Surface Water Management Comprehensive Plan Update Open House

This virtual Open House will close on June 15, 2020

SWMP-homepage.jpg

Welcome 

We would like to welcome you to our "Virtual Open House". The City of Lynnwood would like to share the updated Surface Water Management Comprehensive Plan with our Community Members and gather feed back related to it.

This plan is a major revision to the City’s Surface Water Management Comprehensive Plan that was last updated in 2009. This plan sets a course for stormwater programs and capital projects for years to come and addresses current and anticipated regulatory requirements, future land use designations, emerging stormwater management technologies, existing flooding and water quality problems, and the resources needed for the City to fully implement this plan.

The full plan and appendices can be accessed here: Lynnwood Surface Water Management Comprehensive Plan 2020(PDF, 49MB)  SWMCP Appendices 2020(PDF, 6MB)

INFORMATION USED TO DEVELOP THIS PLAN

Significant research was conducted to create this plan. In addition to the 2009 Surface Water Management Comprehensive Plan, past studies were reviewed for information on drainage and water quality problems and to evaluate the existing surface water management program. 

Public involvement is being conducted during the development of this plan in 2020. The City will follow a State Environmental Policy Act (SEPA) process to identify and analyze environmental impacts associated with implementation of this plan. 

Surface Water Management 2020 Comprehensive Plan(PDF, 49MB) pages 4 - 11

STORM WATER RUNOFF AND IT'S EFFECTS

The City of Lynnwood (City) uses an extensive system of drainage pipes and ditches to convey stormwater runoff to receiving waters, including streams, lakes, and Puget Sound, and to prevent and minimize damage to private properties, city streets, and other infrastructure. Due to extensive alteration of the natural landscape in most areas of Lynnwood, the amount of runoff that occurs during larger storm events is substantial, and runoff during all storm events carries a variety of pollutants to receiving waters. The City is faced with the challenge of conveying stormwater runoff safely and cost-effectively,while preventing or minimizing adverse high-flow impacts (erosion, flooding, and sediment deposition) and water quality degradation in receiving waters.

In 1991, the City established a Surface Water Utility to create a funding source to address stormwater and receiving water management issues citywide. The Surface Water Utility is funded by residential, commercial, and industrial ratepayers. State and federal regulations related to stormwater have evolved over the last 15 years, making it difficult to address all stormwater-related challenges while balancing the costs borne by utility ratepayers. The City must implement and continually improve upon a comprehensive plan for stormwater management to ensure that the program has the resources it needs to serve the community.

Surface Water Management Comprehensive Plan(PDF, 49MB)  Page 5

STORMWATER GOALS AND POLICIES

The existing goals, policies, and regulations were considered when developing the stormwater-specific goals and policies.

The City of Lynnwood Comprehensive Plan describes the long-term direction and vision for the growth and development of the community. Key elements of the comprehensive plan related to stormwater are:

  • The Environmental Element
  • Capital Facilities Element

These elements are the basis for the regulations stated in the Lynnwood Municipal Code (LMC) and day-to-day planning and decision making. 

Lynnwood Surface Water Management Comprehensive Plan 2020(PDF, 49MB)  pages 12 - 29 

SURFACE WATER UTILITY VISION STATEMENT

The overarching mission of the Surface Water Utility is to manage surface water and stormwater in Lynnwood such that: 

Goal-of-Flood-Reduction

Goal-of-Water-Quality-Improvement

Goal-of-Aquatic-Habitat-Condition-Improvement

Goal-of-Infastructure-Upgrading

Goal-of-Public-Education

Goal-of-Funding

Goal-of-Staff-Empowerment-and-Training

BACKGROUND

The City of Lynnwood, in southwest Snohomish County, covers approximately 7.9 square miles. Its 2017 population was 38,300. Since its founding in 1959 along the Interurban streetcar line between Seattle and Everett, the City has transformed from a quiet suburban community to a Regional Growth Center (Lynnwood 2015) composed of dense residential, commercial, and light industrial land uses. 

