COSTS OF NOISE MITIGATION AT SEA-TAC INT'L AIRPORT
Mitigation paper #2 - Bad Noise Contour Predictions
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THE COSTS OF NOISE MITIGATION AT SEA-TAC INT'L AIRPORT
Mitigation paper #2 - Bad Noise Contour Predictions
By: Hans Aschenbach
This paper will contend that noise contour maps for Sea-Tac International Airport (STIA) presented in the Flight Plan FEIS are not accurate. The maps in question are Figures C-6 through C-16 and in particular figure C-7. These maps give predicted noise contours for STIA with and without the third runway for years 2000, 2010 and 2020. Because of inconsistencies in their presentation these maps are not useful in assessing the potential environmental noise impact on the surrounding communities. The maps also inaccurately depict no increase in noise impact on the surrounding community and so mask the true cost of the project by ignoring these significant mitigation costs.
One might ask, what is the importance of these noise contours to the cost issue anyway. The noise contour maps are used to define the boundaries of the Port of Seattle (POS) Noise Remedy Program (NRP). Thus these contours will govern which properties are eligible for an outright buyout and which would be eligible for lesser degrees of mitigation including insulation or nothing at all.
Most airport authorities base their program on a current year noise map. They fund the worst problems first and work outwards as more funds become available. POS has set its program up differently. It has committed to mitigate all properties within a permanent noise contour. Permanent is defined as being at a certain noise exposure for a twenty year period. So the STIA program boundary is based on a twenty year future out-year. In actuality STIA's program is no different from any other. STIA doesn't have enough funds to fully mitigate the problem either the current exposure area or the much smaller future one. So STIA funds the worst areas first placing others on a long waiting list. But because of its program design STIA deals with a much smaller area than it would if it used the current year map.
It is important to note though that the problem at STIA is one of the worst in the country. Thus the assumptions that go into creating the POS future noise contour predictions become all important. By using a smaller future noise contour POS can de-emphasize the enormity of today's noise externality problem at STIA. The costs of mitigating
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the noise problem around STIA are huge in any case. The costs run into the hundreds of millions of dollars since the area surrounding this small airport has always been residential right up to its boundary. But shrinking the twenty year future noise contour means a difference of millions of dollars of program costs.
In order to know the future, it is sometimes best to look at the past. Before we examine the FEIS maps for the year 2000 and beyond, we will explore the history of STIA noise contour predictions for the past twenty years.
STIA NOISE CONTOUR-PREDICTIONS 1973 TO PRESENT:
In 1973 the Port of Seattle and King County produced the Sea-Tac Communities Plan (SCP). This plan had several purposes or effects that are important to note for this paper.
1) The STIA second runway became operational in 1972. The SCP was designed to allay public fears on the seemingly permanent environmental noise effects.
2) It promised to mitigate the environmental noise effects that had a life longer than twenty years.
3) But more important to our discussion, it assured the public that noise was at its peak in 1973; the next twenty years would see significant decreases that would leave noise levels at tolerable levels in the surrounding residential communities.
To that end POS produced a series of noise exposure maps in 1973. The series is typified by:
1) a current year map based on current noise levels and
2) a series of future year noise contour projections based on assumptions made or directed by Port staff.
[Footnote 1] Sea-Tac Communities Plan; Port of Seattle and King County; undated; ch. 5,2 Noise Exposure pp. 11 - 14.
Footnote 2] Note: The current year map and the methodology used to determine it are not the subject of this paper. It is the future year projections and the assumptions behind them in which we are interested.
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A similar series was produced in the early 80's. [Footnote 3] Finally the 90's series is the map recently produced for the Part 150 update. [Footnote 4]
These map series all express a consistent theme: "Forget the past, its a new day and the future noise contours are shrinking.". This message is not quite true. But before we get into the issue of why the Port would rather look forward to new noise contour projections than back to old ones, let us examine the three different series of maps that have been presented and then discuss the comparability between them.
