pacific shall require a SWPPP in the event that nonstormwater discharges are not being controlled. (Ord. 2058 § 9, 2022).
24.08.140 Allowable discharges.
A. The following types of discharges shall not be considered illicit discharges for the purposes of this chapter unless the director and/or designee determines that the type of discharge, whether singly or in combination with others, is causing or is likely to cause pollution of surface water or groundwater:
1. Diverted stream flows.
2. Rising groundwater.
3. Uncontaminated groundwater infiltration as defined in 40 CFR 35.2005(20).
4. Uncontaminated pumped groundwater.
5. Foundation drains.
6. Air conditioning condensation.
7. Irrigation water from agricultural sources that is commingled with urban stormwater.
8. Springs.
9. Water from crawl space pumps.
10. Footing drains.
11. Flows from riparian habitats and wetlands.
12. Discharges from emergency firefighting activities. (Ord. 2058 § 10, 2022).
24.08.150 Small parcel requirement No. 2 – Stabilization of denuded areas.
Repealed by 1816. (Ord. 1482 § 1, 2000).
24.08.160 Small parcel requirement No. 3 – Protection of adjacent properties.
Repealed by 1816. (Ord. 1482 § 1, 2000).
24.08.170 Small parcel requirement No. 4 – Maintenance.
Repealed by 1816. (Ord. 1482 § 1, 2000).
24.08.180 Small parcel requirement No. 5 – Other BMPs.
Repealed by 1816. (Ord. 1482 § 1, 2000).
24.08.190 Large development minimum requirements.
Repealed by 1816. (Ord. 1482 § 1, 2000).
24.08.200 Minimum requirement No. 1 – Preparation of stormwater site plans.
As part of a complete application for the following permits/approvals, all developers/property owners shall submit a stormwater site plan, which shall be prepared in accordance with the Manual.
A. Grading permit;
B. Substantial development permit required under Chapter 90.58 RCW (Shoreline Management Act);
C. Subdivision approval;
D. Short plat approval (industrial and commercial);
E. Conditional use permit;
F. Building permit where the permit relates to 2,000 or more square feet of development coverage within the property, or where development is in a critical area;
G. Planned unit residential development; or
H. Any new development, redevelopment, and construction site activities that result in land disturbance of equal or greater than 7,000 square feet. (Ord. 2058 § 11, 2022; Ord. 1949 § 14, 2017; Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.210 Minimum requirement No. 2 – Construction stormwater pollution prevention plan (SWPPP).
All new development and redevelopment projects are responsible for preventing erosion and discharge of sediment and other pollutants into receiving waters. A construction stormwater pollution prevention plan (SWPPP) shall be part of the stormwater site plan for all projects. The SWPPP shall be implemented beginning with initial soil disturbance and until final stabilization.
The SWPPP shall include a narrative and drawings. All BMPs shall be clearly referenced in the narrative and marked on the drawings. Sediment and erosion control BMPs shall be consistent with the BMPs contained in the adopted manuals. The SWPPP narrative shall include documentation to explain and justify the pollution prevention decisions made for the project. Clearing and grading activities for developments shall be permitted only if conducted pursuant to an approved site development plan. (Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.220 Minimum requirement No. 3 – Source control of pollution.
Source control BMPs shall be applied to all projects, existing land uses and activities, and to all pollutant generating sources. Source control BMPs shall be selected, designed and maintained according to this chapter and the Manual. (Ord. 2058 § 12, 2022; Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.230 Minimum requirement No. 4 – Preservation of natural drainage systems and outfalls.
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 shall not cause a significant adverse impact to downstream receiving waters and down gradient properties. All outfalls require energy dissipation. (Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.240 Minimum requirement No. 5 – On-site stormwater management.
Projects shall employ on-site stormwater management BMPs in accordance with the following project thresholds, standards, and lists to infiltrate, disperse, and retain stormwater runoff to the extent feasible without causing flooding or erosion impacts.
Projects qualifying as flow control exempt in accordance with minimum requirement No. 7 do not have to achieve the LID performance standard, nor consider rain gardens, permeable pavement, and full dispersion. However, those projects must implement other BMPs described in the Manual, if feasible.
A. Project Thresholds. Projects triggering only minimum requirements No. 1 through No. 5 shall either:
1. Use on-site stormwater management BMPs from List No. 1 for all surfaces within each type of surface in List No. 1; or
2. Demonstrate compliance with the LID performance standard. Projects selecting this option cannot use rain gardens. They may choose to use bioretention BMPs as described in the adopted Manual to achieve the LID performance standard.
