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Auxiliary Spillway Construction Updates

The following information provides updates concerning the construction of the auxiliary spillway. For additional information, please see the FAQs below.

May 11 to May 21 – Trail Reclamation

 

Location – Lower Colliery Dam

 

Purpose – To convert construction road into park trail and to repave asphalt trail.

 

As construction winds down on the auxiliary spillway in Colliery Dam Park, work is underway to restore the park and open the auxiliary spillway construction area for public use. This week, crews are repaving the asphalt trail disturbed by the spillway construction. The main trail around the lower reservoir will reopen for public use on Saturday, May 14. Copcan will begin removing the temporary bridge and continue to decommission the road between the bridge and Harewood Mines Road in order to convert it back to a trail. This trail is anticipated to reopen for public use by Saturday, May 21.

April 18 to April 22 – Forebay Excavation

 

Location – Lower Colliery Dam

 

Purpose – To excavate the soil and remove the secant pile wall in front of the spillway.

 

Cutting of the secant pile wall is complete. A silt curtain was installed on April 15th to mitigate silty water getting into the reservoir. Over the weekend, biologists completed fish salvage between the silt curtain and existing bank. This week crews will remove the secant pile and soil in front of the spillway. Crews will construct the forebay inlet channel as the excavation proceeds.

April 11 to April 15 – Cutting the Secant Pile Wall and Channel Construction

 

Location – Lower Colliery Dam

 

Purpose – To complete the channel downstream of the spillway and to cut the secant pile wall in front of the spillway.

 

Crews will complete the rip rap placement on the channel downstream of the spillway and will then start to place top soil. Crews will also be cutting the secant pile wall in advance of removing the soil in front of the spillway next week.

April 4 to April 8 - Channel Construction

 

Location – Lower Colliery Dam

 

Purpose – To construct the channel downstream of the spillway and prepare for the removal of the soil in front of the spillway.

 

Crews will be completing the excavation and starting placement of the rip rap to armour the bottom and sides of the channel downstream of the spillway. The stop logs and guide rails will be installed on the spillway and work will start to remove the portion of the secant pile wall between the spillway outer walls.

March 28 to April 1

 

Location – Lower Colliery Dam

 

Purpose – To prepare for the removal of the soil between the reservoir and auxiliary spillway.

 

The bridge girders are installed. Work continues on the bridge deck and on the finishing the concrete surfaces. Backfill is nearing completion. Trees along the reservoir edge will be removed in preparation for the excavation of the soil in front of the auxiliary spillway.

February 29 to March 11 – Inner Walls and Bridge

 

Location – Lower Colliery Dam

 

Purpose – To pour the inner weir walls and install the bridge girders.

 

The inner weir walls will be poured early the week of February 29th. Once complete, work will begin to install the bridge girders. Crews will continue to backfill the outside of the structure.

February 15 to February 26 – Spillway Floor Slab and Inner Walls

 

Location – Lower Colliery Dam 

 

Purpose – To pour the floor slab, start the inner walls and backfill the structure. Installation of the spillway concrete floor slab rebar will be complete the week of February 15th. Once completed, pouring the floor slab will follow, weather permitting. Once the floor is poured, crews will start placing the interior wall forms. During this period, crews will also start backfilling the outside of the structure.

February 1 to February 12 – Spillway Floor Slab

 

Location – Lower Colliery Dam

 

Purpose – To construct the floor slab and prepare to backfill the structure.

 

The east side exterior spillway wall was poured Friday, January 29. Over the next two weeks, crews will be removing the exterior wall forms, backfilling underneath the spillway floor slab and placing the rebar in preparation for the concrete pour.

January 21 to January 29 – Concrete Walls and Floor Slab

 

Location – Lower Colliery Dam

 

Purpose – To construct the spillway walls and floor slab.

 

The west side exterior spillway wall was poured today. Over the next week, crews will be completing the east side exterior wall forms in preparation for pouring concrete. Crews will also be starting work on the spillway floor.

January 4 to January 15 – Concrete Walls

 

Location – Lower Colliery Dam

 

Purpose – To construct the spillway walls.

 

Over the next two weeks, crews will be erecting the wall forms and installing rebar in preparation for placing concrete.

December 7 to January 1 – Concrete Pouring

 

Location – Lower Colliery Dam

 

Purpose – To commence construction of the spillway structure.

 

Over the next 3 weeks, construction crews will be installing form work, placing rebar, and poiring concrete.

November 23 to December 4 – Excavation of Auxiliary Spillway

 

Location – Lower Colliery Dam

 

Purpose – To prepare ground for auxiliary spillway structure.

 

During this period, construction crews will be undertaking digging and removal of dirt.

November 16 – Tree Removal

 

Location – Lower Colliery Dam

 

Purpose – To provide a safe slope for the excavation for the auxiliary spillway and bridge structure.

 

With the Provincially approved design drawings and further slope analysis, more tree removal was identified. Approximately a dozen trees will be removed. The logs will remain in the park for future park use. The work being carried out is inside the fenced-off construction area. Park users are unaffected by this work.

