Chapter 14.28
SURFACE AND STORM DRAINAGE
Sections:
14.28.010 Purposes.
14.28.020 Definitions.
14.28.030 Small parcel minimum requirements—Applicability.
14.28.040 Small parcel requirement #1—Construction access route.
14.28.050 Small parcel requirement #2—Stabilization of denuded areas.
14.28.060 Small parcel requirement #3—Protection of adjacent properties.
14.28.070 Small parcel requirement #4—Maintenance.
14.28.080 Small parcel requirement #5—Other BMPs.
14.28.090 New development—Applicability.
14.28.100 Redevelopment—Applicability.
14.28.110 Minimum requirement #1—Erosion and sediment control—Applicability.
14.28.120 Erosion and sediment control requirement #1—Stabilization and sediment trapping.
14.28.130 Erosion and sediment control requirement #2—Delineate clearing and easement limits.
14.28.140 Erosion and sediment control requirement #3—Protection of adjacent properties.
14.28.150 Erosion and sediment control requirement #4—Timing and stabilization of sediment trapping measures.
14.28.160 Erosion and sediment control requirement #5—Cut and fill slopes.
14.28.170 Erosion and sediment control requirement #6—Controlling off-site erosion.
14.28.180 Erosion and sediment control requirement #7—Stabilization of temporary conveyance.
14.28.190 Erosion and sediment control requirement #8—Storm drain inlet protection.
14.28.200 Erosion and sediment control requirement #9—Underground utility construction.
14.28.210 Erosion and sediment control requirement #10—Construction access routes.
14.28.220 Erosion and sediment control requirement #11—Removal of temporary BMPs.
14.28.230 Erosion and sediment control requirement #12—Dewatering construction sites.
14.28.240 Erosion and sediment control requirement #13—Control of pollutants other than sediment on construction sites.
14.28.250 Erosion and sediment control requirement #14—Maintenance.
14.28.260 Erosion and sediment control requirement #15—Financial liability.
14.28.270 Minimum requirement #2—Preservation of natural drainage systems.
14.28.280 Minimum requirement #3—Source control of pollution.
14.28.290 Minimum requirement #4—Runoff treatment BMPs.
14.28.300 Minimum requirement #5—Streambank erosion control.
14.28.310 Minimum requirement #6—Wetlands.
14.28.320 Minimum requirement #7—Water quality sensitive areas.
14.28.330 Minimum requirement #8—Off-site analysis and mitigation.
14.28.340 Minimum requirement #9—Basin planning.
14.28.350 Minimum requirement #10—Operation and maintenance.
14.28.360 Minimum requirement #11—Financial liability.
14.28.370 Exceptions.
14.28.380 Experimental BMPs.
14.28.390 Development in critical areas.
14.28.400 City engineer review and approval of required plans.
14.28.410 Establishment of regional facilities.
14.28.420 Bonds and liability insurance required.
14.28.430 City assumption of operation and maintenance.
14.28.440 Retroactivity relating to city maintenance.
14.28.450 Applicability to governmental entities.
14.28.460 Enforcement.
14.28.010 Purposes.
The city council finds that this chapter is necessary in order to promote sound development guidelines and construction procedures which respect and preserve the city’s water sources; to minimize water quality degradation and control the sedimentation of creeks, streams, ponds, lakes and other water bodies; to protect property owners adjacent to developing and developed land from increased runoff rates which could cause erosion of abutting property; to protect downstream owners; to preserve and enhance the suitability of waters for contact recreation and fishing; to preserve and enhance the aesthetic quality of the waters; to maintain and protect valuable groundwater resources; to minimize adverse effects of alterations in groundwater quantities, locations, and flow patterns; to provide for the safety of city roads and rights-of-way; and to decrease drainage related damage to public and private property. (Ord. 2196-97 § 1, 1997: Ord. 2182-96 § 1, 1996)
14.28.020 Definitions.
A. “Basin plan” refers to a detailed analysis for each drainage basin which compares the capabilities and needs for runoff accommodation due to various combinations of development, land use, structural and nonstructural management alternates. The plan recommends the form, location and extent of quantity and quality control measures which optimally would meet the legal constraints, water quality standards, and community standards, as well as identifying the institutional and funding requirement for plan implementation.
B. “Best management practice (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 the Department of Ecology.
C. “City engineer” means the city engineer and/or his designee.
D. “Computations” means calculations, including runoff coefficients and other pertinent data, made to determine the drainage plan with rates of flow of water given in cubic feet per second (cfs) and/or cubic meters per second (cms).
E. “Critical area” refers to areas that are highly susceptible to erosion or flooding such as steep or bare slopes, potential slides, floodplains, streambanks, drainage channels, silt bars, wetlands, bogs, marshes, and poorly drained areas.
F. “Design storm” refers to a rainfall event as stipulated in the storm management manual which, when used for purposes of design, will specify both the return period in years and the duration in hours (as in two-year twenty-four-hour storm).
G. “Detention facilities” means facilities designed to hold runoff while gradually releasing it at predetermined maximum rates.
