Chapter 14.20
STORMWATER MANAGEMENT

Sections:

14.20.010    Declaration of title.

14.20.020    Purpose.

14.20.030    Definitions.

14.20.040    Adoption of technical manual.

14.20.050    Authority.

14.20.060    Applicability.

14.20.070    Exemptions.

14.20.080    Variances.

14.20.090    Discharge of stormwater directly to Puget Sound.

14.20.100    Drainage associated with civil construction and grading activities.

14.20.110    Changes in site topography.

14.20.120    Maintenance of erosion and sedimentation control.

14.20.130    Agreements, easements, tracts, and covenants.

14.20.140    Basin planning.

14.20.150    Maintenance of stormwater facilities by owners.

14.20.160    City acceptance of new stormwater facilities.

14.20.170    City acceptance of existing stormwater facilities.

14.20.180    City inspections of privately maintained stormwater facilities.

14.20.190    Test procedures.

14.20.200    Violations of this code.

14.20.010 Declaration of title.

This code shall be known as the stormwater management code. (Ord. 1169 § 2, 2009).

14.20.020 Purpose.

The purpose of this code is to:

A. Guide development or redevelopment activities within the city of Gig Harbor with regards to stormwater drainage. The provisions of this code establish the minimum standards and construction procedures that must be met before issuance of a permit for development or redevelopment of property;

B. Minimize or eliminate the impacts of increased runoff, erosion, and sedimentation caused by land disturbance, development, and redevelopment;

C. Promote site planning and construction practices that seek to maintain the natural hydrologic conditions;

D. Require that stormwater facilities be operated, maintained, and repaired in conformance with this code. The provisions of this code establish the minimum level of compliance that must be met for maintaining stormwater facilities within the city;

E. Provide for inspection and maintenance of stormwater facilities in the city to ensure an effective and functional stormwater drainage system;

F. Not to create or otherwise establish or designate any particular class or group of persons who will or should be especially protected or benefited by the terms of this code; and

G. Meet the requirements of the city’s National Pollution Discharge Elimination System Permit for Municipal Separate Storm Sewer Systems. (Ord. 1169 § 2, 2009).

14.20.030 Definitions.

“Basin” shall mean an area from which surface runoff is concentrated, usually to a single point such as the mouth of a stream.

“Best management practice” or “BMP” shall mean the schedules of activities, prohibitions of practices, maintenance procedures, and structural and/or managerial practices that, when used singly or in combination, prevent or reduce the release of pollutants and other adverse impacts to waters of Washington.

“Development” shall mean any manmade change to improved or unimproved real estate including, but not limited to, buildings or other structures, placement of manufactured home/mobile home, mining, dredging, clearing, filling, grading, paving, excavation, drilling operations, or the subdivision of property. See also the definitions for redevelopment and land disturbing activity.

“Erosion” shall mean the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep. Also, detachment and movement of soil or rock fragments by water, wind, ice, or gravity.

“Land disturbing activity” shall mean any activity that results in a movement of earth or a change in the existing soil cover (both vegetative and nonvegetative) and/or the existing soil topography. Land disturbing activities include but are not limited to clearing, grading, filling, and excavation. Compaction that is associated with stabilization of structures and road construction shall also be considered a land disturbing activity. Vegetation maintenance practices are not considered land disturbing activity.

“Municipal separate storm sewer system (MS4)” or “stormwater drainage system” means the system of conveyances including sidewalks, roads with drainage systems, municipal streets, catchbasins, curbs, gutters, ditches, manmade channels, or storm drains owned and operated by the city and designed or used for collecting or conveying stormwater.

“Redevelopment” shall mean, where a site that is already substantially developed (i.e., has 35 percent or more of existing impervious surface coverage), the creation or addition of impervious surfaces; the expansion of a building footprint or addition or replacement of a structure; structural development including construction, installation or expansion of a building or other structure; replacement of impervious surface that is not part of a routine maintenance activity; and land disturbing activities.

“Stormwater” shall mean that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes and other features of a stormwater drainage system into a defined surface water body, or a constructed infiltration facility.

