In the Matter of: Expert Arbitration Panel's Review of Noise and Demand/System Management Issues at Sea-Tac International Airport
The Expert Arbitration Panel on Noise and Demand/System Management Issues (the "Panel") set forth in our January 9, 1995 Order on Phase I Noise Issues what we consider to be our responsibilities under Puget Sound Regional Council ("PSRC") Resolution A-93-03 with respect to the reduction in noise impacts that must be shown before the PSRC should approve construction of a third runway at Sea-Tac International Airport. The Resolution requires that we determine whether the Port of Seattle ("POS") "has scheduled, pursued and achieved a reduction in measurable, real on-the-ground noise impacts." We held that to meet its burden under the Resolution, as we interpret it, "the POS must offer us reliable evidence, based upon actual measurements of on- the-ground noise, that by 1996 there has been an objectively measurable, meaningful reduction in aircraft noise impacts in the affected communities surrounding the Airport" [Footnote 1] We suggested that we would address three sets of subsidiary questions before resolving whether the POS had met its burden: "(a) what measures of noise impacts should be used (that is, what noise 'metrics' should be selected), (b) where should the measurements of noise be made, and (c) how much reduction in noise, by these measures, must be achieved, and over what time period?"
Following our January 9, 1995 Order, the Panel has held two rounds of hearings on Noise Issues: one in May 1995, and one in November 1995. The POS, the Airport Communities Coalition (the "ACC") and the Regional Commission on Airport Affairs (the "RCAA") have participated actively in these hearings and have offered the Panel volumes of evidence and distinguished expert testimony on these difficult questions. The Federal Aviation Administration ("FAA") and the Airport Noise Group have also been present. The POS has been represented by Diane Summerhays, from the Port's staff, and by Paul Dunholter, a noise expert with Mestre Greve Associates. The ACC has offered the expert testimony of Sanford
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Fidell of BBN. During the November 1995 hearings, the RCAA offered expert testimony by Alice Suter.
These hearings have led to a resolution of the first two questions. There appears to be no significant dispute about what noise measures should be compiled or where the measurements of noise should be made. As a result of our January 9, 1995 Order, the POS has proposed to offer the Panel a wide variety of noise measurements taken both at the 11 permanent remote monitoring sites and at six supplemental monitoring sites the POS established in response to our Order. [Footnote 2] The POS will no longer rely only upon DNL as measured by the Noise Monitoring System as it existed when the Resolution was enacted. [Footnote 3] The most difficult, third question.
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however remains controversial: "how much reduction in noise, by these measures, must be achieved, and over what time period?"
The Panel has been offered two contrasting approaches to this question. The POS suggests that the Panel should use the following standard to determine whether the POS has satisfied the noise reduction condition of the Resolution:
whether reductions in noise impact are experienced by several thousand affected people as measured on any one measure of noise reduction, provided that the entire record of reductions, taken as a whole, shows a pattern of reductions.
The POS would have the Panel make this determination on the basis of reductions in noise over the period 1989-1990 through 1995.
The ACC, in contrast, has proposed that the Panel should find that the noise reduction condition of the Resolution has been satisfied only if:
The Port of Seattle has demonstrated that its noise
abatement and mitigation program has resulted in a
reduction in average noise levels (Ldn) of at least
4.5 dB for at least half the people who, in April
1993, were exposed to noise in excess of an Ldn of
65 dB. [Footnote 4]
Both the POS and the ACC recognize that the selection of either of these competing standards for judging compliance with the Resolution would determine the outcome of these proceedings. The ACC acknowledges that the POS could satisfy the standard the POS has articulated by showing the reduction in DNL anticipated in its original NVM, and the POS has conceded that it could not meet the standard the ACC has offered to us.
The Panel feels strongly that it would be premature to decide now whether the POS has met its obligation under the Resolution. We will not make that determination until we have reviewed all the data to be offered to us early next year on reductions in noise impact from 1993 through 1995 and on reductions in noise impacts following the Noise Mediation Agreement in 1989 and leading up to the enactment of the Resolution in 1993.
[Page3]We can say now, however, that in making our final judgment we will not adopt the decision standards offered by either the POS or the ACC. The Port's proposal has two fundamental problems: First, the POS minimizes the requirements of the Resolution by keying compliance to what might be insignificant changes in a single measure of noise reduction. Second, the POS relies upon the use of 1989-1990 as the base period even though this approach has been unequivocally rejected by the Panel. [Footnote 5] In addition, by focusing solely upon the number of people affected, the Port's proposal may also unduly minimize the significance of the Resolution. We encourage the POS to assess the percentage of the population affected, and the amount of noise reduction achieved by the noise reduction programs the POS is relying upon to show compliance with the Resolution.
The ACC's standard is also unacceptable for two reasons. First, as we noted in our January 9, 1995 Order, the Panel believes that it should not rely solely upon DNL to measure reductions in noise impacts. Second, the ACC limits itself only to the impact upon people currently exposed to DNL of greater than 65 dB even though the Panel has expressed its concern about the reduction in noise impacts for people in areas beyond that range.