B. Projects triggering minimum requirements No. 1 through No. 9 must meet the requirements described below:
|
Project Type and Location |
Requirement |
|---|---|
|
New development on any parcel inside the UGA, or new development outside the UGA on a parcel less than 5 acres |
Low Impact Development Performance Standard and Post-Construction Soil Quality and Depth as per the adopted manual; or List No. 2 (applicant option). |
|
New development outside the UGA on a parcel of 5 acres or larger |
Low Impact Development Performance Standard and Post-Construction Soil Quality and Depth per the adopted Manual. |
|
Redevelopment on any parcel inside the UGA, or redevelopment outside the UGA on a parcel less than 5 acres |
Low Impact Development Performance Standard and Post-Construction Soil Quality and Depth as per the adopted Manual; or List No. 2 (applicant option). |
|
Redevelopment outside the UGA on a parcel of 5 acres or larger |
Low Impact Development Performance Standard and Post-Construction Soil Quality and Depth as per the adopted Manual. |
Low impact development performance standard – stormwater discharges shall match 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. Projects that require flow control must also match flow durations between eight percent of the two-year flow through the full 50-year flow. (Ord. 1949 § 15, 2017; Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.250 Minimum requirement No. 6 – Runoff treatment.
A. The following require construction of stormwater treatment facilities:
1. Projects in which the total of effective, pollution-generating impervious surface (PGIS) is 5,000 square feet or more in a threshold discharge area of the project; or
2. Projects in which the total of pollution-generating pervious surfaces (PGPS) is three-quarters of an acre or more in a threshold discharge area, and from which there is a surface discharge in a natural or manmade conveyance system from the site.
B. 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 the frequent transfer of oil. High-use sites include:
1. 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;
2. 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;
3. An area of a commercial or industrial site subject to parking, storage or maintenance of 25 or more vehicles that are over 10 tons gross weight (trucks, buses, trains, heavy equipment, etc.);
4. 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 or bicycle use improvements.
C. Phosphorous control shall be required for new/redevelopment projects discharging to:
1. Waterbodies reported under Section 305(b) of the Clean Water Act, and designated as not supporting beneficial uses due to phosphorous;
2. Water bodies listed in Washington State’s nonpoint source assessment required under Section 319(a) of the Clean Water Act due to nutrients.
D. Enhanced treatment for reduction in dissolved metals 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:
1. Industrial project sites;
2. Commercial project sites;
3. Multi-family project sites;
4. Fully controlled and partially controlled limited access highways with Annual Average Daily Traffic (AADT) counts of 15,000 vehicles or more; and
5. All other roads with an AADT count of 7,500 or greater.
However, such sites listed above that discharge directly (or, indirectly through a municipal storm sewer system) to basic treatment receiving waters, and areas of the above-listed project sites that are identified as subject to basic treatment requirements, are also not subject to enhanced treatment requirements. For developments with a mix of land use types, the enhanced treatment requirement shall apply when the runoff from the areas subject to the enhanced treatment requirement comprise 50 percent or more of the total runoff within a threshold discharge area.
E. Basic treatment generally applies to:
1. Project sites that discharge to the ground, unless:
a. The soil suitability criteria for infiltration treatment are met; or
b. The project uses infiltration strictly for flow control – not treatment – and the discharge is within one-fourth mile of a phosphorus sensitive lake (use a phosphorus treatment facility), or within one-fourth mile of a fish-bearing stream, or a lake (use an enhanced treatment facility);
2. Residential projects not otherwise needing phosphorus control as designated by USEPA, the Department of Ecology, or the city;
3. Project sites discharging directly to river segments, and lakes listed in Appendix I-C of the Stormwater Management Manual for Western Washington (2005);
4. Project sites that drain to streams that are not fish-bearing, or to waters not tributary to fish-bearing streams; and
5. Landscaped areas of industrial, commercial, and multi-family 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 within a threshold discharge area.
F. Water quality facilities shall be sized to treat the volume of runoff predicted from a 24-hour storm with a six-month return frequency (a.k.a., six-month, 24-hour storm). Wetpool facilities shall be sized based upon the criteria in the approved manual.
G. Water Quality Design Flow Rate.
1. Preceding Detention Facilities or When Detention Facilities Are Not Required.
a. The flow rate at or below which 91 percent of the runoff volume, as estimated by an approved continuous runoff model, will be treated. Design criteria for treatment facilities are assigned to achieve the applicable performance goal at the water quality design flow rate (e.g., 80 percent TSS removal).
