Kennydale Lakeline Sewer System Improvements

Contact Information
Joe Stowell
Wastewater Utility Engineering Manager
Renton, WA 98057
425-430-7241

The Kennydale Lakeline Sewer System was constructed in 1972 to provide sanitary sewer service to the lakefront homes along Lake Washington from the north end of Coulon Beach Park to the south end of what was Barbee Mill and is now a townhome development named after Barbee Mill. 

The Lakeline System is aging and needs to be repaired or replaced to ensure long-term service. The Wastewater Utility conducted the Kennydale Lakeline Assessment project from 2016-2018, which resulted in a cleaning and inspection project completed in 2018. Based on the 2019 project report, the project team selected a land-based, grinder pump station design as the preferred sewer system to provide the most cost-effective and reliable approach to operating and maintaining the system.

Project Map
Kennydale Lakeline vicinity map

Final Report - Kennydale Lakeline Sewer System Evaluation, Dated 2019

Kennydale Lakeline Sewer System Evaluation Final Report dated July 2019 by Carollo Engineers, Inc.

Project Description

The Kennydale Lakeline Sewer System serves approximately 55 residential lakefront customers. The existing system consists of a flush station, 8-inch cast iron Lakeline sewer pipe buried offshore in Lake Washington, 33 six-inch side sewer lines connecting customers to the Lakeline, and the Lake Washington No. 2 lift station that pumps the flow to the King County regional system.

The system is unique in the City, where the flush station provides “freshening” flow twice daily to aid wastewater movement. However, these flows do not clean the Lakeline, and over time debris builds up, creating partial blockages. This leads to overloaded conditions and reduced capacity in the system.

The system is aging and needs to be repaired or replaced to ensure long-term service and to protect Lake Washington. In 2016, the City hired a consultant team, led by Carollo Engineers, to evaluate the condition of the Lakeline System in two phases. This project team developed alternatives to address the operation, maintenance, and reliability of the Lakeline System. 

In 2017, an assessment of the Kennydale Lakeline Sewer System showed that its aging pipes required urgent maintenance to keep the system functioning properly. As a result, two temporary manholes were installed in Lake Washington to allow for further examination and cleaning of the Lakeline. The cleaning work was finished in 2018, and the lakebed was restored.

In 2020, the City contracted with Carollo Engineers to further analyze the preferred alternative for replacing the Lakeline to address the system's short- and long-term issues.

Project Update

The project team is advancing the design. This phase of design work includes detailed engineering, fieldwork for data collection, and coordination with affected residents. Residents will have continued opportunities to review and voice their feedback on the project at key milestones – please stay tuned!

Project Letter #1 - Mailed January 11, 2021

Project Letter 1 mailed to adjacent properties January 11, 2021:

Kennydale Lakeline Sewer System Improvements Project

This letter is to notify you that the City of Renton is proceeding with the replacement of the Kennydale Lakeline Sewer System with a new land-based sewer system. The city team and the consultant will start field work for preliminary design of a new sewer system beginning the week of January 18. The survey crew will contact property owners in order to gain property access for survey purposes. Please note that we will follow all COVID-19 protocols during our site visits and will coordinate with you before we visit. Please contact me by phone at 425-430-7279 or by email at [email protected] if you have any questions.

BACKGROUND

As you may know, the City of Renton has been reviewing the condition of the aging Kennydale Lakeline Sewer System to determine the best solution for providing long-term sewer service to your property. The Kennydale Lakeline Sewer System was constructed in 1972 to provide sanitary sewer service to the lakefront homes along Lake Washington from the north end of Coulon Beach Park to the south end of what was Barbee Mill, and is now a townhome development named after Barbee Mill.

From 2016-2018, the Wastewater Utility conducted an assessment of the Kennydale Lakeline, which included an attempt to clean and video inspect the entire system in 2018. Due to its location, varying water depth and the original construction methods used, we were only successful in cleaning and inspecting approximately 80 percent of the system.

The Wastewater Utility has also been actively engaged with a multi-agency workgroup that has been studying the problems associated with in-water sewer systems. Many of our neighboring communities have similar concerns about maintaining sewer mains that are under water.