There is in fact a lack of comparability between these series that makes drawing any conclusions about the accuracy of the predictions very difficult --- but not impossible. As an example I have selected the 90's map from each of the series. ( Attachment 1 , Attachment 2 , Attachment 3 )
The first clue - the maps don't even look alike. Let's decompose this further. We have had differences in no less than seven significant areas.
1) Noise Metric ANE (70's series) vs. Ldn (80's & 90's series) [ANE + 35 = Ldn] [Footnote 5]
2) Methodology Actual sound measurement (70's series) vs. INM computer model (80's & 90's) [Footnote 6]
3) Map Design Noise value per quarter section (70's series) vs. continuous curve noise contour (80's & 90's series)
4) Computer Model INM model change by FAA eliminated east/west bulges from 80's series.
[Footnote 3] Sea-Tac International Airport Noise Exposure Update; Port of Seattle; June 1982; Exhibits 6-3 through 6-6
[Footnote 4] Existing Noise Exposure Map 1991; Sea-Tac International Airport; Working Draft.
[Footnote 5] Ldn is an annualized, average, cumulative noise level. It has a built in penalty for night disturbances. ANE is an older noise metric but is similar to Ldn. ANE can be made roughly equivalent to Ldn by using the formula: ANE - 35 = Ldn.
[Footnote 6] INM stands for Integrated Noise Model. It is a computer model to develop noise contours used by the FAA in the Part 150 program. Part 150 sets minimum planning standards for airport noise compatibility.
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5) Scale of Base Map -- Different for all three series
6) Planning Period -- 1973 to 1993 (70's series) vs. 1980 to 2000 (80's & 90's series)
7) Map Year -- Map years of different series are not parallel
To make the map series comparable has been a difficult conversion. It was more than a conversion of apples to oranges; a whole basket of fruit had to be sorted. But as the comparisons were made one consistent truth has emerged: "In twenty years of trying the Port has never gotten its contours right.". POS has always predicted future noise contours smaller than was actually realized.
I created composite maps to compare the three map series. ( Attachment 4 & Attachment 5 ) These two maps give a history of POS noise contour predictions (in dotted lines) and the actual contour when the year is reached (in solid color).
A brief word on methodology is appropriate here. We converted the 1973 series from ANE to Ldn and then converted all three series to a common scale. We made comparisons only of the 75 Ldn contour for simplicity. Wherever the record is complete, the pattern of underprediction is the same for 75, 70, and 65 Ldn. The comparisons between prediction and actuality were made for the area south of the airport. Two thirds of takeoff s are to the south, consequently the southern noise contours are larger and the differences easier to depict.
The maps show, for example, that POS completely missed its projection for 1993 that was made in the 1973 series. (on Attachment 4 , look at 1993 Prediction [referred to as projection] & on Attachment 5 look at 1991 Actual. Missing these predictions by underestimating them of course has very positive consequences for POS in terms of noise mitigation commitments and program dollars; the programs have a smaller area and therefore less cost.
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This map gives the 1973 base year contour in yellow. 75 Ldn reached as far south as S. 255th PI.. POS predicted that the contour would shrink to S. 2 10th St. over the twenty year planning period.(depicted by small dots) POS was relying on a federally mandated phase-out of Stage I aircraft by 1985 This didn't occur until 1986. POS also relied on an early phase out of stage 2 aircraft which didn't occur at all.
This map also depicts the 1984/85 noise contour in orange. Although some shrinkage of the contour occurred from 1973, the rate was not fast enough to attain future predictions made in 1973. POS realized that it would miss targets set for 1993. So when POS passed Resolution 29,4') implementing the Part 150 program, it also changed the Noise Remedy Program planning period out-year from 1993 to the year 2000. POS did not count on the overall rise in operations due to deregulation and hubbing at STIA. POS revised its target to S. 229th St. for 1990, from the 1 993 target of S. 2 10th St.
