A. 
These regulations shall be known as the city of Sumner "stormwater management regulations" and may be so cited.
B. 
The authority for the regulations contained in this chapter is based on RCW 35A.11.020.
C. 
The Storm Drainage Utility, chapter 13.32 SMC, was created and established pursuant to chapters 35A.80 and 35.67 RCW and Article 11 of the Washington State Constitution.
D. 
Illicit Discharge Detection and Elimination Authority. The city is authorized to develop and implement an illicit discharge detection and elimination program for stormwater facilities in the city in accordance with the NPDES Phase II permit.
E. 
Source Control. The city is authorized to develop and implement a source control program for pollution generating sources in the city in accordance with the NPDES Phase II permit.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Ord. 2825 § 1, 2022)
A. 
The purpose of these regulations is to:
1. 
Protect, maintain, and enhance the public health, safety and general welfare by establishing minimum requirements and procedures to control the adverse impacts associated with increased stormwater runoff and water quality degradation for all sites located within the city for which a permit from the city is required prior to land altering activities. Proper management of stormwater runoff will minimize damage to public and private property, reduce the effects of development on land and stream channel erosion and sedimentation, assist in the attainment and maintenance of water quality standards and reduce flooding.
2. 
Detect and eliminate illicit discharges.
3. 
Prevent and reduce pollution in runoff through the requirement of operational source control BMPs, and if necessary, structural source control BMPs or treatment BMPs/facilities, or both, to pollution generating sources associated with existing land uses and activities.
4. 
Meet the requirements of the Western Washington Phase II municipal stormwater permit issued by the Washington State Department of Ecology under the National Pollution Discharge Elimination System (NPDES).
5. 
Regulate all land-disturbing activity to control erosion associated with land-disturbing activities to prevent damage to public or private property and to prevent sedimentation of creeks, rivers, wetlands, and other water resources in the city.
6. 
Establish procedures through which these purposes can be fulfilled.
B. 
The provisions of these regulations shall apply to all development occurring within the incorporated area of the city. The application of these regulations and the provisions expressed herein shall be the minimum stormwater management requirements and shall not be deemed a limitation or repeal of any other powers granted by state statute. The city shall be responsible for the coordination and enforcement of the provisions of these regulations.
C. 
This chapter does not abrogate the technical standards established by any special district that have been developed for the construction and ongoing services provided by the facilities constructed by a special district. When differences in technical standards appear between the city and the special district, the standard that provides the greater protection of public health, resources and properties shall apply.
D. 
To meet the intent of the NPDES permit issued by the Washington State Department of Ecology of providing treated stormwater discharges to the river systems exempt from flow control and to meet the intent of other permit requirements, the city of Sumner requires that all applicants for residential, commercial, institutional and government agency projects implement low impact development (LID) strategies and practices in their stormwater site plan. LID standards and criteria are set forth in the manuals and the Sumner Development Specifications and Standard Details as therein referenced. The city engineer, or his or her designee, may waive LID strategies if he deems that this type of stormwater management is not applicable or feasible for a particular project.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Ord. 2825 § 1, 2022)
A. 
The city of Sumner has adopted the 2019 Washington State Department of Ecology Stormwater Management Manual for Western Washington.
B. 
The city of Sumner has adopted Appendix 1, Minimum Technical Requirements for New Development and Redevelopment, of the 2019-2024 Western Washington Phase II municipal stormwater permit.
C. 
The city of Sumner has adopted the 2012 Puget Sound Partnership Low Impact Development Technical Guidance Manual for Puget Sound together with any amendments or corrections.
D. 
The city of Sumner has adopted, together with any amendments or corrections, the city of Sumner Development Specifications and Standard Details.
E. 
Where there are discrepancies between these adopted references, the standard that provides the most environmental protection shall be used.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Ord. 2586 § 2 (part), 2016; Ord. 2826 § 1, 2022)
A. 
A site development permit is required for any proposed development, land-disturbing activity, stockpiling or application of sediment producing materials unless:
1. 
Otherwise exempt from a site development permit under SMC § 13.48.050.
2. 
If the permittee applies for and is granted a variance by the city in accordance with SMC § 13.48.070.
B. 
A stormwater site plan, approved by the city, is required for all projects for which a site development permit is required unless:
1. 
The proposed actions are exempt from a site development permit under SMC § 13.48.050;
2. 
