PD-17-00001 Marian Meadows Full Record with Index (2)

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Marian Meadows Rezone and Subdivision Final Environmental Impact Statement 3-98 Figure 3-17 Aviation Safety Zones 2 What mandates or standards for airports have been established and how are compatible land uses adjacent to airports determined? The GMA, under RCW 36.70A.510 and RCW 36.70.547, provide that comprehensive plans and development regulations discourage the siting of incompatible uses adjacent to general aviation airports. Prior to siting uses near airports, formal consultation is required with the Aviation Division of WSDOT, which also provides technical assistance in developing plans and regulations. The WSDOT Aviation Land Use Compatibility Program focuses on:  Hazards to aircraft operation, generally including: o Obstructions to the airspace required for flight to, from, and around an airport; o Wildlife hazards; and o Other forms of interference with safe flight, navigation, or communication.  Hazards to persons and property from aircraft operations.  Noise impacts on persons and property from aircraft operations. The major issues regarding hazards to aircraft relate to obstructions that affect flight, takeoff, and landing. The WSDOT Aviation Division accepts the height hazards indicated in the Federal Aviation Administration standards under 14 Code of Federal Regulations (CFR) Part 77, Objects Affecting Navigable Airspace. These regulations establish a three-dimensional space in the air above an airport. Any object that penetrates this volume of airspace is considered to be an obstruction and may affect the aeronautical use of the airspace. This three-dimensional space is also known as an “imaginary surface.” The size of these imaginary surfaces is based on the category of each runway according to the current approach, and to any future approach planned for that runway. For a “visual approach” runway such as the Easton State Airport, the length of the approach surface at the east end of the runway is defined as 5,000 feet with a 20 horizontal to 1 vertical (20:1) slope from the end of the runway. The maximum height allowed at the end of the 5,000-foot radius would be about 250 feet. The allowed height about 1,500 feet from the runway, at the edge of the development site, would be about 75 feet. Native evergreen trees at the edge of the WSDOT airport property, approximately 200 feet from the end of the runway, exceed the height defined by the “imaginary surface” at that point. Outside the 5,000-foot length of the “imaginary surface,” Easton Ridge rises about 2,500 feet at a distance of about 10,000 feet from the runway, an overall slope of about 4:1.