chapter 2 - summary and comparison of alternativescommunity and environment. this chapter also gives...

1 What is the purpose of this chapter?

The primary function of an environmental impactstatement (EIS) is to help the lead agencies (the Cityof Seattle, WSDOT, and FHWA) make informedchoices between reasonable alternatives. This chapterbrings together key information from other chaptersin this Draft EIS to show how the alternatives com-pare to each other and what tradeoffs will have to bemade. Key tradeoffs are highlighted in special boxes.As the lead agencies consider these choices, it isimportant that you, the public, see the same informa-tion and understand how the project could affect ourcommunity and environment.

This chapter also gives a brief summary of the projectpurpose, alternatives being considered, and areas ofcontroversy. This chapter does not give much detailon any particular subject. That's what the rest of theDraft EIS and supporting studies are for. However,this is the only chapter that compares the alternativesto each other. All the information contained in thischapter can also be found elsewhere in this Draft EIS.

2 Where is the project located?

The Alaskan Way Viaduct and Seawall are located indowntown Seattle, Washington. The project area is 4miles long, extending from approximately S.Spokane Street in the south to Ward Street north ofthe Battery Street Tunnel. The Alaskan Way Seawallis within these boundaries, extending from S.Washington Street to Bay Street.

Because the project area is large, it has been dividedinto four sections for discussion in this Draft EIS, asshown in Exhibit 2-1:

• South - S. Spokane Street to S. King Street.

• Central - S. King Street to the Battery StreetTunnel. The central section includes the seawall,Alaskan Way surface street, and the viaduct struc-ture curving up to the Battery Street Tunnel.

• North Waterfront - Pike Street to Broad Street.The north waterfront section includes theAlaskan Way surface street and seawall from thepoint where the viaduct begins to veer off to theBattery Street Tunnel around Pike Street.

• North - Battery Street Tunnel to Ward Street.

3 What alternatives are evaluated in this Draft EIS?

There are five alternatives evaluated in this Draft EISin addition to the No Build Alternative. The fivealternatives all rebuild or replace the existing AlaskanWay Viaduct and the Alaskan Way Seawall. Eachalternative is named according to the type of roadwayproposed through the central section. Improvementsin the south and north sections can mostly be mixedand matched with the central section. A preferredalternative has not been identified.

The alternatives are shown in Exhibit 2-2 anddescribed on the next page:

Alaskan Way Viaduct & Seawall Replacement Project Draft Environmental Impact Statement 3

CHAPTER 2 - SUMMARY AND COMPARISON OF ALTERNATIVES

Exhibit 2-1

Project Purpose

The purpose of the proposed action is to provide a trans-

portation facility and seawall with improved earthquake

resistance that maintains or improves mobility and acces-

sibility for people and goods along the existing Alaskan

Way Viaduct Corridor.

4 Summary and Comparison

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CENTRALS. King - Battery Street Tunnel

N. WATERFRONTPike - Broad

NORTHBattery St. Tunnel - Ward

Seawall

SR 99 Corridor

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The AlternativesRebuild Aerial Tunnel Bypass Tunnel Surface

Exhibit 2-2

Rebuild - Replace the viaduct in its existing locationwith a structure similar to what is there now, includ-ing ramps into downtown at Seneca and ColumbiaStreets. In the south, replace the viaduct with an at-grade roadway and an interchange connecting to S.Atlantic Street and S. Royal Brougham Way (alsocalled SR 519). No improvements would be made tothe Battery Street Tunnel, and nothing would bechanged in the north from the Battery Street Tunnelto Ward Street.

Aerial - Replace the viaduct in its existing locationwith an aerial structure, including new ramps intodowntown at Seneca and Columbia Streets. The aeri-al structure would be about 20 feet wider than theexisting viaduct, which allows for larger lanes andshoulders. In the south, the viaduct would bereplaced with an aerial structure (similar to what isthere now, but also 20 feet wider). An interchangewould connect the aerial SR 99 structure to SR 519at-grade. The Battery Street Tunnel would beimproved by adding emergency exits, upgrading theelectrical system, building a fire suppression system,and improving the ventilation system. Mercer Streetwould be widened from four lanes to a seven-lane,two-way roadway between Fifth and Ninth Avenues.Broad Street would be closed between Fifth andNinth Avenues, and the ramps at Broad Street andMercer Street would be closed. A new two-lane bridgewould be built over Aurora Avenue/SR 99 at ThomasStreet.

Tunnel - Replace the viaduct with a tunnel in the cen-tral section. The tunnel would have three lanes ineach direction. It would also have emergency exits, afire suppression system, and a ventilation system.Ramps into downtown would be provided at S. KingStreet. Additional ramps would be built connectingto the Alaskan Way surface street near Stewart Street.An aerial structure would connect the tunnel fromthe waterfront to the Battery Street Tunnel. In thesouth, the viaduct would be replaced with an at-graderoadway and interchange, similar to what wasdescribed above for the Rebuild Alternative. In thenorth, Battery Street Tunnel, Mercer Street, andThomas Street would be improved as described for

the Aerial Alternative. Also, Broad Street and theBroad and Mercer ramps would be closed asdescribed for the Aerial Alternative.

Bypass Tunnel - Replace the viaduct with a tunnel inthe central section. The tunnel would have two lanesin each direction. It would also have emergency exits,a fire suppression system, and a ventilation system.Ramps into downtown would be provided at S. King

Street. Since the Bypass Tunnel Alternative has fewerlanes on SR 99 than the Rebuild, Aerial, or TunnelAlternatives, the Alaskan Way surface street would beexpanded from four lanes to six lanes through down-town. In the south, the viaduct would be replacedwith an at-grade roadway and interchange asdescribed for the Rebuild and Tunnel Alternatives.In the north, the Battery Street Tunnel, Mercer

Or


Exhibit 2-3

Street, and Thomas Street would be improved asdescribed for the Aerial and Tunnel Alternatives.Also, Broad Street and the Broad and Mercer rampswould be closed as described for the Aerial andTunnel Alternatives.

Surface - Replace the viaduct with an at-grade road-way. The roadway would have three lanes in eachdirection with turn pockets between Yesler Way andPike Street. North of Pike Street, the Alaskan Waysurface street would have two lanes in each direction.Two new overpasses would be built in the central sec-tion. One would be for ferry traffic only. It would belocated along Columbia Street, connecting theColman Dock Ferry Terminal to First Avenue. A sec-ond overpass would be aligned along Seneca Streetconnecting First Avenue to Alaskan Way. Also, in thePioneer Square area, the number of lanes of trafficon First Avenue would be increased from one lane ineach direction to two lanes in each direction.

In the south, between S. Royal Brougham Way andYesler Way, SR 99 would have four lanes in eachdirection. An interchange would connect SR 99 andSR 519, similar to what was described for the Rebuild,Tunnel, and Bypass Tunnel Alternatives. In thenorth, the Battery Street Tunnel, Mercer Street, andThomas Street would be improved as described forthe Aerial, Tunnel, and Bypass Tunnel Alternatives.Also, Broad Street and the Broad and Mercer rampswould be closed as described for the Aerial, Tunnel,and Bypass Tunnel Alternatives.

Options - In addition to the alternatives describedabove, several options can be mixed and matchedwith the proposed alternatives. Exhibit 2-3 shows theproposed alternatives and options. Both alternativesand options are evaluated in this Draft EIS; however,this chapter focuses more on the alternatives. Formore information on the possible options, please seeChapters 5 through 9.

4 How would the alternatives replace the seawall?

All of the alternatives will replace the seawall. Theproposed seawall replacement structures are shown inExhibit 2-4. For the Rebuild, Aerial, and Surface Exhibit 2-4

What is the No Build Alternative andwhy is it evaluated?

The No Build Alternative (often called "no action") is

required by state and federal regulations to be evaluated

in an EIS. The No Build Alternative provides a baseline for

comparison of the other alternatives.

For this project, three No Build scenarios were evaluated:

Scenario 1

Continued operation of the viaduct and seawall with con-

tinued maintenance.

Scenario 2

Sudden unplanned loss of the viaduct and/or seawall but

without major collapse or injury.

Scenario 3

Catastrophic failure and collapse of the viaduct and/or

seawall.

For more detailed information on the No Build

Alternative, please review the technical memoranda and

discipline reports located in the appendices.

Preferred Alternative

The preferred alternative will be based on the alternatives

and options described in this Draft EIS. The preferred

alternative could combine and refine ideas from the cur-

rent alternatives and possibly the options. The preferred

alternative will also have more details on how it could be

built and refinements on how the street landscaping and

amenities could be designed.


Alternatives, the seawall will be replaced by rebuild-ing it, which involves strengthening soils and addingdrilled shafts behind the existing seawall.

The Tunnel and Bypass Tunnel Alternatives willreplace the seawall with the outer wall of the tunnel.In most areas, the new tunnel wall would be builtbehind the existing seawall. There is a small sectionnear S. Washington Street where the tunnel wall willextend out into Elliott Bay. In areas where a tunnel isnot proposed, the seawall would be rebuilt.

Instead of rebuilding the seawall, it is possible toreplace the seawall with the Seawall Frame option asdescribed in Chapter 6.

5 Are the estimated1 costs comparable between thealternatives?

The Tunnel Alternative is the most expensive ($3.8 to$4.1 billion) and the Surface Alternative is the leastexpensive ($2.5 to $2.8 billion) as shown in Exhibit 2-5. The Rebuild and Aerial Alternatives cost the same($3.2 to $3.5 billion), and the Bypass TunnelAlternative is close ($3.1 to 3.4 billion). These costsinclude inflation and take possible construction risksinto account. The range of cost for each alternative isbecause of uncertainties inherent in any large proj-ect.

6 How do the views and noise compare along thecentral waterfront?

The Rebuild and Aerial Alternatives are most similarto the existing viaduct in the central waterfront area.They give drivers and passengers similar views andkeep the same kinds of noise and visual barriersalong the central waterfront. The Aerial Alternative iswider and a bit taller than the Rebuild Alternative,while the Rebuild Alternative's support columns arecloser together.