The city engineer waives the submission of the stormwater site plan in accordance with SMC § 13.48.060; or
3. 
The permittee applies for and is granted a variance by the city in accordance with SMC § 13.48.070.
C. 
The required permit or permits will not be issued for any activity on any parcel or lot until the stormwater site plan has been approved unless the project is exempt or a waiver or variance is granted by the city as identified in this chapter.
D. 
Permit requirements shall be determined by the city engineer based on the permittee's proposed phasing and actions. The design, construction and operation and maintenance of temporary or permanent stormwater or surface water management facilities required for the permit shall be in accordance with these regulations and the standards adopted in SMC § 13.48.030.
1. 
Additions or Modifications to Existing Single-Family Detached Residential Structures and Their Accessory Buildings. If the thresholds in the manual are exceeded, a stormwater site plan is required. Applicants for additions or modifications to single-family residential structures are still required to provide stormwater control for the additional impervious area created by the project by tight-lining flow from the downspouts to the stormwater collection system located in the right-of-way adjacent to the property frontage. If a stormwater collection system is not located within the right-of-way fronting the property, or if site conditions make it physically impossible to connect the downspouts to the stormwater collection system, stormwater control shall be constructed per the single-family residential infiltration system guide contained in the Sumner Development Specifications and Standard Details.
2. 
Projects That Will Construct a Single House on a Single Residential Lot That Is Not Part of a Short Subdivision or Subdivision. If the thresholds in the manual are exceeded, a stormwater site plan is required. If exempt from developing a stormwater site plan, applicants for single-family residential construction on a single residential lot shall still be required to provide stormwater control by tight-lining flow from the downspouts to the stormwater collection system located in the right-of-way adjacent to the property frontage. If a stormwater collection system is not located within the right-of-way fronting the property, or if site conditions make it physically impossible to connect the downspouts to the stormwater collection system, stormwater control shall be constructed per the single-family residential infiltration system guide contained in the Sumner Development Specifications and Standard Details.
E. 
For projects that have extended phasing:
1. 
Additional permit fees shall be required if the length of phasing exceeds the time length of the permit; and
2. 
Financial guarantees shall be extended to cover the proposed length of phasing.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.032)
A. 
A permittee receiving an exemption from the city to obtain a permit or prepare a stormwater site plan:
1. 
Is not authorized to cause illicit discharges, including spills, of oil or hazardous substances;
2. 
Is not relieved from responsibilities and liabilities under state and federal laws and regulations pertaining to those discharges; and
3. 
Is not authorized to allow discharges that would violate standards in the NPDES Phase II permit.
B. 
The following are exempt from obtaining a site development permit:
1. 
Commercial agriculture as exempt in accordance with the manual. Exempt commercial agricultural practices involving working the land for production are generally exempt from this chapter. However, the conversion from timberland to agriculture, and the construction of impervious surfaces, are not exempt.
2. 
Forest practices as exempt in accordance with the manual. Forest practices regulated under WAC Title 222, except for Class IV – General Forest Practices that are conversions from timberland to other uses, are exempt from this chapter.
3. 
Road maintenance as exempt in accordance with the manual. The following road maintenance practices are exempt: pothole 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, and vegetation maintenance.
4. 
Any proposed land-disturbing activity, fill, or cut involving 50 cubic yards of earth or less.
C. 
Projects requiring a site development permit and/or stormwater site plan are exempt from flow control if there is a direct discharge to a water body identified in Appendix 1E of Volume I of the manual; provided, that all of the following conditions are met:
1. 
The permittee constructs the outfall;
2. 
The permittee utilizes an existing outfall, provided the permittee conducts hydraulic modeling and backwater analysis to verify that the existing outfall has sufficient capacity to convey the additional runoff volume and flow without surcharging;
3. 
A hydraulic project approval (HPA), if required, is applied for by the permittee and is issued by the Washington Department of Fish and Wildlife;
4. 
The outfall does not violate any stormwater diversions as documented in Appendix 1E of Volume I of the manual;
5. 
The permittee obtains all other permits required by federal, state and local laws and regulations; and
6. 
The permittee enters into an operations and maintenance agreement with the city. The operations and maintenance agreement may be waived; provided, that:
a. 
The outfall is permitted under Ecology's industrial stormwater general permit or other individual permit that requires the ongoing maintenance and monitoring of the outfall by the permittee;
b. 
Copies of the Ecology-approved permit are submitted to the city; and
c. 
