Chapter 13.32
STORMWATER MANAGEMENT REQUIREMENTS
Sections:
13.32.010 Minimum requirements for drainage improvements.
13.32.020 Drainage plan – Submission.
13.32.030 Drainage plan – Contents.
13.32.040 Development in environmentally sensitive areas or impacting ESAs.
13.32.050 Review and approval of the plan.
13.32.060 Establishment of regional facilities.
13.32.065 Payment in lieu of construction program.
13.32.070 Applicability to government entities.
13.32.080 Protection of public/private rights.
13.32.010 Minimum requirements for drainage improvements.
A. All developments shall comply with the Department of Ecology’s February 2005 Stormwater Management Manual for Western Washington (“2005 SWMM-WW”), except for the following: Section 2.6 – Optional guidance, relating to financial liability and off-site analysis and mitigation, city engineering design standards, city stormwater master plan, and adopted drainage basin plans for all clearing and grading activities, for erosion control during construction and for permanent drainage system improvements.
B. Surface water entering the subject property shall be received at the naturally occurring locations and surface water exiting the subject property shall be discharged at the natural locations with adequate energy dissipaters within the subject property to minimize downstream damage and with no diversion at any of these points.
C. All developments shall do the necessary analysis and install the necessary mitigations to ensure that stormwater exiting their property is discharged at a safe location which will not impact other property owners.
D. All structures shall be built such that finished floor elevations are in conformance with the International Building Code as adopted or hereafter amended.
E. Building plans shall clearly show locations of drainage system and stormwater controls within property limits and any off-site drainage improvements.
F. Considerations for the discharge of water off site include but are not limited to the following:
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; and
6. Structural integrity of abutting foundations and structures.
G. All developers not providing permanent stormwater control facilities will be required to sign a no-protest agreement for future participation in a stormwater-related LID. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2915 § 1, 2006; Ord. 2867 § 2, 2004; Ord. 2579 § 1, 1997).
13.32.020 Drainage plan – Submission.
A. All developers applying for any of the following permits and/or approvals may be required to submit for approval a drainage plan with their application and/or request:
1. Grading permit;
2. Street development permit;
3. Substantial development permit required under Chapter 90.58 RCW (Shoreline Management Act);
4. Subdivision approval;
5. Short subdivision approval;
6. Commercial, industrial or multifamily site plan approval;
7. Rezones;
8. Conditional use permits;
9. Planned unit developments;
10. Building permits, where the permit either (a) authorizes or is for new construction totaling 40 percent or more of developmental coverage within the subject property; or (b) authorizes or is for new construction which, together with pre-existing developmental coverage, would result in 40 percent or more developmental coverage within the property; or (c) is for development in an environmentally sensitive area or which has the potential to impact an environmentally sensitive area;
11. Building permits, where the new development does not involve a change in impervious coverage of a site but where one of the following conditions exists:
a. The stormwater from the existing development is connected to the sanitary sewer system.
b. The drainage system serving the existing development is inadequate to prevent impacts to neighboring properties.
c. Water quality issues are a concern either from the existing development or from the proposed development.
B. In addition, a drainage plan may be required for creation of impervious area, not covered by a permit, which exceeds either:
1. Five thousand square feet; or
2. Forty percent developmental coverage within the subject property.
C. Construction work done under any of the above permits or applications shall not begin until such time as final approval of the drainage plan is obtained in accordance with PTMC 13.32.050.
D. The same plan submitted during one permit/approval process may be subsequently submitted with further required applications. The plan shall be supplemented with such additional information that is requested by the public works department or required by the provisions of the engineering design standards manual and/or DOE Stormwater Management Manual for the Puget Sound Basin.
E. Temporary erosion and sediment control measures may be required under Chapter 5 of the engineering design standards at the discretion of the director for:
1. Site preparation and/or construction of any development; or
2. Creation of impervious area which exceeds either:
a. Five thousand square feet; or
b. Forty percent of the subject property. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2687 § 1, 1999; Ord. 2579 § 1, 1997; Ord. 2126 § 1, 1988; Ord. 1957 § 3, 1983).