The Tunnel Alternative puts the most traffic under-ground and creates the most open space on the cen-tral waterfront. Drivers and passengers would nothave views of downtown, Elliott Bay, and the OlympicMountains like they do today; however, new viewsfrom downtown and along the waterfront will be cre-

ated. The Tunnel Alternative reduces noise along thecentral waterfront more than any of the other alternatives.

The Bypass Tunnel Alternative puts through trafficunderground but also adds two lanes and more traf-fic to the central waterfront. It still creates new openspace and improves views. Noise would be reducedcompared to existing conditions, but the reduction isless than what would be expected with the TunnelAlternative.

The Surface Alternative creates the same new openspace and views as the Bypass Tunnel Alternative butputs more traffic on the central waterfront orthrough downtown. Compared to today, noise islower next to the piers, but higher on the city side.

7 How do the alternatives compare south of S. King Street?

Near the south end of the project area, S. AtlanticStreet and S. Royal Brougham Way provide impor-tant connections to I-90 and arterials like FirstAvenue and Fourth Avenue. This connection is calledSR 519, and it's an important way for traffic to get toand from the stadiums, south downtown, and centraldowntown. The connection from SR 99 to SR 519 atS. Atlantic Street and S. Royal Brougham Way couldbe above, below, or at the same level as SR 99.

If the connection is above SR 99, through traffic willbe on the surface and ramps will lead up to traffic sig-nals. Going up ramps and over SR 99 could be diffi-cult for trucks entering or leaving Terminal 46. If SR99 is built at-grade, the Whatcom Rail Yard and atrack needed for the rail yards in this area would berelocated. If the SR 519 interchange is elevated andrailroad tracks are relocated, vehicle and rail opera-tions would be separated. Currently these operationsare not separated, and there are times when trainsblock the roadway at S. Atlantic Street.

This roadway layout can be flipped, and SR 99 wouldbe elevated with ramps leading down to traffic signalson S. Atlantic Street and S. Royal Brougham Way.With SR 99 elevated, connections to the stadiums and

Pioneer Square area are more circuitous and lessdirect. Railroad tracks would not be relocated if SR 99 were elevated. Therefore, there would still betimes when trains might block the connection at S.Atlantic Street.

The connection with S. Atlantic Street and S. RoyalBrougham Way can be mixed and matched, but forthe Draft EIS, the Rebuild, Tunnel, Bypass Tunnel,and Surface Alternatives have SR 99 on the surfaceand the SR 519 connection is elevated. For the AerialAlternative, SR 99 would be elevated and the SR 519connections would be made at-grade. The SurfaceAlternative also has an option where SR 99 and SR519 would connect at the same level, with traffic sig-nals controlling all traffic.

8 How do the alternatives compare north of BatteryStreet Tunnel?

The Rebuild Alternative proposes no improvementsin the north. All of the other alternatives expand theMercer Street underpass, build a new bridge over SR99 at Thomas Street, close Broad Street from FifthAvenue to Ninth Avenue, and close the ramps atMercer and Broad Streets. In the long run, theseimprovements would benefit traffic circulatingaround the Uptown and South Lake Union neighbor-hoods. Pedestrians would also benefit. Different waysof making these connections can be mixed andmatched with any alternative.

The Aerial Alternative includes an option to lower SR99 and add overpasses at Thomas, Harrison,Republican, Mercer, and Roy Streets. Each new over-pass would have four lanes. New ramps would con-nect SR 99 to Mercer and Roy Streets. Broad Streetwould be closed from Fifth Avenue to Ninth Avenue.This option connects east-west streets in the northend and maintains through traffic on SR 99.

The Surface Alternative includes an option to keepSR 99 as it is, with signals added at Harrison,Republican, and Roy Streets. In addition, this optionwould close Broad Street between Fifth and NinthAvenues and the ramps to Mercer and Broad Streets.This option connects east-west streets in the north 1 Costs are based on preliminary estimates from the Cost Estimate Validation

Process (CEVP®) and assume construction begins in 2008.

Cost of the Alternatives

Exhibit 2-5

Note: These estimated cost ranges include inflation and take possible con-struction risks into account.

Tradeoffs

The Rebuild and Aerial Alternatives give drivers good

views, but create a visual and noise barrier along the cen-

tral waterfront. The Tunnel and Bypass Tunnel

Alternatives remove this barrier and create new open

space, but drivers lose the view. The Surface Alternative

also opens up views, but has heavy traffic volumes.


end by making SR 99 an urban arterial rather than alimited access through route.

9 What will happen to the Battery Street Tunnel?

With the Rebuild Alternative, no changes will be made to Battery Street Tunnel. All other alternativesimprove ventilation, fire suppression, and lightingand make it easier to get out of the tunnel in an emergency.

10 How do traffic speeds vary between the alternatives?

Traffic speeds2 are shown in Exhibits 2-6 and 2-7.Traffic speeds will improve compared to the 2030existing facility for the Rebuild, Aerial, and TunnelAlternatives, particularly in the downtown area andBattery Street Tunnel. For these alternatives, thegreatest increase in speeds will be realized in theWestern/Elliott area. The Aerial and TunnelAlternatives offer the greatest benefits to overall traf-fic flow. The improvement can be attributed to clos-ing difficult ramp connections at Battery Street andimproving ramp connections for Ballard/Interbaytraffic with wider lanes and shoulders.

Most speeds for the Bypass Tunnel Alternative wouldalso be comparable to the 2030 existing facility.However, in the south, northbound traffic would slowdown to 27 miles per hour compared with 46 milesper hour for the 2030 existing facility because of con-gestion near on-ramps from S. Royal Brougham Way.With the Surface Alternative, travel speeds would bereduced in the south and central sections of the proj-ect area by as much as 36 miles per hour and 19 milesper hour, respectively. Travel speeds would bereduced in these areas because SR 99 would havestoplights at nearly every intersection and the roadwaycapacity in the corridor is reduced, increasing conges-tion. For traffic approaching Battery Street Tunneland continuing north along SR 99, travel speedswould be comparable to the 2030 existing facility.

11 How do the alternatives carry different trips, andwould travel times change?

How do travel times through downtown on SR 99vary between the alternatives?

If the Rebuild, Aerial, Tunnel, or Bypass TunnelAlternatives were built, travel times for trips throughdowntown would not change much compared withthe 2030 existing facility, as shown in Exhibit 2-8. TheSurface Alternative would noticeably increase traveltimes for drivers traveling through downtown. Forthe northbound trips between S. Spokane Street andthe Aurora Bridge, travel times would more thandouble.

Exhibit 2-9 shows the number of hours each day thatcongested conditions are forecasted for the SR 99mainline. In the case of the Surface Alternative, thesource of congestion would be the downtown surfacestreet segment, which would be congested for about 9hours a day during a typical weekday. For other alter-natives, congestion would form around the BatteryStreet Tunnel and last from 2 to 5 hours per day.

How do trips destined to and from downtown varybetween the alternatives?

Travel times for trips destined to and from down-town are similar for the Rebuild, Aerial, Tunnel, andBypass Tunnel Alternatives. Even though ramps atColumbia, Seneca, Elliott, and Western are not pro-vided with the Tunnel and Bypass TunnelAlternatives, travel times are not expected to changemuch. For the Surface Alternative, travel times willslightly increase for most trips, except for the north-bound trips between S. Spokane Street and down-town, which will double.

South North

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2030 Existing Facility

Average Traffic Speeds During the PM Peak

Exhibit 2-6

S. Lake Union

Battery StreetTunnel

Downtown

Stadium Area

2 Please note that all traffic information presented in this chapter is based on thePM Peak travel period. For this corridor, the PM Peak period typically occursfrom 4:00 to 5:00 p.m.

How are congested operations on SR 99 defined?

The number of hours SR 99 would be congested was esti-

mated by determining how long the busiest sections of SR

99 would be expected to have regular traffic slow downs

or stop and go traffic.

What is the "year 2030 existing facility" and why is

it evaluated?

The year 2030 existing facility shows how much traffic is

projected to use the existing SR 99 facility in the year

2030. It takes into account future population growth and

other funded transportation projects such as Monorail

and Link light rail. It assumes that the viaduct would

remain in the year 2030 in its existing condition. We know

it is unlikely that the viaduct will last until 2030. However,

the information provides a baseline that can be compared

with traffic conditions for the proposed alternatives.



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Average Traffic Speeds for The Alternatives During the PM Peak

Exhibit 2-7

S. Lake Union

Battery StreetTunnel

Downtown

Stadium Area


How do trips to the Ballard/Interbay area varybetween the alternatives?

For the Rebuild and Aerial Alternatives, travel timesand the route for trips to the Ballard/Interbay areaare comparable to the 2030 existing facility. Traveltimes for the Tunnel Alternative are comparable tothe 2030 existing facility, even though the route is dif-ferent (instead of using ramps to Elliott and WesternAvenues, Ballard/Interbay traffic would travel on theAlaskan Way surface street north of Pike Street).

For the Bypass Tunnel Alternative, travel times forthe southbound trip between the Ballard Bridge andthe stadium area would increase by 8 minutes. Thistrip would take longer because Ballard/Interbay traf-fic would be routed off of the SR 99 mainline to theAlaskan Way surface street. This would slow down

drivers traveling between these destinations.Northbound travel times would improve slightly.

Travel times for trips to and from theBallard/Interbay area would increase the most withthe Surface Alternative. In the southbound direction,travel times would increase by 9 minutes. Northboundtravel times would increase by 8 minutes.

12 How would the alternatives affect other roads?

How do traffic volumes for the alternatives com-pare on the Alaskan Way surface street?

Traffic volumes on SR 99 and the Alaskan Way sur-face street are shown in Exhibit 2-10. For the Rebuildand Aerial Alternatives, traffic volumes in the centralwaterfront area on the Alaskan Way surface street

would be similar to the 2030 existing facility (about11,000 vehicles per day). Traffic volumes on AlaskanWay would nearly double to about 21,000 trips per day for the Tunnel Alternative. For the BypassTunnel Alternative, daily traffic volumes on AlaskanWay would increase to 48,000 trips per day. For theSurface Alternative, Alaskan Way would become SR 99, so traffic would increase to about 74,000 tripsper day.