Water Bodies of Lynnwood Map

Since the Surface Water Utility was founded in 1991, the City has made significant progress in reducing detrimental effects of stormwater runoff on receiving waters in and around Lynnwood. The City has implemented the following significant projects, programs, and policies:

2015

  • The 2015 Perrinville Creek Stormwater Flow Reduction Retrofit study (Perrinville Creek Study) identified retrofit opportunities in the Perrinville Creek drainage basin through hydrologic modeling of that basin.
  • The 2015 Street Edge Runoff Treatment Retrofits project in the Hall Lake Basin installed roadside swales to provide stormwater treatment to runoff entering Hall Lake.

2016

  • The 2016 Scriber Creek Corridor Management Plan identified a suite of capital projects and programmatic activities to reduce flooding downstream of Scriber Lake.
  • The City completed a Low Impact Development (LID) code review of documents that guide development in the City to ensure that LID principles are allowed and encouraged.
  • The City completes a Stormwater Management Program Annual Report to meet NPDES Phase II Permit reporting requirements.

2017

  • The City worked with a consultant to conduct a Benchmarking Analysis in 2017 to better understand the range of activities performed by other jurisdictions in western Washington.

2018

  • The NPDES Permit Compliance Gap Analysis and Needs Assessment was completed in 2018. The City hired a consultant to review the City’s current SWMP activities and identify gaps in the SWMP relative to the requirements of the NPDES Phase II Permit requirements.
  • The Maple Road & Ash Way Intersection and Drainage Improvements project was completed in 2018 through a partnership between the City of Lynnwood, Snohomish County, and the Washington State Department of Transportation (WSDOT).
  • The City of Lynnwood Hatchery and Environmental Education Center at Hall Lake opened for school groups in 2018 to provide a public education about stormwater and aquatic habitat.

2019

  • In 2019, the City developed a Private Facilities Operations and Maintenance Implementation Plan. The plan included review of current policy and an analysis of alternatives related to City participation in private stormwater facility operations and maintenance, such as enforcement, maintenance support, and full take-over of facility ownership and maintenance.

Predicted Impacts of Climate Change

Potential hydrologic changes associated with climate change increase the importance of stormwater management practices that control flows, promote infiltration, and preserve and enhance water quality.

STORMWATER MANAGEMENT ACTIVITIES ADDRESSING CLIMATE CHANGE IMPACTS   Pages 52-53
CLIMATE CHANGE IMPACT                            RESILIENCY-BUILDING ACTIVITY
 RESILIENCY-BUILDING ACTIVITY
  • Lower dissolved oxygen in receiving waters
  • Increased algal blooms in receiving waters

Reduce the amount of nutrients in stormwater through public education or regulations aimed at decreasing fertilizer use, particularly in Hall Lake and Scriber Lake watersheds.

  • Increased flood risk from rivers, streams, and stormwater conveyance system
  • Possible increase in groundwater induced flooding
  • Increased flood risk along coastal areas due to sea level rise and increased surge height
  • Possible loss of stream side vegetation
Purchase land for conservation purposes, which may offset loss of stream side vegetation and reduce flooding impacts by acquiring frequently flooded properties such as strategic land acquisitions in the Scriber Creek corridor to reduce flood impacts and expand stream side vegetation.

 

  • Increased flood risk from rivers, streams, and stormwater conveyance system 
Revisit flood reduction policies, design standards for new development, and priorities for retrofit projects.
RETROFIT PROJECTS 
  • Increased erosion and suspended materials in water bodies
  • Lower dissolved oxygen in receiving waters
  • Increased algal blooms in receiving waters
  • Increased average and summer water temperature
Continue to implement the Hall Lake retrofit program.
CONTROLLING RUNOFF FROM NEW DEVELOPMENT, REDEVELOPMENT, AND CONSTRUCTION SITES
  • Increased winter stream flows
  • Decreased summer stream flows
  • Likely increased magnitude and frequency of peak events in streams
  • Decreased groundwater recharge during summer months
  • Increased groundwater use during summer months
  • Increased flood risk from rivers, streams, and the stormwater conveyance system
  • Increased average and summer water temperature
  • Increased erosion and suspended materials in water bodies
  • Lower dissolved oxygen in receiving waters
  • Increased algal blooms in receiving waters

Continue to require flow control on redevelopment projects and prioritize infiltrating stormwater facilities.

