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3. Affected Environment, EnvironmentalConsequences, and Proposed

Mitigation Measures3.1 Soil Conditions and Contamination

The EIS includes analysis of potential environmental hazards from past land use conditions and fromdemolition and construction associated with the Proposed Project.

3.1.1 Soil Conditions

Soils in the Proposed Project area average about 40 feet thick, overlying limestone bedrock of thePlatteville Formation (Geologic Atlas of Hennepin County, Minnesota Geological Survey, 1989). TheProposed Project area contains a single soil type, identified as U4A - Urban Land Udipsamments(cut and fill land) Complex, with 0 to 2 percent slopes.1 The city of Minneapolis was historicallyexcluded from the Soil Survey because of urban development and extensive soil reworking.

According to the Geologic Atlas of Hennepin County, the surficial soils in the Proposed Project areaare Middle Terrace glacial-meltwater stream sediments of sand, gravelly sand, and loamy sand,which are overlain in places by thin deposits of silt, loam, or organic sediment. The surficial depositsare frequently covered by thick fill or reworked local materials where heavily developed.

3.1.2 Potential Environmental Hazards from Past Uses

3.1.2.1 Background

PurposeA governmental database records search has been completed for the Proposed Project area, whichsupplements Phase I Environmental Site Assessments (ESAs) completed for specific propertieswithin the Proposed Project area. The studies and searches have been used to determine thepotential extent of the environmental hazards from past site uses that could be encountered by theProposed Project. The EIS summarizes the findings of the studies, searches, and surveys as theinformation relates to potential contamination found within the Proposed Project area.

Scope of Environmental Review

Information on soil and contamination conditions has been gathered from the following property-specific documentation available at this time:

Phase I Environmental Site Assessments (ESAs)

Phase II ESAs or comparable investigations

The EDR Radius Map Report with Geocheck[governmental database records search],

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Property-Specific Environmental Reviews within the Proposed Project area have been performed by

American Engineering Testing, Inc. (AET) for the MSFA. Those Reviews and a summary TechnicalMemorandum are included in Appendix B of the EIS. The EDR report of governmental databaserecords search is also included in Appendix B.

3.1.2.2 Affected Environment

Identified Environmental Hazards

Environmental review has identified contaminant impacts to soil, groundwater, and soil gas media onvarious properties. Contaminants include metals, petroleum, volatile organic compounds (VOCs),

and other organic compounds such as polynuclear aromatic hydrocarbons (PAHs) andpolychlorinated biphenyls (PCBs).

These findings are consistent with historical operations within the Proposed Project area, includingthe following: railroad; foundry and ironworks; machining, welding, and sheet metal;blacksmith/tinsmith; electroplating; engraving; plumbing and heating; furniture factory; carpentry andwagonwright; laundry; paint, print, and binding; paper and box factory; bottling and liquor storage;morgue and hospital; warehouse; lumber yard; parking; and auto repair and gas station.

Affected Properties

Environmental review indicates that the identified contaminant impacts result in an affectedenvironment at the following properties within the Proposed Project area (see Figure 3.1-1):

Block 71 300 9th

Avenue South: VOCs, PAHs, and metals including barium, copper, andarsenic

Block 73 424 Chicago Avenue South and 701 4th

Street South (contaminant impacts in LightRail Transit right-of-way adjacent to Block 73): petroleum

Block 94 530 Chicago Avenue South: petroleum and PAHs

Block 106 309 9th Avenue South: VOCs, PAHs, and metals including lead, copper, andarsenic

Metrodome 900 5th Street South: organic vapors (i.e., VOCs) and PCBs

Degree of Certainty

MPCA regulatory files for the identified properties have been requested for review, but the files havenot yet become available for review. Given the information accessed, the degree and distribution ofcontaminated soil conditions is not yet well defined throughout the Proposed Project area. While

potential soil contamination is not considered to be everywhere within the Proposed Project area, itwould be difficult to rule out soil contamination at any given location without further assessment.

3.1.2.3 Environmental Consequences

Direct Consequences

The environmental consequences of contamination in soil, groundwater, and soil gas media begin

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places serves to insulate the underlying natural soils and groundwater from contaminant migration.

The Proposed Project design and construction process is expected to include additional assessmentand removal of contaminant impacts in shallow soils. The Proposed Project is not expected to alterthe general soil conditions or permanently enhance the potential for contaminant migration.However, dewatering during construction has a potential to affect groundwater hydraulic conditionsand the distribution of any associated contamination.

3.1.2.4 Mitigation

Regulatory Considerations

In most cases, mitigation measures for environmental contamination in the State of Minnesota areundertaken in coordination with the MPCA. The MPCA offers the following fee-for-service voluntaryprograms which can provide liability assurances to owners, prospective purchasers, or developers:

Petroleum Brownfield Program (PBP) for petroleum contamination

Voluntary Investigation and Cleanup (VIC) program for non-petroleum impacts

The MPCA voluntary programs operate in coordination with state regulatory programs such asSuperfund and the Petroleum Remediation Program (PRP) to offer liability assurances consistentwith voluntary programs and regulatory statutes, rules, and policies. The voluntary programs alsooffer users prescribed guidelines and standardized approaches for investigation, response actionplanning, remediation, and monitoring of mitigation measures.

Materials Management

During site preparation for the Proposed Project, the MSFA may encounter the presence ofcontamination or solid waste that must be properly managed to minimize risks. The followingmaterials management categories, each requiring unique permitting and documentation measures,are anticipated for materials expected to be encountered within the Proposed Project area:

Landfill disposal/management of hazardous or solid waste

Landfill disposal or potential reuse of regulated fill soil following federal, state and localgovernment notification procedures

Potential on-site or off-site reuse or approved disposal of unregulated fill soil depending on soilcharacteristics and conditions at the prospective receiving site

Potential on-site or off-site reuse or disposal of uncontaminated soil depending on soil suitabilityfor planned construction uses

Soil and bedrock, either contaminated or uncontaminated, which may remain in situ

Discharge or sanitary disposal of potentially contaminated waters which may require advancedplanning, permitting, pre-treatment, or other management measures

Risk Management

The presence of soil gas contamination in the ground may result in migration and encroachment

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The presence of the identified environmental impacts to soil, groundwater, and soil gas media would

require enhanced diligence during planning and construction to manage risks associated withcontaminated media, to coordinate waste stream management, to confirm the presence and degreeof risks, and to mitigate any residual risks which are not remediated.

3.1.2.5 No Action Alternative

If the No Action Alternative is selected, any contaminated media and potential soil contaminationwould remain undisturbed. The mitigation measures to engage regulatory authorities and to managethe waste stream would not be necessary.

Given the limited scope of previous environmental assessments in the area of the existingMetrodome, the degree of inherent risk from in situ contamination is not certain. The potential wouldremain for contaminant migration to affect human health and the environment at affected propertiesand potentially off-site.

3.2 Water Use

3.2.1 Public Water Supply


The City of Minneapolis owns and operates a public water system that provides service to theProposed Project site. The City watermain network in the vicinity of the Proposed Project siteconsists of an existing 12 inch public watermain located in 6

thStreet, an existing 16 inch public

watermain in 11th Avenue, and an existing 12 inch public watermain in Chicago Avenue. The 16 inchwatermain in 11

thAvenue is inside a 30 inch casing pipe under 4

thStreet. See Figure 3.2-1 for

existing utility information.

The peak monthly water demand for the Metrodome is three million gallons, based on theMetropolitan Sports Facilities Commission (MSFC) July 26, 2011 utility invoice. Annual waterdemand for the Metrodome is 18 million gallons, based on MSFC utility invoices from June 2011through May 2012.


The existing water service that serves the Metrodome are proposed to be replaced by a new 12 inchdomestic service, and an 8 inch fire service that will be tapped off the existing 16 inch publicwatermain in 11

thAvenue. The anticipated peak water demand for new Stadium events is 3,000

gallons per minute (gpm). The City of Minneapolis has indicated that the public water system has

adequate capacity to provide service to the new Stadium; however, the developer needs to performengineering studies, including fire flow tests, to verify that the public water system capacity will beadequate for the Proposed Project.

The estimated peak monthly water demand for the new Stadium is approximately one milliongallons, and the estimated annual water demand is approximately 10 million gallons. Because of theLEED certification effort, the new Stadium will use significantly less water than the Metrodome.Reduced flow fixtures will be provided throughout the new Stadium which will perform better than

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In the No Action Alternative the Metrodome would continue to function as it currently does. Nochanges to the public water system would be required to continue to allow the Metrodome tofunction.