How do effects to intersections compare betweenthe alternatives?

In the central section of the project area, the numberof congested and highly congested intersectionsvaries between alternatives, as shown in Exhibits 2-11 and 2-12.

SR 99 Travel Times during the PM Peak (4:00 - 5:00) Exhibit 2-8

What are congested and highly congested intersections?

Congested intersections are intersections that cause driv-

ers considerable delay. A driver might wait between one

and two minutes to get through a traffic signal at a con-

gested intersection. At a highly congested intersection, a

driver might wait two minutes or more to get through the

traffic signal.

The Surface Alternative includes four through lanes on

First Avenue in the Pioneer Square and stadiums area. If

only two lanes were used, congestion on First Avenue

would increase, as would traffic on other parallel streets.


The Rebuild and Aerial Alternatives would have con-gestion similar to the 2030 existing facility in thesouth and central sections. The Tunnel Alternativeresults in the fewest congested intersections in thedowntown area because traffic will be more evenlydistributed on the downtown street grid. The BypassTunnel Alternative also decreases the number of con-gested intersections in downtown compared to the2030 existing facility.

The Surface Alternative increases congestion ondowntown city streets at several locations. With moresignals and slower speeds on SR 99, more driverswould use parallel city arterials. This creates morecongestion, especially on First and Second Avenues.The number of congested intersections in the down-town area would increase from 8 for the 2030 exist-ing facility to 14 with the Surface Alternative.

North of the Battery Street Tunnel, congestion atDenny Way is expected to increase for all of the alter-natives because the Battery Street ramps will beclosed. This closure will cause more drivers to use theDenny Way ramps.

In the north, the number of congested intersectionsis comparable between the 2030 existing facility andthe Rebuild Alternative. The number of congestedintersections would increase for the Aerial, Tunnel,Bypass Tunnel and Surface Alternatives. The numberof congested intersections increases with these alter-natives because expanding Mercer Street is expectedto cause congestion near the intersections where thetwo-way Mercer Street would transition back to a one-way street. However, congestion in this area could bereduced if improvements beyond the limits of thisproject were made. The City of Seattle is currentlystudying several alternatives to improve the roadwaynetwork in the South Lake Union area as a separateproject. Improvements to the roadway network in theSouth Lake Union area are not necessary for northend improvements proposed as part of the AlaskanWay Viaduct and Seawall Replacement Project.

Would any of the alternatives affect traffic vol-umes on I-5 once construction is completed?

The Surface Alternative would add about 22,000 vehi-cles per day to I-5 through the downtown area. TheRebuild, Aerial, Tunnel, and Bypass TunnelAlternatives would not have any effect on I-5.

13 Are some alternatives safer than others?

All alternatives would make SR 99 safer in an earth-quake. Also, at the south end of the Battery StreetTunnel, both the on- and off-ramps will be closed.These ramps have poor sight lines and little distancefor drivers to speed up or slow down (both ramps willbe available for emergency vehicles). The BatteryStreet Tunnel will still have narrow lanes and shoul-ders under all alternatives.

The existing viaduct has narrow lanes, small shoul-ders, and several short and sharp entrance and exitramps, so it's no surprise that years of data show sev-eral high-accident locations. The northbound off-ramp at Seneca Street currently has a lot of accidents.The Rebuild Alternative makes some improvementsat this location, and the Aerial Alternative will makemore. The Tunnel, Bypass Tunnel, and SurfaceAlternatives eliminate the ramp entirely.

The waterfront is a popular pedestrian destination,and to reach it, people mostly need to cross theAlaskan Way surface street. Pedestrians are saferwhen they are separated from high volumes of traf-fic. The Rebuild, Aerial, and Tunnel Alternativesgenerally keep traffic separate from pedestrians. TheBypass Tunnel and Surface Alternatives increase traf-fic volumes in the central waterfront area. This addi-tional traffic would increase the overall number ofvehicle and pedestrian accidents and the potential forinjuries. The Surface Alternative would have thehighest number of injury accidents between vehicles and pedestrians.

The Surface Alternative is a different kind of road-way than the other alternatives when it comes to safe-ty. With this alternative, SR 99 along the waterfrontwould change from a limited access highway to alarge arterial with signalized intersections. There is apotential for accidents to occur in areas on the northand south ends of the corridor where SR 99 wouldtransition from a lower speed, signalized arterial to ahigher speed limited access roadway. The overallaccident rate for the project corridor would increasesubstantially and would be higher than for the otheralternatives being evaluated.

Total Alaskan WayTotal SR 99Total Number of Vehicles per Day

Exhibit 2-10

14 What happens to parking?

Parking will be reduced for all of the alternatives asshown in Exhibit 2-13 on the next page. The SurfaceAlternative requires removing the most parkingspaces (720 parking spaces would be removed), fol-lowed closely by the Bypass Tunnel, in which 710spaces would be removed. The Rebuild Alternativeresults in the fewest number of parking spaces taken;approximately 270 spaces would be removed.

For all of the alternatives, many of the free, long-termparking spaces south of S. King Street would beremoved. The effects of losing long-term parking inthe south would be relatively minor, since there is alot of available long-term parking in the area. Peoplecurrently parking for free would need to pay to park,or they would need to use transit. According to thePuget Sound Regional Council's 2002 parking inven-tory study, parking utilization in the south end is 46.6percent. There are more than five parking facilities inthis area providing more than 6,000 parking spaces.Using the estimated parking utilization in this area,approximately 2,800 spaces would be available on anormal business day.

For all of the alternatives except the RebuildAlternative, short-term, metered parking would belost throughout the project area. Most of these short-term parking spaces would be removed in thePioneer Square and central waterfront areas. Manybusinesses in these areas rely on short-term parkingfor customer and user access. Some parking mitiga-tion options have been identified to help offset lossesof short-term parking:

• Increase utilization of other existing parkingfacilities in the area.

• Lease an existing parking facility and convert it toshort-term parking.

• Purchase property and build new short-term parking.

A parking mitigation strategy for short-term parkinglosses in the Pioneer Square and the central water-front areas will be developed and presented in theFinal EIS.

In addition, 40 short-term metered spaces would beremoved north of the Battery Street Tunnel for allalternatives other than the Rebuild Alternative. In this area, there are several places where people canpark, so effects would be minor and mitigation is not proposed.

15 How would the alternatives affect the characterand views along the central waterfront?

Because the Rebuild Alternative would be similar tothe existing viaduct and surface roadway, the lookand feel of the waterfront in this alternative would beabout the same as it is presently. With the AerialAlternative, the waterfront would experience severalnotable changes. For instance, because the AerialAlternative would be about 50 percent wider andabout 7 feet taller than the existing viaduct, it wouldshade a larger area and block scenic views more thanthe existing viaduct does. Because of its increasedwidth, the aerial structure would extend closer to thewaterfront than the existing viaduct and mightappear to be a more prominent part of the view upand down the surface street.

Both the Rebuild and Aerial Alternatives would havefewer vertical support columns than the existingviaduct, and views beneath the proposed elevatedstructures would seem a little more open if thesealternatives were constructed. In the AerialAlternative, the Alaskan Way surface street corridorwould be reconfigured, with northbound surfacelanes running near the east side of the corridor(beneath the new aerial structure) in the part of thecorridor where parking spaces and the street that


Congested Intersections During the PM Peak (4:00 - 5:00)


Exhibit 2-11


Rebuild Aerial Tunnel Bypass Tunnel Surface

Exhibit 2-12

Congested Intersections for Each Alternative During the PM Peak (4:00 - 5:00)


accesses them are currently located. The corridorwould also include a landscaped median, a land-scaped trolley corridor (beneath the aerial structure),bike lanes, a broadened sidewalk on the east side ofthe Alaskan Way surface street, and a broader water-front promenade. Together, Aerial Alternativeamenities could make the surface street corridorappear to be more visually integrated than it current-ly does. Motorists traveling on the aerial structure

would continue to experience scenic waterfront andcity views.

Between S. King Street and Pike Street, the Tunneland Bypass Tunnel Alternatives would replace theexisting viaduct with tunnels, opening up scenic viewsof piers, Elliott Bay, Puget Sound, and the OlympicMountains to the west, and views of the Seattle sky-line to the east. Views along the central waterfront

and the Alaskan Way surface street would benefitfrom the absence of the viaduct's scale and mass. Thecentral waterfront and the city would seem moreclearly connected than they currently do.

Because motorists on SR 99 would be routed through the proposed tunnels, they would no longerexperience scenic waterfront and city views currently

Tunnel Bypass Tunnel Surface

Conceptual Illustrations of the Alternatives

Rebuild Aerial Cross-sections in the

central waterfront

Exhibit 2-14

How would adjacent properties benefit from removing

the viaduct?

Existing properties adjacent to the viaduct would likely

benefit from the Tunnel, Bypass Tunnel, and Surface

Alternatives because views would improve, which may

encourage redevelopment of these buildings. Conditions

for businesses would not change much from the existing

conditions with the Rebuild and Aerial Alternatives.

Section 4(f)

When a project uses land protected by Section 4(f) -

including any publicly owned land from parks and recre-

ational resources including trails of national, States, or

local significance, or any land from an historic site of

national, State, or local significance - a Section 4(f) evalua-

tion must be prepared. Additional information on 4(f) is

provided in Appendix N.


available from the viaduct between S. King and Pike Streets.

As with the Aerial Alternative, the Alaskan Way sur-face street corridor would be reconfigured in theTunnel and Bypass Tunnel Alternatives and wouldinclude a landscaped median, bike lanes, broadeningof the waterfront promenade, and a landscaped trol-ley corridor. These additions would be beneficial toboth the view and overall character of the waterfront.

The Bypass Tunnel Alternative would include sixAlaskan Way surface lanes in the central waterfront(compared to four in the Rebuild, Aerial, and TunnelAlternatives), resulting in greater overall roadwaywidth. Traffic volumes would increase from 11,000vehicles per day for the 2030 existing facility to48,000 vehicles per day for the Bypass TunnelAlternative. Compared with the Tunnel Alternative, itis possible that the effects of additional pavement andmore vehicles would reduce the sense of connectiongained by removal of the viaduct and lessen benefitsof other proposed improvements.