13.32.030 Drainage plan – Contents.
All persons applying for any of the permits and/or approvals contained in PTMC 13.32.020 shall provide a drainage plan for surface and pertinent subsurface water flows entering, flowing within, and leaving the subject property both during and after construction. The detailed form and contents of the drainage plan shall be described in procedures established by the public works department, or in the engineering design standards manual and/or DOE Stormwater Management Manual for the Puget Sound Basin. The engineering design standards manual, and the DOE Manual, will set forth the manner of presenting the required information which may include but is not limited to the following:
A. Background computations for sizing drainage facilities:
1. Depiction of the drainage area on a topographical map of approved scale and contour interval, with acreage of the site, development, and developmental coverage indicated;
2. Indications of the peak discharge and volume of surface water currently entering and leaving the subject property due to the design storm;
3. Indication of the peak discharge and volume of runoff which will be generated due to the design storm within the subject property if the development or proposed activity is allowed to proceed; and
4. Determination of the peak discharge and volume of water that will be generated by the design storm at various points on the subject property;
B. Proposed measures for handling the computed runoff at the detail level specified in the engineering design standards manual and/or DOE Stormwater Management Manual for the Puget Sound Basin:
1. The design storm peak discharge from the subject property may not be increased by the proposed development; and
2. Retention/detention facilities must be provided in order to maintain surface water discharge rates at or below the existing design storm peak discharge; and
C. Proposed measures for controlling runoff during construction. The requirements of this section may be modified at the discretion of the city public works department in special cases requiring more information. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 2444 § 2, 1995; Ord. 1957 § 4, 1983).
13.32.040 Development in environmentally sensitive areas or impacting ESAs.
Development in environmentally sensitive areas (ESAs) or development which has the potential to impact ESAs must meet the requirements of Chapter 19.05 PTMC or other requirements as determined necessary for the protection of the ESAs as determined by the public works director. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 1957 § 6, 1983).
13.32.050 Review and approval of the plan.
All storm drainage plans prepared in connection with any of the permits and/or approvals listed in PTMC 13.32.020 shall be submitted for review by and approval of the public works department in accordance with the procedures established in the engineering design standards manual and/or DOE Stormwater Management Manual for the Puget Sound Basin. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 2444 § 3, 1995; Ord. 1957 § 7, 1983).
13.32.060 Establishment of regional facilities.
In the event that public benefits would accrue due to modification of the drainage plan for the subject property to better implement the recommendations of the comprehensive drainage plan, the public works department may recommend that the city should assume responsibility for the further design, construction, operation and maintenance of drainage facilities on the subject property. Such decision shall be made concurrently with review and approval of the plan as specified in PTMC 13.32.050. In the event that the city decides to assume responsibility for design, construction, operation, and maintenance of the facilities, the developer will be required to contribute a pro rata share to the construction cost of the facilities. The developer may be required to supply additional information at the request of the public works department to aid in the determination by the city. Guidelines for implementing this section will be defined in the engineering design standards manual and/or DOE Stormwater Management Manual for the Puget Sound Basin. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 1957 § 8, 1983).
13.32.065 Payment in lieu of construction program.
A. Purpose. This section establishes the payment in lieu of construction program (“program”). Application for the program is voluntary and not mandatory. This program shall be available for qualified new development and redevelopment projects required to mitigate for stormwater impacts per Minimum Requirement No. 7 – Flow Control, as defined in the Department of Ecology Stormwater Management Manual (“SWMM”). Property owners, or authorized persons on their behalf, may apply to the director under this program to pay a regional stormwater system development charge in lieu of constructing stormwater flow control best management practices on the project site. The available capacity of a regional stormwater facility to provide stormwater flow control for mitigation of stormwater impacts (“mitigation capacity”) will be allocated to qualifying benefitted premises under this program. A system development charge will be assessed to reimburse the city for the historic capital costs to construct the regional stormwater facilities that provide mitigation capacity for projects approved under the program.
All applications for the program must be reviewed and approved by the director.
B. Benefitted Premises. For purposes of this section, the phrase “benefitted premises” shall mean and refer to the specific parcel(s), tract(s), or lot(s), or portions thereof, the development or redevelopment of which has been approved under this program for mitigation of associated stormwater impacts in lieu of constructing individual stormwater treatment or flow control best management practices on the project site. Such benefitted premises, and associated improvements, shall be described in the voluntary payment agreement. The benefitted premises shall have priority for use of the facility for mitigation. Upon a determination of the availability of excess mitigation capacity, the benefitted premises may be expanded.
C. Regional Stormwater Facility. For purposes of this section, the phrase “regional stormwater facility” shall mean and include:
1. A single stormwater facility designed to provide water quality and/or flow control for a large region or portion of a basin or subbasin and designated by the director to be utilized under the program to provide mitigation capacity; and
2. Multiple stormwater facilities that are designed to provide water quality or flow control for a large region or portion of a basin or subbasin and designated by the director to be utilized under the program to collectively provide mitigation capacity.