October 19 to November 6 – Secant Pile Cut-Off Wall Construction

 

Location – Lower Colliery Dam

 

Purpose – This work is being undertaken to build a cut-off wall.

 

Copcan's subcontractor, Henry Drilling, will commence work on a secant pile cut-off wall on Monday, October 19. It is anticipated this phase of the construction will take three weeks to complete with Henry Drilling working extended hours Monday through Saturday. This work entails drilling a hole while advancing a steel casing. When the proper depth is reached, the casing is removed as concrete is poured. A series of overlapping concrete columns will form the cut off wall. The cut off wall supports the labyrinth weir excavation and prevents seepage from the reservoir.

 

Review of the site resulted in an assessment that between two and six more trees will require removal along the access road to allow room for the drilling equipment and low bed trucks to enter the area. The removed trees will be kept for park use.

September 30 – Public/Worker Safety Exclusion Zone

 

A third phase public/worker safety exclusion zone is now in effect at the Colliery Dams Park as workers prepare the site for the construction of the auxiliary spillway.

 

Click here for third phase map.

September 22 – Public/Worker Safety Exclusion Zone

 

A second phase public/worker safety exclusion zone is now in effect at the Colliery Dams Park as workers prepare the site for the construction of the auxiliary spillway. This new zone is reduced in size from the original exclusion zone created September 15-20.

 

Click here for second phase map.

September 16 to 20 – NOTICE

 

A public/worker safety exclusion zone remains in effect at Colliery Dams Park Wednesday, September 16, through to Sunday, September 20, as crews undertake tree clearing. This zone is a requirement of Work Safe BC when removing trees. The boundary of the exclusion zone is calculated using the estimated height of the tallest trees to be fallen, times twice their individual length.

 

Click here for first phase map.

September 14 to 20 – Clearing and Grubbing

 

Location - Lower Colliery Dam

 

Purpose - This work involves clearing trees and removing grubs from the site of future auxiliary spillway.

 

City crews will undertake work Monday through Sunday. During this period, park users can expect to see site preparation; creation of a construction staging area off 7th St; creation of an access route from 7th St. into the park along an existing trail; temporary closure of the wood bridge crossing Harewood Creek; and site clearing, including grubbing and tree removal, scheduled to begin September 15th.

Aug 17 to 21 – Soil and core sampling

 

Location - Lower Colliery Dam

 

Purpose - This work is being undertaken to determine soil quality and soil composition.

 

City crews will commence work after 7:30 am.  Areas to be tested will be taped off. A flag person will be stationed at each end of the impacted trail to advise trail users to stay on the trail, and if requested, can supply information concerning the project.

August 6 – Test pit work and soil sampling

 

Location – Lower Colliery Dam

 

Purpose - This work is being undertaken to determine soil depth and soil type. 

 

City crews will commence work between 7:00 and 7:30 am. Areas to be tested will be taped off. A flag person will be stationed at each end of the impacted trail to advise trail users to stay on the trail, and if requested, can supply information concerning the project.

 

Q: What work is being undertaken in the Park?

A: The City of Nanaimo is constructing an auxiliary spillway located adjacent to the current spillway alongside the Lower Colliery Dam.  The construction of the auxiliary spillway was chosen by Council from one of the three options acknowledged by the Province’s Dam Safety Section as meeting the requirements to address flow capacity issues associated with the existing spillway.

Q: Where in the park will construction take place?

A: Construction of the new auxiliary spillway will take place next to the Lower Colliery Dam on the south side of the park.  Park users are strongly encouraged to familiarize themselves with posted signs located in the park detailing the location of the construction area.  While construction is underway, park users may – on occasion – be directed to use a trail detour around the construction area.

Q: What are the hours of construction?

A:  Hours of construction are typically 8 a.m. through to 5 p.m., Monday to Friday.  On some occasions, construction may start sooner and end later.  Likewise, where circumstances require it, construction may take place over a weekend.

Q: When will the project be completed?

A: The Province has ordered the City to have the spillway substantially complete by November 15th, 2015.

Q: Can I visit the park during construction?

Yes. While some of the immediate areas around the construction site will be closed, the remainder of the park is open for visitors.

Q: Will the trails be closed?

Our goal is to keep the majority of trails open during construction. However, during some phases of the project, some trails may have to be closed temporarily.

Q: Will any trees be cut down during the construction of the auxiliary spill way?

A: Yes.  To make way for the spillway, some trees will need to be removed.  Care will be taken to limit these trees to only those which directly impact construction activity and/or the installation of the spillway structure.

A: What are you doing to reduce the risk of fire when cutting down trees?

Q: There is a fire hydrant in the park which provides good protection. A fire suppression plan will be in place prior to and during the removal of trees.

Q: Can I still swim at the park?

A: Yes.  Park users wishing to swim in either the lower or upper lake can still do so.

Q: Where can I obtain more information on the Auxiliary Spillway project at Colliery Dams Park.

A: A page containing a wide range of resources concerning the Colliery Dams and the challenges associated with Lower Dam auxiliary spillway can be found on our the Colliery Dams Information page and on this page. We update both pages regularly.

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