Kennydale Lakeline Assessment

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 Wastewater Utility needs to perform regularly scheduled evaluations of the condition of the Kennydale Lakeline Sewer System. These evaluations allow the Wastewater Utility to determine how to properly maintain the facility and evaluate replacement options.

Project Update

In September 2016, the City of Renton successfully performed a routine flush of the Kennydale Lakeline Sewer System along Lake Washington Boulevard North and Mountain View Avenue North. This launched an ongoing, more thorough assessment of the lakeline to identify if upgrades are needed.

The initial phase (Phase 1) of the lakeline assessment included preliminary surveys from land and from the water and connections to properties along the lakeline. Phase 1 helped determine additional evaluations to complete a thorough condition assessment in Phase 2.

The next phase of work (Phase 2) began in August 2017 and continues into 2018. This phase involves in-depth surveys and assessment of the lakeline and its service laterals, which convey sewage from houses to the lakeline. From this detailed assessment, alternatives will be developed to maintain reliable service in the lakeline system area, which will help the city determine what actions may be needed to keep the system working smoothly for years to come. 

During Phase 2, the project team will visit properties along the lakeline to map the horizontal and vertical location of the entire lakeline system and assess component parts, including the mainline pipe, service laterals, cleanouts, and valves.  Homeowners will be contacted by phone, emails, mail, and/or door hangers before property visits.

In August through October 2017, the project team conducted surveys on land and in the water and placed survey markers on or near bulkheads during fieldwork. The team is currently analyzing the data collected from these surveys and planning additional fieldwork anticipated for summer 2018.

Bid Information

Carollo Engineers, Inc. was selected through the Statement of Qualifications procedure for consultant services per the City’s Purchasing, Bidding and Contracting Requirements Policy #250-02. They were chosen based on their proposed approach to the evaluation effort and their significant experience working with lakelines for other jurisdictions.

The Wastewater Utility is recommending that Council award the contract to Carollo Engineers, Inc., in the amount of $283,341, at its regular meeting on Monday, September 12, 2016.

Project Description

The Kennydale Lakeline Sewer System consists of approximately 4,800 linear feet of eight-inch pipe, thought to be ductile iron; 33 six-inch lateral connections from the eight-inch lakeline on shore to serve the homes, each with an existing shut off valve; a flush station at its south end; and the Lake Washington No. 2 Lift Station at its north end that pumps the flows into the King County Wastewater Treatment Division (KC WTD) Eastside Interceptor.

The system operates by the homes connecting to the six-inch laterals, typically either by dual or triple connection, which then flows and holds within the lakeline. The flush station operates twice daily to clear the flows from the lakeline by taking water from Lake Washington and pumping it through the lakeline, up to the Lake Washington No. 2 Lift Station where it is pumped to the KC WTD Eastside Interceptor. This facility provides sanitary sewer service to approximately 55 to 60 single-family homes along the lakefront.

As the scope of work was develped, it was determined that this evaluation would be best in two phases. The first phase includes the initial investigation effort, including working with the city crews as they perform annual maintenance on the lakeline facility in mid-September 2016. This initial effort was estimated to take three months. The second phase takes information learned in Phase 1 allowing a determination of the remaining work including:

  • additional evaluation and permitting
  • site condition/condition assessment
  • alternatives analysis
  • operations and maintenance analysis
  • implementation plan.

This second phase is anticipated to take an additional 18 to 24-months to complete.

Frequently Asked Questions and Project Letters

Frequently Asked Questions

Phase 2 Fieldwork Update letter mailed to adjacent properties on September 19, 2017

Phase 2 Upcoming Fieldwork letter mailed to adjacent properties on August 8, 2017

Phase 1 Project Notice mailed to adjacent properties on September 7, 2016

Contact Information
David Christensen
Wastewater Utility Engineering Manager
Renton, WA 98057
425-430-7212
425-430-7241

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