“Stormwater facility” shall mean 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 ponds, retention ponds, constructed wetlands, infiltration devices, catch basins, oil/water separators, and biofiltration swales. (Ord. 1169 § 2, 2009).

14.20.040 Adoption of technical manual.

The Gig Harbor stormwater management and site development manual, most recent version, hereafter called the “manual,” is hereby adopted as the city’s manual for controlling runoff from new development, redevelopment and construction sites. (Ord. 1169 § 2, 2009).

14.20.050 Authority.

The public works director (director), or an assignee, shall have the authority to administer and enforce this code. The director shall also have the authority to develop and implement procedures to administer and enforce this code. The director may approve, conditionally approve, or deny an application for activities regulated by this code. The director is authorized to develop a regular inspection program for all stormwater facilities in the city. (Ord. 1169 § 2, 2009).

14.20.060 Applicability.

The provisions of this code shall apply to all site development activities, both public and private, within the city of Gig Harbor.

Any land development which is required by operation of any city of Gig Harbor code, state law, or federal law to construct, install, or modify any natural or manmade drainage features within, abutting, or serving the development shall do so in accordance with this code. However, where the provisions of this code directly conflict with any other Gig Harbor code, state or federal law, comprehensive drainage plan, or special study, the more stringent provisions shall apply to the extent permissible by law.

Approval of any land development activity by the city of Gig Harbor does not constitute approval of other applicable permits that may be required by other agencies. The fact that any activity is exempt from the permit requirements of this code shall not constitute an exemption from any other city code, ordinance, or state or federal law. (Ord. 1169 § 2, 2009).

14.20.070 Exemptions.

The following are exempt from the requirements of this code:

A. Site development or redevelopment activities approved under an existing unexpired development permit prior to the effective date of this code. These activities shall instead meet the requirements of the code in place at the time of development permit approval.

B. Site development or redevelopment permit applications that have been deemed a complete application prior to the effective date of this code. These applications shall instead meet the requirements of the code in place at the time the application was deemed complete.

C. 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.

D. Development that is undertaken by the Washington State Department of Transportation in state highway rights-of-way and is regulated by Chapter 173-270 WAC, the Puget Sound Highway Runoff Program.

E. Road construction and/or maintenance activities, including the creation of wetland mitigations sites and storm ponds, undertaken by the Gig Harbor public works department shall be exempt from the administrative requirements of this code, but shall comply fully with the technical requirements contained herein.

F. An excavation below finished grade for basements and footings of a building, retaining wall, or other structure authorized by a valid building permit. This shall not exempt the placement of any fill material removed from such an excavation, and shall not exempt any excavation beyond the limits of the basement or footing excavations nor exempt excavations having an unsupported height greater than four feet after the completion of such a structure.

G. Agricultural crop management outside of critical drainage areas limited to the preparation of soil by turning, discing, or other means endorsed by the local conservation district.

H. Excavation for cemetery graves.

I. The disposal of solid waste, wood waste, problem waste and demolition waste authorized pursuant to Chapter 70.95 RCW, and regulations presently enacted or as may be amended or as specifically approved by the Pierce County health district.

J. The on-site stormwater management for mining, quarrying, excavating, processing, and/or stockpiling of rock, sand, gravel, aggregate, or clay where established and provided by law, and a permit for said activity has been issued by the state of Washington or the federal government, provided such operations do not exceed the minimum requirements of this code at the discharge location to the MS4.

K. Exploratory excavations under the direction of a qualified professional engineer.

L. Grading activities already approved by separate permit granted by any governing authority; provided, that the activities meet the minimum requirements of this code.

M. Emergency sandbagging, diking, ditching, filling, pumping, eductor truck work, or similar work during or after periods of extreme weather conditions when done to protect life or property.

N. Discharges of regulated effluent from any commercial or municipal facility holding a valid state or federal wastewater discharge permit.

O. Discharges from acts of nature not compounded by human negligence.

P. Discharges from properly operating on-site domestic sewage systems.

Q. Discharges from properly applied agricultural chemicals or materials. (Ord. 1169 § 2, 2009).

14.20.080 Variances.

The director of public works may grant a variance from the provisions of this code; provided, that all criteria are met as adopted in GHMC 12.16.010. (Ord. 1169 § 2, 2009).

