Chapter 15.10
DRAINAGE
Sections:
15.10.070 Adjustment and variance criteria.
15.10.090 Low impact development.
15.10.100 Long-term operation and maintenance of post-construction stormwater facilities.
15.10.105 Requirement to implement best management practices.
15.10.010 Purpose.
The purpose of this chapter is to provide for the health, safety, and general welfare of the citizens of Clyde Hill, to manage stormwater drainage, and to enhance the water quality of surface waters through the regulation of non-stormwater discharges from the Clyde Hill municipal stormwater sewer system. This chapter is established to address a community history of drainage issues by controlling discharges into the city’s system and onto neighboring properties. Because of the city’s previous stormwater problems, addressing drainage is a responsibility of those developing or redeveloping property in the city of Clyde Hill. This chapter was also established in compliance with the Federal Clean Water Act and the requirements of the city’s National Pollutant Discharge Elimination System (NPDES) Phase II permit issued by the Washington State Department of Ecology. (Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.020 Roadmap to this chapter.
Repealed by Ord. 947. (Ord. 905 § 2, 2010)
15.10.030 Stormwater drainage requirements – Development less than 43,560 square feet or one acre.
Repealed by Ord. 947. (Ord. 905 § 2, 2010)
15.10.040 Applicability.
This chapter applies to all development, redevelopment, and construction site activities where stormwater from the site drains directly or indirectly into the city of Clyde Hill’s municipal storm sewer system, unless specifically exempted by the city. This chapter applies to both private and public development, including roads. (Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.050 Definitions.
For all development, redevelopment, and construction site activities the definitions published in the then existing Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit shall govern. (Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.060 Stormwater drainage requirements.
Repealed by Ord. 987. (Ord. 984 § 1, 2022; Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.070 Adjustment and variance criteria.
A. Adjustments to the minimum requirements contained in Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit may be granted by the city upon application; provided, that a written finding of fact is prepared addressing the following:
1. The adjustment provides substantially equivalent environmental protections as those required by the Western Washington Phase II Municipal Stormwater Permit;
2. Based on sound engineering practices, the objectives of safety, function, environmental protection and facility maintenance are met.
B. Exceptions or variances to the minimum requirements contained in Appendix 1 of the Western Washington Phase II Municipal Stormwater Permit may be granted prior to permit approval and construction. The hearing examiner may grant a variance following legal public notice of an application for an exception, legal public notice of the decision on the application, and written findings of fact. The application must address each of the factors listed below and must be submitted with the applicable fee, established in the city’s master fee resolution. Exceptions to the minimum requirements may be granted if their application imposes a severe and unexpected economic hardship. To determine whether the application of the minimum requirements imposes a severe and unexpected economic hardship on the applicant, the hearing examiner must consider and document with written findings of fact the following:
1. The current (pre-project) use of the site;
2. How the application of the minimum requirement(s) restrict the proposed use of the site compared to the restrictions that existed prior to the adoption of the minimum requirements;
3. The possible remaining uses of the site if the exception were not granted;
4. The uses of the site that would have been allowed prior to the adoption of the minimum requirements;
5. 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; and
6. The feasibility for the owner to alter the project to apply the minimum requirements.
In addition, any exception must meet the following criteria:
a. 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
b. The exception is the least possible exception that could be granted to comply with the intent of the minimum requirements. (Ord. 959 § 5, 2018; Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.080 Site planning and BMP selection and design criteria.
Repealed by Ord. 987. (Ord. 984 § 2, 2022; Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.090 Low impact development.
In order to promote low impact development using creative approaches to site design, habitat and tree retention, significant reduction of impervious surfaces, changes in traditional site features such as roads and structures in favor of natural habitat features, the director may approve, or for those projects requiring review and approval by the city council, recommend approval of deviations from engineering design and the provisions of Clyde Hill’s development regulations for all development, redevelopment, and construction site activities based upon the following factors:
A. The deviations will produce a compensating or comparable result in stormwater flow control and treatment that is in the public interest;
B. The deviations contribute to and are consistent with the goal of achieving low effective impervious surface area within a development;
C. The proposed development project offers reasonable assurances that low impervious surfaces will be achieved and maintained;
D. The deviations do not threaten public health or safety;
E. The deviations are consistent with generally accepted engineering and design practices and are prepared by a registered professional engineer licensed in the state of Washington with experience in LID design;
F. The deviations promote one or more of the following:
1. Innovative site or housing design;
2. Increased on-site stormwater retention using native vegetation;
3. Retention of at least 60 percent of natural vegetation conditions over the site;
4. Improved on-site water quality beyond that required by current applicable regulations;
5. Retention or recreation of predevelopment and/or natural hydrologic conditions to the maximum extent possible;
6. The reduction of effective impervious surfaces to the maximum extent practicable;
G. The deviations do not allow density greater than what would otherwise be allowed under city regulations then in effect;
H. The deviations do not present significantly greater maintenance requirements at facilities that will be eventually transferred to public ownership;
I. There shall be submitted in conjunction with each such project, covenants, conditions and restrictions which will be binding upon the property all necessary native growth protection easements, impervious surface restrictions and such other critical features as the director may require.