H. “Developer” means the owning individual(s) or corporation(s) or their representative applying for the permits or approvals described in Sections 14.28.030 through 14.28.080 of this chapter.
I. “Developmental coverage” means all developed impervious surface areas within the subject property including, but not limited to, rooftops, driveways, carports, accessory buildings, and parking areas.
During construction “development coverage” shall include the above in addition to the full extent of any alteration of previously occurring soils, slope or vegetation due to grading, temporary storage, access areas, or any other short-term causes.
J. “Drainage area” means the watershed contributing water runoff to and including the subject property.
K. “Drainage plan” means a plan for collection, transport, treatment, and discharge or recycle of water within the subject property.
L. “Environmentally sensitive areas” (as defined in the city zoning code) means any of those areas of the city which are subject to natural hazards or those landform features which carry, hold, or purify water and/or support unique, fragile or valuable natural resources including fish, wildlife, and other organisms and their habitat. Sensitive areas include the following features: geologically hazardous areas; wetlands; streams; flood hazard areas; fish and wildlife conservation areas; and groundwater discharge areas.
M. Existing Site Conditions.
1. For developed sites with stormwater facilities that have been constructed to meet the standards in the minimum requirements of this manual, “existing site conditions” means the existing conditions on the site.
2. For developed sites that do not have stormwater facilities that meet the minimum requirements, “existing site conditions” means the conditions that existed prior to local government adoption of a stormwater management program. If in question, the existing site conditions shall be documented by aerial photograph records, or other appropriate means.
3. For all sites in water quality sensitive areas as identified under Section 14.28.320 of this chapter, Minimum requirement #7—Water quality sensitive areas, “existing site conditions” means undisturbed forest, for the purpose of calculating runoff characteristics.
4. For all undeveloped sites outside of water quality sensitive areas, “existing site conditions” means the existing conditions on the site.
N. “Impervious surface” means a hard surface area which prevents the entry of water into the soil mantle as under natural conditions prior to development. Common impervious surfaces include, but are not limited to, roof tops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, or other surfaces which similarly prevent the natural infiltration of stormwater.
O. “New development” means the following activities: land disturbing activities; structural development, including construction, installation or expansion of a building or other structure; creation of impervious surfaces; and subdivision and short subdivision of land as defined in Chapter 58.17 RCW.
P. “Natural location” of drainage system refers to the location of those channels, swales, and other conveyance systems as defined by the topographic contours existing for the subject property from city of Everett aerial topographic maps dated 4-8-69 and 4-25-71. In cases where the above maps are inconclusive, “natural location” refers to the existing features unless it can be shown from documented maps or photographs that the features have existed less than ten years. In cases of disagreement, the decision of the city engineer as to “natural location” shall be final.
Q. “Peak discharge” means the maximum surface water runoff rates (cfs and cms) determined for the design storms at the point of discharge from the subject property.
R. “Planned residential development” means a land development project comprehensively planned as an entity via a single site plan which permits flexibility in building siting (lot size, setback lines, etc.), mixture of housing types, usable open space, and preservation of sufficient natural feature.
S. “Receiving bodies of water” means all watercourses including creeks, streams, lakes, and other bodies of water into which waters are directed, either naturally, in manmade ditches, or in closed conduit systems.
T. “Redevelopment” means, 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, replacement of impervious surface that is not part of a routine maintenance activity, and land disturbing activities associated with structural or impervious redevelopment.
U. “Retention facilities” means facilities designed to hold water for a considerable length of time and then consume it by evaporation, plant transpiration, or infiltration into the soil.
V. “Runoff control facilities” means any facility installed or constructed in conjunction with a drainage plan for the purpose of treatment or abatement of urban stormwater runoff, excluding retention or detention facilities.
W. “Stormwater management manual” means the manual of technical and administrative procedures established by the city engineer which delineates methods to be used, the level of analysis required, and other details for implementation of the provisions of this chapter.
X. “Subject property” means the tract of land which is the subject of the permit and/or approval action, as defined by the full legal description of all parcels involved in the proposed development. (Ord. 2196-97 § 2, 1997: Ord. 2182-96 § 2, 1996)
14.28.030 Small parcel minimum requirements—Applicability.
The following new development shall be required to control erosion and sediment during construction, to permanently stabilize soil exposed during construction to comply with small parcel requirements #1 through #5 in Sections 14.28.040 through 14.28.080 of this chapter and submit a small parcel erosion and sediment control plan as set forth below:
A. Individual, detached, single-family residence and duplexes (except remodels);
B. Creation or addition of less than five thousand square feet of impervious surface area; or
C. Land disturbing activities of less than one acre. (Ord. 2196-97 § 3(1)(A), 1997: Ord. 2182-96 § 3(1)(A), 1996)
14.28.040 Small parcel requirement #1—Construction access route.
Construction vehicle access shall be limited to one route wherever possible. Access points shall be stabilized with quarry spalls or crushed rock to minimize the tracking of sediment onto public roads. (Ord. 2196-97 § 3(1)(B), 1997: Ord. 2182-96 § 3(1)(B), 1996)