Similar to the Tunnel and Bypass TunnelAlternatives, removal of the viaduct in the SurfaceAlternative would generally benefit scenic east-westviews in the project corridor, as well as views alongthe waterfront-in this case with a surface street that

would combine SR 99 and the current Alaskan Waysurface street. In the Surface Alternative, drivers trav-eling along SR 99/Alaskan Way surface street wouldhave scenic views of the waterfront, but not the broadscenic views available from the existing viaduct. TheSurface Alternative would include a landscaped medi-an, sidewalks on the east side of the surface streetcorridor, bike lanes, a landscaped trolley corridor,and broadening of the waterfront promenade. Likethe Bypass Tunnel Alternative, the SurfaceAlternative would have six surface lanes on AlaskanWay. However, combining the traffic of SR 99 andAlaskan Way would result in the highest traffic vol-umes of any of the alternatives. In the SurfaceAlternative, it is estimated that Alaskan Way surfacestreet would accommodate approximately 74,000vehicles per day, compared to about 11,000 vehiclesper day for the 2030 existing facility. This additionalthrough traffic would turn the central waterfront intoa vehicle-oriented environment, possibly reducing thepotential for visual and physical connection gained byremoving the viaduct.

16 How do effects to parks, recreation, and openspace compare between the alternatives?

By altering the character of the central waterfront,changes to the viaduct (primarily expanding orremoving it) would affect recreational resources

along the project corridor. In the Tunnel, BypassTunnel, and Surface Alternatives, the viaduct wouldbe removed, opening up views and creating opportu-nities for connections between recreational resourcesand the city. However, more numerous surface lanesand high traffic volumes in the Surface Alternative-and to a lesser extent the Bypass Tunnel Alternative-might make recreational resources in the project cor-ridor less desirable to visit or harder to get to. TheAerial Alternative-taller and wider than the existingviaduct-could also affect nearby recreationalresources by affecting scenic views and taking upmore space near the waterfront than the existingviaduct does.

Public open space would be created in several of thealternatives, both on Alaskan Way and elsewhere. Inthe Tunnel and Bypass Tunnel Alternatives, a publicopen space would be created east of the SeattleAquarium on the east side of the Alaskan Way sur-face street. In the Surface Alternative, a similar pub-lic open space would be created east of the Aquariumon the west side of the surface street. In addition, thewaterfront promenade would be broadened in allalternatives except the Rebuild Alternative.

For all of the alternatives, a new over-water pierwould be built near the end of S. Washington Streetconnecting to Colman Dock. The pier would remove

Exhibit 2-15 Exhibit 2-17 Exhibit 2-18Exhibit 2-16

Visual SimulationsExisting View at Union Street Simulation of Rebuild at Union Street Simulation of Aerial at Union Street Simulation of Tunnel, Bypass Tunnel and Surface at Union Street



Alaska Square, a small public access and shorelineviewing area. Alaska Square is currently closedbecause the bulkhead supporting it is failing. AlaskaSquare could be replaced with sidewalks and shore-line viewing near its current location. All of the alter-natives would also require relocating the WashingtonStreet Boat Landing from the foot of S. WashingtonStreet about 125 feet west of its current location.

All of the alternatives would modify the WaterfrontTrail, which is separated from the Alaskan Way sur-face street and shared by bicyclists and pedestrians.In all alternatives, the Waterfront Trail would be

moved from the east side of E. MarginalWay/Alaskan Way to the west side from south of S.Atlantic Street up near Yesler Way. Also in all alterna-tives, the shared use Waterfront Trail in the centralwaterfront area would be replaced with sidewalks andstriped bike lanes along the Alaskan Way surfacestreet. North of Pine Street, the Waterfront Trailwould not change for any of the alternatives exceptthe Tunnel Alternative, which may narrow it slightly.In the Tunnel, Bypass Tunnel, and SurfaceAlternatives, a new mixed-use trail might be added-leading diagonally from the north side of Seahawks

Stadium to the intersection of S. King Street and theAlaskan Way surface street.

17 How do changes to noise levels compare betweenthe alternatives?

Walking along the central waterfront today, it's hardnot to notice the noisy viaduct overhead. A decibellevel of 55 dBA is typical for people talking at a dis-tance of 10 feet, but near the Seattle Aquarium, theexisting decibel level today is often around 73 dBA inthe daytime. Near the viaduct, traffic noise from theviaduct is approximately 10 dBA greater (appears

Rebuild Aerial

Tunnel Bypass Tunnel Surface

Noise Levels for Each Alternative

2030 Existing Facility2002 Existing Facility

Exhibit 2-19

These graphs are showing how loud traffic would be

at various distances from Alaskan Way. If you were

standing where the X is, the noise level would about

72 dBA. This is similar to the noise you would hear

standing 3 feet from a blender.

Appendix F includes the detailed maps and tables of noise

sites and levels measured for this Draft EIS.

twice as loud) than the noise from other sources. Tothe human ear, 65 dBA (a typical washing machinenoise level from 3 feet away) is intrusive. Short-termnoise level measurements taken at the Harbor Stepsand Victor Steinbrueck Park during the daytimeexceeded the FHWA traffic noise abatement criterionof 67 dBA.

The most noticeable change between the alternativeswould be to noise levels for 2030 conditions in thecentral waterfront area. The Tunnel and BypassTunnel Alternatives are expected to have noticeablylower noise levels in the central waterfront comparedto the No Build scenarios. For example, at ColmanDock, the No Build, Rebuild, Aerial, and SurfaceAlternatives would have 2030 peak traffic noise levelsof 71 to 75 dBA, while the Tunnel and Bypass TunnelAlternative noise levels would be 63 to 65 dBA. Tothe human ear, a 5-dBA change in noise is readilynoticeable. A 10-dBA decrease would sound like thenoise level has been cut in half.

The 2030 peak traffic noise levels at the SeattleAquarium are 73 to 74 dBA for the No Build,Rebuild, and Aerial Alternatives. At these same loca-tions, the Surface Alternative would lower noise levelsby approximately 3 to 4 dBA (barely perceptible), andthe noise level would drop noticeably by 9 to 10 dBAfor the Tunnel and Bypass Tunnel Alternatives. Atthe Harbor Steps, the Tunnel and Bypass TunnelAlternatives would lower noise levels by about 5 dBAcompared to the No Build, Rebuild, Aerial, andSurface Alternatives. All of the alternatives may causenoise levels at Victor Steinbrueck Park to fluctuate by1 dBA from the existing conditions, but this changewould not be noticeable to people. Overall, thereduced 2030 noise levels in the central waterfrontarea under the Tunnel and Bypass TunnelAlternatives would make the area more pleasant forpedestrians, residents, and nearby businesses com-pared to the other alternatives.

The 2030 peak traffic noise levels at residences northand south of the central downtown core wouldremain essentially the same as the 2030 existing facili-ty for all of the alternatives. Forty-eight sites were

modeled to see if they met the FHWA noise abate-ment criteria under 2030 conditions; the results areshown in Exhibit 2-20.

All of the alternatives except the Rebuild Alternativewill install jet fans in the Battery Street Tunnel foremergency ventilation purposes. The jet fans will pro-duce noise near the tunnel portals. They will bedesigned not to exceed 57 dBA at the nearest residen-tial property line. If the fans are to be operated regu-larly during nighttime hours, they will be designednot to exceed 47 dBA during those hours.

The Rebuild and Aerial Alternatives may includesound-absorptive materials to reduce noise that is re-flected off the bottom of the elevated structure. Simi-larly, the sound-absorptive material could be usedaround the tunnel portals to reduce the traffic andventilation system noise levels coming out at the tunnel.

The Surface Alternative puts more traffic on AlaskanWay and will divert some traffic to city streets; thiscould cause traffic noise levels to increase on otheradjacent streets.

18. How do effects to fish and wildlife vary betweenthe alternatives?

The dense and highly urban project area does notprovide any notable natural habitat for wildlife onthe land. Where the alternatives vary is in regard tothe aquatic habitat along the shoreline. However, theexisting aquatic habitat is already highly modified bythe urban environment, and no natural shoreline

remains. The existing stormwater facilities are oldand will be replaced with new facilities using currentdesign standards and technology, improving the qual-ity of water discharged. Once the new seawall is com-plete, all of the alternatives would have habitat condi-tions similar to those currently seen along the shore-line, including a vertical concrete seawall.

Between S. Washington Street and Myrtle EdwardsPark, all of the alternatives will construct the new sea-wall landward of the existing seawall. In addition, allof the alternatives will remove and replace a smallsection of existing sheet pile wall from near S. Kingto S. Washington Streets. The only place where thealternatives vary is between Pier 48 (located near S.Washington Street) and Colman Dock (located nearYesler Way), as shown in Exhibit 2-21 on the nextpage. For the Rebuild, Aerial, and SurfaceAlternatives, construction of the new seawall willremain landward of the existing seawall between Pier48 and Colman Dock. Because the new seawall wouldbe entirely constructed landward, when the existingseawall is removed, the volume of aquatic habitat inthe immediate area would increase slightly as shownin Exhibit 2-22.

In comparison, the Tunnel Alternative will extendout into Elliott Bay up to 21 feet between Pier 48 andColman Dock, filling about 4,000 square feet.However, there will be a small net increase in the vol-ume of Elliott Bay and the shoreline habitat areabecause some habitat will be gained when the existingseawall is removed in other locations. The BypassTunnel Alternative would extend up to 58 feet intoElliott Bay between Pier 48 and Colman Dock, fillingabout 15,000 square feet and resulting in a small netdecrease in the volume of Elliott Bay and the shore-line habitat area. The fill placed for both the Tunnel


Chapters 5 through 9 contain information describing why

the over-water pier is needed as part of the project. This

information is located in Question 3 under the sub-head-

ing “How would it change vehicle access for ferries.”

and Bypass Tunnel Alternatives will cause the outfallat Washington Street to be extended further out inElliott Bay.