3.2.2 Groundwater


Based on information provided by AET in their November 21, 2008, letter to the MSFC (see

Appendix B), the groundwater in the Metrodome area is very near the elevation of the existingplaying field. The playing field elevation is approximately 795.9 feet. A groundwater interceptionsystem was constructed as part of the original Metrodome project to prevent groundwater fromentering the Metrodome. During construction of the Metrodome the rapid flow of water made itdifficult for the contractor to lower the groundwater table and construct a sump pump for thegroundwater inception system. There is history of the area near home plate being flooded, which ledto additional small shallow wells drilled into the limestone to lower the water level.

The existing Metrodome groundwater interception system is pumped to the sanitary sewer system.An estimate of the annual groundwater pumping rate was developed by the MSFA based on

observations over a three hour period on June 18, 2013. Based on that information, approximately 6million gallons per year of groundwater from the existing groundwater interception system is pumpedfrom a sanitary lift station to the sanitary sewer. An additional 6 million gallons per year ofgroundwater that infiltrates the existing storm sewer system draining to the storm sewer lift station ispumped from a storm lift station to the storm sewer. The Metrodome does not have a MinnesotaDepartment of Natural Resources (DNR) groundwater appropriation permit.


The playing field elevation for the Proposed Project is 797.5 feet, which is approximately 2 feetabove the current Metrodome playing field elevation. The proposed playing field elevation shouldreduce groundwater pumping frequency compared to existing pumping frequency, but permanentdewatering remains part of the new Stadium design. The MSFA proposes to discharge groundwaterfrom the Proposed Project to the storm sewer system.

The MSFA is currently in the process of conducting additional subsurface investigations to determinethe quality of the groundwater.

Dewatering is anticipated during construction. The contractor shall follow all stipulations found in the

MPCA Construction Stormwater permit and DNR dewatering permit (if required).Any wells constructed for dewatering or water quality monitoring will be subject to the requirementsof Minnesota Statutes Chapter 103I, and Minnesota Rules Chapter 4725. Abandoned wells will needto be properly sealed.

3.2.2.3 Mitigation

Groundwater from permanent dewatering operations should be evaluated for reuse If no reuse

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Monitoring parameters may include the discharge volume and rate of groundwater that is dewatered.

If it is determined that a DNR Water Appropriations permit is not necessary based upon thatinformation, the DNR recommends that the groundwater interception system continue to be meteredfor the new Stadium to be sure discharge rates stay below 10,000 gallons per day and under 1million gallons per year.

The use of wells and/or cut-off walls is anticipated to control groundwater during construction.Discharge of all dewatering efforts will pass through approved on-site best management practices(BMPs) prior to discharge. Construction dewatering should include water quality monitoring todetermine suitability of discharge to storm sewer or sanitary sewer system. Dewatering during

construction will require a City of Minneapolis Temporary Water Discharge Permit.If groundwater is found to be contaminated either during construction dewatering or duringpermanent groundwater pumping, discharge to the sanitary sewer system would likely be required.In the permanent groundwater pumping scenario it may be necessary to design plumbing to allowdischarge to the storm sewer system or to the sanitary sewer system, with a manually operatedvalve controlling which receives the discharge depending on the ground water quality. Periodicgroundwater water quality monitoring will occur to determine the suitability of discharge to storm orsanitary sewers. A water quality monitoring plan will be prepared. The plan will identify the proposedmonitoring locations and a proposed list of analytes to be monitored. The plan will also include

contingencies for increasing the number of analytes monitoring and adding monitoring locationsbased on conditions encountered during construction.


In the No Action Alternative the Metrodome would continue to function as it currently does. Nochanges to the groundwater system would be required to continue to allow the Metrodome tofunction.

3.3 Erosion and Sedimentation

3.3.1 Affected Environment

Soils information is taken from existing geotechnical information, including Report of PreliminaryGeotechnical Exploration and Review: Report No. 01-05-723 prepared by American EngineeringTesting, Inc. dated February 25, 2013 (see Appendix B).

The report in Appendix B identifies existing fill across the new Stadium site that ranges in depthsfrom 5 to 20 feet. Underlying the fill is terrace-deposited sands that consist of poorly graded sand tosilty sand that ranges in depth from 15 to 30 feet across the new Stadium site. Underlying theterrace deposits are glacial deposits that range from a silty sand to a clayey sand and may containcobbles and boulders which extends to bedrock depth. These soils are conducive to infiltration withthe clayey sands as the limiting layer.

Areas with steep slopes are identified as having slopes greater than 1 vertical (v):3 horizontal (h) (12percent or greater). The only area with steep slopes and any ground vegetation present within theProposed Project area is in the northeast quadrant of the existing Metrodome (between the east

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existing ground grade around the new Stadium). The two volumes were then compared in order to

determine an approximate net material export volume. The results are summarized below:

Metrodome bowl volume: 340,000 cubic yards

New Stadium bowl volume: 810,000 cubic yards

Proposed excavation quantity (considering existing Metrodome bowl): 525,000 cubic yards

Net export volume: 470,000 cubic yards

3.3.2 Environmental Consequences

The potential for erosion and sedimentation during Proposed Project construction will exist as soilsare disturbed by excavation and grading. Particular attention should be paid to areas with steepslopes as they can present unstable soil conditions that can result in erosion if not properly managedduring construction activities.

3.3.3 Mitigation

Erosion and sediment control measures planned for use during and after construction of theProposed Project will meet or exceed the requirements of the National Pollution Discharge

Elimination System State Disposal System (NPDES/SDS) Construction Storm Water Permit.2

Although the Proposed Project is within the Mississippi Watershed Management Organization(MWMO) boundary, MWMOs erosion and sediment control requirements are generally lessstringent than those of the City of Minneapolis, and the MWMO tends to defer to the City ofMinneapolis on erosion and sediment control measures. A Stormwater Pollution Prevention Plan(SWPPP) will be prepared for the Proposed Project and will serve as the basis for constructionmanagement of potential erosion and for managing sediment related to the construction activity.BMPs will be developed and employed to manage erosion and sedimentation during siteconstruction. These BMPs may include silt fencing, inlet sediment filters, sediment traps, gritchambers, temporary ditch checks, rock filter dikes, fiber logs, turf reinforcement mats, temporaryseeding, riprap and erosion control blankets for disturbed areas, and seeding or placement of sod orother plant materials for final restoration.

The first phase of construction will include excavation and installation of earth retention systems inthe northeast corner of the Proposed Projects new Stadium site, outside of the footprint of theexisting Metrodome. The earth retention system will likely include driven steel piles. This will be aphased construction project, and therefore erosion and sediment control BMPs shall be modifiedand/or relocated by the contractor as work progresses.

3.3.4 No Action Alternative

With the No Action Alternative, there would be no change to soil erosion or sedimentation conditions.Furthermore, opportunities to potentially improve erosion and sedimentation through BMPs wouldnot be realized.

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3.4 Water Quality: Surface Water Runoff

3.4.1 Stormwater Runoff


The Proposed Project will be constructed in Minneapolis and within the area regulated by theMississippi Watershed Management Organization (MWMO). The Proposed Project area consists of47.4 acres of highly urbanized land uses. These include the existing Metrodome, plazas, streets,parking facilities, a light-rail transit station (LRT), and businesses. Over 91 percent of the ProposedProject area has impervious cover, such as pavement or rooftops. See Figure 3.4-1 for a graphicalrepresentation of the drainage areas and flow patterns discussed below.

At 24.2 acres, the block that will contain the Proposed Projects new Stadium represents the largestportion of the Proposed Project area (from 4

thStreet to 5

thStreet and 11

thAvenue to Kirby Puckett

Place, referred to in this section as the New Stadium Block). This area is owned by the MFSA andincludes the Metrodome, parking lot, plazas, and the portion of 5th Street that will be vacated with theproposed construction. There are approximately 2.6 acres of vegetated landscaping within this area,resulting in 89.4 percent impervious coverage.

The Downtown East Block to the west of the New Stadium Block contains the transit station andassociated plaza. Of this 3-acre parcel, 0.2 acre contains the LRT tracks and platforms, which areassumed to have addressed their stormwater management requirements at the time of their design,and this area is therefore not considered in the discussion below. The remainder of the parcel isconsidered to have 100 percent impervious coverage.

The remaining 23.2-acre portion of the Proposed Project area consists of streets, surface parkinglots, and businesses. These can be further split as follows:

The three blocks immediately to the north and east of the New Stadium Block, which are referred

to as the McClellan and McGrew Blocks, comprise a total of 5.6 acres of surface parking, abusiness, and LRT uses. The blocks have 95.4 percent impervious cover under the No ActionAlternative.

The block immediately to the west of the New Stadium Block by 6th

Street, which is currentlyoccupied by the Hennepin County Medical Examiners building and a surface parking lot, is 2.7acres. Of this, 86.3 percent consists of impervious cover.

