City of Portland, OregonOverlay Zone. There are several contours within the zone. The boundaries of the 65 DNL and 68 DNL noise contours are based on the 1990 Portland International Airport Noise Abatement Plan. The 55 DNL noise contour is based on the 2035 50th Percentile Forecast Noise Exposure Map in the 2010 Portland International Airport Master Plan Update. A set of quarter-section maps, known as the PDX Noise Zone Maps, is available for viewing at the Development Services Center. The maps are the official reference maps for the PDX Noise Zone regulations. The maps show the 55 DNL noise contour and each successively higher noise contour in one DNL increments. https://www.portlandoregon.gov/bps/article/53357 -- Additional Information: Category: Zoning Code Purpose: Map location of noise DNLs for application of regulations. Update Frequency: Not Updated -- Metadata Link: https://www.portlandmaps.com/metadata/index.cfm?=DisplayLayer=53427ArcGIS DynamicMapLayerhttps://hub.arcgis.com/datasets/e6b6fe6c6a6840a096f89f6be703dc64_144engPortlandMaps Open DataPublicAirport Noise DNLS 65 and 68 [Oregon--Portland]Web servicesOregon--PortlandOregonLast Modified: 2024-09-12