14.28.050 Small parcel requirement #2—Stabilization of denuded areas.
All exposed and unworked soils shall be stabilized by suitable application of best management practices (BMPs) including, but not limited to, sod or other vegetation, plastic covering, mulching, or application of ground base on areas to be paved. All BMPs shall be selected, designed and maintained in accordance with an approved manual. From October 1st through March 31st, no soils shall remain exposed for more than two consecutive days. From April 1st through September 30th, no soils shall remain exposed for more than seven consecutive days. (Ord. 2196-97 § 3(1)(C), 1997: Ord. 2182-96 § 3(1)(C), 1996)
14.28.060 Small parcel requirement #3—Protection of adjacent properties.
Adjacent properties shall be protected from sediment deposition by appropriate use of vegetative buffer strips, sediment barriers or filters, dikes or mulching, or by a combination of these measures and other appropriate BMPs. (Ord. 2196-97 § 3(1)(D), 1997: Ord. 2182-96 § 3(1)(D), 1996)
14.28.070 Small parcel requirement #4—Maintenance.
All erosion and sediment control BMPs shall be regularly inspected and maintained to ensure continued performance of their intended function. (Ord. 2196-97 § 3(1)(E), 1997: Ord. 2182-96 § 3(1)(E), 1996)
14.28.080 Small parcel requirement #5—Other BMPs.
As required by the city, other appropriate BMPs to mitigate the effects of increased runoff shall be applied. (Ord. 2196-97 § 3(1)(F), 1997: Ord. 2182-96 § 3(1)(F), 1996)
14.28.090 New development—Applicability.
A. All new development that includes the creation or addition of five thousand square feet or more of new impervious surface, and/or land disturbing activity of one acre or greater, shall comply with minimum requirements #1 through #11 in Sections 14.28.110 through 14.28.360 of this chapter and shall prepare a stormwater site plan, large parcel erosion and sediment control plan and drainage plan.
B. All new development that includes the creation or addition of five thousand square feet or more of new impervious surface and land disturbing activity of less than one acre shall comply with minimum requirements #2 through #11 in Sections 14.28.270 through 14.28.360 of this chapter and the small parcel minimum requirements found in Sections 14.28.030 through 14.28.080. This category of development shall also prepare a stormwater site plan, a small parcel erosion and sediment control plan and a drainage plan.
C. Sites creating or adding less than five thousand square feet of new impervious surface and disturbing less than one acre of land need only comply with the small parcel minimum requirements found in Sections 14.28.030 through 14.28.080 of this chapter.
D. This section does not apply to the construction of individual, detached, single-family residences and duplexes. Those types of new development are included in the small parcel minimum requirements.
E. Requirements for stormwater site plans and erosion and sediment control plans are found in the city of Everett stormwater management manual. (Ord. 2196-97 § 3(2), 1997: Ord. 2182-96 § 3(2), 1996)
14.28.100 Redevelopment—Applicability.
A. Where redevelopment of five thousand square feet or more occurs, the new development minimum requirements #1 through #11, Sections 14.28.110 through 14.28.360 of this chapter, shall apply to that portion of the site that is being redeveloped, and source control BMPs shall be applied to the entire site, including adjoining parcels if they are part of the project. A stormwater site plan shall also be prepared.
B. In addition to the above requirements, where one or more of the following conditions apply, a stormwater site plan shall also be prepared that implements the minimum requirements to the maximum extent feasible, for the entire site, including adjoining parcels if they are part of the project. Application of this requirement shall not interfere with existing land uses on the site or preclude the intended use of the redeveloped portion of the site. An adopted and implemented basin plan (minimum requirement #9, Section 14.28.340 of this chapter) may be used to develop redevelopment requirements that are tailored to a specific basin.
1. Existing sites greater than one acre in size with fifty percent or more impervious surface.
2. Sites that discharge to a receiving water that has a documented water quality problem. A documented water quality problem includes, but is not limited to, water bodies:
a. Listed in reports required under Section 305 (b) of the Clean Water Act, and designated as not supporting beneficial uses;
b. Listed under Section 304(l)(1)(A)(i), 304(l)(1) (A)(ii), or 304(l)(1)(B) of the Clean Water Act as not expected to meet water quality standards or water quality goals;
c. Listed in Washington State’s Nonpoint Source Assessment required under Section 319(a) of the Clean Water Act that, without additional action to control nonpoint sources of pollution, cannot reasonably be expected to attain or maintain water quality standards.
3. Sites where the need for additional stormwater control measures has been identified through a basin plan, the watershed ranking process under Chapter 400-12 WAC, or through Growth Management Act planning. (Ord. 2196-97 § 3(3), 1997: Ord. 2182-96 § 3(3), 1996)
14.28.110 Minimum requirement #1—Erosion and sediment control—Applicability.
A. All new development and redevelopment that includes land disturbing activities of one acre or more shall comply with erosion and sediment control requirements #1 through #14, Sections 14.28.120 through 14.28.250 of this chapter. Compliance with the erosion and sediment control requirements shall be demonstrated through development and implementation of a large parcel erosion and sediment control plan.
