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Middlebelt Transport and Storage Tunnel ProjectEvergreen-Farmington Sewage Disposal SystemAnswers to questions about how tunnel construction will impact residents in Farmington Hills

1. Why is this project being constructed?

The Middlebelt Transport and Storage Tunnel is being constructed to reduce the risk of sanitary sewer over-flows (SSO) that can occur when the Farmington Interceptor becomes overloaded during heavy rain storms. The 9-foot-diameter tunnel will follow Middlebelt Road from I-696 to 13 Mile Road and be able to store 3.6 million gallons of sewage and stormwater. It will be constructed 32 to 86 feet below ground.

SSOs occur when sanitary sewers become overloaded with stormwater and can result in sewage flowing out of manhole covers or backing up in residents’ basements. Stormwater gets into sanitary sewers in a variety of ways such as footing drains from homes, sewer pipe joints and manhole covers. In the case of the Farmington Interceptor, the Michigan Department of Environmental Quality (MDEQ) is requiring the improvement to be undertaken to comply with SSO policy revisions.

The project is being constructed by the Office of the Oakland County Water Resources Commissioner (WRC) as part of a Consent Order agreement with the MDEQ. The WRC operates the Evergreen-Farmington Sew-age Disposal System (EFSDS) that provides sewer service to 15 communities including Farmington Hills.

2. When and where will work start?

The work along Middlebelt Road is being undertaken in a single construction contract. Ric-Man Construc-tion will tunnel 7,600 feet north from the east side of Middlebelt Road north of the I-696 freeway, ending on the northwest corner of Middlebelt Road and 13 Mile Road.

It is anticipated that construction will begin in December 2014 which will consist of site preparation and shaft construction at the downstream site north of I-696. Tunnel construction will begin in April 2015 and continue through April 2016. Once the tunnel is complete, four additional access shafts and two diversion structures will be constructed along Middlebelt Road to complete the project. These shafts will be construct-ed between April 2016 and September 2016. An estimated construc-tion schedule is shown on the adjacent map.

The bulk of the con-struction activity will be completed working from the downstream shaft, TS-1, north of I-696.

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3. How will construction impact traffic along Middlebelt Road?

Mining operations will originate (TBM launch) from the downstream access shaft, TS-1, north of I-696 with the majority of the excavated material from the tunnel remaining at the site for future backfill once the down-stream structure is completed. There should be minimal impact on traffic along Middlebelt Road during the tunneling activity. There may be an increase of truck traffic at the site but no lane closures are anticipated during the tunneling.

The upstream shaft, TS-6, or recovery shaft, is located on the northwest corner of Middlebelt Road at 13 Mile Road. The southbound right turn lane from Middlebelt Road onto westbound 13 Mile Road will be closed during the entire time construction is taking place from this shaft.

In the spring of 2016, work on the four manhole structures, TS-2 through TS-5, and two control structures, DC-1 and DC-2, will take place in the center of Middlebelt Road just south of 12 Mile Road to just south of 13 Mile Road. During construction, traffic will be reduced to one northbound lane and one southbound lane around the equipment from April 2016 to September 2016. It will be necessary to close Middlebelt Road be-tween Highmeadow Road and Millbrook Street during construction of TS-5 and DC-2. This approach saves an estimated $600,000, minimizes environmental impacts and expedites the overall schedule. Middlebelt Road will be closed to through traffic between 12 and 13 Mile Roads between June and August 2016.

4. Where will construction materials be stored?

Construction materials will be stored near either the launching or recovery shaft sites. Machinery and supplies will be stored at these locations during the majority of the construction schedule when crews are not working.

5. How does tunneling construction work?

Tunneling is an underground construction method where a tunnel boring machine (TBM) is used to mine or “drill” a tunnel for installation of a sewer pipe. Construction activities are conducted through an access shaft and most activities take place underground. Earth removed from the tunnel is lifted out of the access shaft by a crane and hauled away from the site by trucks. Other above ground work includes the installa-tion of manhole structures at points along the tunnel path. Manhole construction will have a similar impact, but should only last approximately six weeks at each structure location.