Since the methodologies are different between the two series it is questionable as to whether the systems can even be compared. The point is made however that the future predictions made in 1973 were completely unrealistic.
The newest layer in grey is the actual 75 Ldn contour of the 1991 Noise Exposure Map. The east/west bulges that previously covered parts of SeaTac City and Burien have disappeared. [Footnote 7]
This contour also illustrates that in the previous five years the noise problem actually got worse due to increased air traffic at STIA. The noise contour grew on the north /south axis (in the south from S. 242nd St. to S 244th St.). This may seem a small
[Footnote 7] Letter from POS Planner Diane Summerhays to Eric Shields, Planning Director, City of Des Moines; dated 17 Aug 1992. In the letter Ms. Summerhays attributes the disappearance of the bulges to a change in the INM without further explanation.
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change, but please recall that POS had predicted shrinkage to 229th St.. Not only was the magnitude of the change wrong but the direction of the change was wrong as well.
The final element on this map shows where POS believes 75 Ldn will be in the year 2-000.(depicted in dots) Year 2000 is .the contour on which the current Noise Remedy Program (NRP) is based and the prediction made in 84/85 is its basis.
POS predicts that in the next seven years, 75 Ldn will shrink from S. 244th St. to S. 214th St. This prediction which was made in l985 continues to stand. POS has not revised it despite the following facts:
A. All Stage I aircraft operations have now been discontinued, so no gain can be made there.
B. Sixty-three percent of the jet fleet currently operating at STIA are already Stage 3. STIA is relying on the conversion of the remaining 37% of the Stage 2 fleet to achieve these gains. Even if the full phase out of stage 2's occurred by year 2000 we are not sure that this contour shrinkage would occur. Many Stage 3 aircraft are not much quieter than the Stage 2. But a federal waiver already allows for an extension of 15% of the stage 2 fleet until the year 2004. (see explanation below) So POS can rely at best on a further reduction of only 22 % of the stage 2 fleet by year 2000.
STIA is also relying on the reduction of Stage 2 night flights to achieve some of the goal but has recently granted variances to that 'voluntary' program. Due to airline financial troubles we believe that the variances will continue.
In light of 1) the current enlarging trend of the noise contours; 2) currently increasing number of aircraft operations; and 3) industry resistance to Stage 2 phase-out which has already been supported by the federal government (see below), we don't believe that the predicted year 2000 noise contour is realistic.
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CONCLUSION to STIA Noise Contour Predictions -1973 to Present:
For twenty years, POS has been predicting that the noise contours around STIA would shrink in a substantial way. When POS found that its 1993 targets would not be achieved, it changed the rules and set the achievement date to the year 2000. The result has been a serious underestimation of costs and mitigation measures for buyout and insulation.
Our research has found that minimal shrinkage has taken place during the period in which the bulk of aircraft conversion from Stage 1 to Stage 3 has already taken place.
In light of the current noise contour expansion trend and other facts presented, we do not believe that the Port of Seattle can achieve its current goal for year 2000.
THE CURRENT SITUATION of NOISE CONTOUR MAPS in FLIGHT PLAN:
The previous discussion of historical noise contour predictions serves to establish that something is amiss in POS ability to predict accurate noise contours. The inaccuracy of past predictions sheds grave doubt on year 2000 and other contours presented in the Flight Plan EIS. In fact Flight Plan states on page C-24: "The primary time period for analysis was 2020, which is representative of the long term noise environment.". This is the first deficiency. The analysis should have concentrated on the year 2000 where at least some credible assumptions could have been made. The idea that anyone could make accurate noise projections 30 years into the future for purposes of serious analysis, is absolutely ludicrous. The way POS has handled the past twenty years of predictions is only further reason to give no credibility to these year 2020 predictions and to judge the entire analysis inadequate.
