Basin 40 CIPP Sewer Lining Project - Phase 2
Project Status
To help keep area residents informed of our construction progress, we will post project updates to this site on a regular basis. Click here to see status updates.
Project Details/Neighborhood
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The project area is bounded by SE 40th Street, 90th Avenue SE, SE 44th Street, SE 42nd Place, and Lake Washington
Background
Construction of most of Mercer Island’s sanitary sewer system occurred in the 1950s and 1960s. Given the sewer system’s age, groundwater seepage (infiltration) and stormwater runoff (inflow) – known collectively as infiltration and inflow (I/I) – are prevalent in the sanitary sewer. The trenchless technology of cured-in-place-pipe (CIPP) lining is an efficient and cost-effective way to reduce I/I from aging pipes as well as restore their structural integrity. In 2018, closed circuit television (CCTV) equipment identified sewer basin 40 as a prime candidate for CIPP lining – finding all the usual I/I sources, i.e., pipe fractures, cracks, active infiltration, infiltration stains, joint separations, and joint offsets. In February, March, and April of 2023, Phase 1 lined more than 4,000 feet of existing 8-inch sewer mains in the basin 40 area bound by SE 40th Street, 96th Avenue, and SE 41st Street.
Description
Phase 2 consists of installing more than 12,000 feet of CIPP into the remaining 8-inch, 10-inch, and 12-inch diameter sewer mains in basin 40. There will be minimal disturbance to properties and roads since the mains will be accessed from the existing network of sewer manholes. In addition, 113 service connection seals (SCS) will be installed to seal the joint that connects the sewer mainline to side sewer laterals serving the adjacent homes. These laterals are very common locations for I/I.
Project Timeline
Budgeted (Q3 of 2021 – Q1 of 2024)
Planning/Design (Q3 of 2021 – Q2 of 2023)
Under Construction (Q3 of 2023– Q1 of 2024)
Completed (Q1 of 2024)
Estimated Budget
$2,000,000.00
Contact
Christopher Marks, City of Mercer Island Utilities Engineer: chris.marks@mercerisland.gov
Status Updates
April 24, 2024
Photos:
1. A sample of cured liner is cut from each batch and sent to a lab for 3rd party testing. The lab reports verify that all installed liner meets or exceeds the project specifications.2. The final step of the lining process involves grouting the ends of the cured liner where it protrudes into the manhole channel. The grout creates a smooth and watertight seal.
2. The final step of the lining process involves grouting the ends of the cured liner where it protrudes into the manhole channel. The grout creates a smooth and watertight seal.
Substantial completion of this contract was reached on April 8th, 2024. The project, which has been underway since September of 2023, lined more than 12,000 feet of existing sewer main with cast-in-place pipe and installed 111 service connection seals. A few minor items such as review of lab test reports and organization of post CCTV videos remain prior to final project completion. As a result of the project, the majority of Sewer Basin 40, which was previously the oldest sewer collection area on the Island, is now the newest with a 50-year design life. The basin is expected to see lower inflow and infiltration, lower maintenance costs, and lower sewer treatment costs.
March 29, 2024
Construction on the project was extended an additional 2 weeks after progress was disrupted by material shortages. Only two pipe segments remain to be lined and a handful of service connection seals remain to be installed. Residents are advised that next week, traffic impacts can be expected in the vicinity of East Mercer Way and Mercerwood Drive in the form of single lane closures. Crews will be working from the manholes in the roadway to install a number of service connection seals. Please reduce speeds and watch for flaggers and construction equipment within the work zone. No disruptions to individual sewer services are anticipated.
February 16, 2024
Photos:
1. Basin 40 backyard sewer manhole
2. Basin 40 custom barge for CIPP
3. Basin 40 sewers w tough access
The first half of February saw Insta-Pipe successfully line the most difficult sewer mains of this project. Up until now, crews had been working out of an assortment of specially equipped box trucks meant for collecting CCTV, jetting, bypassing, curing, and reinstating, but steep narrow driveways and backyard manhole locations in the final phases of the project meant the team had to re-configure their work plan. So, from 4022 E Mercer Way to the Mercerwood Shore Club boat ramp, crews hand carried lines and equipment overland, deployed a custom barge, and winched CIPP liner material through nearly 1000 feet of existing and previously lined sewer main to execute the work. This difficult access led to a few very long work days, finishing up after dark. The project is nearly complete, with only about 600 feet of liner and less than 60 service connection seals remaining to install. All work should be finished by the end of March.