Use of LID facilities shall require approval by the public works director. Prior to plan approval of LID facilities, a soils report must be prepared by a professional engineer, geologist, hydrogeologist, or engineering geologist licensed in the state of Washington and submitted to the public works director for review and approval. If LID facilities are found to be feasible, the final signed/stamped soils report must include a statement that the use of the proposed LID facility will not result in springs, surface flooding, seepage into downstream basements or crawl spaces, or slope instability.
Prior to final approval of the LID facility construction, a registered professional engineer licensed in the state of Washington and experienced in LID design shall submit to the city “as built” plans of the LID facility and certification that the facility has been constructed as shown on the “as built” plans. (Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.100 Long-term operation and maintenance of post-construction stormwater facilities.
A. The person or persons holding title to the property shall remain responsible for the facility’s continual performance, operation and maintenance in accordance with the standards and requirements of the most current version of Washington State Department of Ecology’s Stormwater Management Manual for Western Washington and remain responsible for any liability as a result of these duties.
B. The city is authorized to inspect a private stormwater drainage facility at least annually unless there are maintenance records justifying a different frequency pursuant to CHMC 15.10.110. (Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.105 Requirement to implement best management practices.
A. Best management practices (BMPs) as specified in Ecology’s Stormwater Management Manual for Western Washington shall be applied to:
1. Any activity that might result in a prohibited discharge; and
2. All existing, new, and proposed business and commercial entities (including, without limitation, publicly and privately owned institutional, commercial, and industrial sites; multifamily sites; and home-based businesses) that have the potential to discharge pollutants into the city’s stormwater drainage system, regardless of whether the property is covered under a separate NPDES permit.
a. Pollutants shall be controlled by implementing appropriate source control and/or treatment BMPs as specified in the Ecology Manual.
b. Pollutants associated with land uses or activities not addressed in the Ecology Manual shall be controlled using BMPs reviewed and accepted by the city.
B. If, upon inspection of existing BMPs, the director determines that the BMPs are inadequate at controlling prohibited discharges or pollutants, the director may require any person responsible for a property or premises which is, or may be, the source of a prohibited discharge or pollutant to implement, at the responsible person’s own expense, additional BMPs to prevent the further discharge of prohibited discharges or pollutants into the stormwater drainage system.
C. Failure to implement and maintain such required BMPs shall constitute a violation of this chapter subject to enforcement under the provisions in CHMC 15.10.120. (Ord. 987 § 3, 2022)
15.10.110 Inspection.
A. Authority. Whenever implementing the provisions of this chapter, or whenever there is cause to believe that a violation of this chapter has been or is being committed, the city’s inspector is authorized to inspect during regular working hours and at other reasonable times all existing private stormwater facilities, new development, redevelopment, and construction sites within Clyde Hill to determine compliance with the provisions of this chapter. The city shall have the authority to periodically inspect private stormwater facilities for compliance with this chapter. Inspection frequency may include, but is not limited to:
1. Routine inspections;
2. Random inspections;
3. Inspections based upon complaints or other notice of possible violations;
4. Inspections of drainage basins or areas identified as higher than typical sources of sediment or pollutants;
5. Inspections of potential pollution-generating sources on all public and private properties;
6. Joint inspection with other agencies under environmental or safety laws.
The city shall have the authority to inspect suspected or confirmed sources of prohibited stormwater discharges and pollutants, and to determine the effectiveness of BMPs.
B. Inspection Procedures.
1. Prior to making any inspections on private property, the inspector shall present identification credentials, state the reason for the inspection and request entry. Any private landowner engaging in new development, redevelopment, or construction activities as defined under this chapter must, as a condition of the building permit required for such development, consent to the creation of an easement for purposes of ingress and egress for inspection of the site.