As a result of the 2018 assessment, which included cleaning and inspection, our current participation in the in-water sewer workgroup and the historical attempts to maintain this system, the Wastewater Utility has reached the following conclusions:
1. The majority of this sewer system cannot be reached by land-based maintenance vehicles.
2. Approximately 250 feet of the southern portion of this system cannot be reached from land or water.  The main is so close to the shoreline that the water depth is inadequate to allow for water-based access and homes prevent access from land.
3. Approximately 840 feet of the system centered on the Kennydale Beach Park cannot be cleaned or inspected due to limited access, sags in the pipeline, and bends at pipe joints which prevent the passage of a video camera and jetter hose.
4. Debris, including failed portions of the existing cast-iron pipe’s cement lining, remain in the pipeline.
5. Due to the inability to rapidly access this system, any blockage that may occur within that portion of the pipeline that is located under the lake could take a long time to locate and clear.
6. Current environmental regulations and permitting highly discourage the use of in-water sewer systems.

Therefore, the Wastewater Utility has determined that the best solution to continue to serve the lake side homes and provide a sewer system that is maintainable is to construct a new system that is not located in the lake.

We have done our best to update our list of existing property owners along the lake. If you are a new resident or you have changed your contact information since we were in contact with you in 2018, please email me at [email protected] with your updated contact information so that we may keep you informed of the progress of this project.

For updates as this project progresses, please visit the City of Renton’s webpage at rentonwa.gov/lakeline.

Sincerely,
 
John Hobson
Wastewater Utility Project Manager

Project Letter #2 - Mailed May 20, 2021

Project Letter #2, mailed to adjacent properties on May 20, 2021:

Kennydale Lakeline Sewer System Improvements Project

The City of Renton’s design team has completed the initial property visits to take photographs and get a general idea of how each homesite will be served by the new grinder pump sanitary sewer system.

The next phase of work will include on-site surveying to gather the necessary information to allow for the preparation of a personalized design for each property. The property-specific design will show where the proposed grinder pump station, control panel, electrical connection, and pressure line may be located. When the Design Team has completed each of the individual site-plans, we will coordinate a meeting with each property owner to review the proposed plan to make sure that it meets both the owner’s needs as well as the city’s. These meetings will take place sometime in the fall of this year. 

The Design Team’s surveyors, KPG, will begin the surveying on or about June 1, 2021. It is anticipated that it will take approximately 1 month to complete the survey work for the entire neighborhood. The estimated time to complete the survey of each property is between 4 and 8 hours.

The surveyors will contact each property owner prior to entering their property. Contact will be made by door-knocking and/or phone call. If you have specific concerns or requirements that need to be addressed prior to entry, please contact me at 425-430-7279 or at [email protected] and I will coordinate the surveyors site visit to meet your needs. 

For updates as this project progresses, please visit the City of Renton’s webpage at rentonwa.gov/Lakeline.

Sincerely,
 
John Hobson
Wastewater Utility Project Manager

Project Letter #3 - Mailed October 5, 2021

Project Letter #3, mailed to adjacent properties on October 5, 2021:

Kennydale Lakeline Sewer System Improvement Project: Property-Specific Grinder Pump Plan and Owner Meeting  

This letter is to notify you that the City of Renton’s design team is nearing completion on your property’s sewer design plan and would like to arrange a meeting with you to review it. This meeting will allow the City to present our proposed design for your particular property and provide you with an opportunity to review and comment on your respective site plan prior to its finalization.

Your property’s sewer plan will be sent to you prior to the meeting to give you time to formulate any questions or concerns that you may have with the proposed plan.

We would like to schedule an in-person meeting with you at your property between November 1 and November 12. To learn about the sewer systems and sign-up for an in-person property owner meeting, please visit kennydalelakeline.participate.online. Please sign-up for a property owner meeting by October 24. If you miss the sign-up window, you may receive a phone call or email requesting a meeting to discuss the project. 

You can also email us at [email protected] to request a meeting. We will respond to your meeting request as soon as possible and will stay in touch with you to confirm the meeting date and time. If you prefer an online meeting instead, that can be arranged as well.