All of the alternatives include building an over-waterpier between Pier 48 and the existing Colman Dockto provide vehicle access to the Colman Dock FerryTerminal. The new pier will increase over-water shad-ing by 33,000 square feet for the Rebuild, Aerial, andSurface Alternatives. For the Tunnel Alternative, thenew pier would shade about 29,000 square feet inaddition to the 4,000 square feet of new fill at thislocation, altering a total of 33,000 square feet.Likewise, the Bypass Tunnel Alternative would alter33,000 square feet, with about 18,000 square feet ofnew shading and 15,000 square feet of new fill.Opportunities to restore habitat functions at variouslocations along the Seattle shoreline are being identi-fied for all alternatives to mitigate the effects betweenPier 48 and Colman Dock. Enhancements beyondthose required for mitigation might also be undertak-en to restore some of the habitat functions that nolonger exist along this urban shoreline as shown inExhibit 2-23.

19 How do the alternatives affect water quality?

For more than 100 years, the development and use ofbuildings and roadways in Seattle has altered the nat-ural patterns of stormwater runoff and added con-taminants to stormwater flows. As a result, stormwa-ter from the project area, discharged from 19 majorand many smaller outfalls, contributes to water quali-ty de-gradation in nearby waters, including Elliott Bayand other parts of Puget Sound, the Duwamish River,and Lake Union.

The project area, approximately 98 acres, is less then5 percent of the total surface area of the drainagebasin. Because the project area contributes a verysmall portion of the total stormwater flow within thedrainage basin, the overall effect of the project onwater quality will not be substantial. Nevertheless, allopportunities to minimize water pollution effectsfrom the project area are important beneficialchanges in stormwater control and management.

Two approaches were developed, as part of this DraftEIS, to improve stormwater performance within theproject area. Each approach, or more likely a combi-nation of both, can be utilized with any of the alterna-tives. The two stormwater approaches for the project are:

• Best Management Practice (BMP)

• Convey and Treat

Both stormwater approaches will help improve waterquality because they will reduce the total amount ofpollutants from the project area at discharge loca-tions as compared to existing conditions. The overallquantity of pollutant reduction is about the sameunder either approach. Either approach will require

coordination and cooperation with Seattle PublicUtilities and King County, the responsible jurisdic-tions for drainage and sewage facilities serving theproject area.

Changes to Elliott Bay at S. Washington StreetRebuild, Aerial and Surface Tunnel Bypass Tunnel

What is a BMP?

A Best Management Practice (BMP) is an action or struc-

ture that reduces or prevents pollutants from entering the

stormwater and degrading water quality

What is a Combined Sewer Overflow (CSO)?

Combined sewers carry sewage from homes and business-

es in the same pipe with stormwater. Combined sewer

overflows (CSOs) occur when the rainfall volumes exceed

the pipe capacity. When a combined sewer overflows,

water is discharged directly to the Puget Sound without

being treated at a treatment plant.


Historic Washington Street Boat Landing

Exhibit 2-21

Terminal 46

Port of Seattle

Pier 48Pier 52

Colman Dock

Pier 54

Pier 55

Pier 56

Pier 57

Pier 58

Pier 59

Pier 63

Pier 62

Pier 66

Pier 67

Pier 66

Pier 69

Pier 70

Habitat Change for Fish and Aquatic Life

Pier 48 may be removed and habitat could be enhanced.

Stormwater enters Elliott Bay without

being treated.

New stormwater treatment will be added.

Shelf could attract new aquatic life along the

new seawall

Pier 48 shading limits habitat value. Most waterfront habitat is degraded and

there is a lot of trash.

Vertical seawall provides little habitat.

Today

A new pier will shade the water and limit

habitat value.

After

After

Today After

Today

Today

After

Exhibit 2-23

After



BMP Approach

The BMP Approach would collect runoff and treat itand/or detain it based on current WSDOT and Cityof Seattle stormwater manuals. Stormwater that isseparated in pipes will use treatment BMPs.Stormwater that is discharged into the combinedsewer system will use detention BMPs.

Convey and Treat Approach

The Convey and Treat Approach would integrate theproject's stormwater runoff strategies with sys-temwide improvements in Seattle's combined sewersystem. This would be achieved by collectingstormwater in the central waterfront area and convey-ing it to a reconfigured combined sewer system.Combined sewage would then be conveyed to theWest Point Sewage Treatment Plant for secondarytreatment. This would occur during dry weather orsmall storms. However, during larger storms, some ofthe stormwater will move to the Denny WayCombined Sewer Overflow (CSO) Treatment Facilitynear the northwest end of the project area.Combined stormwater and wastewater south ofColumbia Street would be conveyed to a new CSOstorage and primary treatment plant proposed byKing County, near S. Royal Brougham Way. TheConvey and Treat Approach assumes a greater vol-ume of stormwater would be discharged at the RoyalBrougham and West Point outfalls than under exist-ing conditions. The Convey and Treat Approach willreduce the volume of untreated stormwater, resultingin a higher quality discharge. See Exhibit 2-24.

Major use of the Convey and Treat Approach in theproject's stormwater strategies would require the con-struction of the Royal Brougham CSO TreatmentFacility at an earlier date. It would also require thisnew facility to be larger than initially thought toaccommodate flows from the project corridor. Thisapproach also affects the West Point SewageTreatment Plant and will require close integrationwith King County's wet weather operations.

North and south of the central waterfront area, bothapproaches would use the same methods. Stormwater

BMPs for treatment and detention are likely to beused south of S. Royal Brougham Way and north ofVine Street. For the section of Broad Street to beclosed under all but the Rebuild Alternative,stormwater will likely be conveyed to the combinedsewer system rather than to direct discharge at LakeUnion.

Final outfall configurations for stormwater outfallsand discharge points will be considered after selec-tion of a preferred alternative and the final choice ofstormwater management strategies. The stormwateroutfalls serve a larger vicinity than just the projectarea, so most existing major outfalls will likely bemaintained or replaced at their existing locationsalong the seawall. However, the Tunnel and BypassTunnel Alternatives will require the WashingtonStreet outfall to be extended further into Elliott Bay.

Improvements to the Battery Street Tunnel willinclude a fire suppression system for all alternativesexcept the Rebuild Alternative. The Tunnel andBypass Tunnel Alternatives will also include a firesuppression system in the new tunnel structures inthe central waterfront area. In an emergency, it ispossible that runoff from this system could dischargedirectly into Elliott Bay. Such a discharge could resultin temporary and localized decreases in dissolvedoxygen that would be allowable under state waterquality regulations.

20 What other issues were considered in this Draft EIS and how do they compare between the alternatives?

How many buildings would need to be acquired tobuild the alternatives?

None of the alternatives would acquire any residen-tial buildings. As shown in Exhibit 2-26, the SurfaceAlternative requires relocating the most businessesand employees, and it requires the largest area ofproperty acquisitions. The Surface Alternative needsmore property because of the relocated railroad tailtrack south of the Burlington Northern Santa Fe(BNSF) Seattle International Gateway (SIG) RailYard. If the tail track were relocated to Railroad WayS. instead of S. Royal Brougham Way, the SurfaceAlternative would have a similar number of acquisi-tions and displacements as the Tunnel or BypassTunnel Alternatives.

Stormwater Distribution

Exhibit 2-24

Note: These numbers represent the 90th percentile of construction time esti-mated for the project. This means there is a 90% chance the actualconstruction time would be equal to less than this estimate.

Exhibit 2-27

How would neighborhoods be affected?

The Rebuild and Aerial Alternatives would notchange neighborhood character along the centralwaterfront. The other alternatives would give theseneighborhoods a stronger connection with the water-front, although the Bypass Tunnel and SurfaceAlternatives add more lanes and more traffic onAlaskan Way. This would diminish some of the senseof connection. At the north end of the corridor allalternatives except the Rebuild Alternative wouldimprove east-west connections between the Uptownand South Lake Union neighborhoods.

Do effects to historic resources vary between the alternatives?

The corridor contains two National Register historicdistricts (Pioneer Square and Pike Place Market) andnumerous other National Register properties. Thelead agencies have worked hard to avoid possibleeffects to resources eligible for listing in the NationalRegister of Historic Places.

All of the alternatives will demolish two resourcesthat are eligible for listing in the National Register:the Alaskan Way Viaduct, and portions of theAlaskan Way Seawall. All of the alternatives maypotentially remove the Washington-Oregon ShippersCooperative Association (WOSCA) freight house.The Battery Street Tunnel, which is eligible for listingin the National Register, would be modified under allof the Build Alternatives except the RebuildAlternative. The Washington Street Boat Landing,which is also listed in the National Register, will beremoved during construction and relocated west ofits current site after construction.

The Tunnel, Bypass Tunnel, and Surface Alternativeswill affect one additional building (the One YeslerBuilding) in the Pioneer Square Historic District.This building could be relocated to a parking lotacross the street, or to a site just to the west of its cur-rent location. The Tunnel and Bypass TunnelAlternatives also involve minor alterations to theAntique Importers/Snowboard Connection building,which is in the Pioneer Square Historic District, and

the basement of the Catholic Seamen's Club, which iseligible for listing in the National Register.

The Surface Alternative assumes two lanes are addedon First Avenue through Pioneer Square. The addi-tional lanes would require strengthening the areaways (spaces under sidewalks initially createdwhen Pioneer Square streets were raised after the1889 fire) under the sidewalks, which could affecttheir historic qualities.

How would air quality differ between the alternatives?

Air pollution related to transportation would be simi-lar under all of the alternatives. Future carbonmonoxide and particulate matter concentrationswere predicted to be below the National Ambient AirQuality Standards (NAAQS) for all alternatives. Dailypollutant emissions from traffic were predicted to belower in 2030 than today for all of the alternatives,with only small differences between the alternatives.

Are effects to groundwater similar between the alternatives?

Groundwater flow would not be negatively affectedby any of the alternatives. While groundwater levelsmay change slightly along the new seawall under allof the alternatives, the potential groundwater buildup(mounding) will be within the existing groundwaterfluctuations resulting from tides in Elliott Bay. Forthe Tunnel and Bypass Tunnel Alternatives, ground-water flow in the vicinity of the tunnel will flowaround, under, or over the tunnel structure.

