Runway Extension Proposed

The long-awaited environmental analysis of the County’s proposal to extend the runway at Gnoss Field was finally released for public review in December after a three-year wait. MCL submitted extensive recommendations for the scope of the environmental analysis in August 2008 (see below) and commented on the EIR/EIS in Feb. 2012.

Because both the Federal Aviation Administration (FAA) and the County were required to fulfill their respective federal and California State environmental requirements, the report consists of two parallel, almost identical, volumes – a Draft Environmental Impact Report (Draft EIR), and a Draft Environmental Impact Statement (Draft EIS), plus a Technical Appendix.

The proposal to extend the runway to the north by 1,100 feet beyond its present length of 3,300 feet has been in the Airport Master Plan since 1989. The stated need for the project is to allow existing aircraft to fly at design capacity when the air temperature is high (around 100 degrees F) and under other adverse weather conditions. The project also involves extending the adjacent taxiway and Runway Safety Areas. The extension will require realigning drainage channels and extending a levee to protect the runway and taxiway from flooding.

It is not surprising that a number of environmental issues examined in the draft documents stem from the airport’s location in an area of diked former tidal marshlands. Gnoss Field lies within the original floodplain of the Petaluma River, whose wetlands comprise the largest remaining intact salt marsh system in the San Francisco Bay Region. The original airport dates from 1939, when a grass landing strip was built on the diked field. Since that time, as the airport has expanded to its current condition, levees and drainage channels with pumps have played an essential role in preventing the facilities from flooding.

The extension will require filling 74 acres of wetlands and about 2 ½ acres of channels. Various agencies, including the County, the U.S. Army Corps of Engineers, and others will have to determine whether the proposed fill and mitigation plan, still to be developed, is consistent with wetland and waterway protection policies.

The Draft EIR has identified a number of areas of potential controversy that will be addressed during public review and may represent tradeoffs between different policy objectives:

• The proximity to Redwood Landfill and the potential for bird strikes
• Concerns of residents south of the airport about aircraft noise and overflights
• Possible increase in air contaminants and greenhouse gas emissions
• Potential for flooding from sea level rise due to climate change
• Construction noise and traffic concerns

The public has also expressed concerns over the potential for increased air traffic and larger planes to use the airport. Pilots who are familiar with the operational characteristics of the field assure that numerous obstacles such as the proximity of Mt. Burdell to the northwest, and the KCBS radio towers to the southeast make this growth unlikely. Others are not so certain and believe that larger aircraft will come with the extension.

2012 Documents and Correspondence

• February 6, 2012 - MCL comments on Gnoss Field EIR/EIS

2008 Documents and Correspondence

• August 27, 2008 - MCL comments on Gnoss Field Scoping