Immediately west of the Downtown East Block, the two blocks that are currently occupied by theStar Tribune office building and a surface parking lot comprise a total of 5.8 acres. The blocks

have 89.8 percent impervious cover in the existing condition. For this EIS, these will be referredto as the East/West Alternate Plaza Configuration.

The block in the southeast quadrant of 6th

Street and Chicago Avenue currently contains theFirst Covenant Church and a surface parking lot. A portion of this block, 1.2 acres, is proposed tobe redeveloped with the Proposed Project under Reserved Parking Plan A. This block isconsidered to have 100 percent impervious cover.

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Regulatory Environment

The regulatory environment has changed significantly since the existing Metrodome was constructedbeginning in 1979. Except for the transit station, the parcels within the Proposed Project area weredeveloped prior to the implementation of regulations to manage stormwater runoff for quantity orquality. When construction began on the transit station in the early 2000s, stormwater regulationswere in effect, but these were likely less stringent than the current requirements for the City ofMinneapolis. The following agencies have regulatory requirements that govern the management ofstormwater runoff for the Proposed Project:

The City of Minneapolis

The MWMO, which currently does not have a permit program

The MPCA, under the Clean Water Act NPDES permit program

In addition, the Minnesota Department of Transportation (MnDOT) may have interest, and mayrequire a permit, if the Proposed Project discharges additional runoff to their storm drain system tothe north of the New Stadium Block. See discussion under Section 3.4.2 for more informationregarding specific stormwater requirements.

Downstream Systems and Receiving Waters

Runoff from the Proposed Project area currently drains into several municipal and MnDOT trunkstorm drain and tunnel systems which ultimately discharge into the Mississippi River. The river is notcurrently impaired for any construction-related parameters, so additional treatment of the runoff isnot required. The discussion within this section is divided into the various blocks within the ProposedProject area.

New Stadium Block The Metrodome building and adjacent parking lot drain by a private 48inch storm drain to a deep municipal storm tunnel under 11 th Avenue. A small percentage of theNew Stadium Block drains by surface flow onto the surrounding streets. Runoff reaching 5

th/6

th

Street and 11th Avenue ultimately drains by municipal storm drainage pipes into the 11 th Avenuetunnel mentioned above. Runoff reaching Chicago Avenue/Kirby Puckett Place drains bymunicipal storm drainage pipes to a municipal storm tunnel farther north on Chicago Avenue.The 11

thAvenue tunnel and the Chicago Avenue tunnel collecting stormwater runoff from the

Metrodome ultimately discharge to the Mississippi River upstream of the I-35W Bridge. Runofffrom the portion of the block that reaches 4

thStreet flows into a storm drain constructed by

MnDOT and ultimately to a storm tunnel that is owned by MnDOT. This tunnel discharges to theRiver downstream of the I-35W Bridge.

Downtown East Block Runoff from this block drains to municipal storm drainage pipes onKirby Puckett Place and on Park Avenue, both of which ultimately drain to the above-mentionedChicago Avenue tunnel.

McClellan and McGrew Blocks The McClellan Block and a portion of the westerly McGrewBlock drain to the Chicago Avenue tunnel. The easterly and remainder of the westerly McGrewBlocks drain to public storm drainage pipes in 3 rd Street and ultimately to the MnDOT tunnel.

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westerly block drains to a municipal storm drainage system in 5th

Avenue that ultimately drains to

a municipal storm tunnel in Washington Avenue. The Washington tunnel ultimately connects tothe tunnel in Portland Avenue.

Based on information received from City of Minneapolis Engineering and Public Works staff, thedownstream systems can be characterized as follows:

The 11th Avenue tunnel, built in the 1930s, has capacity and condition issues.

The Chicago Avenue tunnel, built in the 1880s, is in poor condition. It also has capacity issues.

The Portland Avenue tunnel has capacity (pressurizes) and condition issues.

The MnDOT tunnel has capacity constraints.


The land use, amount, and degree of impervious soils and surfaces, and soil types influence thequantity of stormwater runoff and peak discharge rate from a site. With greater amounts ofimpervious soils and surfaces, less rainfall is able to infiltrate into the soil. Consequently, a highervolume of stormwater runoff will be generated than for the same area with less impervious soils andsurfaces. Similarly, higher levels of impervious soils and surfaces generally result in higher peak

discharge rates.Changes in land cover are expected as a result of the redevelopment within the Proposed Projectarea. In general, the draft design plans have been used to identify and evaluate the anticipatedchanges. Where less is known about the ultimate land use and cover types, the worst-case hasbeen assumed for impacts to stormwater runoff. Based on the worst-case assumptions for changesin land cover type as described below, it is estimated that the Proposed Project will add 1.3 acres ofimpervious surface within the Proposed Project area. If less impervious surface is included in thefinal design, the impacts to stormwater runoff will be less than those shown in this EIS. Thepreliminary design scenario for the proposed stormwater system is presented below. As

geotechnical investigations are completed and modifications are made to the site plan, there may bemodifications to the stormwater design. However, it is expected that the overall concept will remainthe same and that the general mitigation results will be similar to those presented below. See Figure3.4-2 for a representation of the proposed drainage boundaries, flow patterns, and potential BMPlocations.

New Stadium Block It is anticipated that the amount of impervious surface will not increaseover the No Action Alternative and may decrease by up to 20 percent. This EIS assumes nodecrease in impervious surface will result from the Proposed Project. The draft design plans

indicate that stormwater runoff from the New Stadium Block will be directed off-site by stormpipes to three different systems: 6

thStreet, Chicago Avenue, and 11

thAvenue. Under the

Proposed Project more of the New Stadium Block will potentially drain to the 6th

Street municipalstorm drainage system and to the Chicago Avenue storm drainage system. The third dischargepoint would be to the 11

thAvenue tunnel by the existing 48 inch pipe connection.

Downtown East Block It is anticipated that there would be no change in land cover types or to

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Chicago Avenue tunnel system, with the entire westerly McGrew Block directed to that system.

Consequently, under the Proposed Project there will be less runoff from these blocks dischargingto the MnDOT tunnel.

Hennepin County Medical Examiner Block The EIS assumes that the northern portion of theblock would have 100 percent impervious cover. The overall percentage of impervious cover onthe block would be 91.1 percent, up from 86.6 percent in the No Action Alternative. HennepinCounty staff have reported drainage problems at their building. If the northern portion of theblock is redeveloped as a public plaza, the design will not exacerbate these problems.

First Covenant Church Partial Block - The east portion of the block, which is currently a

surface parking lot, will continue to have 100 percent impervious cover under the ProposedProject Reserved Parking Plan A. It is anticipated that there would be no change in in flowpatterns for this block.

East/West Alternate Plaza Configuration The draft design plans indicate that these blocksmay be converted to public plazas with flexible programmable spaces. Because the nature of theplazas is yet to be determined, the EIS assumes that these blocks would have 100 percentimpervious cover under the Proposed Project with the East/West Alternate Plaza Configuration.It is also anticipated that there would be no change in flow patterns for this block under the

Proposed Project. Streets and Transitway 5

thStreet will be vacated with the Proposed Project and is assumed

to remain 100 percent impervious. Stormwater management for this area will be included withthe New Stadium Block. It is expected that there will be no changes to the transitway or otherstreets under the Proposed Project.

3.4.1.3 Mitigation

The Proposed Project will meet the rate and volume control requirements of the City of Minneapolisand MPCA. The draft design plans include BMPs that will be implemented in various locations as

part of the Proposed Project (Figure 3.4-2). Potential BMPs being explored include undergroundperforated pipe galleries, hydrodynamic separators (also known as water quality treatmentmanholes), tree trenches with Stockholm or similar soil, permeable pavement, infiltration beds, andrainwater harvesting. Determination of the BMPs to be used will be made during final design of eachblock.

With the worst-case assumptions for the changes in land cover types under the Proposed Project,there would be a 1.3-acre increase in impervious surface. This would result in higher volumes ofrunoff from the Proposed Project over those of the No Action Alternative. The primary stormwater

BMP for the Proposed Project is underground perforated pipe galleries for infiltration. This systemtypically reduces the volume of runoff from a site. Several of the other BMPs being explored alsohave the potential to reduce the volume of runoff. Therefore, under the Proposed Project, it isexpected that the runoff volume will be reduced from that of the No Action Alternative.

As with the runoff volume, the peak discharges from the overall Proposed Projects Stadium sitewould be expected to increase from those of the No Action Alternative without the incorporation of

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discharge rates to the various systems are maintained where practicable. Increased flow rates to

specific systems, if any, will be discussed with City of Minneapolis staff during final design. With theimplementation of the BMPs, it is expected that the Proposed Project will reduce runoff volumes anddischarge rates below those of the No Action Alternative.