Copies of all reports are submitted to the city at the time of submittal to Ecology.
D. 
Projects exempt from a site development permit are exempt from preparing a stormwater site plan.
(Formerly 13.48.034; Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Ord. 2586 § 2 (part), 2016)
A. 
The city engineer or his or her designee may waive the submission of plans, calculations, and other data if it is found that the nature of the work applied for is such that reviewing of plans is not necessary to obtain compliance with this regulation.
B. 
If a site development permit is required for a project but applicable project thresholds are below those in the manual, the submittal of a stormwater site plan may be waived by the city at the discretion of the city engineer or his or her designee.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.036)
A. 
The city engineer or his or her designee may grant a written variance from any requirement of this chapter if there are exceptional circumstances applicable to the site such that strict adherence to the provisions of these regulations will result in unnecessary hardship and not fulfill the intent of this chapter. A written request for variance shall be provided to the city and shall state the specific variances sought and reasons for their granting. The city engineer or his or her designee shall not grant a variance unless and until completion of legal public notice of an application for variance, completion of legal public notice of the city's decision on the application, and written findings of fact that document the city's determination to grant a variance.
B. 
Variances from this chapter and the documents adopted in SMC § 13.48.030 may be permitted only after a determination by the city engineer or his or her designee using the stormwater comprehensive plan and/or employing the following criteria:
1. 
Sufficient capacity of downstream facilities under design conditions;
2. 
Maintenance of the integrity of the receiving waters;
3. 
Possibility of adverse effects of retention/detention;
4. 
Utility of regional retention/detention facilities;
5. 
Capability of maintenance of the system;
6. 
Structural integrity of abutting foundations and structures;
7. 
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 ways to meet the intent of the minimum requirements has been made;
8. 
That the granting of the variance 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;
9. 
The variance is the least possible exception that could be granted to comply with the intent of the NPDES Phase II permit and the minimum requirements of the manual; and
10. 
Adherence to the minimum requirements outlined in the manual imposes a severe and unexpected economic hardship. To determine whether the application imposes a severe and unexpected economic hardship, the project applicant must consider and document the following before the city can grant written findings of fact:
a. 
The current (pre-project) use of the site;
b. 
How the application of the minimum requirement(s) restricts the proposed use of the site compared to the restrictions that existed prior to the adoption of the minimum requirements;
c. 
The possible remaining uses of the site if the variance was not granted;
d. 
The uses of the site that would have been allowed prior to the adoption of the minimum requirements;
e. 
A comparison of the estimated amount and percentage of value loss as a result of the minimum requirements versus the estimated amount and percentage of value loss as a result of requirements that existed prior to adoption of the minimum requirements;
f. 
The feasibility for the owner to alter the project to apply the minimum requirements.
C. 
Variances from the erosion and sediment control ordinance may be permitted only after determination by the city engineer or his or her designee employing the following criteria:
1. 
There are unique circumstances applicable to the subject property or to the intended use, such as topography, location or surroundings, which do not generally apply to other properties or classes of use;
2. 
Such a variance is necessary for the preservation and enjoyment of a substantial property or class of use;
3. 
The granting of such variance will not be materially detrimental to the public welfare or injurious to the property, water quality, environment, habitat, or improvements in the vicinity;
4. 
The granting of such variance will not adversely affect any applicable comprehensive drainage or zoning plan;
5. 
The variance is the minimum necessary to afford relief.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.038)
All state and federal governmental entities shall be required to comply with the terms of this chapter when developing and/or improving land including, but not limited to, road building and widening within the city limits.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.040)
A. 
Whenever conflicts exist between federal, state, or local laws, ordinances, or rules, the more restrictive provision shall apply.
B. 
Neither these regulations nor any administrative decision made under it:
1. 
Exempts the applicant from procuring other required local, state, and federal permits or complying with the requirements and conditions of such permits; or
2. 
Limits the right of any person to maintain, at any time, any appropriate action, at law or in equity, for the relief of damages against the applicant arising from the permitted activity.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.050)
The city engineer or his or her designee is the designated agent for the issuance of permits and approvals in the city. The city engineer or his or her designee shall have the authority to set administrative procedures and policies to carry out the purposes and intent of this chapter, related regulations, and policies.
(Ord. 2316 § 1 (part), 2010; Ord. 2356 § 11 (part), 2011; Formerly 13.48.060)