B. All new development and redevelopment that includes land disturbing activities of one acre or less shall comply with the small parcel minimum requirements found in Sections 14.28.030 through 14.28.080 of this chapter. (Ord. 2196-97 § 3(4)(A), 1997: Ord. 2182-96 § 3(4)(A), 1996)
14.28.120 Erosion and sediment control requirement #1—Stabilization and sediment trapping.
All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1st to April 30th, no soils shall remain exposed for more than two consecutive days. From May 1st to September 30th, no soils shall remain exposed for more than seven consecutive days. Prior to leaving the site, stormwater runoff shall pass through a sediment pond or sediment trap, or other appropriate BMPs. (Ord. 2392-99 § 1, 1999: Ord. 2196-97 § 3(4)(B), 1997: Ord. 2182-96 § 3(4)(B), 1996)
14.28.130 Erosion and sediment control requirement #2—Delineate clearing and easement limits.
In the field, clearing limits and/or any easements, setbacks, sensitive/critical areas and their buffers, trees and drainage courses shall be marked. (Ord. 2196-97 § 3(4)(C), 1997: Ord. 2182-96 § 3(4)(C), 1996)
14.28.140 Erosion and sediment control requirement #3—Protection of adjacent properties.
Properties adjacent to the project site shall be protected from sediment deposition. (Ord. 2196-97 § 3(4)(D), 1997: Ord. 2182-96 § 3(4)(D), 1996)
14.28.150 Erosion and sediment control requirement #4—Timing and stabilization of sediment trapping measures.
Sediment ponds and traps, perimeter dikes, sediment barriers, and other BMPs intended to trap sediment on-site shall be constructed as a first step in grading. Earthen structures such as dams, dikes, and diversions shall be seeded and mulched according to the timing indicated in erosion and sediment control requirement #1, Section 14.28.120 of this chapter. (Ord. 2196-97 § 3(4)(E), 1997: Ord. 2182-96 § 3(4)(E), 1996)
14.28.160 Erosion and sediment control requirement #5—Cut and fill slopes.
Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. In addition, slopes shall be stabilized in accordance with erosion and sediment control requirement #1, Section 14.28.120 of this chapter. (Ord. 2196-97 § 3(4)(F), 1997: Ord. 2182-96 § 3(4)(F), 1996)
14.28.170 Erosion and sediment control requirement #6—Controlling off-site erosion.
Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. (Ord. 2196-97 § 3(4)(G), 1997: Ord. 2182-96 § 3(4)(G), 1996)
14.28.180 Erosion and sediment control requirement #7—Stabilization of temporary conveyance.
All temporary on-site conveyance channels shall be designed, constructed and stabilized to prevent erosion from the expected velocity of flow from a two-year, twenty-four-hour frequency storm for runoff volumes expected during the construction phase. Stabilization adequate to prevent erosion of outlets, adjacent streambanks, slopes and downstream reaches shall be provided at the outlets of all conveyance systems. (Ord. 2196-97 § 3(4)(H), 1997: Ord. 2182-96 § 3(4)(H), 1996)
14.28.190 Erosion and sediment control requirement #8—Storm drain inlet protection.
All storm drain inlets made operable during construction shall be protected so that stormwater runoff shall not enter the conveyance system without first being filtered or otherwise treated to remove sediment. (Ord. 2196-97 § 3(4)(I), 1997: Ord. 2182-96 § 3(4)(I), 1996)
14.28.200 Erosion and sediment control requirement #9—Underground utility construction.
The construction of underground utility lines shall be subject to the following criteria:
A. Every effort shall be made to close utility lines by the end of the day;
B. Where consistent with safety and space considerations, excavated material shall be placed on the uphill side of trenches; and
C. Trench dewatering devices shall discharge into a sediment trap or sediment pond. (Ord. 2196-97 § 3(4)(J), 1997: Ord. 2182-96 § 3(4)(J), 1996)
14.28.210 Erosion and sediment control requirement #10—Construction access routes.
Wherever construction vehicle access routes intersect paved roads, provisions must be made to minimize the transport of sediment (mud) onto the paved road. If sediment is transported onto a road surface, the roads shall be cleaned thoroughly at the end of each day. Sediment shall be removed from roads by shoveling or sweeping and be transported to a controlled sediment disposal area. Street washing shall be allowed only after sediment is removed in this manner. (Ord. 2196-97 § 3(4)(K), 1997: Ord. 2182-96 § 3(4)(K), 1996)
14.28.220 Erosion and sediment control requirement #11—Removal of temporary BMPs.
All temporary erosion and sediment control BMPs shall be removed within thirty days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. (Ord. 2196-97 § 3(4)(L), 1997: Ord. 2182-96 § 3(4)(L), 1996)
14.28.230 Erosion and sediment control requirement #12—Dewatering construction sites.
Dewatering devices that don’t achieve state water quality standards shall discharge into a sediment trap or sediment pond. (Ord. 2196-97 § 3(4)(M), 1997: Ord. 2182-96 § 3(4)(M), 1996)
14.28.240 Erosion and sediment control requirement #13—Control of pollutants other than sediment on construction sites.
All pollutants other than sediment that occur on-site during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. (Ord. 2196-97 § 3(4)(N), 1997: Ord. 2182-96 § 3(4)(N), 1996)
14.28.250 Erosion and sediment control requirement #14—Maintenance.
A. All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with the city of Everett’s stormwater management manual and design and construction standards and specifications.