Table 3.4-1. Stormwater Runoff Summary Before/After Project

StormDrainage

System

DrainageArea

(acres)

Before /After

ImperviousPercentage

Before /After

RunoffCurveNumber

Before /After

Peak Discharge Without Mitigation*(cubic feet per second)

2-Year

Before /After

10-Year

Before /After

100-Year

Before /After

Drainage to 11th

Avenue Storm Tunnel

Drainage to6

thSt. Storm

Drain

6.3 / 7.5 92.7% /84.5%

97 / 94 21 / 26 33 / 42 48 / 62

Drainage to11th Ave. By

Ex. 48 Pipe

21.1 / 18.7 89.1% /96.9%

95 / 97 72 / 65 98 / 101 96 / 146

CombinedFlows

27.4 / 26.2 89.1% /93.3%

95 / 96 93 / 91 127 / 142 145 / 208

Drainage to Chicago Avenue TunnelDrainage toPark Ave.Storm Drain

1.3 / 1.4 100% /100%

98 / 98 5 / 5 8 / 8 12 / 12

Drainage toChicago Ave.

Storm Drain

6.0 / 7.9 94.2% /100%

85 / 98 22 / 30 34 / 46 50 / 66

CombinedFlows

7.0 / 9.4 95.2% /100%

87 / 98 28 / 36 43 / 54 62 / 79

Drainage to MnDOT Tunnel SystemDrainage to3rd/4th St.Storm Drain

3.0 / 1.6 74.9% /76.6%

89 / 92 9 / 7 16 / 11 23 / 17

Drainage to Portland Avenue TunnelDrainage toPortland Ave.Storm Drain

2.9 / 2.9 100% /100%

98 / 98 11 /11 17 / 17 24 / 24

Drainage to5th Ave. StormDrain

2.9 / 2.9 80.1% /100%

93 / 98 8 / 11 14 / 17 21 / 24

Combined 5.8 / 5.8 90.0% / 95 / 98 19 / 22 30 / 34 44 / 49

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3.4.2 Stormwater Management

As noted in Section 3.4.1, there are a variety of governmental units with regulatory authority overstormwater runoff from the Proposed Project, notably the City of Minneapolis and MPCA. TheMWMO has standards for stormwater management. However, the MWMO relies on the City ofMinneapolis to review plans and implement stormwater and erosion control ordinances that are atleast as stringent as the WMO standards. Chapters 54 and 52 of the City Code provide themechanisms for enforcement of the Citys standards. On June 26, 2013, the MPCA reissued theNPDES/SDS general permit for discharges of stormwater associated with construction activity. Thenew permit, which takes effect on August 1, 2013, conforms to new federal requirements. In general,

the new permit imposes more stringent permanent stormwater management requirements as well asmore stringent construction erosion and sediment control requirements.

The City of Minneapolis and the MPCA requirements are dependent in part on the downstreamreceiving system. The Proposed Project does not fall within an area that has been designated asflood prone by the City of Minneapolis, but as noted above the downstream infrastructure does havecapacity limitations. The Proposed Project drains to the Mississippi River. According to the CleanWater Act section 303(d) List of Impaired Waters (also known as the Total Maximum Daily Load orTMDL List), the Mississippi River is not impaired for construction-related parameters. The currentstandards of the City of Minneapolis and MPCA specific to the Proposed Project area aresummarized in Table 3.4-2. The MWMO has recently updated their management plan and will beworking with the affected cities to revise or determine new water quality and volume controlstandards. Therefore, the table also includes the proposed MWMO standards because they mayhave implications for portions of the Proposed Project that are constructed at a later time.

Table 3.4-2. Stormwater Management Criteria

Stormwater

Requirement

Current Permitting AuthorityPotential Future

Standards

City of Minneapolis MPCA MWMO

Volume Control Not applicable Current rule: Desired butnot required for projectsnot draining to impaired orspecial waters

New rule: Retain thevolume equivalent to 1

inch of runoff from theadded impervious surface

It is anticipated that avolume control standardwill be in place in 2013.

Rate Control Do not exceed existingcondition peakdischarge rates for the2-, 10-, and 100-year

SCS T II/24

Not applicable to projectsnot draining to impaired orspecial waters

Do not exceed existingcondition peak dischargerates for the 2-, 10-, and100-year storms, SCST II/24 h

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StormwaterRequirement

Current Permitting Authority

Potential Future

Standards

City of Minneapolis MPCA MWMO

Water Quality 70% Total SuspendedSolids (TSS) removalfrom project runoffgenerated by a 1.25-inch rainfall

Current rule: -inch ofrunoff from the addedimpervious surface(For filtration BMPs, thesystem must have a

reasonable chance ofachieving 80% TSSremoval.)

New rule: 1 inch of runofffrom the added impervioussurface

90% TSS removal fromrunoff generated by the95

thpercentile daily

rainfall total (currently1.17 inches in 24 hours)

over the entire area ofthe site (not just the siteareas being developed ordisturbed)


With the possible exception of the existing transitway, there are no stormwater BMPs to managestormwater for water quality treatment or rate and volume attenuation in the Proposed Project area.Stormwater runoff currently discharges to the municipal and MnDOT storm drain systems and thento the Mississippi River untreated.


Based upon the draft design plans, the assumptions described above, and the stormwater report forthe Proposed Project, there will be an increase in impervious surface of approximately 1.3 acreswithin the 47.4-acre study area. As noted above, the small increase is based upon worst-case

assumptions for land cover types. Without mitigation, the additional impervious surface wouldincrease the volume of stormwater runoff, as there would be slightly less surface area for rainfall topercolate into the ground or be intercepted by vegetation. The increase in impervious surfaces isalso associated with increased peak discharges, as the runoff moves more quickly over paved orother hard surfaces than it does over grass or vegetated surfaces. Finally, increased runoff is oftenassociated with increase pollutant loading, depending on the land use of the contributing area, asthe runoff picks up particles within its flow path. Pollutants associated with runoff may includesediment, deicing and anti-icing chemicals, phosphorus and other nutrients because of fertilizers,hydrocarbons and other chemicals associated with automobiles, and litter, as well as other

pollutants.

3.4.2.3 Mitigation

Stormwater BMPs will be constructed to manage runoff from the Proposed Project. Potential BMPsbeing explored include underground perforated pipe galleries, hydrodynamic separators (also knownas water quality treatment manholes), tree trenches with Stockholm or similar soil, permeable

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Table 3.4-3. Required Water Quality Volume for 1.25-inch Rainfall

Storm DrainageBlock

Drainage Area

(acres)Runoff CurveNumber

Runoff Depth

(inches)

Water QualityVolume(cubic feet)

New Stadium Block 24.19 96 0.83 72,947

Downtown East Block 2.89 98 1.03 10,853

McClellan Block 2.89 98 1.03 10,853

McGrew EasterlyBlock

1.14 98 1.03 4,281

McGrew WesterlyBlock

1.57 98 1.03 5,896

Medical ExaminerBuilding

2.7 96 0.86 8,425

First Covenant ChurchPartial Block

1.2 98 1.03 4,487

East/West AlternatePlaza Configuration

5.81 98 1.03 21,819


With the No Action Alternative, there would be no change to the existing stormwater conditions andno consideration of BMPs to potentially improve stormwater runoff quantity and quality.

3.4.3 Receiving Water Bodies


Runoff from the Proposed Project drains into several municipal and MnDOT storm drain systems

before discharging into the Mississippi River. There are three separate outfalls to the river, two ofwhich are roughly in line with Chicago and 11

thAvenues, respectively, and the third being just

downstream of the I-35W Bridge. At these locations, the river is considered impaired for mercury,PCB, and fecal coliform, but it is not currently impaired for any parameters that would beexacerbated by construction of the Proposed Project. There are approximately 36,800 square milesthat drain into the Mississippi River upstream of the MnDOT storm tunnel outfall.

In the No Action Alternative, the current Metrodome field is at or below the groundwater elevation,and there is a permanent dewatering program in place. The groundwater is pumped and discharged

to the municipal sanitary sewer system. See Section 3.2 for more discussion on the existingMetrodome dewatering system and potential changes with the Proposed Project.


Given the large area that drains into the Mississippi River upstream of the Proposed Project,changes in peak discharge rates and runoff volumes are unlikely to have a significant effect on theflow rates and water levels within the river channel. However, potential impacts to the existing public

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determine if infiltration is possible at these locations. If, as the design advances, it is determined that

infiltration is not possible, other types of BMPs will be implemented. These may include bioretention,water quality manholes, tree trenches, and rainwater harvesting. These provide a varying degree ofstormwater management. Water quality manholes typically provide the lowest level of water qualitytreatment and do not provide volume retention or rate control.


Under the No Action Alternative there would be no change to the existing stormwater conditions andno consideration of BMPs to potentially improve stormwater runoff quantity and quality.

