7401 LARIMER RD 2021-12-21 - Laserfiche WebLink

• y • April 10,2020 Page 3 • Relocate the UNT from its current east-west location at the common property line so that it runs north-south and extends to the northern boundary of the Golden Eagle Farms property. • Fill in approximately 200 feet of the south end of Ditch 3 and seed and vegetate this area to ensure soil stability. • Relocate the remainder of Ditch 3 to the east so that it is at least 15 feet from the Tonnes property boundary.This area will also be seeded and vegetated to ensure soil stability. • Fill and level the Golden Eagle Farms property a minimum of 15 feet to the east of the relocated Ditch 3 channel at the current elevation of the Tonnes property to alleviate slope stability concerns. Site location and features are shown in Figures 1 and 2. Restoration Components Unnamed Tributary Restoration The UNT will be relocated from its current location along the shared property boundary between the Tonnes and Golden Eagle Farms properties.The existing UNT along the shared boundary will be backfilled and compacted as shown in the Restoration Drawings included as Attachment 1.The UNT will be rerouted north approximately 840 feet through the Golden Eagle Farms property to the northern property boundary,where it will join an existing drainage ditch that flows east for approximately 1,200 feet before discharging to the Marshland Drainage Canal. The reconstructed UNT channel at the upper end will be approximately 3 feet deep, have a bottom width of 4 feet, and be constructed with 3-horizontal-to-1-vertical (3H:1V) side slopes.This slope was determined using guidance from a geotechnical investigation conducted at the site and presented in the geotechnical report, Geotechnical Investigation and Recommendations, which is included as Attachment 2. The depth and width will decrease incrementally to match the dimensions of the existing drainage ditch at the northern property boundary.Side slopes will continue to be 3H:1V. The side slopes will tie into the existing grade.Where the UNT intersects the drainage ditch at the northern property boundary,a culvert crossing will be installed to allow utility access for a utility easement owned by Puget Sound Energy.The culvert will be a 6-foot-diameter corrugated metal pipe(CMP) or high-density polyethylene (HDPE) pipe buried 2 feet below the channel bottom and have a minimum of 1 foot of cover to the roadway.The culvert is designed to meet American Association of State Highway Transportation Officials(AASHTO) H-20 loading requirements,as required by Puget Sound Energy. A 25-foot stream buffer will be established along each side of the new alignment of the UNT in accordance with City of Everett requirements and as shown in the Restoration Drawings(Attachment 1). The buffer will be seeded and planted with native trees and shrubs. No trees will be planted within the easement owned by Puget Sound Energy;the easement will only be planted with shrubs.