21 What will happen during construction?

How do construction durations compare betweenthe alternatives?

The Aerial Alternative would take the longest time tobuild, as shown in Exhibit 2-27. The Rebuild andSurface Alternatives would take the shortest amountof time to build.

How do effects to roadway capacity compare dur-ing construction?

The project assumes SR 99 would not be completelyclosed and could be constructed in the estimatedtimeframe (7.5 to 11 years). However, partial roadwayclosures and detours would be required. Two lanes oftraffic would be maintained in the AWV Corridor


Number of Buildings, Employees, and Acres Affected

Note: For the Surface Alternative, the number of buildings, employees affect-ed, and total acres required would be similar to the Tunnel or BypassTunnel if the tail track extends north of S. Royal Brougham Way.

Exhibit 2-26


during peak traffic hours, or a comparable detourwould be provided. SR 99 could be closed during off-peak traffic hours, such as nights and weekends, andfor up to 2-week periods. SR 99 between Pike Streetand Denny Way (including the Battery Street Tunnel)could be closed during summer months for up to 10weeks for all alternatives except the RebuildAlternative.

Roadway closures during construction vary by alter-native, location, and construction stage. Overall, thepercentage of lost roadway capacity is the least forthe Tunnel and Bypass Tunnel Alternatives, as shownin Exhibit 2-28. The Aerial Alternative has a similarlost roadway capacity during construction, but wouldtake more time to build. The Rebuild and SurfaceAlternatives would have the highest loss of roadwaycapacity during construction, although they also takethe least amount of time to build. Lower roadwaycapacity will affect freight traffic in the corridor aswell as other travelers.

How does construction truck traffic comparebetween the alternatives?

For all alternatives and options, trucks will most like-ly be the primary mode for transporting materialseither into or out of the project area, though rail carsor barges may also be used. All of the alternativeswould increase truck traffic in the area, since equip-ment, soil, and materials would be trucked in and outof the area. Both tunnel alternatives require moretrucks because a large volume of soil would need tobe excavated. The Tunnel Alternative would requirethe most truck trips, followed by the Bypass Tunnel

Alternative. Truck traffic volumes would be highestduring the 2- to 4-year period when the tunnel isbeing constructed. Specific truck routes will be devel-oped to help minimize possible effects to traffic in the area.

How would transit be affected during construction?

For all alternatives, the Waterfront Streetcar wouldbe removed for the entire construction period. Itwould be replaced at the end of construction. A shut-tle service could be provided through the construc-tion area to mitigate this loss. Other transit serviceswould be affected by route changes, and travel timesmay increase due to additional congestion in thearea. As part of the project, the lead agencies willwork with transit providers to discuss constructionactivities that would affect transit routes and work onfinding acceptable alternate routes as needed. Inaddition, the lead agencies will provide funds toenhance transit during construction.

How do construction effects to rail yards comparebetween the alternatives?

The Aerial Alternative would affect rail yards in theproject area less than the other alternatives. Effects to rail yards for the remaining alternatives would be similar.

For the Aerial Alternative, the Whatcom Rail Yardlocated at the south end of the project area would be closed for the entire construction period. No other changes would be needed to other rail yardsfor this alternative.

For all alternatives except the Aerial Alternative, theWhatcom Rail Yard would be relocated into theBNSF Seattle International Gateway (SIG) Rail Yard.The Whatcom Rail Yard would be closed while it wasbeing relocated, and the BNSF SIG Rail Yard wouldremain open while it is being reconfigured. For thesealternatives, the tail track would also be moved. Theexisting tail track would be maintained during reloca-tion of the tail track. In the central and north water-front areas, construction effects are similar between

the alternatives. There will be times when construc-tion would occur over the existing BNSF tracks; how-ever, the rail line would remain open throughout theconstruction period.

The lead agencies will carefully coordinate construc-tion activities with the BNSF and Union PacificRailroads to maintain the functions of their tracksduring project construction.

How do parking effects during construction com-pare between the alternatives?

The alternatives would remove a similar number ofparking spaces. The Rebuild Alternative wouldremove slightly less parking than the other alterna-tives during construction because no work is pro-posed to occur north of the Battery Street Tunnel.

About 1,100 parking spaces in the project area will beremoved during construction. These spaces includeparking spaces under the existing Alaskan WayViaduct and under the ramp on Railroad Avenue S.Most of these spaces are short-term, metered spaces,though there are many free, long-term parkingspaces located under the viaduct south of S. KingStreet. Farther away from the project area, parkingspaces may need to be removed to make room fordiverted traffic and maintain smooth traffic flow.

Lost short-term parking could be mitigated by a com-bination of increasing utilization of other existingparking facilities, leasing an existing parking facilityand converting it to short-term parking, and purchas-ing property and building new short-term parking. Aparking mitigation strategy will be included in theFinal EIS that will mitigate losses of short-term park-ing during and after construction of the preferredalternative.

What traffic detours are proposed during con-struction and what are the tradeoffs?

There are two proposed construction detours: theBroad Street Detour and the Battery Street FlyoverDetour option.

What is the tail track?

The tail track is a single railroad track that connects the

Burlington Northern Santa Fe (BNSF) Seattle International

Gateway (SIG) Rail Yard on the east side of SR 99 to the

Whatcom Rail Yard located west of SR 99.

The tail track is used to assemble and sort railcars for both

the Whatcom and BNSF SIG Rail Yards.

Exhibit 2-29 Visual simulation of Broad Street Detour

Exhibit 2-30

Visual simulation view to the north of the Battery Street Flyover Detour

Broad Street Detour

For this detour, the improvements associated with theWidened Mercer Underpass would need to be con-structed north of the Battery Street Tunnel, prior todetouring traffic. The Widened Mercer Underpassimprovements include constructing a new bridgeacross Thomas Street and widening Mercer Streetbetween Fifth and Dexter Avenues.

With the Broad Street Detour, southbound SR 99traffic would be diverted off of Aurora Avenue/SR99at Broad Street. This would require widening theexisting Aurora/SR 99 off-ramp to Broad Street fromone lane to two lanes. Also, Broad Street would bereconfigured so traffic headed eastbound near DennyWay is diverted to the new bridge at Thomas Street.A two-lane temporary bridge would be built over theBNSF railroad tracks from approximately the inter-section of the Alaskan Way surface street and VineStreet up to the intersection of Broad Street andWestern Avenue. Traffic would be routed downBroad Street and over the BNSF railroad tracks to theAlaskan Way surface street. Southbound SR 99 trafficwould continue to travel south on the Alaskan Waysurface street until it would connect to either the tem-porary viaduct near Pike Street (for the AerialAlternative), the existing viaduct, or the new tunnel(for the tunnel alternatives). The Broad Street Detourwould increase traffic using Broad Street over exist-ing conditions. Northbound traffic would continue touse the Battery Street Tunnel.

Other features of the Broad Street Detour include:

• Southbound traffic from the Ballard/Interbayarea would travel under the railroad tracks atBroad Street by using an underpass. Northboundtraffic would use ramps on Elliott and WesternAvenues. Routes would frequently changethroughout construction, but access would beprovided.

• The Battery Street Tunnel would not need to beclosed entirely throughout construction.

Battery Street Flyover Detour Option

The Battery Street Flyover Detour option could beused instead of the Broad Street Detour. This optioninvolves constructing a temporary side-by-side aerialstructure that would connect to the Battery StreetTunnel near First Avenue and Battery Street. Itwould rise over existing buildings between WesternAvenue and the Alaskan Way surface street and touchdown at street level. This detour would allow north-bound and southbound traffic to travel on the tempo-rary aerial flyover while the existing Battery StreetTunnel connection is torn down and rebuilt. A com-parison between the two detours is shown in Exhibit2-31.

Other features of the detour option include the following:

• Ramps would be provided on the structure con-necting to Elliott and Western Avenues.

• No improvements would be required to SR 99 orother streets north of the Battery Street Tunnel.

• The Battery Street Tunnel may need to be closedfor up to 10 weeks during one summer toupgrade the Battery Street Tunnel to add fireand life safety improvements.

22 How do effects to the character and views alongthe corridor compare during construction?

For any of the alternatives, construction equipmentand materials would clutter views in the corridor, andnighttime lighting could affect some people withinone or two blocks of construction and staging areas.

Overall, the Aerial Alternative would have the great-est effect on views and character of the area becausea temporary aerial structure would stretch from S.Royal Brougham Way to near Pike Street for up to 7years during construction. A picture of what the tem-porary structure would look like is shown in Exhibit 2-32. In the south end of the corridor, thetemporary structure would have only minimal effectsto the surrounding industrial landscape. Along thewaterfront, the temporary aerial structure wouldtower above the pedestrian corridor, shade part ofthe area, and dominate views from the historic water-


Temporary Aerial Structure Simulation

View to the south from Union (Waterfront Park)

at the west side of Alaskan Way surface street.

Exhibit 2-32


front piers. It would also partially obstruct views frombuildings located in the space between the AlaskanWay surface street and the viaduct. Also, effects toviews depend on the detour selected, as shown inExhibits 2-29 and 2-30. The temporary viaduct wouldbe in place for about 7 years, along with the BroadStreet Detour. If the Battery Street Flyover Detouroption were built, the temporary viaduct wouldremain in place about 4 years.

In general, the most noticeable change to views withthe Rebuild Alternative is that the viaduct would bebraced during construction. The temporary bracingwould make the viaduct look bulkier and would blocksome views through and under the viaduct.

For the Tunnel, Bypass Tunnel, and Surface Alter-natives, the effects to views depend on the detourselected, as previously described. Also, for theTunnel and Bypass Tunnel Alternatives, a lot of con-struction would be underground, which would mini-mize effects to views and surrounding areas com-pared with the other alternatives.

