Item No. ____7a_Supp__________
Date of Meeting: _October 20, 2009


Impacts to the Port of Seattle and
Neighboring Businesses

Howard Hanson Dam was built in 1962 for flood
control in the Kent Valley
The Valley is now home to industrial, commercial,
manufacturing, retail and residential units
Plus roads, bridges, railroad lines, electrical
substations, fuel pipelines, sewage treatment
plants, hospitals, schools and more
Damage discovered during the Jan. "09 rain event
will limit the dam"s effectiveness until a permanent
repair is in place
A repeat "09 rain event will result in significant
flooding downstream

'-
Howard.A Hanson
V Dam and Reserv'oibr

"lstoy of Local Hooding

1950's

Inflow to the dam reservoir peaked at 30,500
cubic feet per second (cfs); all outlets closed
Pool of Record - elevation 1,188.9 feet (above
sea level)
Dam water storage capacity kept the Auburn
gauges below 12,000 cfs (flood stage)
Overall, the dam kept river flow rates just
below the over-topping/breach level
May 2009 tests showed that the Dam can no
longer safely provide this protection

1206"_______Spillway

1189"_______Record Pool, Jan 2009

1167"_______Conservation Pool, May 2009 test

1155"_______Current "safe operation" level

1075"_______"Empty" Pool


Army Corps is installing grout as a temporary
fix while searching for a permanent solution
Cannot predict how well temporary "fix" will
work, cannot fully test until next spring
Odds of flooding as high as 1:3 for a single
event during the 2009-10 season
King County and City of Renton have pre-
declared an emergency
State Office Emergency Management at Alert
Level 2

May take 5 years or more for a permanent
solution, probably a cutoff wall
400,000 sandbags have been ordered
As many as 35,000 people may need to be
evacuated from flood plain
County spending $35 million on mitigation
efforts
Proposed raising of levees may not be possible
FEMA says severe flooding in the area could
cause in excess of $4 billion in damage


NOAA has predicted we are in a mild El Nino
this winter
El Nino can mean average precipitation totals
may be slightly lower for the year
Does not mean we will not have rain and lots
of it
In 4 of the last 5 El Nino years, there has been
major flooding in the region

Scenario 1: 17,600 cfs river flow rate at Auburn
gauge
Scenario 2: 12,800 dam discharge rate (this is
water released from the dam, it will combine
with an unknown volume of water from
downriver tributaries resulting in a river flow
rate higher than the 17,600 in Scenario 1
Local flood planning has included a 25,000 cfs
level as well

SCENARIO 1:
Losses in the flood plain
with intact levees
Direct building economic
losses
Overtopping only, no
breaks in levee

SCENARIO TWO:
At 12,800 HH Dam discharge
rate

Green = $1m - $5m
Red = $10m  $68m

SEAPORT:
Increased siltation in the Turning Basin and
navigable waterway
Large debris and hazards to navigation washed
downriver into Duwamish and Elliott Bay
Potential damage to vessels at Harbor Island
Marina - including Police Boat
Storm water back-up at area facilities
Contamination of area facilities if upriver Waste
Water Treatment Plant fails

AIRPORT
Electrical power outages at airport and other
facilities that could last several days or weeks
Shut down of jet fuel lines to airport
A recent study showed  of all airport
employees (POS and all others ) live in
impacted areas  either in the flood zone, or
use transportation routes through it

ALL
Disruption to transportation routes for trucks,
trains, bridges and roadways
Commuters from the south will have difficulty
getting to work
Closure of Distribution Centers in Valley may
impact movement of freight and air cargo
Staff absenteeism for employees living in
potential evacuation areas

80% of the region"s food storage is in the
valley
Warehouse distribution system is the largest in
the Northwest  so not possible to just move
things elsewhere
State of Alaska depends on cargo flights from
SeaTac for winter supplies
Local companies and jurisdictions are looking
to the POS for assistance, e.g. relocation sites

County estimates as many as 35,000 people
may need to be evacuated from the Valley
They are planning on needing shelter
accommodations for up to 5000
King County has requested rental of Smith
Cove Cruise Terminal as a temporary shelter

POS Working groups are being established for:
Keeping staff, customers and public informed
Identifying potential staffing problems
Keeping air cargo and freight moving through the area
Land use issues
Utility concerns  electricity, natural gas, jet fuel, waste
water
Debris management, clean-up activities
Ensuring coordination of agencies and that Port issues
are considered in the regional planning process

Although PSE has plans for maintaining electric
power supply to STIA, there is increased risk of
extended interruption
RCW 39.04 and Res 3605 recognize emergency
in "real, immediate threat to the proper
performance of essential functions"
CEO declared emergency on October 16
Authorizes procurements and staff effort to
establish emergency backup power generation
at STIA