2. Downstream of Detention Facilities.
a. The water quality design flow rate must be the full two-year release rate from the detention facility.
b. Alternative methods may be used if they identify volumes and flow rates that are at least equivalent.
c. That portion of any development project in which the above PGIS or PGPS thresholds are not exceeded in a threshold discharge area shall apply on-site stormwater management BMPs in accordance with Minimum Requirement No. 5.
H. Stormwater treatment facilities shall be:
1. Selected in accordance with the process identified in approved manual; and
2. Designed in accordance with the design criteria in the approved manual; and
3. Maintained in accordance with the maintenance schedule in the approved manual.
The discharge of untreated stormwater from pollution-generating impervious surfaces to ground water shall not be permitted, except for the discharge achieved by infiltration or dispersion of runoff from residential sites through use of on-site stormwater management BMPs. (Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.260 Minimum requirement No. 7 – Flow control.
Projects must provide flow control to reduce the impacts of stormwater runoff from hard surfaces and land cover conversions. The requirement below applies to projects that discharge stormwater directly, or indirectly through a conveyance system, into a fresh water body.
A. Flow control is not required for projects that discharge directly to or indirectly through an MS4 to the White River, downstream of the confluence with Huckleberry Creek, subject to the following restrictions:
1. 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; and
2. 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:
a. 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.
b. 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; and
3. 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; and
4. 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; and
5. Any erodible elements of the manmade conveyance system must be adequately stabilized to prevent erosion under the conditions noted above.
If the discharge is to a stream that leads to a wetland, or to a wetland that has an outflow to a stream, both this minimum requirement and minimum requirement No. 8 apply.
B. The following require construction of flow control facilities and/or land use management BMPs that will achieve the standard flow control requirement per the approved manual:
1. Projects in which the total of effective impervious surfaces is 10,000 square feet or more in a threshold discharge area; or
2. Projects that convert three-fourths acre or more of native vegetation to lawn or landscape, or convert two and one-half acres or more of native vegetation to pasture in a threshold discharge area, and from which there is a surface discharge in a natural or manmade conveyance system from the site; or
3. Projects that through a combination of effective impervious surfaces and converted pervious surfaces cause a 0.1 cubic feet per second increase in the 100-year flow frequency from a threshold discharge area as estimated using an approved model.
That portion of any development project in which the above thresholds are not exceeded in a threshold discharge area shall apply on-site stormwater management BMPs in accordance with minimum requirement No. 5.
C. Stormwater discharges shall match developed discharge durations to predeveloped 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. The predeveloped condition to be matched shall be a forested land cover unless:
1. Reasonable, historic information is available that indicates the site was prairie prior to settlement; or
2. The drainage area of the immediate stream and all subsequent downstream basins have had at least 40 percent total impervious area since 1985. In this case, the predeveloped condition to be matched shall be the existing land cover condition. Where basin-specific studies determine a stream channel to be unstable, even though the above criterion is met, the predeveloped condition assumption shall be the “historic” land cover condition, or a land cover condition commensurate with achieving a target flow regime identified by an approved basin study.
This standard requirement is waived for sites that will reliably infiltrate all the runoff from impervious surfaces and converted pervious surfaces.
Flow control BMPs shall be selected, designed, and maintained in accordance with the approved Manual. (Ord. 1949 § 16, 2017; Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.270 Minimum requirement No. 8 – Wetlands protection.
The following requirements must be met in addition to meeting minimum requirements elsewhere in this chapter:
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.
B. Stormwater treatment and flow control facilities shall not be built within a natural vegetated buffer, except for:
1. Necessary conveyance systems as approved; or
2. As allowed in wetlands approved for hydrologic modification and/or treatment in accordance with the approved manual. (Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.280 Minimum requirement No. 9 – Operation and maintenance.
The party (or parties) responsible for maintenance and operation of the stormwater facility shall be identified in the operation and maintenance manual; a copy of the manual shall be retained on site or within reasonable access to the site, and shall be transferred with the property to the new owner. A log of maintenance activity that indicates what actions were taken shall be kept and be available for inspection by the local government. (Ord. 1816 § 4, 2012; Ord. 1482 § 1, 2000).
24.08.290 Minimum requirement No. 10 – Operation and maintenance.
Repealed by Ord. 1816. (Ord. 1482 § 1, 2000).
24.08.300 Minimum requirement No. 11 – Financial liability.
Repealed by Ord. 1816. (Ord. 1482 § 1, 2000).
24.08.310 Exceptions.
Repealed by Ord. 1816. (Ord. 1482 § 1, 2000).
24.08.320 Director.
A. The public works director or a designee shall administer this chapter and shall be referred to as the director. The director shall have the authority to develop and implement administrative procedures to administer and enforce this chapter.