Both the POS and the ACC recognized, during the course of the hearings, that ultimately the Panel will have to rely upon its best professional judgment to make its determination. We therefore plan to examine all of the data that are shown to us, and to consider all of the evidence we have been offered about how to interpret the significance of these data, to determine whether, taken as a whole, the pattern of change in noise impacts is sufficient, in our judgment, to meet the requirements of the Resolution.
We recognize, as both the POS and the ACC appear to, that our judgment about compliance will ultimately have a political or social character. At the same time, we believe, as both the POS and ACC do in different ways, that our exercise of judgment should reflect the best insights we can gain from established scientific sources about the significance of changes in various noise metrics as indicators of changes in the impact of noise on the people in the communities surrounding the Airport.
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[Footnote 1] We restated this test the following way: "The question we must decide is whether there has been a reduction in real noise impacts that by objective measures is significant and meaningful." We explained that we do not believe that either an "unreasonable" (i.e. unreachable or infeasible) or a "meaningless" (i.e. inappreciable) reduction in noise was contemplated ...
[Footnote 2] The locations of the supplementary monitoring sites reflected community input by the ACC and RCAA and are no longer seriously in dispute. The residents of Mercer Island have suggested that the noise impacts they experience may not be captured by the monitoring system being used by the POS. The Panel acknowledges their criticisms, but finds that, for the Panel's purposes, the Port's expanded monitoring system(including the supplemental sites) adequately reflects the levels experienced by a representative sample of the impacted population.
Some questions have been raised about the methods proposed by the P0S to "back-calculate" noise measurements for past periods of time as set forth in the August 16, 1995 report "Methodology for the Measurement and Prediction of Aircraft Noise Levels at Seattle-Tacoma International Airport" submitted by the POS. Although the Port's method of back-calculation depends upon some strong assumptions about the flight tracks used by aircraft serving the Airport in the past and about the engines used on those planes, the Panel accepts the Port's approach as reasonable under the circumstances and notes that no alternative method was offered to the Panel.
[Footnote 3] When these proceedings began in August 1994, the POS presented the Panel with its July 1994 Noise Validation Methodology ("NVM"). In our January 9, 1995 Order, we found that the POS needed to revise its NVM to enlarge its scope. The original NVM was designed only to show compliance with certain components of the 1989 Noise Mediation Agreement: the "Noise Budget", the "Nighttime Stage II Limitations Program", the ground runup noise restrictions and the residential insulation program. The Panel ruled that compliance with the Noise Mediation Agreement was a necessary, but not sufficient, condition for satisfying the Resolution. The Panel explained that to satisfy the Resolution, the POS had to demonstrate to our satisfaction that it had provided reasonable, but meaningful reductions in noise impacts in the affected communities between the time of passage of the Resolution (in 1993) and the time for PSRC approval of the third runway (April 1996). In response, the POS submitted a Revised NVM to the Panel in connection with our hearings in May 1995.
The revised NVM submitted by the POS fell short of the Panel's expectations because, in spite of our January 9, 1995 Order, the revised NVM did not articulate any method for analyzing data to be collected or for interpreting the results to determine whether the noise reduction condition of the Resolution has been met. Instead, the revised NVM simply presented the noise and operations "metrics" that would be collected, the Port's response to the Panel's concern that more monitoring sites needed to be established, and a method to use the new measurements to "back-calculate" the needed metrics for past years.
At the May 1995 hearings, the Panel expressed its concerns about the inadequacy of the revised NVM, especially given the fact that only 11 months remained until the April 1, 1996 deadline in the Resolution. With input from the POS, the Panel established a schedule for submission of the missing pieces of the NVM, namely the data analysis methodology and the decision criteria. The POS responded by finally submitting its method of data analysis in August 1995 and its proposed method of evaluation in October 1995.
[Footnote 4] The ACC has urged us only to consider the reductions in noise impacts that can be attributed solely to efforts of the POS and to reject reductions in impacts that have resulted from national initiatives to reduce aircraft-generated noise. We do not believe that in enacting the Resolution, the PSRC intended to require the POS to achieve a meaningful reduction in noise impacts without taking into account the results of the national Stage II phase-out. The national program focuses on the composition of airline fleets, not on airport fleet mixes. The POS has demonstrated that the airlines operating at Sea-Tac have shifted to Stage III aircraft there at levels above national norms. We reject the ACC's suggestion.
[Footnote 5] The Panel noted during both the May 1995 and November 1995 hearings that it stands by its January 1995 decision to use 1993 as the "base period" for the assessment of reductions in noise impacts. We will not elaborate here all of our comments on this contentious issue. The POS should show changes in each of the metrics it relies upon for the period 1993 through 1995, and relate its analysis of the significance of noise reductions to those changes, even if the rest of its proof continues to focus on changes between 1989/1990 and 1996. We do want to repeat, however, an important caveat offered in our January 1995 order [RCAA note: at p.6 of said order]. While we will focus on the reduction in noise impacts from 1993, "[t]he Panel believes ... that the significance of the 1993-96 data will be best understood in the context of as much earlier data as the POS can make available to us." As we have said before, in judging whether the observed reductions in noise impacts are both "reasonable" and "meaningful," the Panel will not ignore improvements achieved under the Noise Mediation Agreement before the Resolution was enacted.