D. Voluntary Payment Agreement. For purposes of this section, the phrase “voluntary payment agreement” shall mean and refer to that agreement entered into by and between the property owner and the city which sets forth the terms and conditions pursuant to which the applicant agrees to pay a system development charge in consideration for the city’s covenant to make mitigation capacity available to mitigate stormwater impacts associated with development or redevelopment of the benefitted premises.
E. Regional Stormwater System Development Charge. A regional stormwater system development charge is a charge assessed to the property owner which represents the property owner’s equitable share of the present worth of capital cost associated with the city-owned regional stormwater facilities that will be designated under the program to mitigate for stormwater impacts associated with the permitted project, along with the costs of financing the facility. An applicant qualified under this program shall be assessed a regional stormwater system development charge for a specific stormwater facility in the program. The methodology for calculation of the regional stormwater system development charge is defined in the city of Port Townsend regional stormwater facility plan for each specific facility. The system development charge for each regional stormwater facility included in the program shall be established by ordinance of the city council. Regional stormwater system development charges shall be in addition to any established city-wide system development charges for stormwater.
F. Calculation – Payment. The amount of surface area requiring stormwater mitigation will be calculated based upon the proposed project as approved by a city of Port Townsend construction permit. An applicant cannot pay for and reserve mitigation capacity within a regional stormwater facility for potential future mitigation needs. Each system development charge assessed shall be paid to the city at the time of construction permit issuance.
G. Maintenance Surcharge. A maintenance surcharge may be assessed upon the benefitted premises in addition to the surface water rate or charges. The maintenance surcharge is intended to equitably recover the maintenance costs associated with the regional stormwater facility as defined in a regional stormwater plan. For purposes of this section, the term “maintenance” shall mean and include ongoing maintenance, operation, repair, and replacement. For purposes of this section, the term “maintenance costs” shall mean, as applicable, (1) the total costs of maintenance of a regional stormwater facility for which all, or substantially all, of the capacity of the regional stormwater facility to provide stormwater treatment or flow control is allocated to provide mitigation capacity under this program, or (2) the total increase in the costs of maintenance of a regional stormwater facility that has been expanded to provide mitigation capacity under this program.
The maintenance surcharge will be calculated by multiplying the total maintenance costs for the regional facility by the percentage of total mitigation capacity of the regional facility allocated to the benefitted parcel. The maintenance surcharge for each regional stormwater facility included in the program shall be established by ordinance of the city council.
H. Rules and Regulations. The director is authorized to develop and publish rules and regulations implementing this section; provided, that such rules and regulations shall be consistent with the provisions of this section.
I. Qualification. In order to qualify for the program outlined under this section:
1. The applicant shall submit a completed application, on forms provided by the department, prior to final approval of construction permits for the proposed project;
2. The proposed project must be considered a new development or redevelopment project, as those terms are defined in the Department of Ecology SWMM;
3. The proposed project must be located in an area defined by the city of Port Townsend regional stormwater facility plan and the regional stormwater-facility-specific ordinance;
4. The director must determine that the regional stormwater facility has mitigation capacity available for the proposed project;
5. The project must comply with all applicable portions of the Department of Ecology SWMM and city of Port Townsend regional stormwater facility plan;
6. The applicant shall provide all information requested by the city that is reasonably related to qualification for the program; and
7. The property owner shall execute a voluntary payment agreement with the city, in a form approved by the director and the city attorney. The benefitted premises shall be designated in the voluntary payment agreement.
The covenants set forth in the voluntary payment agreement shall, upon recording with the Jefferson County auditor, or successor, be credited to and considered as a benefit to the benefitted premises running with the land; provided, that the city’s covenants shall not apply to additional stormwater mitigation required for redevelopment or new development of any portion of the benefitted premises. It shall be the responsibility of the applicant to timely record the voluntary payment agreement as provided herein and submit a copy of the recorded agreement to the director. The city shall maintain a copy of the agreement in the city’s permanent records. (Ord. 3266 § 1 (Exh. A), 2021).
13.32.070 Applicability to government entities.
A. All municipal corporations and governmental entities shall be required to submit a drainage plan and comply with the terms of this chapter when developing and/or improving land including, but not limited to, road building and widening within the areas of the city.
B. It is recognized that many other city, county, state and federal permit conditions may apply to the proposed action and that compliance with the provisions of this chapter does not constitute compliance with such other requirements. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 1957 § 12, 1983).
13.32.080 Protection of public/private rights.
Implementation of any provision of this chapter shall not cause nor be construed as an infringement of the rights of individuals, municipalities, or corporations other than the developer seeking a permit or approval as described in PTMC 13.32.030. (Ord. 3266 § 1 (Exh. A), 2021; Ord. 2579 § 1, 1997; Ord. 1957 § 14, 1983).