14.20.090 Discharge of stormwater directly to Puget Sound.

Development or redevelopment sites that abut Puget Sound or tidally influenced areas of rivers and streams discharging into Puget Sound do not need to meet the flow control requirements of the manual provided sufficient BMPs are provided to mitigate increased release rates and potential for erosion. All other requirements of the manual shall be met. (Ord. 1169 § 2, 2009).

14.20.100 Drainage associated with civil construction and grading activities.

A. All civil construction activities shall conform to the requirements of Chapters 12.02 and/or 12.06 GHMC.

B. All grading activities shall conform to the requirements of Chapter 14.40 GHMC.

C. All site development and redevelopment activities shall meet the requirements of the manual.

D. Stormwater flows shall be accepted onto, and shall be discharged from, a project site at the natural or otherwise legally existing locations. (Ord. 1169 § 2, 2009).

14.20.110 Changes in site topography.

A. The maximum surface gradient on any artificially created slope without a retaining structure shall be two feet of horizontal run to one foot of vertical fall (2:1). This gradient may be increased to that gradient which can be demonstrated through engineering calculations to be stable, if, in the opinion of the director, it has been demonstrated by the applicant through engineering calculations performed by a qualified professional engineer that surface erosion can be controlled to that erosion rate equal to a properly stabilized 2:1 slope under the same conditions.

B. Any rockery or other retaining structure greater than four feet in height must be permitted under a separate building permit issued by the city.

C. The applicant shall at all times protect adjacent private properties and public rights-of-way or easements from damage occurring during development. The applicant shall restore private property and public improvements damaged by his/her operations.

D. The applicant shall be responsible for obtaining and coordinating all required state or federal permits associated with the disturbance of wetlands or other regulated activities. (Ord. 1169 § 2, 2009).

14.20.120 Maintenance of erosion and sedimentation control.

It shall be the responsibility of the contractor performing the land disturbing activities to maintain all temporary erosion and sediment control and drainage facilities in good operating condition at all times, as described in the manual. It shall be the responsibility of the property owner to maintain all permanent erosion and sediment control and drainage facilities in good operating condition at all times, as described in the manual. (Ord. 1169 § 2, 2009).

14.20.130 Agreements, easements, tracts, and covenants.

A. Each development installing stormwater facilities or drainage systems beyond the city’s right-of-way shall submit a completed stormwater facilities maintenance agreement on a city form prior to approval of construction.

B. Drainage easements shall be provided for all stormwater conveyance systems that are not located in public rights-of-way or tracts. Said drainage easements shall be granted to the parties responsible for providing ongoing maintenance of the systems and shall be of sufficient width to accommodate maintenance equipment and excavations relative to the depth and size of the systems.

C. Drainage easements through structures are not permitted.

D. Stormwater facilities that are to be maintained by the city, together with maintenance access roads to said facilities, shall be located in public right-of-way, separate tracts dedicated to the city, or drainage easements located in designated open space. The exception is for stormwater conveyance pipes that may be located within easements on private property; provided, that all catch basins can be accessed without entering private property.

E. All runoff from impervious surfaces, roof drains, and yard drains shall be directed so as not to adversely affect adjacent properties. Wording to this effect shall appear on the face of all binding site plans, short plats, boundary line adjustments, and final plats/PRDs, and shall be contained in any covenants required for a development. (Ord. 1169 § 2, 2009).

14.20.140 Basin planning.

An adopted and implemented basin plan tailored to a specific basin may be used to develop requirements for source control, stormwater treatment, streambank erosion control, wetlands, and water quality sensitive areas. Adopted and implemented watershed-based basin plans may be used to modify any or all of the minimum requirements addressed in the manual; provided, that the level of protection for surface or ground water achieved by the basin plan will equal or exceed that which would otherwise be achieved by implementation of the provisions of this code in the absence of a basin plan. Basin plans shall evaluate and include, as necessary, retrofitting of BMPs for existing development and/or redevelopment in order to achieve watershed-wide pollutant reduction goals. Standards developed from basin plans shall not modify any of the above requirements until the basin plan is formally adopted and fully implemented by the city. (Ord. 1169 § 2, 2009).