3.5 Water Quality: Wastewaters3.5.1 Wastewater Production and Associated Infrastructure


The City of Minneapolis owns and operates a public sanitary sewer system that provides service tothe new Stadium site. The City sanitary sewer network in the vicinity of the new Stadium siteconsists of an existing 54 inch sewer in Chicago Avenue and a 10 inch sewer in 11 th Avenue. SeeFigure 3.2-1 for existing utility information. These City sewers ultimately discharge into the

Metropolitan Council Environmental Services (MCES) interceptor sewer (1-MN-310) underWashington Avenue. The MCES interceptor has a capacity of 120 million gallons per day (mgd). In2009 the average daily flow was less than 40 mgd, and peak flow was less than 70 mgd.

The peak monthly wastewater generated by the Metrodome is three million gallons, based on theMSFC July 26, 2011, utility invoice. Annual wastewater generated by the Metrodome is 18 milliongallons, based on MSFC utility invoices from June 2011 through May 2012. Permanent dewateringof groundwater discharged to the sanitary sewer system is estimated by the MSFA to be anadditional 6 million gallons per year (see Section 3.2.2.2 for background).


The existing sanitary services that serve the Metrodome (off 5 th Street near the southeast portion ofthe Metrodome and off 11

thAvenue near the 5

thStreet/11

thAvenue intersection) are proposed to be

replaced by four new sanitary sewer connections: three new service connections (two 12 inch andone 10 inch) to the 54 inch sewer in Chicago Avenue and a new 10 inch connection to the 10 inchsewer in 11

thAvenue. All but the lower three levels of the new Stadium will flow by gravity to the

public sanitary sewer system. The lower three levels will be pumped into the public sanitary sewersystem.

The estimated peak sanitary sewer flow generated by the new Stadium is 3,000 gpm. Groundwaterdewatering discharge to the sanitary sewer system is estimated to be approximately 10 gpm, withlittle to no assumed difference between average discharge and peak discharge. A formal designsubmittal to the City of Minneapolis to determine the adequacy of the existing sanitary sewer systemhas not yet been made, and the City has not evaluated the capacity of their system.

The estimated peak monthly wastewater generated by the Proposed Projects new Stadium is

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The Proposed Project does not propose any on-site cooling towers, therefore no cooling tower blow

down will be generated.3.5.1.3 Mitigation

The MSFA will submit to the City of Minneapolis the sanitary sewer design. The City will thendetermine the adequacy of the existing sanitary sewer system to provide service to the newStadium. At this time, the MSFA has not identified any adverse effects associated with the ProposedProject on the capacity of the sanitary sewers. Therefore, no capacity mitigation measures areproposed.

The pedestrian tunnel referenced in the Draft EIS and previously proposed to connect the DowntownEast Parking Ramp to the Proposed Projects new Stadium is no longer under consideration. Theremoval of the pedestrian tunnel eliminates the previously identified conflict with the existing 54 inchsanitary sewer in Chicago Avenue/Kirby Puckett Lane.

The MSFA will submit to the Metropolitan Council the building plans for a Sewer Availability Charge(SAC) determination.


In the No Action Alternative the Metrodome would continue to function as it currently does. No

changes to the wastewater system would be required to continue to allow the Metrodome tofunction.

3.6 Site-Generated Waste

3.6.1 Background

3.6.1.1 Purpose

Existing environmental hazards posed by known or potential historical chemical releases are

addressed in Section 3.1. This section discusses potential environmental hazards associated withdemolition, construction, and operation activities within the Proposed Project area.

3.6.1.2 Organization

Within each subheading of Section 3.6.2 below, potential environmental hazards are subdivided intothe following categories:

Solid waste

Hazardous and regulated waste

3.6.2 Affected Environment

3.6.2.1 Solid Waste

Demolition Phase

The Proposed Project would involve complete demolition of the Metrodome including outlying

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It is estimated that the demolition would generate 80,000 tons of concrete debris, 2,600 tons

of separated steel, and 3,500 tons of miscellaneous demolition debris. It is estimated that a minimum of 75 percent of the solid wastes generated during demolition

would be recycled.

The remainder would be disposed at a state permitted landfill.

If the east-west orientation of the West Plaza is selected, the Proposed Project would alsoinvolve the demolition of the existing Star Tribune building on the block bounded by 4

thand 5

th

Streets, and Park and Portland Avenues (this is not included in the demolition debris andrecycling quantities above).

Under both plaza options, the existing building on the block bounded by 3rd

and 4th

Streets andPark and Chicago Avenues would be demolished to either accommodate plaza area(North/South Alternate Plaza Configuration) or a new parking structure (East/West AlternatePlaza Configuration) (this is not included in the demolition debris and recycling quantities above).

Construction Phase

Construction of the Proposed Projects new Stadium would generate construction-related wastematerials such as wood, packaging, excess materials, and other wastes, which would be either

recycled or disposed.Operation Phase

New Stadium operations would generate solid wastes such as food waste, packaging, beveragecontainers, paper, and other wastes, similar to the current Metrodome operation.

3.6.2.2 Hazardous and Regulated Waste

Demolition Phase

Hazardous waste is not anticipated to be generated during Proposed Project demolition, except asfollows:

Abatement and removal of regulated materials such as asbestos, lead-based paint, refrigerationequipment, lights, or other regulated wastes would be necessary if they are encountered duringdemolition.

As part of the Proposed Project, a pre-demolition survey would be completed on the existingstructures to determine the environmental hazards that could be encountered duringdemolition of the Metrodome and other properties defined under the Proposed Project, and

in removing and disposing of construction debris.Construction Phase

Site preparation for the Proposed Projects new Stadium would generate large quantities of earthmaterials (possibly 100,000 cubic yards or more) which would require proper management ordisposal. The environmental review has identified potential contamination in soil and water within theProposed Project area which would require advanced planning for proper management and

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per calendar month. These types ofde minimis uses do not typically lead to regulated waste

releases, discharges, or emissions. Two 660 gallon tanks are planned to be used for storage of diesel fuel for a standby electric

generator at the new Stadium. The Metrodome property is identified as a registeredUnderground Storage Tank facility with two 1,000 gallon tanks containing diesel fuel. Registeredstorage tanks are required to comply with federal and state regulations for installation andsystem monitoring.

3.6.3 Environmental Consequences

3.6.3.1 Solid WasteDemolition and Construction Phases

If solid waste recycling falls short of the 75 percent minimum projections, the Proposed Projectwould require disposal of solid waste materials at area landfills, thereby shortening the operating lifeof those landfill facilities. Handling, transportation, and disposal of solid wastes generated during thedemolition, site preparation, and construction of the Proposed Project would also result in transientenvironmental consequences in the areas of traffic; vehicle-related air emissions; odors, noise, anddust; surface water runoff; erosion and sedimentation; and visual impacts.

Operation Phase

The Proposed Projects new Stadium operations would generate solid wastes on an ongoing basis,similar to the Metrodome. A recycling center would be designed and constructed to encouragerecycling of metals, plastics, paper, and other materials generated by the ongoing operations of thenew Stadium. Wastes that cannot be recycled would be managed in accordance with federal, state,and local regulations.


Demolition Phase

If hazardous or regulated waste materials are discovered during demolition, those materials will behandled through established federal, state, and local statutes and regulations for abatement,mitigation, disposal, and recycling.

Construction Phase

Site preparation for the Proposed Project may result in the excavation of soils which arecontaminated and would require disposal at area landfills. The environmental consequences would

be identical to those stated above for solid waste.Operation Phase

Stadium operation would generate small quantities of hazardous wastes on an ongoing basis, similarto the Metrodome as described above in Section 3.6.2.2.

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3.6.4 Mitigation

3.6.4.1 Solid Waste

Demolition and Construction Phases

Mitigation measures for potential environmental hazards associated with solid waste generatedduring demolition and construction of the Proposed Project include the following:

Solid waste materials generated during demolition, site preparation, and construction must bedisposed in an MPCA-approved demolition landfill, or separated and recycled. Management ofsolid waste would be in accordance with state statutes and regulations.

To the extent feasible, demolition debris and salvaged materials would be segregated intoalternate waste streams for recycling/reuse. Separate dumpsters will be on site for variousmaterials.

Metals (iron, aluminum, steel, etc.) to be recycled; material will be placed in the appropriatedumpster for scrap metal recycling.

Aggregate (concrete, asphalt) to be recycled; material will either be placed in theappropriate dumpster for aggregate materials or taken directly off site.

Fiber (cardboard, paper) to be recycled; material will be placed in the appropriate dumpsterfor recycling.

Wood (mixed) to be recycled; material will be placed in the appropriate dumpster forrecycling.

Soils meeting MPCA unregulated fill criteria may also be reused.

Remaining material will be placed in a separate dumpster to be delivered for further wasteprocessing.