B. All temporary erosion and sediment control BMPs shall be maintained in a satisfactory condition until such time that clearing and/or construction is completed, permanent drainage facilities are operational, and the potential for erosion has passed.
C. As construction progresses and seasonal conditions dictate, the erosion control facilities shall be maintained and/or altered as required by the city engineer to ensure continuing erosion/sedimentation control. (Ord. 2196-97 § 3(4)(O), 1997: Ord. 2182-96 § 3(4)(O), 1996)
14.28.260 Erosion and sediment control requirement #15—Financial liability.
To the extent permitted by law, performance bonding, or other appropriate financial instruments acceptable to the city, shall be required for all projects to ensure compliance with the approved erosion and sediment control plan. (Ord. 2196-97 § 3(4)(P), 1997: Ord. 2182-96 § 3(4)(P), 1996)
14.28.270 Minimum requirement #2—Preservation of natural drainage systems.
Natural drainage patterns shall be maintained and discharges from the site shall occur at the natural location. (Ord. 2196-97 § 3(5), 1997: Ord. 2182-96 § 3(5), 1996)
14.28.280 Minimum requirement #3—Source control of pollution.
A. Source control BMPs shall be applied to all projects to the maximum extent feasible. Source control BMPs shall be selected, designed, and maintained according to the city of Everett stormwater management manual.
B. An adopted and implemented basin plan (minimum requirement #9, Section 14.28.340 of this chapter) may be used to develop source control requirements that are tailored to a specific basin, however, in all circumstances, source control BMPs shall be required for all sites. (Ord. 2196-97 § 3(6), 1997: Ord. 2182-96 § 3(6), 1996)
14.28.290 Minimum requirement #4—Runoff treatment BMPs.
All projects meeting the criteria given in Sections 14.28.090 and 14.28.100 of this chapter shall provide treatment of stormwater runoff in accordance with the requirements of this section.
Runoff treatment shall be required when either of the following thresholds is exceeded:
A. Five thousand square feet or more of impervious area that is subject to significant pollutant deposition is created or redeveloped; or
B. An acre or more of intensively managed pervious area is created or redeveloped.
Impervious areas considered to be subject to significant pollutant deposition shall include but not be limited to the following: (1) driveable surfaces (i.e., roads, parking areas, storage areas, and driveways) which are regularly utilized by motorized vehicles or equipment, and (2) non-driveable impervious surfaces (i.e., rooftops, patios, and sidewalks) in areas of significant pollutant deposition.
Pervious areas considered to be intensively managed shall be defined as those areas which are maintained with the use of pesticides, herbicides, and/or fertilizers and shall include but not limited to (1) lawn areas, (2) golf course greens, and (3) vegetated ball fields.
The first priority for treatment shall be to infiltrate as much as possible of the six-month, twenty-four-hour storm runoff, only if site conditions are appropriate and ground water quality will not be impaired. Direct discharge of untreated stormwater to ground water is prohibited.
Runoff treatment BMPs shall be sized to capture and treat the six-month, twenty-four-hour storm runoff from the areas contributing runoff to the runoff treatment BMP. All treatment BMPs shall be selected, designed, and maintained according to the city of Everett’s stormwater management manual.
Stormwater treatment BMPs shall not be built within environmentally sensitive areas or their required buffers, unless allowed for in the city’s zoning code, except for necessary conveyance systems as approved by the city. (Ord. 2392-99 § 2, 1999: Ord. 2196-97 § 3(7), 1997: Ord. 2182-96 § 3(7), 1996)
14.28.300 Minimum requirement #5—Streambank erosion control.
This requirement applies when five thousand square feet or more of impervious surface is added or created by a project and stormwater runoff is discharged directly or indirectly to a stream:
A. Streambank erosion shall be controlled by limiting the peak rate of runoff from individual development sites to fifty percent of the existing condition two-year, twenty-four-hour design storm for the developed runoff rate from the two-year, twenty-four-hour storm, while maintaining the existing condition peak runoff rate for the ten-year, twenty-four-hour and one-hundred-year, twenty-four-hour design storms. As the first priority, streambank erosion control BMPs shall utilize infiltration to the fullest extent practicable, only if site conditions are appropriate and groundwater quality is protected. Streambank erosion control BMPs shall be selected, designed, and maintained according to the city of Everett’s stormwater management manual.
B. Streambank erosion control BMPs shall not be built within environmentally sensitive areas or their required buffers (except as allowed in the city’s zoning code), except for necessary conveyance systems as approved by the city.