Update stormwater regulations and supporting documents.

PUBLIC EDUCATION AND PUBLIC INVOLVEMENT
  • Lower dissolved oxygen in receiving waters
  • Increased algal blooms in receiving waters
Educational campaigns to encourage the public to decrease pollutant generation, such as by decreasing fertilizer use, particularly in Hall Lake and Scriber Lake watersheds.
  • Wetland conversion from perennial to seasonal
  • Possible loss of streamside vegetation
  • Decrease in cooler/oxygenated aquatic habitat

Form a stakeholder group for Scriber Lake and facilitate volunteer events to remove invasive species and restore habitat.

Continue to conduct educational programs at the Lynnwood Hatchery and Environmental Education Center at Hall Lake.

OPERATIONS AND MAINTENANCE
  • Increased flood risk from rivers, streams, and stormwater conveyance system
Operations and maintenance activities including street sweeping and spot checks of inlets and other critical points in the stormwater conveyance system before storms.


Lynnwood Surface Water Management Comprehensive Plan(PDF, 49MB)
  pages 30 - 43   SWMCP Appendices(PDF, 7MB)

RECOMMENDATIONS

This section is generally organized by NPDES Phase II Permit (Permit) components and includes summarized recommendations.

Recommendations for an Asset Management program are included within the Asset Management and Mapping subsection.

The Private Facility Inspection Program is included within the Controlling Runoff from New Development, Redevelopment, and Construction Sites subsection.

Additional actions related to building climate change resiliency are included at the end of this chapter. 

A detailed list of recommendations with associated funding and staffing requirements, support those requirements, and a proposed implementation schedule for each tier is provided in Appendix E. Additional actions related to building climate change resiliency are included at the end of this chapter.

Surface Water Management Comprehensive Plan(PDF, 49MB) pages 44 - 53

SWMCP-Appendices-2020.pdf(PDF, 7MB)

 

CAPITAL IMPROVEMENT PROGRAM

The purpose of the Surface Water Capital Improvement Program (CIP) is to define capital projects that make progress towards the City’s goals of flood reduction, water quality improvement, aquatic habitat improvement, asset management, and efficient use of utility funds. 

Program Development Process 

The City maintains and regularly updates a list of needed projects. The following section describes the process that was used to identify problems and develop and prioritize solutions. A summary of projects in different geographic areas of the City is included.

2016 Scriber Creek Corridor Management Plan (Figure 5-1 pg. 57 of SWMCP)

  • Small Berm Installment*: Berm open channel segments of Scriber Creek between driveway culverts near Flynn’s Carpets, the Old Buzz Inn, and Eunia Plaza to protect low-lying areas of adjacent properties. $230,000
  • Maximize off-channel Storage on the property north of 188th Street SW by excavating portions of the property to create new wetlands. $690,000
  • 188th Street SW Flood Wall: Construct a short concrete wall near the Scriber Creek culvert crossing to provide additional food storage in the vacant property upstream. $410,000
  • Culvert Replacement 189th St SW: Replace the existing culvert with a larger fish passable culvert to reduce road overtopping and reduce damage caused by flooding. $600,000
  • Culvert Replacement 190th St SW $710,000
  • Culvert Replacement 191st St SW $550,000
  • Scriber Creek Culvert Replacement at Casa Del Rey Condominiums Driveway*: Replace the existing undersized culvert with one larger, flow-aligned culvert to reduce headloss and provide a natural streambed for physical habitat. $680,000
  • Parkview Plaza Culvert Replacement*: Increase the culvert size at Parkview Plaza and raise the bank west of the culvert to reduce flooding of 196th Street. $480,000
  • Remove Diversion Structure and ineffective Oil/Water Separator downstream of 196th Street SW Incorporate necessary fish passage improvements to the existing culverts. $350,000
  • Old 196th Street SW: Raise access driveways for the Great Floors and Parkview Plaza buildings and raise the frequently flooded low portions of Old 196th Street roadway 1 foot. $490,000