A plan for solid waste stream management would be prepared for the Proposed Project whichwould emphasize recycling/reuse of demolished materials to the extent feasible.

Operation Phase

For the Proposed Projects new Stadium operations phase, a recycling center would be establishedto encourage recycling of metals, plastics, paper, and other materials. Wastes that cannot berecycled would be managed in accordance with federal, state, and local regulations.


Demolition and Construction Phases

Mitigation measures for the identified potential environmental hazards associated with hazardousand regulated waste during demolition and construction include the following:

Any buildings to be removed for the Proposed Project will be inspected for hazardous andregulated materials and these materials will be abated or removed prior to demolition The

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Disposal of low-level-contaminated soils will occur at an acceptable regulated fill soil site or

MPCA-approved landfill. Disposal of higher-level-contaminated soils will occur at an MPCA-approved sanitary landfill.

Contaminated water recovered during construction (e.g., during dewatering) will be treatedby a qualified contractor to state standards, prior to a permitted discharge event.

If previous unknown regulated materials or wastes are discovered during construction, theContractor will notify the MSFA immediately. The MSFA will notify regulatory authorities asrequired and take appropriate actions to manage the regulated materials or wastes.

It is expected that temporary aboveground storage tanks (ASTs) will be used on-site to storepetroleum products and other materials during construction.

Any storage tanks will be protected with secondary containment and designed to meet allregulatory requirements including spill and overfill protection, leak monitoring, corrosionprotection, etc.

These tanks will be monitored on a regular basis, and spill containment will be incorporatedinto the design of the tanks.

Spill containment and cleanup materials will be stored on-site to contain and cleanup smallspills.

If abandoned underground storage tanks (USTs) or other storage structures are encounteredduring site preparation activities, they and their contents will be assessed, removed, anddisposed according to federal, state, and local statutes and regulations.

A management plan will be developed for the Proposed Project to minimize impacts to soils andgroundwater in the event a release of hazardous substances occurs during construction. If arelease were to occur, the MSFA will comply with federal and state release reporting statutesand regulations.

Operation Phase

To the extent feasible, alternative non-hazardous materials would be used for Proposed Projectfacility maintenance to minimize generation of hazardous and regulated wastes resulting from facilityoperations.

3.6.5 No Action Alternative

Under the No Action Alternative additional solid waste would not be generated for disposal. The

mitigation measures to manage solid, hazardous, and regulated waste would continue for theMetrodome as occurs today.

Given the limited scope of previous environmental assessments and building pre-demolitioninspections in the Proposed Project area, the degree of inherent risk from land use environmentalhazards is not certain. The potential would remain for disturbance within the Proposed Project areathat could affect human health and the environment in the area and potentially off-site.

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non-event scenarios. In addition, a freeway operations analysis was completed to determine the

impacts that event traffic would have on the regional freeway network. For the purposes of thissection, the terms event or NFL event are intended to mean any capacity event at the newStadium.

For a complete technical analysis of the traffic issues associated with this Proposed Project, pleaserefer to the Minnesota Multi-Purpose Stadium Traffic and Parking Technical Memorandum (July2013) in Appendix B.

3.7.1.1 Analysis Scenarios

Several different scenarios were analyzed to identify the potential impacts of the Proposed Projectcompared to the Metrodome use. Those scenarios are:

Weekday AM peak hour (non-event)

Weekday PM peak hour (non-event)

Weekend (Sunday) event arrival

Weekend (Sunday) event departure

Weekday (Monday or Thursday evening) event arrival coinciding with the PM peak hour

Weekend (Sunday) event arrival with Park Avenue/Portland Avenue temporary closures between4

thStreet and 5

thStreet

Background (non-event) traffic levels for a 12:00 PM game start compared with a 3:00 PM or 6:00PM game start were similar; therefore, only one weekend event arrival scenario was analyzed.Similarly, background traffic volumes for both weekend and weekday event departures were similar,so only one departure scenario was analyzed. Traffic operations were analyzed for one hour of thepre-event arrival period and one hour of the post-event departure period.

Each of the above event scenarios was analyzed for the No Action (existing Metrodome) andProposed Project conditions in year 2017 (one year after opening of the new Stadium) and 2030(forecast year). In addition, each Proposed Project scenario was analyzed for two possible parkingplans, for a total of 32 separate scenarios. The parking plans are discussed further in Section3.7.1.4.

3.7.1.2 Assumptions and Methodology

The traffic analysis in the Proposed Project study area is generally bounded by Washington Avenueto the north, the I-35W corridor on the east side of downtown Minneapolis, 10

thStreet to the south,

and the I-394 corridor on the west side of downtown Minneapolis. The specific intersectionsanalyzed for each scenario are discussed within the following sections. Most of the intersectionsincluded in the analysis are currently signalized and are assumed to remain signalized in the futureconditions.

In addition to the Proposed Project, several independent infrastructure improvements are plannedwithin the traffic analysis study area for the Proposed Project.

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The Central Corridor LRT line will share the existing Hiawatha LRT alignment within the study

area, using the same stations. The Central Corridor LRT project is being led by Metro Transitand is planned to open in 2014.

TheAccess Minneapolis Ten-Year Transportation Action Plan identifies several other potential futurerecommended roadway improvements near the study area that have not been included in theanalysis of the Proposed Project because they are not currently programmed or funded. Thepotential improvements as identified in the plan are as follows:

Two-way operations on Park Avenue South and Portland Avenue South

Two-way operations on 9th Street South and 10th Street South, east of 5th Avenue South

New exit ramp from westbound I-94 to 7th

Street South

Changes to Washington Avenue South and 3rd Street South interchanges at I-35W

The assumptions for each of the analysis scenarios are summarized in Tables 3.7-1 andTable 3.7-2 below.

Table 3.7-1. Non-Event Analysis Assumptions

Analysis Parameter Assumption

Background GrowthRate

0.5% per year

Traffic VolumesExisting peak hour turning movement volumes, counted for alldowntown Minneapolis intersections in 2011 as part of thedowntown signal retiming project

Roadway Network5 Street South closed between 11 Avenue South and eitherChicago Avenue or Park Avenue

All other roadways remain open

Signal TimingAM peak proposed AM peak planPM peak proposed PM peak plan

Table 3.7-2. Event Analysis Assumptions


Stadium Capacity65,000 attendees No Action73,000 attendees Build

Background GrowthRate

0.5% per year

Background Traffic

Weekday event arrival 100% of PM peak hourWeekend event arrival 25% of AM peak hourWeekend event departure 25% of PM peak hourExisting peak hour turning movement volumes were based onturning movement counts conducted for all downtownMinneapolis intersections in 2011 as part of the downtown signal

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Roadway Network

4th

Street South closed between Park Avenue and NormMcGrew PlaceNorm McGrew Place closed between 3

rdStreet South and 4

th

Street SouthChicago Avenue closed between 6

thStreet South and 3

rdStreet

South5th Street South closed between 11th Avenue South and Park

AvenueAll other roadways remain open

Event Mode Split

500 attendees No Action walk/bike1,000 attendees Proposed Project walk/bike500 attendees Metro Transit regular bus routes1,850 attendees Metro Transit express bus2,000 attendees charter bus11,810 attendees No Action LRT and Commuter Rail (2017)16,410 attendees Proposed Project LRT and Commuter Rail(2017)26,410 attendees No Action LRT and Commuter Rail (2030)

31,010 attendees Proposed Project LRT and Commuter Rail(2030)

Event AutoOccupancy

2.75

Event Peak Arrival

PM peak hour (4:30-5:30 PM) coincides with peak event arrivalfor 7:00 PM weekday game start

10:30-11:30 AM for a 12:00 PM weekend game start50% attendees arrive in peak hour

Event Peak Departure3:00-4:00 PM for a 3:00 PM weekend game end70% attendees depart in peak hour

Event Signal TimingWeekday event arrival proposed PM peak planWeekend event arrival proposed AM peak planWeekend event departure proposed PM peak plan

The number of permanent seats in the Proposed Projects new Stadium is planned to beapproximately 65,500 but with the ability to expand to 73,000 seats through the use of temporaryseating inside the new Stadium. Therefore all scenarios were analyzed for a capacity event of73,000 attendees as a worst case scenario.

The number of attendees using transit to travel to and from NFL events was based on ridershipforecasts provided by Metro Transit in December 2012. The 2017 ridership forecasts include theHiawatha LRT, Central Corridor LRT, and Northstar commuter rail lines. The 2030 ridershipforecasts also include the Southwest LRT and Bottineau LRT lines.

