
COMMISSION AGENDA
Tay Yoshitani, Chief Executive Officer
March 20, 2012
Page 2 of 6
Based on design refinements, the current estimated capital cost for the project is $1,833,000.
There is a potential additional expense cost of $150,000 if stormwater needs to be pumped to an
alternative location for treatment during the construction period. The estimated capital cost at the
beginning of design was $1,631,000. The difference in cost is primarily due to design revisions
that improve the constructability and minimize the potential for damage to the pond liner and
underdrain system. The current design eliminates the previously proposed drilled foundations
that would have penetrated the pond liner and potentially damaged the underlying drainage
system. The design now includes gravity foundations that will be installed above the pond liner
with additional support posts and structural support cables.
The Project Labor Agreement (PLA) was evaluated and it is recommended that a PLA not be
used for this project.
BACKGROUND:
Ponds are an attractant to wildlife, particularly waterfowl. Lagoon 3, with an approximate length
of 1,200 feet and width of 500 feet, is identified as one of the most prominent waterfowl
attractants at STIA. Pond liners are presently being used to prevent vegetation growth which
would give rise to a variety of food resources and therefore would be a further attraction for
wildlife. However, snails, which provide a food source for some waterfowl and shorebirds, have
been found recently in the lagoon.
Lagoon 3 lies in the area within a 10,000-foot radius of the runway centerline, which is defined
as the Federal Aviation Administration (FAA) critical zone with respect to airport wildlife
hazard management. Over 75% of all civil bird-aircraft strikes occur within a horizontal distance
of 10,000 feet from an airfield. The U.S. Department of Agriculture’s (USDA’s) Wildlife
Services, through an interagency agreement with the FAA, compiled 109,085 wildlife strike
reports from 1,659 U.S. airports and 534 foreign airports from January 1990 to December 2010.
The number of reported wildlife strikes is estimated to represent only about 39% of the wildlife
strikes that have occurred.
Wildlife strikes are an increasing and significant potential hazard at STIA. A total of 69 wildlife
strikes were recorded at STIA in 2010. In 2011, the number of wildlife strikes increased to 101.
The frequency with which hazardous birds were harassed and lethally removed has increased
dramatically since 2002 when Lagoon 3 monitoring for 1 to 2 hours per week began. During
2009, a total of 144 birds were dispersed and 29 lethally removed. By contrast, in 2011 a total of
819 birds were dispersed and 65 lethally removed.
Besides being an air safety hazard, bird strikes can result in significant costs from the damage to
aircraft. The estimated cost of at least one 2010 bird strike at STIA is known to exceed $450,000.
On April 4, 2006, a US Airways Airbus 319 struck a single Green-winged teal (duck) when over
IWS Lagoon 3. After the bird was ingested into the engine the aircraft made an precautionary
landing at STIA. The cost to the airline was 85 hours out of service in Seattle. When sufficient
repairs could not be made here, the aircraft was shuttled back to the east coast for further
evaluation and repairs. The final costs for damage and downtime were not available to the Port
of Seattle. Damage from a bird-aircraft strike at the Orlando-Sanford Airport in 2010 reportedly
cost $4,570,000.