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City of MinneapolisI-35W North & South Storm Tunnel

S.F. 194

35W South Tunnel Outfall 35W North Tunnel Outfall

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35W North TunnelConstructed in 1965 Material concrete (not reinforced)

8 14 foot diameter 9,415 feet / 1.8 miles in length Roughly 80 100 feet below the surface 62% Minneapolis Flow / 38% MnDOT Flow Funding need $5.5 million

35W South TunnelConstructed 1961 to 1964 Material concrete (not reinforced) 8 14 foot diameter 24,540 feet / 4.7 miles in length Roughly 80 100 feet below the surface 85% Minneapolis Flow / 15% MnDOT Flow Funding need - $14 million

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35W North Tunnel Tunnel built to accommodate citystorm water that was originally draining

to the sanitary system and freewaydrainage Agreements between the City ofMinneapolis and MnDOT regarding thetunnel construction and maintenance

35W South Tunnel Original flow - west to east to theMississippi River Freeway bisected the original flowpattern Tunnel built to accommodate city andfreeway drainage Agreements between the City ofMinneapolis and MnDOT regarding thetunnel construction and maintenance

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Current Bonding Request2012 $4.5 million State, $4.5 million Local

* Request based on 2006 Tunnel Condition Assessment Report which identified segments of the tunnel and cost estimates.

Current Bonding Request2013 $4.5 million State, $4.5 million Local

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Deficiencies to beAddressed

Groundwater Longitudinal Cracks

Liner FailureVoids outside the tunnel

Holes in the Liner

Groundwater Longitudinal Cracks

Liner FailureVoids outside the tunnel

Holes in the Liner

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City of MinneapolisI-35W North & South Storm Tunnel

Solutions Removing sedimentation and debris from the tunnel

Sealing open joints, fractures, and cracks

Repairing holes and erosion in the tunnel liner

Grouting voids outside of the liner

Solutions Removing sedimentation and debris from the tunnel

Sealing open joints, fractures, and cracks

Repairing holes and erosion in the tunnel liner

Grouting voids outside of the liner

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City of MinneapolisI-35W North & South Storm Tunnel

Need to manage the condition before it becomes asafety issue

The City of Minneapolis needs to continue to takerain water out of the sanitary system and into thestorm water system to avoid Combined SewerOverflows (CSO) and to meet the requirements ofthe Metropolitan Council Environmental Services(MCES) Inflow and Infiltration (I/I) Program

MnDOT supports this work and funding request

Need to manage the condition before it becomes asafety issue

The City of Minneapolis needs to continue to takerain water out of the sanitary system and into thestorm water system to avoid Combined SewerOverflows (CSO) and to meet the requirements ofthe Metropolitan Council Environmental Services(MCES) Inflow and Infiltration (I/I) Program

MnDOT supports this work and funding request