2. If the property or any building or structure on the property is unoccupied, the inspector 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.
3. If after reasonable effort the inspector 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 stormwater system creates an imminent hazard to persons or property, the inspector may enter.
4. 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 inspector shall obtain a search warrant, prior to entry, as authorized by the laws of the state of Washington.
5. The inspector may inspect the stormwater system without obtaining a search warrant provided for in subsection (B)(4) of this section, provided the inspection can be conducted while remaining on public property or other property on which permission to enter is obtained.
6. Inspections of private stormwater facilities may include the following activities:
a. Inspection, sampling, and testing of any constructed stormwater facility for the purpose of determining compliance with standards for inspection, maintenance, or repair adopted by the director and applicable to the facility;
b. Investigation of the integrity of any constructed stormwater facility components using any appropriate test deemed necessary, including, but not limited to, dye or smoke testing or video surveys;
c. Creation of records reasonably necessary to document conditions related to compliance with the standards described above, including but not limited to photographs, video, measurements, and drawings; and
d. Inspection and copying of nonconfidential records relating to inspection, maintenance, or repair of the constructed stormwater facilities.
7. Inspections of sources of prohibited stormwater discharges and pollutants and BMPs may include, but are not limited to:
a. Examination of vehicles, trailers, tanks, or mobile or stationary equipment which could cause a prohibited discharge;
b. Inspection, sampling, and testing of any area, discharge, metal, or drainage facility for the purpose of determining the potential for contribution of pollutants to drainage facilities or waters of the state;
c. Screening for and/or tracking illicit discharges or illicit connections;
d. Inspecting land uses and potential pollution-generating activities to ensure that appropriate source control BMPs are implemented and maintained;
e. Investigation of the integrity of drainage facilities on the premises using appropriate tests including but not limited to dye or smoke testing or video surveys;
f. Creating records reasonably necessary to document conditions related to stormwater pollution or BMPs implemented on the premises, including but not limited to photographs, video, measurements and drawings; and
g. Inspection and copying of nonconfidential records relating to site activity or processes presently or previously occurring, including but not limited to safety data sheets, stormwater pollution prevention plans, spill response plans, hazardous waste manifests, drainage inspection records, state or federal stormwater permits, or other records related to prohibited connections or discharges.
8. Subject to the limitations in this subsection (B), the director shall have the right to set up devices on any premises as are necessary in the director’s opinion to conduct monitoring or sampling of discharge from stormwater facilities.
9. Any temporary or permanent obstruction to the safe and easy access to the premises and any stormwater facility to be inspected and/or sampled shall be promptly removed by the property owner at the written or oral request of the director. The director may follow up oral requests with written requests if the obstruction is not removed. Such obstructions shall not be replaced. The costs of removing obstructions shall be borne by the property owner.
C. Inspection Requirements. The public works director is authorized to develop inspection procedures and requirements, including checklists, for all stormwater facilities in the city of Clyde Hill. The director has the right to require the property owner to install monitoring equipment as necessary to ensure compliance with this chapter. Sampling and monitoring equipment shall be maintained at all times in a safe and proper operating condition at the property owner’s expense. All devices used to measure stormwater flow and water quality shall be calibrated to ensure their accuracy. The director shall maintain records of all notices and orders given, issued warnings, and inspections not taken place due to denial of access.
D. Inspection Fees. Inspection fees shall be established by the city’s master fee resolution. (Ord. 987 § 4, 2022; Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)
15.10.120 Enforcement.
Any person violating the provisions of this chapter shall be subject to those penalties outlined in Chapter 15.13 CHMC. In the alternative, the director, at the director’s sole option, may enforce the provisions of this chapter utilizing the following procedures:
A. Notice and Order to Cease Violation.
1. Whenever the director has reason to believe that a condition exists in violation of this chapter, and its rules, regulations, or standards, the director may cause a notice and order to be issued to the owner or operator of the source of this violation, the person in possession of the property where the violation originates, and/or the person otherwise causing or responsible for the violation, which may include an order to immediately cease the activity causing the violation or take another action to abate the violation.
2. The notice and order shall include the following information:
a. The name(s) of the person(s) determined to be responsible for the violation and/or the owner of the property where the violation is occurring or has occurred;
b. The address or legal description of the real property on which the violation exists or occurred;
c. A description of the conditions found to be in violation, including the specific provision of this chapter which has been violated;
d. If applicable, a brief description of any activity that is causing the violation to exist or occur;
e. A statement of the corrective action required to be taken. If a director has determined that corrective work is required, the order shall require that all required permits be secured, that work physically be commenced, and that the work be completed within such times as a director determines are reasonable under the circumstances;
f. The signature and written name of the city official issuing the notice and order;
g. The contact information for the city’s designated contact person or office to which questions regarding the notice and order may be directed; and
h. The date of the notice and order.