6. What type of construction activities will we see?

The excavation shaft will be the first visible part of construction. After the shaft is constructed, the most common activity seen will be removal of soils excavated by the TBM. A crane is used to remove the soil from the shaft and dump it into trucks that take the soil away. Wooden boards (called “lagging”) and steel ribs will be stored at the shaft site and lowered into the tunnel to create the tunnel support system, known as the primary liner. The ribs and lagging are placed as the soils are excavated. Example of Excavation Shaft Construction

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Once the soils have been excavated and the primary liner installed, pipe will be delivered to the site. The pipe will then be lowered into the shaft and placed inside the primary liner to form the final sewer tunnel pipe. Follow-ing this, the pipe is grouted in place.

Each shaft site will incorporate a finished structure once the tunnel construction is completed. During the construction of these intermediate shafts trucks will be delivering materials to each shaft construction site.

During construction of the four manhole structures, TS-2 through TS-5 in the center of Middlebelt Road, a large drill is used to cut a hole through the road pave-ment and install supports that connect into the sewer pipe. These manhole structures will provide future access to the tunnel for maintenance purposes. Vent posts at control structures, DC-1 and DC-2, will then be added to the side of the road to allow trapped air to safely escape from the tunnel and manhole structure.

7. What is the sequence of construction activities?

Ric Man Construction will begin mining from the TS-1 launch shaft just north of I-696 and work northward. Once they reach the recovery shaft, TS-6, they will remove the TBM. A nine-foot-diameter pipe will be installed from each of the mining shafts once the mining activities have been completed.

Construction of manhole structures in the center lane of Middlebelt Road will occur once the tunneling is completed. Construction crews will drill and construct manhole structures. Manhole structures are con-structed after the pipe has been inserted.

8. How will shaft locations be secured at night?

Mining shafts are equipped with heavy steel covers when construction is not taking place. A construction crane is needed to remove the cover from the shaft.

9. Will there be any visible signs of the project once it is completed?

The majority of construction is taking place underground and will remain underground. The tops of the two control structures, DC-1 and DC-2, will be visible at grade once completed. There will also be a vent post located along Middlebelt Road between Morningview Road and 12 Mile Road and between Highmeadow Road and Millbrook Street. The vent posts are approximately 8 feet high and resemble lamp posts (without the lamp). There will also be two metal cabinets located at the control structures that house the equipment. These metal cabinets are similar to those used for traffic signal controls at intersections.

Example of Manhole Structure Construction

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10. Will Middlebelt Road remain open during construction?

Middlebelt Road will remain open throughout con-struction except between June 2016 and August 2016. During this time, Middlebelt Road will be closed between Highmeadow Road and Millbrook Street for construction of TS-5 and DC-2. Local access will be available to the streets in this area. The right-hand, southbound lane on Middlebelt Road at 13 Mile Road will be closed for almost one and a half years. From April 2016 to September 2016, Middlebelt Road traffic will be reduced to one lane for southbound and north-bound traffic at each manhole construction location. This should only be the same location for approximate-ly six weeks at a time. Otherwise, short delays may be experienced due to lane closures. The length of delay will depend on the time of day and amount of traffic.

11. How will construction impact local schools?

There are no expected impacts to local schools. The closure of Middlebelt Road near 13 Mile Road has been scheduled for the summer of 2016. This sched-ule was coordinated with the Farmington Hills School District to avoid impacting bus routes during the school year.

12. Who should I call if I have a question or complaint during the project?

If you have questions or concerns, call Pat Roberts, Site Representative, from the Oakland County Water Resource Commissioner’s Office, at (248) 343-0197. He will be responsible for answering calls from 9:00 am - 4:00 pm on weekdays. He will coordinate all calls requiring a field evaluation with Dan DiPonio, the Resi-dent Engineer. Messages can be left on the answering machine after 4:00 pm on weekdays and on weekends at (248) 858-0739 or (248) 431-7998. Calls will be returned the next business day.

Project ParticipantsOakland County Water Resources CommissionerCity of Farmington HillsWest Bloomfield TownshipCity of Keego HarborCity of Orchard LakeWade TrimNTH Consultants

Two-way traffic will be maintained on Middlebelt Road around three manhole construction areas.

There will be no through access on Middlebelt Road between Highmeadow Road and Millbrook Street during manhole construction from June 2016 to August 2016.

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The presentation can be viewed on the Oakland County website:www.oakgov.com/water/pages/projects