King County flood district board to decide on best fix for Kent levee

Robert Gilbert, a consultant and University of Texas professor, tells the King County Flood Control District executive committee Wednesday his opinions about plans by Kent and the county to repair a 2.5-mile Green River levee. - STEVE HUNTER, Kent Reporter
Robert Gilbert, a consultant and University of Texas professor, tells the King County Flood Control District executive committee Wednesday his opinions about plans by Kent and the county to repair a 2.5-mile Green River levee.
— image credit: STEVE HUNTER, Kent Reporter

The King County Flood Control District Executive Committee expects to decide within two weeks whether to choose the city of Kent or King County plan to spend millions of dollars to repair a 2.7-mile stretch of a Green River levee to improve flood protection and reduce insurance costs to businesses.

The four-member committee heard a one-hour report Wednesday at the King County Courthouse in Seattle by a third-party consultant it hired to help resolve a dispute between Kent and the county about the best way to repair the Briscoe-Desimone Levee that runs from South 200th Street to South 180th Street.

Kent proposes to install a flood wall at an estimated cost of $17 million. The county proposes a setback levee with estimated costs of $420 million to $920 million because of the need to buy property and reconfigure roads.

Robert Gilbert, a University of Texas professor of civil, architectural and environmental engineering, was hired for $25,000 by the flood district as an independent consultant to review the two proposals.

Metropolitan King County Councilwoman Julia Patterson, who serves on the flood district executive committee along with county council members Reagan Dunn, Kathy Lambert and Larry Gossett, said she came away much more informed after Gilbert's report.

"I think the flood district made an excellent decision to bring an outside expert in to bring us additional information and an unbiased perspective," Patterson said. "I think we do have enough information now that we will be able to move forward with a decision. I don't know where my colleagues are and what their decision will be, but it's time for us to act."

The committee is expected to meet again in about two weeks during a special meeting to pick a levee repair plan. That recommendation will go to the full flood district board (the nine members of the county council) for final approval. Dunn and Patterson each expect the full board to follow the recommendation of the committee.

"I believe we have all the information that the experts can possibly provide," Patterson said. "That's the hard part of our job is that now we have to make a decision. But we definitely have a perspective that is different than what we had from either King County or Kent. It's added a dimension to the discussion that will allow us to act and within two weeks we will make a decision on how to move forward with that levee."

Dunn agreed action is needed.

"We are going to break the logjam," Dunn said. "It's like you're looking at a Chevy or a Ford. The bottom line is both of these will protect businesses, property, people and the environment as well but we need to make a decision."

The flood district is funded by a property tax assessment of 10 cents per $1,000 assessed valuation to fund projects. That tax brings in about $35 million per year to help pay for projects along six rivers in the county.

Kent Mayor Suzette Cooke attended the meeting along with City Councilwoman Elizabeth Albertson and Public Works Director Tim LaPorte.

"I'm very pleased with the report," Cooke said in front of the committee. "It was a very even report and more objective than what I expected."

Cooke said city businesses need to know how the flood district plans to repair the levee. The levee helps protect from flooding about $650 million worth of property and 18,400 jobs at a variety of businesses in Kent, Tukwila and Renton, including the Boeing Space Center, the Starbucks Roasting Plant, IKEA and the Alaska Airlines Call Center, according to Kent officials.

"The businesses need economic stability and this unknown factor of how the district is going to proceed with the levee leaves many of the tenants somewhat on the edge as to what their future is going to be to be able to reinvest in their business and equipment," Cooke said. "The jobs that are impacted by the decision you make are key to us.

"My recommendation is to do something sooner rather than later while we focus on a longer term and full levee system (repair). I would applaud that."

The city has spent about $713,000 (from its storm water utility fund) over the last two years on three engineering consultant companies (Boston-based GEI Consultants, Inc., GeoEngineers, Inc., of Seattle and Northwest Hydraulics, of Tukwila) in connection with Briscoe Levee repairs. GEI and GeoEngineers each recommended a steel sheet pile flood wall be constructed along the levee to improve flood protection. The city estimates the project could be completed in one year. About 4,000 feet of the levee would be repaired in four segments.

The City Council's Public Works Committee also recommended on Jan. 14 that the full council approve an additional $736,544 contract with GEI for a final levee design, if the flood district board picks Kent's option. That contract could go to the full council in February or March for approval in an effort to meet deadlines to hold on to the $7 million state grant awarded by the Legislature last year to the district to repair the levee. That grant could be taken away if no repair plan is established by the end of June.

The project is part of a larger effort by Kent to have the entire levee system within city limits accredited by the Federal Emergency Management Agency (FEMA) in order to remove properties behind the levee from FEMA flood maps to reduce development restrictions and flood insurance requirements in the Kent Valley.

"Property protection in the floodplain and the need for flood insurance is the motivation to improve the levee to get it accredited so that businesses would not be required to buy flood insurance," Gilbert said.

The consultant said the two proposals are quite similar as far as public safety and property protection.

"The public safety risk is relatively low now and you can't really distinguish between the two," said Gilbert, whose recent work includes analyzing the performance of offshore platforms and pipelines in hurricanes; managing earthquake and flooding risks for the Sacramento-San Joaquin Delta in California; and performing a forensic analysis of the New Orleans levee failures after Hurricane Katrina. "The best way to prepare is to get people out of harm's way."

Gilbert added that the Howard Hanson Dam upstream on the Green River provides most of the flood protection for the valley and people would be able to evacuate the area if a major flood event hit Kent.

Gilbert said Kent's plan is the most cost effective to protect property to reduce flood insurance costs while the county's proposal with large setbacks provides added benefits to the environment.

Gilbert questioned the need for a 500-year levee protection plan by the county versus the 100-year proposal by Kent because the dam upstream controls so much of the river flow. That's the reason Gilbert recommended the flood district look at a system-wide analysis to manage overall costs and benefits, considering the dam and land-use as well as the levees.

Kent has hired consultants who have already designed 35 percent of the flood wall plan. Gilbert said that makes the cost estimate more accurate than the county proposal that is conceptual rather than an actual design.

The county plan is much more expensive because of the need to purchase property, relocate businesses and reconfigure roads, such as West Valley Highway, while the city's proposal would continue to use the West Valley Highway for levee protection along the river near South 180th Street. The county also would do work on both the right and left banks as opposed to Kent's plan to repair only the right bank.

"The bottom line is with the county approach you will spend a lot of money to get an environment that will create green space and a habitat for fish," Gilbert said to the committee. "It will allow the area to come back to the way the valley was before the dam was built, but is that worth the cost? Your job is difficult."

But the flood district committee has more information now to work with before making a decision.

"We were caught between two competing perspectives on how to address this problem," Patterson said. "There were two competing points of view on safety, environmental issues and on cost. I don't know if there was anything we could have done than bring in a third opinion."

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