B. The director may approve, conditionally approve or deny an application for activities regulated by this chapter.
C. The director shall enforce this chapter. (Ord. 1726 § 3, 2009; Ord. 1482 § 1, 2000).
24.08.330 Inspection.
All activities regulated by this chapter, except those exempt under PMC 24.08.090, shall be inspected by the director or designee. The director or designee 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; installation of permanent stormwater control facilities; landscaping, retaining walls and completion of project; maintenance and operation of stormwater control facilities following completion of the project; and maintenance and operation of stormwater control facilities on any property which is classified as a pollutant generating source. When required by the director, a special inspection and/or testing shall be performed.
A. Construction and Development Inspection. The public works director or designee shall have the right to enter onto the property of any site for which a development permit has been issued, during regular business hours, or at any other time reasonable in the circumstances, for the purpose of review of erosion control practices and drainage facilities, and to ensure compliance with the terms of such permit.
B. Inspection for Cause. Whenever there is cause to believe that a violation of this chapter has been or is being committed, the public works director or designee shall have the right to enter the property to inspect the property during regular business hours, and at any other time reasonable in the circumstances.
C. Inspection for Maintenance and Source Control Best Management Practices. The public works director or designee shall have the right to enter the property to inspect drainage facilities in order to ensure continued functioning of the drainage facilities for the purposes for which they were constructed, and to ensure that maintenance is being performed in accordance with the standards of this chapter and any maintenance schedule adopted during the plan review process for the property. The public works director or designee also may enter the site for the purposes of observing source control best management practices. The property owner or other person in control of the site shall allow any authorized representative of the public works director or designee access during regular business hours, or at any other time reasonable in the circumstances, for the purpose of inspection, sampling, and records examination.
D. Inspection Procedure. Prior to making any inspections, the public works director or designee shall present identification credentials, state the reason for the inspection and request entry of the owner or other person having charge or control of the property, if available, or as provided below.
1. If the property or any building or structure on the property is unoccupied, the public works director or designee shall first make a reasonable effort to locate the owner or other person(s) having charge or control of the property or portions of the property and request entry.
2. If, after reasonable effort, the public works director or designee is unable to locate the owner or other person(s) having charge or control of the property, and has reason to believe the condition of the site or of the drainage facilities creates an imminent hazard to persons or property, the inspector may enter.
3. Unless entry is consented to by the owner or person(s) in control of the property or portion of the property or unless conditions are reasonably believed to exist which create imminent hazard, the director and/or designee shall obtain a warrant, prior to entry, as authorized by the laws of the state of Washington. The director and/or designee may inspect the stormwater system without obtaining a warrant provided the inspection can be conducted while remaining on public property or other property on which permission to enter is obtained.
4. Water sampling and analysis for determination of compliance with this chapter shall be allowed, subject to the procedures set out herein, as follows:
a. Sample Collection. When the public works director or designee has reason to believe that a violation exists or is occurring on a property, the public works director shall have the authority to set up on the site such devices as are necessary to conduct sampling, inspection, compliance monitoring, or flow measuring operations.
b. Sample Analysis. Analysis of samples collected during investigation of potential violations shall be analyzed by a laboratory certified by the State Department of Ecology as competent to perform the required analysis using standard practices and procedures.
c. Cost of Sample Collection and Analysis. If it is determined that a violation of this chapter exists on the site, the owner of the property shall pay the city’s actual costs for collecting samples and for laboratory analysis of those samples. If it is found that a violation does not exist, the city will pay such charges. (Ord. 2058 § 13, 2022; Ord. 1482 § 1, 2000).
24.08.340 Enforcement.
A. 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. Enforcement action shall be in accordance with this chapter whenever a person has violated any provision of this chapter. The choice of enforcement action and the severity of any penalty shall be based on the nature of the violation, the damage or risk to the public or to public resources, and/or the degree of bad faith of the person subject to the enforcement action.
B. Emergency Access and Repairs. 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.
C. 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. 2058 § 14, 2022; Ord. 1482 § 1, 2000).
24.08.350 Stop work order.
The director shall have the authority to serve a person a stop work order if an action is being undertaken in violation of this chapter. If a portion of a project is in violation of this chapter, the director may issue a stop work order for the entire project.
A. Content of Order. The order shall contain:
1. A description of the specific nature, extent and time of violation, and the damage or potential damage; and
2. A notice that the violation or the potential violation cease and desist, and, in appropriate cases, the specific corrective action to be taken within a given time. A civil penalty under PMC 24.08.360 may be issued with the order.
B. Notice. A stop work order shall be imposed by a notice in writing, either by certified mail with return receipt requested, or by personal service, to the person incurring the same.
