HomeMy WebLinkAboutPN_Project Narrative_220629_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 (City) became 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.
To facilitate the yearly routine levee inspection efforts – required and overseen by the USACE – the City
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 river’s side 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 the City about necessary corrective actions and risk
management. The inspection requires clearing a four-foot-wide path behind the floodwall to provide
accessibility for the inspection, amounting to approximately 18,000 square feet of cleared area.
Clearing the inspection path behind the floodwall is not only a routine maintenance activity that’s
essential to upkeeping a City public works facility, but it’s also a component of an agreement with the
USACE that facilitates future inspections by their staff. Recent, periodic and annual inspections have
flagged the density of the vegetation on the river’s side of the floodwalls as “unacceptable.” As such,
vegetation maintenance ensures that the Cedar River 205 Project will 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 days in July
of 2022.
There are no other permits required.
The project area is located in a medium and heavy industrial employment area, and the
proposed work will not alter the use of this area.
There are no hazardous, steep slope, or wetland areas on the project site. The work is within the
100-year floodplain and high-intensity regulated shoreline of the Cedar River.
Soil types in the area vary. 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 composition of the existing shoreline is: rip rap along the airport clear zone (downstream
portion of left bank); mixed vegetation that consists of blackberries and knotweeds, elsewhere.