The state Department of Ecology has fined the Port of Seattle and two contractors $20,000 for water quality violations at Sea-Tac International Airport.

Ecology found that the port, which operates the airport, and the contractors allowed four releases of muddy stormwater from Sea-Tac north expressway project into storm systems that drain to Gilliam Creek and Des Moines Creek.

The violations occurred in November and December 2006, and January and August this year.

Ecology issued the penalty jointly to the port and to Mowat Construction Co. of Woodinville and Scarsella Brothers Inc. of Seattle, contractors for the airport expressway project.

The port is building a segment of light rail and re-aligning roadways to and from State Route 518 to link Sound Transit's Sound Link light rail project to the airport.

"The port and its contractors must prevent untreated, muddy water from entering these streams," said Ecology's Kevin Fitzpatrick, who oversees water quality activities for northwest Washington.

"This project will continue for two more years, marking it particularly important to take all steps needed to protect the environment."

Four incidents prompted Ecology's actions:

Nov. 10, 2006-A temporary stormwater detention pond overflowed after a pump was left on, causing an estimated 45,000 gallons of untreated, muddy stormwater to discharge into a storm drain that emptied into Gilliam Creek.

Dec. 14, 2006-A sump, plugged with leaves, was unable to pump water to catch basins at the construction site. While crews tried to fix the pump, they broke off its outlet pipe, rendering the pump inoperable.

For about two hours, approximately 12,000 gallons of muddy stormwater overflowed and entered the storm drain.

Jan. 3, 2007-Another sump pump got plugged with leaves and released an undetermined amount of muddy stormwater into the east fork of Des Moines Creek.

Aug. 20, 2007-An undersized sump pump that didn't meet specifications under the port's stormwater control plan allowed an undetermined amount of muddy stormwater to overflow into a ditch that drained to nearby Gilliam Creek.

"We take our role as environmental stewards seriously and we regret the incidents that led to this notice of penalty," said Aviation Managing Director Mark Reis.

"In each case, Port staff discovered the violations, reported the incidents to the Department of Ecology, and worked with on-site contractors and Department of Ecology staff to take immediate corrective action"

The port, Mowat Construction Co. and Scarsella Brothers Inc. may appeal the penalty to Ecology and to the state Pollution Control Hearings Board within 30 days.