C. Effective Date. The stop work order issued under this chapter shall become effective immediately upon receipt by the person to whom the order is directed.
D. Compliance. Failure to comply with the terms of a stop work order shall result in enforcement actions including, but not limited to the issuance of a civil penalty. (Ord. 1482 § 1, 2000).
24.08.360 Civil penalty.
A person who fails to comply with the requirements of this chapter, who fails to conform to the terms of an approval or order issued, who undertakes new development without first obtaining city approval, or who fails to comply with a stop work order issued under these regulations shall be subject to a civil penalty.
A. Amount of Penalty. The penalty shall not be less than $250.00 for each violation. Each day of continued violation or repeated violation shall constitute a separate violation. For subsequent violations occurring within 24 months of a prior violation, the penalty shall be not less than $500.00 for each violation. Each day of continued violation or repeated violation shall constitute a separate violation.
B. Aiding or Abetting. Any person who, through an act of commission or omission, aids or abets in the violation shall be considered to have committed a violation for the purposes of the civil penalty.
C. Notice of Penalty. A civil penalty shall be imposed by a notice in writing, either by certified mail with return receipt requested or by personal service, to the person incurring the same from the city. The notice shall describe the violation, approximate date(s) of violation(s), and shall order the acts constituting the violation to cease and desist, and, in appropriate cases, require necessary corrective action within a specific time.
D. Application for Remission or Mitigation. Any person incurring a penalty may apply in writing within seven calendar days of receipt of the penalty to the city for remission or mitigation of such penalty. Upon receipt of the application, the director may remit or mitigate the penalty only upon a demonstration of extraordinary circumstances, such as the presence of information or factors not considered in setting the original penalty or by a compensatory agreement, as described within PMC 24.08.120(S), being established. The decision may be appealed to the hearing examiner as designated within Chapter 2.06 PMC within 14 calendar days of the decision. (Ord. 2058 § 15, 2022; Ord. 1726 § 4, 2009; Ord. 1482 § 1, 2000).
24.08.370 Penalties due.
Penalties for violations of this chapter shall become due and payable 10 days after receipt of written notice of the violation, unless application for remission or mitigation is made or an appeal is filed. Whenever an application for remission or mitigation is made, penalties shall become due and payable 30 days after receipt of the decision regarding the remission or mitigation. Whenever an appeal of a penalty is filed, the penalty shall become due and payable after all review proceedings and a final decision has been issued confirming all or part of the penalty. If the amount of a penalty owed the city is not paid within the time specified, the city may take actions necessary to recover such penalty. (Ord. 1482 § 1, 2000).
24.08.380 Penalty recovered.
The city’s portion of funds obtained by prosecutions shall be placed in the city’s stormwater operations fund. (Ord. 1726 § 5, 2009; Ord. 1482 § 1, 2000).
24.08.390 Exceptions.
After a public hearing, the hearing examiner may grant an exception from the requirements of this chapter. In granting any exception, the hearing examiner may prescribe conditions that are deemed necessary or desirable for the public interest. (Ord. 1726 § 6, 2009; Ord. 1482 § 1, 2000).
24.08.400 Finding of fact.
Exceptions to minimum requirements Nos. 1 through 11 may be granted prior to permit approval and construction. An exception may be granted following a public hearing, provided that a written finding of fact is prepared, that addresses the following:
A. The exception provides equivalent environmental protection and is in the overriding public interest; and that the objectives of safety, function, environmental protection and facility maintenance, based upon sound engineering, are fully met;
B. That there are special physical circumstances or conditions affecting the property such that the strict application of these provisions would deprive the applicant of all reasonable use of the parcel of land in question, and every effort to find creative ways to meet the intent of the minimum standards has been made;
C. That the granting of the exception will not be detrimental to the public health and welfare, nor injurious to other properties in the vicinity and/or downstream, and to the quality of waters of the state; and
D. The exception is the least possible exception that could be granted to comply with the intent of the minimum requirements. (Ord. 1482 § 1, 2000).
24.08.410 Prior approval.
Any exception shall be approved prior to permit approval and construction. (Ord. 1482 § 1, 2000).
24.08.420 Duration of exception.
Exceptions granted shall be valid for two years, unless granted for a shorter period. (Ord. 1482 § 1, 2000).
24.08.430 Right of appeal.
All actions of the director shall be final and conclusive, unless within 14 calendar days of the date of the director’s action the original applicant or an adverse party gives written notice of appeal to the hearing examiner as designated within Chapter 2.06 PMC. (Ord. 1726 § 7, 2009; Ord. 1482 § 1, 2000).