7401 LARIMER RD 2021-12-21 - Laserfiche WebLink

�► i April 10, 2020 Page 4 Ditch 3 Restoration Ditch 3 is located along the shared property boundary running north to south on the east side of the Tonnes property.Approximately 200 feet of Ditch 3 will be backfilled and compacted as shown in the Restoration Drawings (Attachment 1)to pre-project conditions.The remainder of Ditch 3 (approximately 420 feet) will be relocated east approximately 35 feet from its current location. The new channel will be approximately 2.5 feet deep, have a bottom width of 4 feet, and be constructed with 3H:1V side slopes.The side slopes will tie into the existing grade. The new Ditch 3 channel and disturbed areas to the east of Ditch 3 will be seeded and planted with native trees and shrubs to reduce erosion and protect against slope failures. Bonneville Power Administration power transmission lines and utility easement cross Ditch 3 as shown in the Restoration Drawings (Attachment 1).The disturbed area within the utility easement will be seeded. No shrubs or trees will be planted in the utility easement. An existing culvert and road crossing allowing for access to the Tonnes property from the Golden Eagle Farms property will be removed and replaced if necessary for utility access. Grade Restoration The existing (undisturbed)grade on the Tonnes property where the UNT will be filled and removed will be filled and leveled as needed to remove any existing cracks and slumping. The existing elevation will then extend out 25 feet onto the Golden Eagle Farms property along the property boundary in this area.A grade will then be constructed at a slope of 4H:1V to tie into the existing grade on the Golden Eagle Farms property.This slope was determined using guidance from the geotechnical investigation. For the common boundary running east to west adjacent to Ditch 3,the existing topography will extend out 15 feet onto Golden Eagle Farms property along the shared boundary and then slope down to the ditch bottom at a 4H:1V slope as verified by the geotechnical investigation. The grading extents will be as shown in the Restoration Drawings (Attachment 1). All disturbed areas shall be seeded and,where outside of the utility easement, planted to promote slope stability. Soil Augmentation Soil augmentation to a depth of 6 inches on the Tonnes property will include importing and distributing a 60/40 topsoil mix across areas that have been filled. The topsoil will then be extended another 25 feet onto the Tonnes property and will taper in depth from 6 inches to 0 inches where it meets the existing grade.The topsoil area will then be seeded with a pasture seed mix. The area is shown in the Restoration Drawings(Attachment 1).