Projects from the Perrinville Creek Stormwater Flow Reduction Retrofit Study (Figure 5-2 SWMCP pg. 59)

  • Blue Ridge Pond Site 22-1: Replace the existing pond orifice with a smaller size to maximize pond storage leading to flow reduction. $25,000
  • Pipe detention Site 26-1: Intercept drainage from residential areas near 74th Ave W and slowly release runoff to attenuate peak flows. $300,000
  • Copper Ridge Pond Site 20-1: Modify the existing Copper Ridge detention pond orifice control structure. $25,000
  • Pipe Detention Site 19-1: Detain and slowly release runoff back into the storm system in 196th St SW. $1,123,000

Projects Related to Flood Reduction (Figure 5-3 SWMCP pg. 61)

  • 44th Avenue Flood Notification Signage: Install signs that warn motorists if there is “water over roadway” until the flooding problem can be addressed through a future CIP project. $180,000
  • 44th Avenue W. roadway raising at
  • Scriber Creek crossing (Phase 2)
  • Replace the existing culvert with a larger fish
  • passable culvert to reduce road overtopping
  • and reduce damage caused by flooding. $14,000,000

Projects Related to Water Quality Aquatic Habitat Improvement (Figure 5-4 SWMCP pgs. 62 and 63)

  • Lake Management Plan for Scriber Lake: Scriber Lake is impaired by phosphorous. The previous plan was not successful due to site access constraints. A new Lake Management Plan is needed. $60,000
  • Street Edge Runoff Treatment Retrofits in the Hall Lake Basin: Retrofit multiple residential blocks upstream of Hall Lake with bioretention to reduce nutrient, bacteria, and toxin loading to Hall Lake. $500,000
  • 180th St SW Bioretention Swale: Install a bioretention swale and permeable pavement sidewalk to provide treatment to reduce the transport of sediment, oil, and heavy metals into Scriber Creek. $210,000
  • Golde Creek Stormwater Pond Retrofit: Rehabilitate the existing stormwater pond to provide treatment for runoff discharging to Golde Creek and eventually to Swamp Creek. $400,000

Projects Related to Infrastructure Protection, Maintenance, and Upgrades (Table 5-1 SWMCP page 64)

  • Stormwater Infrastructure Management Plan: Develop an infrastructure management plan starting with a gap analysis to determine critical data needs and identify a new schema. $200,000
  • Annual System Rehabilitation and Replacement: Annual funding up to $30,000 per project will be provided for routine infrastructure replacement projects too small for independent CIP projects. $100,000 (annual cost)
  • Funding for Strategic Opportunities to Improve the Stormwater System: Annual funding will be set aside for adding stormwater improvements to projects driven by other agencies, jurisdictions, or private development. $100,000 (annual cost)

Details related to project development are provided in Appendix F and detailed summary sheets for each project are provided in Appendix G.

Lynnwood Surface Water Management Comprehensive Plan 2020(PDF, 49MB)

SWMCP Appendices 2020(PDF, 6MB)

PLAN IMPLEMENTATION

The major components of plan implementation include utility rate implementation, staffing needs, additional resource needs, completion of PIC projects that address existing stormwater issues, interdepartmental collaboration, and interagency collaboration.

The activities and projects listed in this section would  be funded by revenue from the stormwater utility. A financial analysis was conducted to define utility rate adjustments that are necessary to implement this plan.

In October 2019, the City approved the following stormwater rates for 2020 through 2025 to support the implementation of the Minimum tier of SWMP activities and the Priority CIPs.

