San Francisco International airport is currently saddled with chronic delays due to bad weather limiting arrival and departure capacity. In an effort to remove of these delays the FAA and the Airport Authority have come up with a number of options to prevent delays. The most popular idea is to expand the distance between SFO's parallel runways, allowing for simultaneous use of both runways for landing during poor weather conditions. As this would require parts of the bay to be filled in environmentalists and airport expansionists have been battling to show that the bay should or shouldn't be filled in.