C. An adopted and implemented basin plan (minimum requirement #9, Section 14.28.340 of this chapter) may be used to develop streambank erosion control requirements that are tailored to a specific basin. (Ord. 2196-97 § 3(8), 1997: Ord. 2182-96 § 3(8), 1996)
14.28.310 Minimum requirement #6—Wetlands.
A. The requirements below apply to sites immediately adjacent to a wetland and must be met in addition to meeting other requirements. “Immediately adjacent” for purposes of this requirement shall mean those parcels that are wholly or partially contained within a wetland delineated in accordance with Everett’s zoning code including the wetland outlet and those parcels that abut a wetland buffer. In addition, these requirements apply if a wetland is proposed for stormwater detention for upstream development (assuming all other local, state and federal approvals are obtained).
1. Discharges to wetlands shall maintain the hydroperiod and flows of existing site conditions to the extent necessary to protect the characteristic uses of the wetland. Prior to discharging for storage to a wetland, alternative discharge locations shall be evaluated, and natural water storage and infiltration opportunities outside the wetland shall be maximized.
2. Created wetlands that are intended to mitigate for loss of wetland acreage, functions, and values shall not be designed to also treat or store stormwater.
3. In order for constructed wetlands to be considered treatment systems, they must be constructed on sites that are not wetlands and they must be managed for stormwater treatment. If these systems are not managed and maintained in accordance with the city of Everett stormwater manual for a period exceeding three years, these systems may no longer be considered constructed wetlands. Discharges from constructed wetlands to waters of the state (including discharges to natural wetlands) are regulated under Chapter 90.48 RCW, Chapter 173-201 WAC, and Chapter 173-200 WAC.
4. Stormwater control BMPs shall not be built within environmentally sensitive areas or their required buffers (except as allowed in the city’s zoning code), except for necessary conveyance systems as approved by the city.
5. Stormwater discharges to wetlands must be controlled and treated to the extent necessary to meet State Water Quality Standards, Chapter 173-201 WAC or Groundwater Quality Standards, Chapter 173-200 WAC, as appropriate.
B. An adopted and implemented basin plan (minimum requirement #9, Section 14.28.340 of this chapter) may be used to develop requirements for wetlands that are tailored to a specific basin. (Ord. 2196-97 § 3(9), 1997: Ord. 2182-96 § 3(9), 1996)
14.28.320 Minimum requirement #7—Water quality sensitive areas.
A. Where the city determines that the minimum technical requirements in Sections 14.28.030 through 14.28.080 do not provide adequate protection of water quality sensitive areas, either on-site or within the basin, more stringent controls shall be required to protect water quality.
B. Stormwater control BMPs shall not be built within environmentally sensitive areas or their required buffers (except as allowed in the city’s zoning code), except for necessary conveyance systems as approved by the city.
C. An adopted and implemented basin plan (minimum requirement #9, Section 14.28.340 of this chapter) may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. (Ord. 2196-97 § 3(10), 1997: Ord. 2182-96 § 3(10), 1996)
14.28.330 Minimum requirement #8—Off-site analysis and mitigation.
Where identified in a city-approved basin plan or required in the project’s SEPA approval, development projects greater than one acre shall conduct an analysis of off-site water quality impacts resulting from the project and shall mitigate these impacts. The analysis shall extend one-fourth of a mile downstream from the project or to a point specified in the projects’ SEPA approval. The existing or potential impacts to be evaluated and mitigated shall include, at a minimum, but not be limited to:
A. Excessive sedimentation;
B. Streambank erosion;
C. Discharges to groundwater contributing or recharge zones;
D. Violations of water quality standards; and
E. Spills and discharges of priority pollutants. (Ord. 2196-97 § 3(11), 1997: Ord. 2182-96 § 3(11), 1996)
14.28.340 Minimum requirement #9—Basin planning.
Adopted and implemented watershed-based basin plans may be used to modify any or all of the minimum requirements; provided, that the level of protection for surface or groundwater achieved by the basin plan will equal or exceed that which would be achieved by the minimum requirements 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 implementation is initiated by the city. Basin plans shall be developed according to WAC 400-12-500. (Ord. 2196-97 § 3(12), 1997: Ord. 2182-96 § 3(12), 1996)
14.28.350 Minimum requirement #10—Operation and maintenance.
An operation and maintenance schedule shall be provided for all proposed stormwater facilities and BMPs, and the party (or parties) responsible for maintenance and operation shall be identified. (Ord. 2196-97 § 3(13), 1997: Ord. 2182-96 § 3(13), 1996)
14.28.360 Minimum requirement #11—Financial liability.
To the extent permitted by law, performance bonding or other appropriate financial instruments acceptable to the city shall be required for all projects to ensure compliance with these minimum requirements. (Ord. 2196-97 § 3(14), 1997: Ord. 2182-96 § 3(14), 1996)
14.28.370 Exceptions.
Exceptions to minimum requirements #1 through #10 in Sections 14.28.110 through 14.28.350 of this chapter may be granted prior to permit approval and construction. An exception may be granted by the public works director; 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 requirements 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. 2196-97 § 3(15), 1997: Ord. 2182-96 § 3(15), 1996)