Furthermore the most significant contours for predicting noise impacts on the surrounding community are the year 2000 contours because they will add to an existing noise environment that has been
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in place well past the twenty year exposure criterion used by POS. The year 2000 contours were not even presented in the DEIS. Thus the public has not yet been given the opportunity to even comment on them.
FIGURE C-7 of FLIGHT PLAN FEIS
Figure C-7 shows two 65 Ldn noise contours at STIA for the year 2000: 1) STIA without the project and 2) STIA with the third runway. However the third runway contour shown is for the runway used in a "mitigated" fashion. Flight Plan p. C-26 states that: "Under the mitigation assumption, the runway would handle daytime arrivals only.".
This 'mitigation assumption' is absolutely ridiculous. It is analogous to a developer saying that a 400,000 square foot (sf) addition to an existing 'million sf office complex will not have any effect on LOS for surrounding streets. When asked to justify the statement the developer states: "Yes I'm building it but I'm not going to use it much." Every use has a projected traffic demand. POS cannot define its demand in order to mask the effects of the noise externality on the surrounding community.
On the other hand if we accept the mitigated scenario then we must again ask the question posed bv airport planner Jerry Bogan: "How much bang are we going to get for our buck on the third runway". If we use the third runway for daytime landings only, Bogan's contention is proved. [Footnote 8] The third runway will not give us any significant capacity over that which we would gain by installing a new set of navaids on the second runway.
Flight Plan only presents limited information about the map in figure C-7 and the mitigation scenario. The following points must be
[Footnote 8] "Discussion of Airspace and Runway Capacity Issues and Alternatives" by Gerald Bogan in Regional Commission on Airport Affairs document dated 21 Jan 1993. A copy of this document was presented to each of the members or the PSRC Transportation Policy and Executive Boards.
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addressed in order to get to the true story behind the 'mitigated' third runway.
1) All assumptions underlying the two contours must be presented in detail. It is difficult to imagine how Flight Plan was able to get the contour for the third runway scenario entirely contained within the 'no project' contour. Given the right assumptions however black can become white and three runways can have less noise impact than two.
2) It is known that on previous noise contour maps, that POS has assumed away all Stage 2 flights by the end of 1999. POS has done this despite the history of federal waivers extending Stage I aircraft. And, incredibly, POS has made this assumption in the face of federal policy defined in CFR 14 Part 91.873 that allows U.S. air carriers an unretrofitted Stage 2 waiver of up to 15% of their fleets until the year 2004. POS argues that its 'voluntary' Mediated Agreement calls for a local Stage 2 phase out by the end of 2001. On some noise maps POS has made a 5% Stage 2 adjustment for year 2000 contour predictions. We don't know if they have done that on map C-7 and in any case it is not enough. In light of airline financial problems we expect the airlines to take full advantage of the 15% federal waiver beyond year 2000.
Furthermore POS was recently unable to get the airlines to even reschedule Stage 2 flights away from the nighttime hours of midnight to 6 AM as called for under the Mediated Agreement. If POS is unable to get a schedule change, one wonders how POS will be able to achieve a 'voluntary' phaseout of aircraft that still have substantial economic life.
This 15% Stage 2 assumption change alone would expand both noise contours presented in Figure C-7 and would give a truer picture of the extent of the noise problem and the associated mitigation costs.
3) POS must expound on the "mitigated" runway scenario if it wishes to use it as the basis of a noise contour. POS must declare what legal guarantees it will give that the 'mediated' scenario will be used, for
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how long, and what the maximum number of daytime arrivals would be. POS also must explain how it can justify expenditure of half a billion taxpayer dollars to construct a limited use, mediated runway.
4) A more likely scenario for the third runway would be full utilization. The FEIS should have shown such a map under two scenarios: 1) three runways with equal distribution of landings and takeoffs and 2) the third runway with its likely more than 33 % of operations; probably 50% of operations.