If you have questions, would like to request an interpreter for the meeting, or need additional information before scheduling a property owner meeting, please contact me at [email protected]

Sincerely,

John Hobson

Project Manager
Wastewater Utility
425-430-7279

 



Project Letter #4 - Mailed January 10, 2022

Project Letter #4, mailed to adjacent properties on January 10, 2022

RE: Kennydale Lakeline Sewer System Improvement Project: Property Owner Meetings and Project Update

In November 2021, the City of Renton’s design team held its first round of meetings with most of the property owners to discuss draft site plans for the new land-based sewer system that is currently proposed. The meetings allowed property owners to review and comment on their respective site plans during the early design stage. Several comment themes and questions were echoed amongst property owners over the course of the meetings. In order to provide the same level of information to everyone, common property owner questions and the responses from the city are provided below for your information. We recognize the list does not capture every question asked by property owners, as some questions were site-specific, and we are responding separately to these site-specific issues as we continue to work with neighbors on designs for individual properties. To ensure that we get feedback from all affected property owners, we will be conducting another round of individual property meetings for those property owners that could not schedule a meeting during the initial property visits. 

What is wrong with the existing Lakeline sewer system?

The existing Lakeline was constructed in 1971 and was constructed of 8-inch cement-lined cast iron pipe. Beginning in 2016 and continuing through 2018, the city and its consultants conducted the Kennydale Lakeline Assessment Project to evaluate the existing condition of the in-lake sewer system. Results from the assessment determined that the aging pipes (50+ years old) were nearing the end of their service life and requires replacement.

The city conducted a cleaning project in 2018 to address the immediate needs of the system by cleaning the in-lake sewer main and removing partial blockages. Due to the many bends in the sewer, the city was unable to clean and inspect approximately 20 percent of the Lakeline. Therefore, the conditions that caused these blockages remain, and the condition of those sections of pipe remain unknown.

The in-lake pipes appear to be degrading both from the inside and outside due to a combination of age and interaction of pipe material and the environment they are around. Because of the inability to readily access the Lakeline, a full blockage or failure of the Lakeline sewer system would result in interruption of all sewer service to Kennydale Lakefront homes until the emergency could be resolved. Because there would be no way to determine where the blockage was in the sewer, and the need to arrange for the necessary barges, divers, and specialty equipment to locate the blockage and make repairs, the existing system could be out of operation for several weeks or months. Should the sewer main corrode through or break, raw sewage could flow into Lake Washington causing an environmental emergency. The goal of the project is to address the deteriorating condition of the pipes and ensure construction of a new fully accessible sewer system before an incident occurs which can shut down the existing sewer system. 

Why is a land-based sewer system chosen to replace the existing in-lake sewer system?

In 2019, the city and its consultants began exploring options to replace the in-lake sewer service. Project alternatives included an in-lake gravity sewer beyond the existing private docks, an in-place replacement, or a land-based system using grinder pumps and a force main. The land-based sewer system was chosen based on the following criteria:

Current state and federal environmental permitting regulations require that an on-land option is pursued over in-lake options, if technically feasible. Grinder pumps are the only feasible land-based option and have far lower estimated costs ($7-10 million) than the in-lake alternatives ($25 million for in-place and $52 million for further into the lake). Septic tanks were not considered because King County and state regulations prohibit their use in shoreline areas. 

A land-based sewer system can be readily accessed for routine and emergency repairs. There are no environmental permits required to gain access and maintain this type of system.

An in-lake system cannot be readily accessed for routine or emergency repairs. To undertake only repairs or maintenance requires extensive permitting (from the Army Corps of Engineers, Washington State Department of Ecology, Washington State Department of Fish and Wildlife, Native American Tribes, etc.) for any work in or near the lake. Some of these permits have a “fish window” which only allows work to take place between July 1 and September 30. In-lake work requires water-based equipment (barges and underwater manhole access caissons) and specialized personnel which takes time to arrange for and is very costly. In addition, annual maintenance of the Ballard Locks can restrict the ability to mobilize the necessary barges to get them to an in-lake sewer system. Much of the southern portion of the current lake-line is in water that is too shallow to allow a barge to get close enough to perform work on the sewer. The existing private docks extend far enough into the lake, and are in close enough proximity to each other, to prevent a barge from reaching much of an in-place sewer replacement.    


What is happening now?

We have begun designing the new land-based sewer system and grinder pumps. The project is still in the preliminary design phase and working towards the 30% design milestone.  At 30% design, the design concept will be further evaluated before being further refined in engineering detail and used to generate a more accurate cost estimate. Project impacts are still being determined on a property-by-property basis and have not been finalized. The project team held its first round of property owner meetings in November 2021 to collect feedback on the preliminary site plans, including siting of grinding pump stations and associated equipment. It’s important for the project team to hear feedback from property owners early in the design process so their input can be considered and incorporated before design decisions have been made. If you haven’t met with the project team yet, the second round of property owner meetings is anticipated be held in late January 2022 and early February 2022. 