14.28.380 Experimental BMPs.
Experimental best management practices are defined as BMPs which have not been tested and evaluated by the Department of Ecology in collaboration with local governments and technical experts. Experimental BMPs will not generally be allowed in the city of Everett until they have been recognized and approved by the Department of Ecology. (Ord. 2196-97 § 3(16), 1997: Ord. 2182-96 § 3(16), 1996)
14.28.390 Development in critical areas.
Development which would increase the volume or rate of discharge due to any storm from the subject property shall not be permitted in areas designated as critical areas in the basin plan. Critical areas are those in which existing flooding, drainage, erosion and/or instability conditions present an imminent likelihood of harm to the welfare and safety of the surrounding community, or to the integrity of the surface water or groundwater system. Development shall not be permitted in these critical areas until such time as the existing community hazard is alleviated and it is adequately demonstrated that the proposed development will not cause a recurrence of the problem nor the occurrence of any new drainage-related problem. The city engineer may also designate as critical any area in which comparable problems would occur in the future due to any increase in volume or peak discharge. The requirements of this section shall apply regardless of any other city regulation. Where applications of the provisions of this section will deny all reasonable use of the property, the restrictions on development contained in this section may be waived for the subject property; provided, that the resulting development shall be subject to all the remaining terms and condition of this chapter. All decisions based on the provisions of this section shall be compatible with the comprehensive drainage plan for the basin in which the subject property is located. For development in areas designated as critical, the developer shall provide information regarding volume and rate of discharge for a range of storms as specified in the procedures manual. (Ord. 2196-97 § 4, 1997: Ord. 2182-96 § 4, 1996)
14.28.400 City engineer review and approval of required plans.
All plans prepared in connection with this chapter shall be submitted for review and approval by the city engineer. (Ord. 2196-97 § 5, 1997: Ord. 2182-96 § 5, 1996)
14.28.410 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 basin plan, the city engineer may recommend that the city should assume responsibility for the further design, construction, operation and maintenance of the drainage facilities, or any increment of the responsibility of the facilities on the subject property. Should establishment of a regional detention facility at a location not contained in the subject property entail a greater public benefit, the city engineer may require the developer to participate in the cost of such an off-site regional detention facility in lieu of constructing on-site detention facilities. Such decision shall be made concurrently with review and approval of the plan as specified in this chapter. In the event that the city decides to assume responsibility for all or any portion of the 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 city engineer to aid in the determination by the city. Guidelines for implementing this section will be defined in the procedures manual or by the city engineer. (Ord. 2196-97 § 6, 1997: Ord. 2182-96 § 6, 1996)
14.28.420 Bonds and liability insurance required.
A. The city engineer is authorized to require developers constructing retention/detention and/or other drainage treatment/abatement facilities serving areas larger than one acre to post surety bond(s) or other form of guarantee acceptable to the city.
B. Where such developers have previously posted, or are required to post, other such bonds on the facility itself or on other construction related to the facility, such person may, with the permission of the city engineer and to the extent allowable by law, combine all such bonds into a single bond; provided, that at no time shall the amount thus bonded be less than the total amount which would have been required in the form of separate bonds; and provided further, that such a bond shall on its face clearly delineate those separate bonds which it is intended to replace.
C. Performance Bond. Prior to commencing construction, the developer constructing the facility shall post a performance bond in an amount of one hundred twenty percent of the cost of construction per the approved drainage plans. After determination by the city engineer that all facilities are constructed in compliance with the approved plans, the performance bond shall be released. Alternatively, an equivalent cash deposit to an escrow account administered by a local bank designated by the city may be acceptable.
D. Maintenance Warranty Bonds. After satisfactory completion of the facilities and release of the performance bond by the city, the developer constructing the facility shall commence a two-year period of satisfactory maintenance of the facility. A warranty bond to be used at the discretion of the city engineer to correct deficiencies in said maintenance affecting public health, safety and welfare must be posted and maintained throughout the two-year maintenance period. The amount of the warranty bond shall be ten percent of the estimated construction cost of the drainage facilities. In addition, the warranty bond shall cover the cost of design defects and/or failures in workmanship of the facilities throughout the two-year maintenance period. Alternatively, an equivalent cash deposit to an escrow account administered by a local bank designated by the city may be acceptable.