A number of operational situations exist that point to the third runway getting as many as half of STIA operations. 1) The first and second runways are too close together. 2) the proposed new generation of jumbo jets are projected to be too heavy to operate on the existing runways. A third runway built to a higher strength standard will likely receive all new jumbo jet operations. It is likely that operations on either the first or second runways will dwindle to a spillover status.
5) A much more detailed set of year 2000 noise contour maps must be produced also showing 70 and 75 Ldn. STIA is unique among all of the proposed Flight Plan sites in that it will have many times the noise mitigation costs of any of the sites. These costs must be taken into account if an adequate cost comparison between sites is to be made. The $50 million [Footnote 9] built into Flight Plan for STIA noise mitigation is for second runway mitigation only and is totally inadequate in light of recent cost revelations by POS. Not only will the third runway evaluated under the National Environmental Protection Act (NEPA) force POS to assume left over second runway mitigation, but the third runway will also shift noise westward by several thousand feet potentially forcing POS to re-insulate residential property and institutions to a higher standard than is currently being done i.e. custom insulation ($18,000 per home) vs. standard insulation ($8,000 per home).
[Footnote 9] PSATC Flight Plan Project DEIS; PSRC and POS; dated Jan 1992; Table 2 Flight Plan Phase III Capital Cost Estimates p. C-84.
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SUMMARY
POS has been able to mask the enormity of the noise mitigation problem by basing its Noise Remedy Program on future noise contours. Other airports have based their programs on the current year noise map and funded the worst problems first. STIA has always projected out twenty years. In theory the results might be the same for both types of programs if the noise contours shrink as predicted. Not only have the contours at STIA not shrunk, but STIA has never had to discuss the true costs of the noise problem in the Highline Community area as a result of its clever program design.
Only recently has POS released estimates for potential insulation obligations within the existing Noise Remedy Program Area (NRPA) that total $255.9 million. [Footnote 10] We estimate that the current NRPA contains half or less of the residential and institutional properties currently eligible for insulation under federal Part 150 guidelines. Dealing with the current (1991) boundaries of 65 Ldn could swell potential insulation obligations to $500 million. This figure does not include potential buyout areas that qualify under the POS criterion that they be located in 75 Ldn for at least twenty years. Obviously, POS does not want to discuss noise mitigation costs of half a billion dollars and still present STIA as the low cost expansion site.
FINAL CONCLUSION:
By using inaccurate and meaningless noise contours for the third runway in year 2000, Flight Plan has been able to mask noise mitigation costs at STIA. The Flight Plan consultant has somehow made the year 2000 contour with the third runway smaller than the contour without the runway. This deceptive contour makes it seem that the third runway will not have any associated noise mitigation costs. The National Environmental Policy Act will make any rise in
[Footnote 10] "Estimated Remaining Mitigation Costs for the Second Runway at Sea-Tac Int'l Airport" by Hans Aschenbach. This information was developed from POS documents distributed to members of the Port*s Technical Review Committee and through personal interviews with Earl Mundy, Manager of Noise Remedy, POS.
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noise a mitigatable item. Given the size and density of the residential community in the Highline area, noise mitigation for the STIA third runway could run into the hundreds of millions of dollars. Those costs would be mandatory under NEPA, not voluntary as Part 150 noise mitigation is.
Those hundreds of millions of dollars added to the already inflated cost of the third runway might lead to a different project decision. Of all the Flight Plan sites considered only STIA is surrounded by such a dense residential community. For other sites buyout of all noise affected properties within 65 Ldn has actually been proposed. A proposal of that sort for STIA would cost many BILLIONS of dollars. Among all the Flight Plan site alternatives, noise mitigation costs are only a significant cost item for the STIA site. By avoiding a discussion of those costs, the STIA site has been inappropriately presented as a lower cost site.
Thus the entire Flight Plan recommendation is suspect and quite probably has led to adoption of an uneconomic project decision.
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