23 How does construction noise compare?

Noise during construction would be bothersome tonearby residents and businesses, particularly sinceconstruction activities would occur 24 hours a day.All of the alternatives would generate similar types ofnoise that would occur sporadically in different loca-tions throughout the 7.5- to 11-year construction peri-od. Common noise sources would include front-endloaders, pile-placement machinery, dump trucks, andgenerators. The loudest and most disruptive con-struction activities would be pile placement (includ-ing driving sheet pile), followed by work with jack-hammers.

Existing outdoor noise levels in the project arearange from 71 to 83 dBA, which is typical for majordowntown metropolitan areas. Typical noise levelsfrom construction equipment would range from 69to 106 dBA 50 feet from the source; however, themajority of typical construction activities fall withinthe 75- to 85-dBA range at 50 feet. Peak noise frompile driving is about 106 dBA at 50 feet. Noise at 65

dBA is generally intrusive; 80 dBA is disruptive andrequires people to shout to be heard. Hearing protec-tion is recommended at noise levels above 90 dBA.Noise levels between 110 and 120 dBA are typical of a rock concert.

For all of the alternatives, noise for certain types ofconstruction activities, like pile placement andviaduct demolition, could exceed City of Seattle noiseregulations. Exceedances are expected to occur in thedaytime and nighttime, which would require a noisevariance from the City of Seattle. The RebuildAlternative would have the greatest noise and vibra-tion effect, followed by the Aerial Alternative,because construction of their structures through thecentral section would require a considerable amountof pile placement. The Rebuild Alternative wouldcause the most construction noise heard by the pub-lic, since it would require more pile placement nearbusinesses and residences than other alternatives.

For all alternatives, reconstruction of the seawall andconstruction of the over-water pier could generate in-water noise and vibration levels that might disturbfish and marine life. These potential effects could bemitigated using alternate construction methods, suchas constructing in-water improvements behind a cofferdam.

24 How would vibration effects during constructioncompare?

Demolishing the viaduct and pile placement wouldcause high vibration levels during construction, possi-bly affecting older historic buildings and areaways.During viaduct demolition, extremely fragile struc-tures closer than 100 feet would be at risk of damage.For pile driving, extremely fragile structures closerthan 400 feet would be at risk. To avoid damage, spe-cial precautions would be taken to limit damage toextremely fragile structures. This may include usingpilings that do not need to be driven into the ground.

25 Do the construction effects to businesses and thelocal economy vary between the alternatives?

The project area contains a mix of commercial, retail,industrial, and service-related businesses that wouldeach be affected by construction in different ways.This project is different from many others because ofthe many years needed for construction. Althoughthe amount of disturbance will vary from place toplace and from time to time while the project is built,the extended construction period will make it espe-cially hard on some businesses.

Some businesses in the construction area may beperiodically inconvenienced by noise from the con-struction, while other businesses, such as those locat-ed along the central waterfront, could be negativelyaffected by a decline in sales if people choose toavoid the area during construction. Businesses in thesouth, along the central waterfront, in PioneerSquare, and in the Pike Place Market area would alsobe affected by traffic detours, congestion, noise, dust,changes to access, and lost parking. Businesses in thenorth end of the project area would mostly be affect-ed by noise, dust, traffic detours, and congestion.

The number of buildings located within 50 feet of thefacility is shown in Exhibit 2-33. Overall, the RebuildAlternative has the fewest buildings located within 50feet, whereas the Surface Alternative has the mostbusinesses located within this distance. Additionally,the Rebuild Alternative does not propose improve-ments north of the Battery Street Tunnel, so it would

Exhibit 2-33

have fewer overall effects than the other alternatives,which have effects from both construction and pro-longed detours at Broad Street.

Specific mitigation measures for affected businesseswill be provided in the Final EIS. Potential mitigationmeasures are identified in Chapter 10.

26 What other construction issues were considered?

Are any additional properties required for con-struction, and do the properties needed varybetween the alternatives?

All of the alternatives require property acquisitionsor leases for construction staging areas. In general,the number of properties needed for constructionstaging is similar between the alternatives. The fewestnumber of staging areas are required for the RebuildAlternative, because no improvements are planned inor north of the Battery Street Tunnel. After construc-tion, the properties could be leased to new tenants,redeveloped, or sold.

How do construction effects to parks and recre-ation compare between the alternatives?

For all alternatives, the Waterfront Trail locatedbetween S. Royal Brougham Way and Bell Streetwould be removed during construction. Bicycle andpedestrian routes during construction will be pro-posed once a preferred alternative has been selected.

Noise and dust would affect open spaces atWaterfront Park, Pier 62/63, and Victor SteinbrueckPark. Also, for the Aerial, Tunnel, Bypass Tunnel,and Surface Alternatives, temporary trestles for theBroad Street Detour would temporarily alter viewsand increase noise and traffic, which would affectpeople visiting Myrtle Edwards Park and the pro-posed Olympic Sculpture Park. If the Battery StreetFlyover Detour were constructed, views to these twoparks would not be affected, but views between Pikeand Battery Streets would be affected.

In addition, all of the alternatives could affect recre-ational facilities that depend on admission fees ifpeople avoided the waterfront due to construction.

This could affect the economic viability of the facili-ties listed below:

• Tillicum Village at Blake Island Park - Privateferry service to Blake Island State Park is provid-ed from Pier 56.

• The Seattle Aquarium is primarily funded byadmissions. If admissions drop during construc-tion, programs may be compromised and plansto upgrade the facility may be delayed. In addi-tion, the animals at the Aquarium may be affect-ed by construction noise.

• The summer concert series at the Pier 62/63Park could be affected by construction noise.

Overall, the Aerial Alternative would increase prox-imity impacts, such as increased noise to parks andrecreational areas along the waterfront, more thanthe other alternatives because a temporary aerialstructure would be built directly adjacent to the waterfront between S. Royal Brougham Way and Pike Street.

Specific mitigation measures identifying possiblepedestrian and bicycle routes and mitigation meas-ures for parks and recreational facilities will be devel-oped as part of the Final EIS.

How do construction effects compare for neighborhoods?

For people working or living right next to the work-site, construction will sometimes be inconvenient andat other times will be quite disruptive. For many peo-ple, construction sites seem like a barrier, even whentemporary sidewalks or other routes are available.Because of this, construction activities could tem-porarily increase the perception of separationbetween parts of each of the neighborhoods in theproject corridor. The Surface Alternative would havethe least perceived separation. The Tunnel andBypass Tunnel Alternatives have a lot of work belowground, which would lessen some of the perceivedseparation because it can be temporarily coveredover. The Rebuild and Aerial Alternatives, with a lotof temporary aboveground structures, would have themost perceived separation.

Would the elderly, disabled, low-income, orminorities be affected during construction?

Construction effects to disadvantaged communitiesinclude increased congestion, reduced mobility,increased response time for emergency services, andincreased noise. For all alternatives, temporary con-gestion during construction would affect low-income,homeless, elderly, or disabled people and the organi-zations that strive to serve them. Although construc-tion effects to disadvantaged communities are proba-ble, it appears they can be avoided, minimized, ormitigated. At this point, it is too early to develop aspecific construction mitigation strategy for disadvan-taged communities; however, continued outreachwith service providers will be critical to minimizingand avoiding impacts where feasible. This mitigationwill be developed for the preferred alternative andincluded in the Final EIS.

How do construction effects compare for utilitiesand public services?

An extensive network of utilities is located in theproject area. For all of the alternatives, many of theseutilities will need to be moved at least once duringconstruction. Among the alternatives, the TunnelAlternative will require the most effort to relocateutilities, followed by the Bypass Tunnel Alternative.

During construction, unplanned interruptions oraccidental disconnections associated with utility relo-cations could occur. In addition, when utilities arerelocated, there are times when reliability of the utili-ty systems may be reduced. These risks can bereduced through advanced planning and coordina-tion.

The Tunnel Alternative would have the most effecton utilities in the south (S. Spokane to S. KingStreets). In the central section, the TunnelAlternative requires the most utilities to be relocated,followed by the Bypass Tunnel Alternative. TheAerial Alternative would fall next in line, followed bythe Rebuild and Surface Alternatives.



In the north waterfront section, the Bypass TunnelAlternative would affect slightly more utilities thanthe Tunnel Alternative. The other alternatives wouldrequire less relocation and be relatively similar.

In the north, the Rebuild Alternative would requirethe fewest number of utilities to be relocated since noimprovements are proposed. The remaining alterna-tives would have similar effects to utilities, though theBypass Tunnel Alternative would not require relocat-ing telephone or fiber-optic lines.

During construction, public services (including emer-gency services, school buses, and solid waste collec-tors) would be affected by traffic delays and detours.Specifically, Fire Station No. 5, located near ColmanDock on the waterfront, would be relocated duringconstruction. The place where fire services would betemporarily relocated has not yet been determined,but the lead agencies would work with the SeattleFire Department to make sure they are relocated toan adequate location.

How do air quality effects during constructioncompare?

Air quality effects between the alternatives would varyin the exact locations and timing of the constructionactivities, but overall, the alternatives would all havethe same kinds of effects.

Do construction effects to fish and wildlife varybetween the alternatives?

For all the alternatives, construction of the over-waterpier between S. Washington Street and Yesler Wayand seawall construction near S. King Street up toPike Street will require some in-water work. In-waterconstruction activities such as placing piles for theover-water pier or removing the existing seawallwould disturb sediments along the shoreline.

All alternatives would strengthen soil with cementgrout behind the sheet pile wall from S. King Streetto near S. Washington Street. The sheet pile wall willbe removed, which could require working in thewater. Effects to fish and wildlife during sheet pileremoval are similar between alternatives, and mitiga-tion would also be similar.

The Rebuild, Aerial, and Surface Alternatives wouldreplace the seawall from S. Washington Street up toabout Pike Street using soil improvements anddrilled shafts. Possible effects are the same as previ-ously described. Potential noise impacts to fish,wildlife, or bald eagles from pile placement may beavoided or minimized by using Best ManagementPractices.

For the Tunnel and Bypass Tunnel Alternatives, theseawall would become the outer wall of the new tun-nel, beginning at S. Washington Street and continu-ing to about Pike Street. A secant pile wall (similar toa row of continuous drilled shafts) would be con-

structed instead of soil improvements. In most places,the tunnel wall would be built behind the existing sea-wall, though between S. Washington Street andYesler Way, the wall would extend between 21 and 58feet out into Elliott Bay depending on which tunnel isconstructed.

