
COMMISSION AGENDA
Tay Yoshitani, Chief Executive Officer
December 2, 2010
Page 2 of 7
BACKGROUND:
Funding for the Adaptive Management phase, and other stormwater work, was authorized by the
Commission on April 11, 2006. Subsequently, based on water quality monitoring data, it was
determined that water quality treatment upgrades were needed in the SDE4, SDS1, SDS4, and
SDN1 sub-basins to help meet permit effluent limitations. On October 27, 2009, the
Commission authorized a project budget of $1,500,000 that included final design, preparing
construction documents, advertising for bids and constructing the projects. At that time,
construction was scheduled to start late summer 2010. Subsequently staff determined that
construction could be deferred until spring 2011 with the intent of obtaining efficiencies and cost
savings by combining and bidding this project with another stormwater project that was
scheduled for 2011. This combination did not materialize due to schedule uncertainties that
developed later with the other project. The deferral will meet the needs of the project sponsor
since the new facilities are primarily intended to provide treatment benefits during the summer
season, and will enable the post-construction earthwork to be stabilized before the fall and winter
wet season to minimize potential erosion control problems.
As final design was being completed, staff in consultation with the design Consultant determined
that additional budget for the design Consultant and Port staff would be required to complete the
final design and support the project during construction. On November 18, 2010 the Commission
was notified of a budget increase of $300,000, and staff has included that amount in this request.
The $300,000 is for an increased cost of design and internal Port tasks driven by the schedule
revision and attempting to combine projects noted above.
On December 1, 2010, the Port received the final Engineer’s estimate for construction prepared
by the A/E. The estimate is significantly higher than previous estimates and the budget. The
increased cost is due to: the specialized bioswales filter media material required to provide
increased zinc and copper treatment efficiency in order to meet the permitted water quality
discharge limitations; increases in the bid items for temporary erosion and sediment control,
over-excavation and backfill of unsuitable material and other unforeseen field conditions; and
increases to estimated quantities and unit prices of several construction items. Staff recommends
the overall construction contingency budget also be increased from the usual 10% of the
engineer’s estimate to 20% to account for higher than normal uncertainty in the estimated filter
media bid cost. This results in a total budget increase request of $843,000, including the previous
$300,000 notification increase, bringing the total project budget to $2,343,000.
PROJECT JUSTIFICATION:
The CSMP was initiated in June 2002 in response to permit conditions associated with the
Airport’s Master Plan Update. Stormwater flow control and water quality treatment facilities
best management practices (BMPs) were implemented during 2005 through 2007 under the
CSMP and are now operational. The Stormwater Engineering Report submitted to the
Department of Ecology guided the implementation of BMPs to meet the effluent limitations
prescribed in the NPDES permit in effect at that time. The BMPs were based on an All Known
Available and Reasonable methods of Treatment (AKART) report approved by Ecology. The
original design and construction of each CSMP facility incorporated an approach focused on