Who is paying for the project?

The grinder pump system is different in terms of complexity and cost of construction per customer relative to the typical gravity sewer systems in Renton. The final cost of the project is being refined as design progresses and impacts are known. As of right now, the city intends to pay for the installation of the new sewer system and abandonment of the Lakeline through our Sewer capital improvement program. The cost of ongoing maintenance will be evaluated with completion of design. We are evaluating the best way to recover these additional costs with an understanding on the impact to the individual homeowner as well as other rate payers in the city. This will include conducting a financial analysis to evaluate how the project impacts the city’s monthly residential sewer rates.

How will the pump stations be sized?

Each individual pump station will be sized for year-round typical occupancy of a single-family home, regardless of current use or historical use in the past. The current plan is to install the largest pump station allowable based on each property’s site constraints. For most properties, this means a 231-gallon holding tank. A tank of this size will allow for normal usage for up to one day in case of a power outage.

How will the pump station be powered?

The current proposal is to power the grinder pumps utilizing power from the respective properties electrical service. This may be through a separate meter or through improvements to the existing service.

We are aware of concerns for pump station operations when power outages occur. Backup power schemes are currently being evaluated by the project team, with additional backup plans in case of a prolonged power outage. We will also be consulting with King County and Puget Sound Energy to identify ways to reduce power outages.

What are the homeowner’s responsibilities?

The city has heard concerns about the significant change to the existing sewer system. Maintenance options and monitoring systems are still being developed by the design team, which is typical in the early design process. Based on early feedback from homeowners, the design will include remote monitoring of the new land-based sewer system by the city, with additional monitoring support provided by homeowners (via on site alarm) as a backup to the remote monitoring. Once the project is fully designed, the city will have a better idea of the city’s responsibilities and the homeowner’s responsibilities. The city will provide that information to the homeowner as the design progresses and in advance of construction.

What is happening next?

The project team will continue to actively evaluate feedback from property owners and incorporate that feedback into individual draft site plans as feasible. We will continue to report on issues and questions raised by Lakeline neighbors in addition to responding to individual concerns and requests. The project team wants to meet with all property owners before reaching the 30% design milestone. If you haven’t met with the project team yet, the second round of property owner meetings is anticipated to be held in late January 2022 or early February 2022. You will be able to sign-up for a property owner meeting by visiting https://kennydalelakeline.participate.online/.

You can also email us at [email protected] to request a meeting. We will respond to your meeting request as soon as possible and will stay in touch with you to confirm the meeting date and time.  If you prefer an online meeting instead, that can be arranged as well.

We will continue to provide timely information and updates via email, our project website, and other outreach as the project progresses. This is a very important project to ensure the long-term viability and operability of the sewer system that services your home, and we want homeowners to be active partners in this project. If you have questions, would like to request an interpreter for the meeting, or need additional information before scheduling a property owner meeting, please contact the city’s project manager John Hobson, at [email protected]

Sincerely,

Martin Pastucha
Public Works Department Administrator

Project Letter #5 - Mailed July 7, 2023

Project Letter #5, mailed to adjacent properties on July 7, 2023

RE: Kennydale Lakeline Sewer System Improvement Project: Project update


We apologize for the extended pause in communications about the Kennydale Lakeline Sewer System Improvement Project. We appreciate your active participation in the project and hope that it will continue. Since you last heard from us, the city and design team have been busy researching questions and incorporating property owner feedback as appropriate, while advancing the design. 

The project has reached the preliminary (30%) design milestone and the city is reviewing the preliminary design plans, and cost estimates for the construction, operation, and maintenance of the new sewer system to replace the existing sewer system located in Lake Washington that serves your home. This is an important milestone that will allow us to further engage with you and other stakeholders in the project including Puget Sound Energy (PSE), King County, and state agencies that regulate work in or adjacent to Lake Washington.

We will continue to provide information and updates as the project progresses. This is a critical project to ensure the long-term viability and operability of a sewer system that serves your home, and we want homeowners to continue to be active partners in this project.

Please note that John Hobson has recently retired from the City of Renton. We are thankful for John’s leadership at the city and for his work on the project. Joe Stowell, Wastewater Utility Engineering Manager, is now the project manager. If you have questions about the project moving forward, please contact Joe by emailing [email protected] or (425) 430-7212.

Sincerely,

Martin Pastucha
Public Works Department Administrator

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