3. A notice and order may be amended at any time to correct clerical errors. An amendment made pursuant to this subsection shall not affect the validity or effective date of the original notice and order.
4. The notice and order shall be served upon all persons identified in the notice and order by one of the following methods:
a. By personal service;
b. By certified mail, sent to the last known address of all the persons identified in the notice and order; or
c. If the address of all persons identified in the notice and order is unknown, by posting a copy of the notice and order in a conspicuous place at the site of the violation.
B. Warning Notice as an Alternative to Notice and Order.
1. As an alternative to issuing a notice and order, the director may issue a warning notice to the owner or operator of the source of the violation, the person in possession of the property where the violation originates, and/or the person otherwise causing or responsible for the violation of this chapter if, in the opinion of the director, the apparent violation can be voluntarily corrected within a reasonable amount of time. A warning notice is a communication by the director containing recommended actions that may be taken by the person(s) responsible for an apparent violation in order to potentially avoid the issuance of a notice and order.
2. The warning notice shall include the following information:
a. The name(s) of the person(s) determined to be responsible for the apparent violation;
b. The address or legal description of the real property on which the apparent violation exists or has occurred;
c. A description of the apparent violation, including the specific provision of this chapter which appears to have been violated;
d. If applicable, a brief description of any activity which is causing the apparent violation to exist or occur;
e. A description of any recommended corrective action;
f. A deadline by which corrective action should be completed in order to avoid issuance of a notice and order;
g. The signature and written name of the city official issuing the warning notice;
h. The contact information for the city’s designated contact person or office to which questions regarding the warning notice may be directed; and
i. The date of the warning notice.
3. A warning notice may be amended at any time to correct clerical errors. An amendment made pursuant to this subsection shall not affect the validity or effective date of the original warning notice.
4. The warning notice shall be served upon the responsible person(s) by one of the following methods:
a. By personal service;
b. By certified mail, sent to the last known address of the responsible person(s); or
c. If the address of the responsible person(s) is unknown, by posting a copy of the warning notice in a conspicuous place at the site of the apparent violation.
5. The recipient(s) of a warning notice shall respond to the notice within 30 calendar days from the date of receiving the notice unless the notice specifies a different time period. The recipient(s) may respond to a warning notice once in any of the following ways:
a. Cure the Apparent Violation in a Timely Manner. The recipient(s) of a warning notice may cure the apparent violation described in the notice within the time period specified in the notice. In such event, the recipient shall promptly notify the city when the apparent violation has been cured, and the city shall promptly inspect the site for compliance.
b. Request for Alternative Corrective Action. The recipient(s) of a warning notice may submit a written request to the city proposing an alternative to the city’s recommended corrective action to cure the apparent violation. The request shall describe the proposed alternative correction action and how it is functionally equivalent to the corrective action recommended by the city. The director, at the director’s sole option, may agree to the request for an alternative corrective action. The director’s decision to grant, deny, or partially grant a request for an alternative corrective action shall be in writing. If the violation is not cured, the director may issue a notice and order as provided in subsection (A) of this section.
c. Request Additional Time. The recipient(s) of a warning notice may submit a written request to the city requesting additional time to cure the apparent violation. Any such request shall explain why the circumstances surrounding the apparent violation support the request for additional time. The request shall propose a timeline or schedule pursuant to which the responsible person(s) will cure the apparent violation. The director may agree to a reasonable proposal requesting additional time. The director’s decision to grant, deny, or partially grant a request for additional time shall be in writing. If the violation is not cured by the new deadline, the director may issue a notice and order as provided in subsection (A) of this section.
d. Contest the Warning Notice. The recipient(s) of a warning notice may contest the accuracy, validity, or appropriateness of the notice by requesting the director amend the warning by providing a written request to the director within 30 calendar days from the date of receiving the warning notice. Any such request is limited to one opportunity.
6. The director may issue a notice and order for a violation of this chapter irrespective of any previous issuance of a warning notice regarding the violation. (Ord. 987 § 5, 2022; Ord. 947 § 1, 2016; Ord. 905 § 2, 2010)