100 Year Flood

 What would be the impact of a 100-Year-Flood on Skagit County?

The first European settlers in Skagit County built dikes and levees to protect farmland from floods. The Skagit River was a transportation waterway, causing towns and cities to be built on its banks. In the past century, the population of Skagit County has grown from 14,272 to 102,979 with significant development in the flood plain.

Damages today from a 100-year-flood event would carry significantly larger economic and ecological risks because of the significant population growth that has taken place. The U.S. Army Corps of Engineers has been actively seeking a solution for flood control in the Skagit Valley since 1922. Due to funding requirements and lack of local consensus a solution for 100-year flood protection has not been implemented.

A 100-year flood event in Skagit County could potentially:

• Stop traffic on Interstate 5, SR-20 and SR-9. 23,000 commuter trips take place each day to and from Fidalgo Island. I-5 is utilized by 65,000 vehicles each day. Highway closures and resulting traffic delays due to a 100 year flood event are estimated to cost over $15,000,000. Army Corps of Engineers, August 2001.
• Shut down sewers, wastewater treatment, and major storm water pumping systems would cease to function.
• Shut down the Anacortes Water Treatment Plant could be down for up to 45 days or more, cutting off water to the Cities of Anacortes and Oak Harbor, the Town of La Conner, both petroleum refineries and NAS Whidbey.
• Devastate the economy of the entire region. Damages could exceed $1 billion dollars and thousands of people would be unable to get to work. Water, road, railroad and pipeline transportation to the refineries would be in jeopardy forcing shutdowns for an industry employing more than 800 workers with annual payrolls exceeding $57 million. Washington State exports to Canada are worth approximately $6.6 billion and overland imports exceed $14.3 billion annually. 95% of all commercial goods between British Columbia and Washington are shipped overland. Washington State Office of Trade and Economic Development.

Are you ready for a flood?

The Skagit Risk is published by the Skagit County Public Works Department and contains important information to help Skagit County residents prepare for and respond to flooding situations. If you live in a potential flood area (see page 4 and 5) please keep this publication in an easy-to-find location in your home, farm or business.

Skagit County has a long history of flooding. In the past 100 years, the Skagit River has exceeded flood stage more than 28 times. In November of 1990 and 1995, rains from warm Pacific storms, coupled with high mountain snow pack turned the region into a federally declared disaster area.

Even those living well outside of the designated flood plains are not immune to flooding.

Major highways and railroads would be closed in the event of a significant flood. Interstate 5, State Routes 20, 9, and 536 lie in the Skagit River Flood plain. Interstate 5 alone is utilized by 65,000 vehicles a day. 23,000 commuter trips are made daily to and from Anacortes on Highway 20. In 1995, the railroad bridge between Burlington and Mount Vernon was undermined and was closed for two weeks at a cost of millions to Burlington Northern Santa Fe.

Municipal infrastructure would be in jeopardy during a 100-year flood. The municipal waste water treatment plants in Burlington and Mount Vernon, serving more than 15,000 homes and businesses, would be under water and could be down for weeks costing millions to get back on line, as well as creating a significant health risk.

Most of Burlington's and 40% of Mount Vernon's sewage collection system would be damaged or destroyed during a major flood. It could take months to restore normal operations.

The Anacortes Water Treatment Plant located in the Riverbend area near Mount Vernon is in serious jeopardy by any flood exceeding the 40-year level. Flooding could put it out of operation for up to 45 days, shutting off the primary source of water for both refineries on March Point, the cities of Anacortes, La Conner, Oak Harbor, NAS Whidbey and significant portion of Skagit Public Utility District #1. Flood fight operations went into effect at the plant in both 1990 and 1995 with major sandbagging efforts.

106,000 people live in Skagit County with approximately 30,000 living in the flood plain. In the past 100 years, population growth has steadily climbed from 14,272 in 1900 to 102,979 in 2000. Projections of future growth could take that number has high as 140,000 by 2020.