The trip distribution and routes of vehicular traffic arriving to and departing from an NFL event were

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effectively. Operations of LOS D or better are generally considered acceptable to drivers under peak

conditions.3.7.1.3 Local Roadway Network Weekday Non-Event Analysis

The analysis of the weekday peak hour non-event conditions was used to identify the expectedimpacts of the closure of 5

thStreet between 11

thAvenue and either Chicago Avenue or Park

Avenue. This segment of 5th

Street currently carries approximately 2,955 vehicles per day (2010count, according to the City of Minneapolis Transportation Data Management System) and thesurrounding transportation network will need to absorb this traffic. All analysis was completed for2017, one year after Stadium opening, and the future year 2030. The intersections included in the

analysis were discussed with the City of Minneapolis and were selected based on the availablealternate routes for the 5

thStreet traffic as well as known driver behavior and traffic patterns. The

intersections included in the weekday non-event analysis are shown in Figure 3.7-2.

Sensitivity testing was performed using the Metropolitan Council regional travel demand model todetermine if the permanent closure of this segment of 5th Street would be expected to result inchanges to the traffic volumes on the regional transportation network. This could occur if, forexample, a driver on westbound I-94 decided to use the 11

thStreet South exit rather than the 5

th

Street South exit into downtown Minneapolis. The regional model showed that with 5th

Street closed,the traffic volume change on any freeway mainline segment or ramp was less than 500 vehicles perday. The existing daily volume on the 11th Street South exit ramp is approximately 15,000 vehiclesper day, and therefore even 500 vehicles per day would represent a very minor change that wouldlikely not be distinguishable from the daily variability in volume. Therefore, the 5

thStreet closure

would be expected to have very little, if any, impact on the regional transportation network accordingto the model, and no further analysis of the freeway system was completed for this scenario.

Two roadway network options were analyzed for the 5th

Street closure (see Figures 3.7-3 and3.7-4):

Option 1: 5th

Street closed from 11th

Avenue S to Chicago Avenue, with traffic rerouted toWashington Avenue and 7th Street S

Option 2A: 5th


Avenue S to Chicago Avenue, with traffic rerouted onto anew westbound lane (contraflow lane) on 6 th Street, which is currently a one-way eastboundroadway

Option 2B: 5th


Avenue S to Park Avenue, with traffic rerouted onto a newwestbound lane (contraflow lane) on 6

thStreet, which is currently a one-way eastbound

roadway

Under all options, the existing median separating 5 th Street and 6th Street was assumed to beremoved. The 5

thStreet/11

thAvenue signalized intersection was assumed to be reconfigured and

realigned to be a perpendicular intersection with three westbound lanes (one right-turn and two left-turn lanes) and the traffic signal would need to be reconstructed at the new location. Therealignment of the intersection provides improved approach geometry on 5

thStreet as well as

providing greater queuing distance on 11th Avenue between 5th Street and 6th Street. The segment ofth th

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The assumptions regarding traffic rerouting and geometrics are described in the followingparagraphs.

Option 1 Assumptions

For the purposes of the analysis, all traffic on 5th

Street was assumed to use either 7th

Street orWashington Avenue. This is a worst case scenario since drivers could choose other routes based ontheir ultimate destination. Based on existing peak hour turning movement volumes along 5

thStreet,

in the AM peak approximately 50 percent of traffic on 5 th Street was assumed to reroute to 7 th Streetand 50 percent was assumed to reroute to Washington Avenue, both via 11

thAvenue. In the PM

peak approximately 60 percent of traffic on 5th

Street was assumed to reroute to 7th

Street and 40

percent was assumed to reroute to Washington Avenue, both via 11

th

Avenue. Traffic diverted to 7thStreet and Washington Avenue was assumed to turn at the intermediate intersections along theroute, similar to the existing travel patterns on 5

thStreet. The remaining rerouted traffic on 7

thStreet

was assumed to use Park Avenue to return to 5 th Street, and traffic diverted to Washington Avenuewas assumed to use Portland Avenue to return to 5

thStreet. Since it is likely that not all traffic has

destinations on 5th Street and would choose to go back to the 5 th Street corridor, this is aconservative assumption that represents the worst case.

To accommodate the increased westbound left-turn volume on 5th

Street and southbound volume on11

thAvenue, an additional southbound lane was assumed that would operate as a through lane at

the 6th Street intersection and would end as a right-turn only lane at 7th Street. The additionalsouthbound lane could be accommodated within the existing roadway cross-section (i.e., curbsremain in place) but would likely result in the loss of on-street parking. The design would need toaddress the expected increase in conflicts between southbound right-turn vehicles and the existingsouthbound bicycle lane. The improved geometrics for Option 1 are shown in Figure 3.7-3.

In addition to the 5th

Street/11th

Avenue intersection, the traffic signal at 5th

Street/Chicago Avenuewould need to be modified because of the removal of the east leg of the intersection.

Option 2 Assumptions

In the Option 2 scenarios, all traffic on 5th Street was assumed to use the 6 th Street contraflow lane,via 11

thAvenue, with the exception of traffic destined for southbound Chicago Avenue, which was

assumed to use 7th

Street. This assumption was made because of the difficulty of making awestbound left-turn movement from the 6th Street contraflow lane onto Chicago Avenue, whichwould cross three lanes of opposing eastbound traffic. This movement would likely experiencedelays because of the lack of gaps in eastbound traffic. If either Option 2A or 2B is chosen, left-turnmovements from the contraflow lane could have potential issues with delay and queuing in the singlewestbound lane. This is a potential issue that would need to be addressed through a combination of

roadway, signal, and stadium design measures. Traffic diverted from 5th

Street to 6th

Street wasassumed to use Chicago Avenue or Park Avenue to return to 5

thStreet.

To accommodate the increased westbound left-turn volume on 5th

Street at 11th

Avenue and thesouthbound right-turn volume on 11

thAvenue at 6

thStreet, an additional southbound lane was

assumed to be added on 11th

Avenue from 5th

Street to 6th

Street, which would end as a right-turnonly lane at 6th Street. The additional southbound lane could be accommodated within the existing

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Parking lane or bump-outs

Three eastbound through lanes

One westbound through lane

Pedestrian zone/sidewalk

Security wall/boulevard

Two-way bicycle facility (on the new Stadium site)

West of Chicago Avenue, the westbound bicycle movement is planned to be accommodated along

the existing 5

th

Street right-of-way. This right-of-way is not planned to be vacated but could beoperated as either a roadway, a local access route, or as part of the plaza. The design of the 6th

Street section from Chicago Avenue to Park Avenue is still being discussed by the MSFA and City ofMinneapolis but is expected to include:

Pedestrian zone/sidewalk

Parking lane or bump-outs

Three eastbound through lanes

One westbound through lane (ending as a right-turn only lane at Park Avenue) Pedestrian zone/sidewalk

The location and design of the eastbound bicycle facility on 6th

Street from Park Avenue to ChicagoAvenue is one key issue left to be resolved. The options being considered include an on-street lanelocated between the eastbound and westbound vehicle lanes or an off-street facility on the northside of the roadway, north of the pedestrian walkway. The off-street option would likely requireacquisition or easement of Hennepin County property. This is discussed further in the BicycleFacilities section (Section 3.7.3.2). Several issues have been identified that factor into the selection

of one of these alternatives: If the eastbound bicycle facility between Park Avenue and Chicago Avenue is located on-street,

conflicts would be created by eastbound bicycles at the 6th

Street/Chicago Avenue intersectioncrossing the westbound vehicle lane and pedestrian walkway to reach the two-way bicyclefacility. These conflicts would also exist if Option 2A were chosen.

If the eastbound bicycle facility between Park Avenue and Chicago Avenue is located off-street,conflicts would be created by eastbound bicycles at the 6

thStreet/Park Avenue intersection

crossing the westbound vehicle lane and pedestrian walkway.

In addition to the 5th Street/11th Avenue intersection, the traffic signal at 6th Street/11th Avenue wouldneed to be modified to accommodate the beginning of the westbound traffic lane on 6

thStreet.

Option 2A would also require modifications to the traffic signals at 6 th Street/Chicago Avenue, andOption 2B would require modifications to the signals at 6

thStreet/Chicago Avenue and 6

th

Street/Park Avenue.

Th i d ki l ithi th P d P j t t d t

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As shown by the intersection LOS results, all the options have one or more intersections with pooroperations. Under Option 1, the Washington Avenue/11

thAvenue intersection is expected to operate

over capacity in the AM and PM peak hours, primarily because of the increase in northbound left-turn traffic from 5

thStreet. The intersection would already be expected to operate at LOS F in the No

Action PM Peak hour conditions, with 5th

Street open to traffic, but the intersection delays atWashington Avenue/11th Avenue and 5th Street/11th Avenue would be expected to increasesignificantly in the AM peak hour and further increase in the PM peak hour as a result of the 5

th

Street closure.