Bi-Monthly Stormwater Utility Rates
Customer Classification 2020 2021 2022 2023 2024 2025
Residential Singe / Duplex Unit   $27.03 $27.84 $28.68 $29.54 $30.43 $31.34
Residential Multifamily and Mobile    $27.03  $27.84 $28.68 $29.54 $30.43 $31.34
Commercial Industrial Sites   $27.03  $27.84 $28.68 $29.54 $30.43 $31.34
Special Surface Water Rate, Income Level Status A*  $10.82  $11.14  $11.47  $11.81  $12.16  $12.52
Special Surface Water Rate, Income Level Status B*  $12.16  $12.52  $12.90  $13.29  $13.69  $14.10
Special Surface Water Rate, Income Level Status C*  $13.51  $13.92  $14.34  $14.77  $15.21  $15.67
 * Income Label Status pursuant to the Snohomish County assessor’s office real property taxes exemption process 


ADDRESSING STAFFING NEEDS

 Under the current level of staffing, City staff are not able to meet all the current requirements of the NPDES permit and will not be able to address the new activities. Also, current staffing levels will not be adequate to meet the new and expanded requirements of the 2019–2024 Phase II Permit and defined SWMP goals during future years. Refer to Appendix E for a detailed estimate of staffing needs.

The City will need staff to manage the construction management and project management aspects of proposed CIP projects. These costs are included in Appendix G.

Schedule of CIP project Implementation (SWMCP Table 6-1 pg. 73)

 CIP projects were developed for known problems that include issues such as neighborhood-scale flooding, poor water quality, and failing infrastructure.

 The City will implement stormwater CIP projects in the order shown in Table 6-1.

 There are several projects that are not included in this plan due to high costs and low relative priority. These projects include additional flood reduction projects in the Scriber Creek Corridor, including the eventual raising of 44th Avenue West where the temporary flood notification signage is planned.

Table 6-1. Capital Improvement Program Implementation Schedule. Pg, 73 
Project Name 2020 2021 2022 2023 2024 2025 out years*
Stormwater Infrastructure Management Plan  $100,000  $100,000          
Raise Old 196th Street SW  $250,000   $170,000        

Remove Diversion Structure and Oil/Water Separator downstream of 196th Street SW

 $250,000   $300,000        
Scriber Creek Culverts (1): Parkview Plaza Culvert Replacement - a.     $250,000   $500,000      
Scriber Creek Culverts (2): Parkview Plaza Culvert Replacement at Casa Del Ray Condominiums Driveway - a.    $250,000     $500,000    
Scriber Creek Culverts (3): Replace 191st Street SW Culvert             $550,000
Scriber Creek Culverts (4): Replace 190th Street SW Culvert              $710,000
Scriber Creek Culverts (5): Replace 189th Street SW Culvert              $600,000
188th Street SW Flood Wall   $250,000 $500,000          
Install small berms near Eunia Plaza and Flynn’s Carpets - a.           $100,000 $200,000  
Maximize of-channel storage on the property north of 188th Street SW - b.     $115,000 $450,000        
Annual System Rehabilitation and Replacement    $100,000 $100,000 $100,000 $100,000 $100,000  
Street Edge Runoff Treatment Retrofits in the Hall Lake Basin - c.  $50,000 $200,000          
Golde Creek Stormwater Pond Retrofit - d.     $200,000          
180th Street SW Bioretention Swale - b.     $200,000          
44th Avenue Flood Notification Signage - d.   $50,000            
Funding for Strategic Opportunities to Improve the Stormwater Management Program     $100,000        $100,000  
Pipe Detention Site 19-1 - e, f.         $850,000      
Copper Ridge Site 20-1 - f.           $25,000    
Blue Ridge Pond Site 22-1 - f.           $25,000    
Pipe Detention Site 26-1 - f.           $300,000    
 TOTAL $950,000  $2,015,000 $1,220,000 $1,450,000 $1,050,000 $400,000  $1,860,000


Lynnwood Surface Water Management Comprehensive Plan 2020(PDF, 49MB)
  pages 66 - 75

SWMCP Appendices 2020(PDF, 7MB)

YOUR THOUGHTS

How the City of Lynnwood manages stormwater affects our community, our drinking water supply and our environment. Your feedback is an important part of updating our surface water management plan. The City looks for your feedback through a 30-day period on-line open house. 

To provide your valuable comments, you can fill out the survey below and take part in the process of adapting the 2020 Surface Water Management Comprehensive Plan.

Location

Virtual Open House, 19100 44th Ave W, Lynnwood 98036  View Map

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