HomeMy WebLinkAboutUtilities 2015-01-27 Item 2B - Discussion - Briscoe/Desimone Levee Rehabilitation with US Army Corps of EngineersCity of Tukwila
Jim Haggerton, Mayor
INFORMATIONAL MEMORANDUM
TO: Mayor Haggerton
Utilities Committee
FROM: Bob Giberson, Public Works Director
BY: Ryan Larson, Senior Program Manager
DATE: January 23, 2015
SUBJECT: Briscoe /Desimone Levee
Project No. 81441202
Army Corps of Engineers' PL 84 -99 Rehabilitation
ISSUE
Information on the proposed US Army Corps of Engineers (Corps) PL 84 -99 Rehabilitation of the Desimone Levee.
BACKGROUND
The City of Kent, under Tukwila Interlocal Agreement No. 14 -020, and under a separate Interlocal Agreement with the
King County Flood Control District (KCFCD), is designing and constructing improvements to the Briscoe /Desimone
Levee Project. The Briscoe Levee is on the right bank (easterly side) of the Green River primarily within the City of
Kent and the Desimone Levee is further downstream on the right bank entirely within the City of Tukwila. Kent has
received a shoreline variance for the project from the City of Tukwila to construct a levee profile different from the
profile adopted in the City's Shoreline Master Program. Kent's construction of the Desimone Levee floodwall is
scheduled to begin in late February 2015.
In 2014, the KCFCD notified the Corps that the Desimone Levee, within the area of the proposed floodwall, suffered
flood related damage and requested assistance under the Corps PL 84 -99 Program. The PL 84 -99 Rehabilitation
Program provides emergency assistance to local sponsors to repair damaged flood control facilities with an 80%
federal /20% local (KCFCD) cost share.
The Corps reviewed the Desimone Levee and determined that the existing damaged levee only provides a 1 -2 year
level of flood protection and immediately began designing a repair for the damaged portion. The Corps completed
preliminary design and provided 65% plans to the City in early January 2015. The planned repairs call for excavating
and rebuilding the Desimone Levee using a large quantity of rocks, similar to the repair that was completed to the
Tukwila 205 Levee in 2008.
ANALYSIS
Kent's Briscoe /Desimone Levee Project includes installing a floodwall, grading above the ordinary high water line,
removal of invasive plants, and significant plantings on the existing levee. The Corps' PL 84 -99 Rehabilitation Project
would eliminate Kent's proposed bank and vegetation work and provide an armored levee with limited vegetation
consistent with Corps standards. The Corps' reconstruction using a large quantity of rocks is not consistent with the
Tukwila's Shoreline Master Program or the Shoreline Variance issued to the City of Kent for the construction of the
Briscoe /Desimone Project.
Staff is currently working with the Corps on their PL 84 -99 design to attempt to lessen the effects of the planned rock
placement and provide additional vegetation. A copy of the 65% Corps plans will be available during the meeting for
discussion.
RECOMMENDATION
Information only.
W:\PW Eng \PROJECTS\A- DR Projects \Brisco - Desimone Levee (81441202) \Info Memo Corps PL8499 - Update 1 -23 -15 sb.doc