Do construction effects to water quality andgroundwater vary between the alternatives?

Construction staging locations have the potential tohave spills and stormwater runoff that contain con-taminants, such as fuel or oil from machinery. Inaddition, pH can be altered if runoff comes in con-tact with concrete during the curing process. BestManagement Practices would be in place to containand treat runoff. The Best Management Practicesused at construction staging areas would not varybetween alternatives.

The spoils removed during soil improvements,drilled shafts, and slurry wall construction would bedisposed of in a manner to protect water quality. Thespoils contain a mix of soil, cement grout or ben-tonite (an absorbent clay), and a high percentage ofwater. The water could have a pH approaching 10(which is too high-a pH of 7 is considered to be nor-mal). This water will be treated as needed to reducepH, total suspended solids (soil particles), and otherpollutants. The way water in the spoils is treatedwould not vary between the alternatives, but theamount of spoils would vary somewhat.

What is pH?

pH is a measurement of the acidity or alkalinity in a sub-

stance. A pH level of 7 is considered normal. If runoff

becomes too basic (too alkaline) or too acidic, it can harm

aquatic life when discharged.

Exhibit 2-34

The amount of spoils anticipated for each alternative is:

• Rebuild 256,000 cubic yards

• Aerial 286,000 cubic yards

• Tunnel 241,000 cubic yards

• Bypass Tunnel 201,000 cubic yards

• Surface 178,000 cubic yards

Construction of the cut-and-cover tunnel structuresfor the Tunnel and Bypass Tunnel Alternatives wouldlikely require continuous dewatering during con-struction. This water would be treated as necessaryprior to discharge to reduce pH, total suspendedsolids, and other pollutants as needed and then dis-charged into Elliott Bay. The type of treatment willbe determined during the permitting and designphases of the project. Dewatering also has the poten-tial to cause settlement in the area if proper dewater-ing techniques are not used. Dewatering is not antici-pated for drilled shafts associated with the Rebuild,Aerial, or Surface Alternatives.

Under the Tunnel and Bypass Tunnel Alternatives,the new seawall would be constructed on the water-side of the existing seawall in the vicinity of S.Washington Street. As a result, both the storm drainand combined sewer outfall at Washington Streetwould need to be extended further into Elliott Bay.

How much soil would be excavated and how muchcontaminated material would be removed by thealternatives?

Exhibit 2-34 compares the estimated volume of soilsto be excavated and the portion expected to be con-taminated for each alternative. The soil excavationvolumes include construction spoils and potentiallycontaminated materials.

How do construction effects to potential cultur-al/archeological artifacts compare?

Soil excavation and improvement work could affectunknown archaeological deposits that may be locatedwithin parts of the project site.

In general, archaeological artifacts would be dis-turbed least by construction of the RebuildAlternative, followed closely by the Surface andAerial Alternatives. Construction of the BypassTunnel and Tunnel Alternatives has the potential toaffect archaeological resources the most, because ofthe large volume of soil that would need to be exca-vated for these alternatives.

27 What are the cumulative effects of major projectsunderway or planned in Seattle?

Cumulative effects occur when the effects of separateprojects combine to have more substantial combinedeffects. The Link light rail project and MonorailGreen Line would both be nearing completion whenmajor construction starts on the viaduct in 2008. Ifthese projects overlap, traffic, noise, and utilityeffects would be intensified. Other transportationprojects that may overlap with the viaduct are SR 519phase II, Colman Dock Ferry Terminal Expansion,Mercer Street corridor improvements, SpokaneStreet Viaduct, and I-5 improvements. These projectsare all being closely coordinated to minimize cumula-tive construction effects.

28 What issues are controversial?

The following four issues appear to be the most con-troversial at this time.

What type of structure should be built along thecentral waterfront?

An aerial structure, tunnel, or surface roadway hasvery different effects on the character of the sur-rounding area. People who have provided commentsso far have expressed wide-ranging opinions on whattype of viaduct replacement structure is preferred.There are many people who think the viaduct is avisual barrier between downtown and the waterfront,and they want to see the viaduct removed andreplaced with a tunnel structure. An aerial structureis noisier than a tunnel or surface roadway, whichmakes the area less pleasant for pedestrians, resi-dents, and businesses adjacent to the viaduct and

people engaging in other activities along the water-front. Conversely, there are many people who likethe views from the viaduct as they are driving or wholike the structure itself. In addition, some people pre-fer driving at or above ground as opposed to in anunderground tunnel. Finally, some people are inter-ested in returning Alaskan Way to a surface arterialor are interested in seeing the least expensive solu-tion.

How much roadway capacity in the corridor canbe provided by the alternatives?

The Rebuild, Aerial, and Tunnel Alternatives main-tain or improve roadway capacity on SR 99 and main-tain or improve travel times. The Bypass TunnelAlternative reduces roadway capacity on SR 99, but itmaintains overall capacity in the corridor because theAlaskan Way surface street would be expanded to sixlanes to offset losses to SR 99 capacity. Even thoughSR 99 capacity is similar for the Bypass TunnelAlternative, travel times for trips headed from theBallard/Interbay area to the stadium area wouldincrease. The Surface Alternative would reduce road-way capacity in the SR 99 corridor by as much as 60percent in the downtown area. As a result, traveltimes through the corridor would increase, and somedrivers are expected to avoid the corridor, adding tocongestion on I-5 and other local city streets.

Is continuous construction (24 hours a day, 7 daysa week) needed?

Obviously, continuous construction would directlyaffect people and businesses in the corridor morethan a daytime construction schedule. There's noquestion construction can be noisy and disruptive.Even with continuous construction, the project wouldtake from 7.5 to 11 years to build. If construction isstopped or slowed down at night or on weekends, thetime lost has to be made up by extending the totalconstruction time. That also increases costs becauseof inflation. The tradeoff is between intense, continu-ous construction that finishes as fast as possible butcan be painful while it lasts, and a more moderatepace of construction with breaks and lulls that contin-ues for many more years.



Can SR 99 be closed entirely for construction?

This Draft EIS evaluates effects assuming that SR 99would not be completely closed during construction.Two lanes of traffic would be maintained in the AWVCorridor during peak traffic hours or detours wouldbe provided. During non-peak periods, such as night-time or weekends, lanes could be restricted or por-tions of the corridor could be closed. The sectionthrough Battery Street Tunnel (between SenecaStreet and Denney Way) could be closed for as muchas 10 weeks during one summer.

These are the minimum closures or restrictions. If SR99 were closed for extended periods, the overall timeneeded (and cost) might be reduced. Extended clo-sure would likely have effect on traffic over a largerarea of the city and region. Some of these effectsmight be reduced by additional transit service andimprovements to other roadways. Different ways tobuild the project, including long closures of SR 99and a variety of construction techniques, could con-tinue to be explored as the preferred alternative isdeveloped and will be presented in the Final EIS.

29 What issues remain to be resolved?

The preferred alternative needs to be determined. Itwill be selected by the lead agencies (City of Seattle,WSDOT, and FHWA) in 2004. The preferred alterna-tive will combine and refine ideas from the currentalternatives and options. The preferred alternativewill also have more details on how it could be builtand refinements on how the street landscaping andamenities could be designed.

Information in the Draft EIS, available funding, andpublic comments received during the Draft EIS com-ment period will all be considered before a decisionis made. When the preferred alternative is chosen,operational and construction effects for it will be fur-ther evaluated. This analysis will be included in the Final EIS.

In general, transit trips into downtown are projectedto substantially increase by 2030 regardless of thealternative selected for this project. Currently, it is

estimated that 23 percent of trips entering downtownenter via transit or other modes (bikes and pedestri-ans). That number is predicted to nearly double bythe year 2030. Currently, funded transit service with-in the Puget Sound region for the year 2030 is notexpected to meet the projected demand without addi-tional investments in the region. Therefore, addition-al investments in transit are needed to meet regional2030 transit goals. This overall transit gap is a region-al transportation planning issue and beyond thescope of this project.

This project includes a variety of investmentsdesigned to decrease reliance on single-occupancyvehicles and increase other modes of transportationduring construction of the project. Some of theseinvestments could also provide long-term benefitsonce the project was completed. The investments pro-posed as part of constructing this project are identi-fied in a Flexible Transportation Package, describedin more detail in Chapter 10 and Appendix B, Section 3.1.8.

30 What adverse effects from the project would notbe mitigated?

Once constructed and with reasonable mitigation, byand large, all alternatives improve conditions com-pared to today and do not have many adverse effects.However, there are some adverse effects that cannotbe mitigated.

The Bypass Tunnel Alternative would increase traveltimes between the Duwamish and Ballard/Interbayindustrial areas. This would adversely affect driverstraveling between these areas. This route is importantfor freight.

The Surface Alternative increases congestion at manyintersections through the downtown area, increasestraffic volumes on city streets and adds traffic to I-5.Combined with slower speeds, travel times for tripsthrough downtown would substantially increase.

Along the central waterfront, the Aerial Alternativewould increase the width, and therefore the shadow,of the structure. This would increase the visual effects

of the structure on pedestrians and increase the barri-er effect between the waterfront and downtown core.

During construction, all alternatives would have someadverse effects that cannot be mitigated.Construction activity and detours would be disruptiveto all areas along the corridor at one time or another.While efforts would be made to keep traffic moving,overall congestion along the corridor and in thedowntown area would increase during construction.

Along the central waterfront, access to the pierswould be maintained, but would become more diffi-cult when the construction activity is nearby. Theseperiods would likely last for several months. Evenwith a dedicated public information campaign, park-ing shuttles, and other mitigation, there would likelybe substantial adverse effects to some local business-es.

To reduce the total time needed for construction,work would go on almost continuously (24 hours aday, 7 days a week). Even by avoiding noisy activitiesduring nighttime hours and using the quietest equip-ment and techniques available, there would beunavoidable disturbance to nearby areas.

chapter 2 - summary and comparison of alternativescommunity and environment. this chapter also gives...

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