14.20.150 Maintenance of stormwater facilities by owners.

For privately maintained stormwater facilities and BMPs, the maintenance requirements specified in this code, including the manual, shall be enforced against the owner(s) of the subject property served by the stormwater facility. (Ord. 1169 § 2, 2009).

14.20.160 City acceptance of new stormwater facilities.

The city may accept for maintenance those new residential stormwater facilities constructed under an approved permit that meet the following conditions:

A. Improvements in residential plats/PRDs have been completed on at least 80 percent of the lots, unless waived by the director; and

B. All drainage facilities have been inspected and accepted by the director and said drainage facilities have been in satisfactory operation for at least two years; and

C. All drainage facilities reconstructed during the maintenance period have been accepted by the director; and

D. The stormwater facility, as designed and constructed, conforms to the provisions of this code; and

E. All easements and tracts required under this code, entitling the city to properly operate and maintain the subject drainage facility, have been conveyed to the city and have been recorded with the Pierce County auditor; and

F. For nonstandard drainage facilities, an operation and maintenance manual, including a maintenance schedule, has been submitted to and accepted by the city; and

G. A complete and accurate set of reproducible mylar record drawings and a digital file in a drafting format acceptable by the director have been provided to the city of the stormwater facilities. (Ord. 1169 § 2, 2009).

14.20.170 City acceptance of existing stormwater facilities.

The city may accept for maintenance those stormwater facilities for residential developments existing prior to the effective date of this code that meet the following conditions:

A. Improvements in residential plats/PRDs have been completed on at least 80 percent of the lots; and

B. An inspection by the director has determined that the stormwater facilities are functioning as designed; and

C. The stormwater facilities have had at least two years of satisfactory operation and maintenance, unless otherwise waived by the director; and

D. The person or persons holding title to the properties served by the stormwater facilities submit a petition containing the signatures of the title holders of more than 50 percent of the lots served by the stormwater facilities requesting that the city maintain the stormwater facilities; and

E. All easements required under this code, entitling the city to properly operate and maintain the subject stormwater facilities, have been conveyed to the city and have been recorded with the Pierce County auditor; and

F. The person or persons holding title to the properties served by the stormwater facilities show proof of the correction of any defects in the drainage facilities, as required by the director; and

G. A complete and accurate set of reproducible mylar record drawings and a digital file in a drafting format acceptable by the director have been provided to the city of the stormwater facilities; and

H. The stormwater facilities meet current design standards as defined in the manual or a variance has been approved. (Ord. 1169 § 2, 2009).

14.20.180 City inspections of privately maintained stormwater facilities.

The director is authorized to develop an inspection program for privately owned and maintained stormwater facilities in the city. The party (or parties) responsible for maintenance and operation shall be identified. The purpose of this inspection program shall be to determine if said storm water facilities, conveyance structures, and water quality facilities are in good working order and are properly maintained, and to ensure that stormwater management BMPs are in place and that nonpoint source pollution control is being implemented. Critical stormwater facilities, as so deemed by the director, may require a more frequent inspection schedule. (Ord. 1169 § 2, 2009).

14.20.190 Test procedures.

In the event that water quality testing is utilized in determining whether a violation of this section has occurred, said water quality test procedures shall be followed as described in the most recent edition of the Code of Federal Regulations, Part 136. (Ord. 1169 § 2, 2009).

14.20.200 Violations of this code.

The placement, construction or installation of any structure, or the connection to a public storm drainage facility, or the discharge to a public drainage facility or any activity which violates the provisions of this code shall be and the same is hereby declared to be unlawful and a public nuisance. The city may take enforcement action as set forth in Chapter 12.17 GHMC to ensure that any such activity, code violation or property condition declared to be a public nuisance ceases and is abated through the use of civil or criminal penalties and stop work orders, as well as any other remedies which are set forth in this code, the Gig Harbor Municipal Code, or any applicable ordinance or statute, including but not limited to revocation of any permits. The choice of enforcement action taken and the severity of any penalty shall be determined as set forth in Chapter 12.17 GHMC. (Ord. 1169 § 2, 2009).