Construction noise programs need to include both proactive avoidance of noise and the reactive ability to control noise if it becomes problematic. Proactive measures include “buy quiet” programs using product and vendor guidance sheets or lists of acceptable equipment along with soundscape management plans and contractor noise control plans. Reactive measures include use of a noise control plan to observe and inspect the work, enforce limits, and hold contractors accountable.
A comprehensive noise specification provides control over the amount of noise generated. It can include definitions, time and equipment restrictions, source emission limits, receptor limits, a noise control plan, penalties, and incentives.
A noise mitigation or control plan incorporates soundscape goals in the bid process. To accommodate the NPS soundscape plan, the contractor proposes equipment locations, times, and durations, including worst-case scenarios. The contractor also predicts noise levels, identifies impacts, and commits to mitigation. The noise control plan then becomes enforceable in the field.
Once noise specifications are in place, enforcement can hold a contractor accountable. This requires compliance measurements and mechanisms for complaint investigations. Thalheimer emphasized that whoever interacts with a contractor has to be authorized to do so. A training program and guidance manual for park managers could demonstrate generic noise specification and compliance measures.
Expectations have to be realistic, Thalheimer said. Construction projects are not going to be inaudible, and interests inevitably conflict. The use of the best available controls and techniques can manage, mitigate, and minimize noise, but flexibility will be needed once a project begins. For instance, park managers may need the flexibility to approve construction that exceeds a source limitation without exceeding a receptor limitation. Good public outreach can prepare park visitors for noises that are unavoidable.