January 17, 2024
Photo: buried at varying depths of 2-12 inches, backyard manhole covers are located and raised to allow access to the sewer main.
By the end of 2023, Insta-Pipe had lined over 10,600 of the roughly 12,000 feet of sewer mains identified for the project. This week crews continued working in the backyards of lakefront homes in the 4000-4100 block of East Mercer Way, where they raised several manhole covers to finish grade. This work is expected to continue into next week before the contractor switches their efforts back to installing service connection seals.
November 21, 2023
Photo 1: A “Top Hat” seals the joint where each individual sewer connection meets the newly lined sewer main.
Photo 2: Crews load the top hat onto an inflatable rubber bladder unit, or “packer”, which will be towed into position with a robotic crawler.
Crews are working to line and install Top Hats in the areas of 91st Ave SE, 92nd Ave SE, and along the shoreline of Lake Washington. Top Hats arrive from the factory impregnated with a UV curable resin. Crews ready the top hat for installation by applying an epoxy sealant that will provide the final bond between the liner and the service connection, and by loading the top hat onto an inflatable rubber bladder unit, or “packer”. A robotic crawler will tow the packer into position where it will be inflated, and UV cured. The curing process takes less than 10 minutes so each sewer service connection is only blocked off for a very short period.
November 16th 2023
Click for PDF file of the door hanger
Last week crews installed a combined 560 feet of liner in the four sewer segments located in the vicinity of 95 Pl SE and 95th Ave SE and also near Shoreclub Dr and 96th Ave SE. This week, crews are working in the areas of 91st Ave SE, 92nd Ave SE, and along the shoreline of Lake Washington.
Did you receive a notice on your door? It means that Insta-Pipe will be working to line segments of sewer main that impact your residence. You will receive additional notice in the form of a door knock from the contractor the day that work is scheduled to be performed. Please limit sink, laundry, toilet, shower/bath and other facility usage to a minimum during the day of work. Refer to the door hanger or the project webpage for additional information. Still have questions? Contact Chris Marks, City of Mercer Island Utilities Engineer, 206-677-1027, or speak directly with the Contractor on the day of by looking for someone in a yellow construction vest.
Week of October 30th 2023
Photo 1: traffic control along E Mercer Way.
Photo 2: Not all manholes are equally as accessible. This will need to be raised by the contractor and the fence reconfigured.
Last week Insta-Pipe lined the busy segment of E Mercer Way between SE 40th St. and Mercerwood Shore Club. So far, the Contractor has installed over 6,500 linear feet of liner into Basin 40’s 8-inch, 10-inch, and 12-inch sewer mains. Crews will spend the next couple weeks lining the remaining sewer mains located in the Mercerwood neighborhood before shifting their efforts to the much less accessible sewer mains located east of E Mercer Way. A secondary crew will also be dispatched to re-visit previously lined segments and begin installing service connection seals (SCS) or “top-hats” (named for their shape). Installation of the SCS is the final step of the CIPP process. The SCS fortifies the joint where each individual sewer connection meets the newly lined sewer main. The joint is a common source of unwanted infiltration. Over 100 SCS are slated to be installed during the course of this project.
October 19, 2023
Photo 1: Reduce speeds and watch for flaggers and construction equipment within the work zone
Photo 2: Forward and rear facing cameras on the UV light train monitor the curing real time.
Photo 3: The robotic cutter is used to reinstate each service lateral after the liner has cured.
This week Insta-Pipe finished lining segments along 95th Place SE, 92nd Ave SE, and SE 42nd St. Crews worked closely with School District staff to minimize traffic disruptions during school pick-up and drop-off hours. We appreciate the patience shown by residents and road users as this necessary work is performed.
10/23 Notice:
Heads Up - The City’s cured-in place pipe (CIPP) sewer lining project continues next week in the Mercerwood and East Mercer neighborhoods. Starting Monday, October 23rd, single lane and shoulder closures will be impacting travel along E Mercer Way between SE 40th St and the entrance to Mercerwood Shore Club . The City’s contractor (Insta-Pipe) will be working from manholes within the roadway to install over 1,200 feet of CIPP liner into the existing sewer main. Access to all private driveways will be maintained throughout the project's duration. Road users should expect minor delays and reduced speeds along this route through Friday, October 27th . Watch for flaggers, construction vehicles, and sewer bypass equipment each day between the hours of 7am and 7pm.
October 11, 2023
Photo 1: A sewer bypass plug is inserted into the upstream pipe.