Under Options 2A and 2B, the 5th

Street/11th

Avenue intersection is expected to operate overcapacity in the AM peak hour and the Washington Avenue/11

thAvenue intersection is expected to

operate over capacity in the PM peak hour. However, both intersections were also shown to operatepoorly in the No Action peak hour conditions, and the impacts of the 5

thStreet closure on the

roadway network, particularly the 5th

Street/11th

Avenue and Washington Avenue/11th

Avenueintersections, are substantially mitigated in this option by the addition of the westbound contraflowlane on 6

thStreet.

The need for a northbound left-turn lane on 11th

Avenue S at 6th

Street was evaluated. The expectedlow volume of vehicles making this movement and the adequate number of gaps in southboundthrough traffic in the modeling indicated that the left-turn lane would not be needed to maintain traffic

flow on 11

th

Avenue S during peak hours.Table 3.7-3. 2017 Weekday Non-Event Analysis Results AM Peak

Intersection

Overall Intersection Level of Service

No Action

Option 1 Reroute to 7

thSt

and WashingtonAve

Option 2A Contraflow toChicago Ave

Option 2B Contraflowto Park Ave

Washington Ave S/11

th

Ave S DF

D DWashington Ave S/ChicagoAve S

C or better C or better C or better C or better

Washington Ave S/Park Ave S C or better C or better C or better C or better

Washington Ave S/PortlandAve S


5th

St S/11th

Ave S F F F F

5 St S/Chicago Ave S C or better C or better C or better C or better 5

thSt S/Park Ave S C or better C or better C or better C or better

5th

St S/Portland Ave S C or better C or better C or better C or better 6

thSt S/11

thAve S C or better C or better C or better C or better

6 St S/Chicago Ave S C or better C or better D C or better

6th

St S/Park Ave S C or better C or better C or better C or better 7 St S/11 Ave S C or better C or better C or better C or better

7 St S/Chicago Ave S C or better D C or better C or better

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Table 3.7-4. 2017 Weekday Non-Event Analysis Results PM Peak

Intersection


No Action


thSt

and WashingtonAve


Option 2B Contraflow toPark Ave

Washington AveS/11

thAve S

F F F F

Washington Ave

S/Chicago Ave SC or better C or better C or better C or better

Washington AveS/Park Ave S


Washington AveS/Portland Ave S


5th

St S/11th

Ave S C or better C or better C or better C or better

5 St S/ChicagoAve S


5th

St S/Park Ave S C or better D C or better C or better

5 St S/PortlandAve S


6 St S/11 Ave S C or better C or better C or better C or better

6th

St S/ChicagoAve S


6th

St S/Park Ave S C or better C or better C or better C or better 7

thSt S/11


7 St S/Chicago

Ave S


7th


thSt S/Portland

Ave SC or better C or better C or better C or better

Total Number of Intersections Operating at Each Level of Service

Level of Service Cor better

14 13 14 14

Level of Service D 0 1 0 0Level of Service E 0 0 0 0

Level of Service F 1 1 1 1

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Table 3.7-5. 2030 Weekday Non-Event Analysis Results AM Peak

Intersection


No Action


thSt

and WashingtonAve



Washington AveS/11

thAve S

F F E E

Washington Ave






5th

St S/11th

Ave S F F F F

5 St S/ChicagoAve S


5th

St S/Park Ave S C or better C or better C or better C or better


C or better D C or better C or better


6th

St S/ChicagoAve S

C or better C or better E C or better

6th


thSt S/11


7 St S/ChicagoAve S

C or better D C or better C or better

7th St S/Park Ave S C or better C or better C or better C or better 7

thSt S/Portland




13 11 12 13


Level of Service F 2 2 1 1

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Table 3.7-6. 2030 Weekday Non-Event Analysis Results PM Peak

Intersection


No Action


thSt

and WashingtonAve



Washington AveS/11

thAve S

F F F F

Washington Ave






5th

St S/11th

Ave S C or better D D D

5 St S/ChicagoAve S


5th

St S/Park Ave S D E D D




6th

St S/ChicagoAve S

C or better C or better D D

6th


thSt S/11


7 St S/ChicagoAve S


7th St S/Park Ave S C or better C or better C or better C or better 7

thSt S/Portland




13 12 11 11


Level of Service F 1 1 1 1Mitigation Measures

The following summarizes the impacts expected as a result of the permanent closure of 5th

Streetnext to the new Stadium, as well as recommended mitigation measures to improve traffic operations.

Option 1

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including the existing bike lane, and removal of some of the existing metered on-streetparking between 5

thStreet and 7

thStreet. The additional lane would end as a right-turn only

lane at 7th Street. Conflicts between the southbound bicycle lane and the southbound right-turn traffic would need to be addressed as the design plans advance.

Capacity improvements were analyzed at the Washington Avenue/11th

Avenue intersectionto better accommodate the increased northbound left-turn traffic. These improvementsincluded adding a second northbound left-turn lane or modifying the signal phasing to splitphased for northbound/southbound. While these changes increased the capacity of thenorthbound movements, they had significant negative operational impacts on thesouthbound 11

thAvenue movements and on the overall intersection delay. Therefore,

capacity improvements are not recommended at the Washington Avenue/11th

Avenueintersection.

Modifications to the existing traffic signals at 5th Street/11th Avenue and 5th Street/ChicagoAvenue will be needed to accommodate the changed intersection geometrics and traffic flowas a result of the 5th Street closure.

Conflicts because of eastbound bicycle traffic on 6th

Street crossing the pedestrian walkwayon the north side of 6

thStreet to reach the off-street two-way bicycle facility on the Stadium

site would need to be addressed as the design plans advance.

Option 2 A/B

Additional capacity is needed on 11th

Avenue from 5th

Street to 6th

Street to accommodatethe rerouted 5

thStreet traffic. This would require restriping of the existing roadway section,

including the existing bike lane. The additional lane would end as a right-turn only lane at 6th

Street. The additional southbound lane is not expected to impact any on-street parking.Conflicts between the southbound bicycle lane and the southbound right-turn traffic wouldneed to be addressed as the design plans advance.

The existing roadway section on 6

th

Street from 11

th

Avenue to either Chicago Avenue orPark Avenue would need to be restriped to accommodate the proposed parking, vehicle,sidewalk, and bicycle lane configuration. Some loss of on-street metered parking spacesmay occur.

Modifications to the existing traffic signals at 5th

Street/11th

Avenue, 6th

Street/11th

Avenue,6

thStreet/Chicago Avenue, 6

thStreet/Park Avenue (Option 2B only), and 5

thStreet/Chicago

Avenue would be needed to accommodate the changed geometrics and traffic flow as aresult of the 5

thStreet closure.

Conflicts because of eastbound bicycle traffic on 6th

Street crossing the westbound trafficand pedestrian walkway to reach the off-street two-way bicycle facility on the Stadium sitewould need to be addressed as the design plans advance.

Geometric design and operational considerations for left-turn movements from thewestbound 6

thStreet contraflow lane would need to be addressed because of the potential

for delay and queuing of westbound traffic during peak traffic periods.

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3.7.1.4 Local Roadway Network Event Analysis

The event analysis was used to identify the impacts of the Proposed Project on the local roadwaynetwork, compared with the impacts of the existing Metrodome use. Field observations conducted infall 2012 during a weekday and weekend NFL event provided the following information:

Temporary road closures are currently used from approximately two hours before game startuntil about one hour after game end on the following segments:

5th

Street from 11th

Avenue to Park Avenue

4th

Street from Park Avenue to Norm McGrew Place

Chicago Avenue from 3rd Street to 6th Street

Norm McGrew Place from 3rd

Street to 4th

Street

Several of the road closures listed are soft closures, with access still allowed to parking lotsand properties located on these blocks, including:

Access provided to Hennepin County facilities on Chicago Avenue between 5th

Street Southand 6

thStreet South

Access provided to parking lot driveways on Norm McGrew Place between 3rd

Street S and

4th Street S

The temporary road closures are accomplished using City of Minneapolis dump trucks, trafficcontrol officers, and movable barricades.

Traffic control officers are currently used at the following intersections:

4th

Street/Chicago Avenue (LRT crossing)

4th

Street/Park Avenue

5th

Street/11th

Avenue 5

thStreet/Park Avenue

6th

Street/11th

Avenue

6th

Street/Chicago Avenue

Event arrival was generally uncongested.

Pedestrian flows are heaviest along 4th

Street, 6th

Street, and 11th

Avenue. Washington Avenue,3

rdStreet, and 5

thStreet also appeared to be secondary routes. With 4

thStreet closed east of

Park Avenue, pedestrians use the roadway to walk towards the Metrodome. Pedestrian flowsappeared to be highest in the hour immediately before game start and 15 minutes immediatelyafter game end.

The large volumes of pedestrian crossings at key intersections impacted traffic turningmovements, includin

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