E. Liability Insurance. The developer constructing the facility shall maintain a liability insurance policy in the amount of five hundred thousand dollars per individual, one million dollars per occurrence, and five hundred thousand dollars property damage, which shall name the city as an additional insured and which shall protect the city from any liability up to those amounts for any accident, negligence, failure of the facility, or any other liability whatsoever, relating to the construction or maintenance of the facility. Said liability policy shall be maintained for the duration of the facility by the owner of the facility; provided, that in the case of facilities assumed by the city for maintenance, pursuant to Section 14.28.430 of this chapter, said liability policy shall be terminated when city council accepts the facility and city maintenance responsibility commences. (Ord. 2196-97 § 7, 1997: Ord. 2182-96 § 7, 1996)
14.28.430 City assumption of operation and maintenance.
A. The city may assume the operation and maintenance of retention/detention or other drainage treatment/abatement facilities after the expiration of the two-year operation and maintenance period in connection with the subdivision of land if:
1. All of the requirements of Section 14.28.420 of this chapter have been fully complied with; and
2. The facilities have been inspected and accepted by the utility department after two years of operation in accordance with the procedures manual; and
3. All necessary easements entitling the city to properly maintain the facility have been conveyed to the city and recorded with the Snohomish County auditor; and
4. The warranty bond required in Section 14.28.420(D) of this chapter has been extended for one year, covering the city’s first year of operation and maintenance; and
5. The developer has supplied to the city an accounting of capital, construction, and operation and maintenance expenses or other items for the drainage facilities up to the end of the two-year period.
B. In the event that the city elects not to assume the operation and maintenance responsibility for the facilities, it will be the responsibility of the developer to make arrangements with the occupants or owners of the subject property for assumption of maintenance in a manner subject to the approval of the city engineer or in accordance with the procedures manual. Such arrangements shall be completed and approved prior to the end of the two-year period of developer responsibility.
C. If the city elects not to assume operation and maintenance responsibility, the drainage facilities shall be operated and maintained in accordance with the arrangements as approved by the city engineer. The city may inspect the facilities in order to ensure continued use of the facilities for the purposes for which they were built and in accordance with these arrangements. (Ord. 2196-97 § 8, 1997: Ord. 2182-96 § 8, 1996)
14.28.440 Retroactivity relating to city maintenance.
A. If any developer constructing retention/detention or other drainage treatment/abatement facilities and/or receiving approval of drainage plans prior to the effective date of the ordinance codified in this chapter re-evaluates according to the requirements of this chapter the facilities and/or plans so constructed and/or approved and demonstrates to the city engineer’s satisfaction acceptable compliance with its requirements, the city may, after inspection, acceptance, and acknowledgment of the proper posting of the required bonds and insurance as specified in Section 14.28.430 of this chapter, assume operation and maintenance of the facilities.
B. In cases in which all or part of the drainage facilities are not accessible for maintenance purposes due to overlying structures or other causes, the city shall be indemnified from all costs and held harmless from damages and injuries which might occur due to failure of design or workmanship of those segments, and further will not be responsible for their maintenance, replacement, or rehabilitation. (Ord. 2196-97 § 9, 1997: Ord. 2182-96 § 9, 1996)
14.28.450 Applicability to governmental entities.
A. All municipal corporations and government 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, facilities, and parking lots 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. 2196-97 § 10, 1997: Ord. 2182-96 § 10, 1996)
14.28.460 Enforcement.
A. The city reserves the right to enter the subject property from time to time to ascertain that all drainage facilities are functioning. In the event deficiencies are found, the property owner shall make such corrections as are necessary within fifteen days of the date of notice by the city.
B. Any person or persons violating this chapter or rule or regulation adopted hereunder, or by any act of commission or omission procures, aids, or abets such violation, shall be guilty of a misdemeanor and, upon conviction, shall be punished by a fine not to exceed one thousand dollars and/or imprisonment for a term not to exceed ninety days. Each day such violation continues shall be considered an additional misdemeanor offense.
C. Any condition which constitutes or will constitute a violation of any of the provisions of this chapter or rules or regulations adopted hereunder shall constitute a nuisance for which the city may seek legal or equitable relief to enjoin any acts or practices or abate any said conditions. In the event the property owner shall fail to make corrections, within fifteen days of the date of notice by the city, the city may revoke the right to occupancy of the subject property, may charge the property owner with a misdemeanor punishable by fines, and may enter on to the subject property and take such corrective action as may be required to make the drainage facilities perform as required by the approved drainage plan. All costs for corrective measures and enforcement actions shall be borne by the property owner.
D. Notwithstanding any other provision of this chapter, whenever the city engineer finds that a violation of this chapter or rules or regulations adopted hereunder has created or is creating an unsanitary, dangerous, or other condition which, in his judgment, constitutes an immediate hazard, he may suspend or revoke any permit for which the approval of a drainage plan is required on the project or development where the violation exists and suspend or terminate operations under the permit immediately.
E. Any person causing material to be discharged to or enter the drainage system of the city shall be liable for all costs incurred by the city or others in cleaning up or correcting said action and may be charged with a misdemeanor punishable by fines.
F. Penalty or enforcement provisions provided herein shall not be exclusive, and the city may pursue any remedy or relief deemed appropriate.
G. The city council may institute a suit for a mandatory injunction directing a person to remove a structure or make the same comply with its terms. If the city council is successful in its suit, the respondent shall bear the costs of the action, including reasonable attorney fees.
H. The failure or refusal of the city to enforce any provision of this chapter, and as hereafter amended, shall not constitute a waiver or bar to prevent enforcement thereof against any person for a subsequent violation hereof, or for any other violation by any other person. (Ord. 2196-97 § 11, 1997: Ord. 2182-96 § 11, 1996)