Photo 2: A bypass pump temporarily diverts the upstream sewer flows around the segment to be lined.
Photo 3: The use of layflat hose provides residents unrestricted access to the street and private driveways.
Insta-Pipe crews worked through heavy rains, lining the long segment of 8-inch sewer main that spans 94th Ave SE between SE 43rd St. and 93rd Ave SE. They also lined their first 12-inch segment of sewer main near Mercerwoood Shoreclub’s boat launch. Their efforts this week add another 1,500 linear feet to the project total.
October 6th, 2023
Photo 1: Watch for the “Utility Work Ahead” signs as they indicate crews are working in the area
Photo 2: Each crate weighs more than 3 tons and delivers approximately 1,700 feet of liner to the project site
Photo 3: The robotic cutter is primarily used to reinstate service connections after lining, but it can also be used to cut away unwanted buildup or protruding obstacles within the pipe before lining.
This week, Insta-Pipe crews installed cast-in-place pipe (CIPP) liners in over 2,600 linear feet of sewer mains on 90th, 91st, and 93rd Avenues. Next week, crews will be working on 92nd and 94th Avenues. Liner material arrives in light-proof crates weighing about 3 tons and containing about 1,700 feet of liner each. A robotic cutter is used to reopen service connections after lining, and it is also used to cut away unwanted buildup or protruding obstacles within the pipe prior to lining.
September 26th, 2023
The City’s contractor (Insta-Pipe, Inc.) will begin working in the areas of sewer basin 40 (90th Ave SE to Lake Washington between SE 44th St and SE 40th St) starting the week of September 25th. Work includes cleaning, CCTV inspection, and installation of approximately 12,000 feet of CIPP liner into the existing City sewer mains. Minor traffic impacts at intersections as well as single lane closures and shoulder closures should be expected as crews access the sewer mains from the existing network of sewer manholes. Expect traffic impacts to be localized to a single street or intersection at a time. Crews will generally work from NE to SW within the project area, only spending a few days at each location before progressing to the next. No street or intersection closures are anticipated and access to all private driveways will be maintained throughout the project duration. Equipment on site will be a combination vacuum truck, various box trucks outfitted for CCTV, sewer main cleaning, or liner insertion and curing, a trailer-mounted high pressure jetter, and sewer bypass equipment. Working hours are 7am to 5pm, Monday through Friday. Construction is expected to occur over the next 8 months, with an anticipated completion of May 2024.
August 2023
With both the construction and construction support services contracts in place, a pre-construction meeting has been scheduled for the first week of September, and product design submittals have begun rolling in. Over the next month, the City, along with Staheli Trenchless Consultants, will work to review and approve Insta-Pipes project schedule, traffic control plans, construction methods and products, as well as notifications to residents.
July 2023
On July 5th during the special hybrid city council meeting, the contract was awarded to the Insta-Pipe Inc., the lowest responsible bidder. In the following weeks, City staff will finalize the contract with Insta-Pipe Inc. as well as work with Staheli Trenchless Consultants to negotiate a contract for construction support services. Construction is tentatively scheduled to begin in the early fall of 2023 and extend through June of 2024.
June 26th, 2023
Staheli Trenchless Consultants completed Phase 2 design on May 22nd. On May 24th, City staff solicited construction bids. The City received three bids and intends to award the Phase 2 construction contract to the lowest responsive bidder at the July 5th regular City Council meeting.
February 22, 2024
Photos:
1. Difficult to reach sewer main located in the backyards of the lakefront homes
2. Impossible to reach by vehicle, this manhole is located in a resident’s backyard, inside a laurel hedge
3. The contractor deploys and operates a robotic cutter from a barge specifically outfitted for this project segment
The first half of February saw Insta-Pipe successfully line the most difficult sewer mains of this project. Up until now, crews had been working out of an assortment of specially equipped box trucks meant for collecting CCTV, jetting, bypassing, curing, and reinstating, but steep narrow driveways and backyard manhole locations meant the team had to re-configure their work plan. So, from 4022 East Mercer Way to the Mercerwood Shore Club boat ramp, crews carried lines and equipment overland, deployed a custom barge, and winched CIPP liner material through upwards of 1000 feet of existing and previously lined sewer main to execute the work. This difficult access led to a few very long work days, finishing up after dark. The project is nearly complete, with only about 600 feet of liner and less than 60 service connection seals remaining to install. All work should be finished by the end of March.
SU0108 Project Location (2 MB) 11/16/23 Insta-Pipe Door Hanger (485 KB)