By: Barbara E. Lichman, Ph.D., J.D.

In a June 19, 2020 Findings of Fact, Conclusions of Law, and Judgment (“Judgment”), the District Court of Jefferson County, Colorado, in Board of Commissioners of Adams County v. City and County of Denver, recounted in detail the expert testimony offered by Adams County, that fatally undercuts the traditional reliance by the City of Denver, operator of Denver International Airport (“DIA”), and airport operators in general, on “noise modeling” in place of “noise monitoring” to determine the impacts of the aircraft noise on surrounding communities.

The Judgment exhaustively recounted evidence offered by Adams County, detailing the flaws in the noise modeling utilized by DIA to document compliance with the noise provisions of the “Intergovernmental Agreement [for a new airport], (‘IGA’),” originally entered into between the two parties on April 21, 1988, when the plan for development of the new Denver airport was being initiated.

Specifically, the IGA establishes certain Noise Exposure Performance Standards (“NEPS”), as well as a specific mechanism for calculating the NEPS, including the requirement for use of “noise monitoring,” rather than “noise modeling” to determine compliance with noise limits established in the IGA.

Despite the specific requirement for noise monitoring, Denver persisted, over the years, in the use of various noise models, insisting that they accurately depict noise impacts. Nevertheless, evidence from noise experts for Adams County established, to the satisfaction of the Court, that there was “a wide discrepancy between values estimated by ARTSMAP [noise model] and the values [ ] measured by the ANOMS noise monitoring system,” Judgment, pp. 2-3. According to the evidence presented in Court, the ARTSMAP noise model seriously underestimated noise levels as compared to those reflected on the actual monitors. Judgment, p. 22.

Ironically, the Judgment comes just 60 days after the Federal Aviation Administration (“FAA”), in its April 14, 2020 Report to Congress, repudiated noise monitoring on the purported ground that “real world situations” such as “monitoring” can include “various sources of error” such as, for example, traffic noise, FAA Report, § 7, which allegedly cause noise to be overstated. The Adams County Judgment, based on credible expert testimony, has, however, has undercut that claim.

In the final analysis, the Judgment serves at least two purposes: (1) theoretically, it reinforces the viewpoint of those who live with airport noise on a daily basis and seek actual noise measurement, not mathematical synthesis, to validate their observations; and (2) practically, the Judgment penalizes the violator and thereby sets an example for other airports that might be disposed to taking a shortcut in the calculation of noise impacts. Of course, the Judgment is subject to appeal. Stay tuned for the next chapter.

Source: Aviation & Airport Development Law News