HomeMy WebLinkAboutPN_Project_Narrative_210623_v1Cedar River 205 Levee Inspection Vegetation Clearing Project
Project Narrative
The Cedar River levees are part of the Cedar River Section 205 Flood Damage Reduction Project (Cedar
River 205 Project) constructed in cooperation with the United States Army Corps of Engineers (USACE).
The levees are located on the lower 1.25 miles of the Cedar River and extend from Williams Avenue
North to the mouth of the Cedar River at Lake Washington. The Cedar River 205 levees protect portions
of downtown Renton, the Boeing 737 plant, and the Renton Airport from the 100-year flood. Following
the completion of the project, the City of Renton became of the local sponsor of the project and entered
into an agreement with the USACE for maintenance and inspection of the flood protection facilities
under PL84-99.
In order to facilitate the yearly routine levee inspection efforts required and overseen by the USACE, the
City of Renton will perform limited clearing of vegetation along the left bank of the Cedar River from
Logan Avenue North to the North Boeing Bridge on the riverside of the levee floodwalls. This clearing
will allow the inspection team from the USACE to evaluate the physical features of the levees, verify the
levee system operations and maintenance, and inform on necessary corrective actions and risk
management. The inspection requires clearing a path of at least 4-feet behind the floodwall in order to
provide accessibility for the inspection amounting to approximately 18,000 square feet of area.
Clearing the inspection path behind the floodwall is not only a routine maintenance activity of an
essential City of Renton Public works facility, but is also a necessary component of agreement with the
USACE that would facilitate future inspections by USACE staff. Recent periodic and annual inspections
have flagged the density of the vegetation on the riverside of the floodwalls as “unacceptable”. As such,
vegetation maintenance would ensure that the Cedar River 205 Project would remain compliant with
the terms of its operation and maintenance manual and PL84-99 requirements.
Therefore, a shoreline exemption permit is requested for this project under the category of “normal
maintenance and repair of existing structure or development”.
The following is additional information about the proposed work:
Anticipated Dates of work: Vegetation clearing will take place for approximately 1-2 weeks in
July of 2021.
There are no other permits required.
The project area is a medium and heavy industrial employment area, and the proposed work
will not alter the use of the area.
There are no hazardous areas, steep slopes or wetlands on the project site. The work is within
the 100-year floodplain and high-intensity regulated shoreline of the Cedar River.
Soil type in the area varies. Below the top surface (grass, concrete or asphalt), the soil consists
of a mix of sand and silt.
The total estimated cost of the vegetation clearing work is approximately $4,000.
There will be no excavation or filling activities.
No trees will be removed or impacted.
The closest area of work to the Ordinary High Water Mark is 5-feet.
The nature of the existing shoreline is rip rap along the airport clear zone (downstream portion
of left bank) and a vegetation mix of blackberries and knotweeds elsewhere