20-101905-Trench Impact Assessment-05-12-2020-V1
Sergey Adzhigirey
Wetland and Wetland Buffer Waterline
Trench Impact Assessment
for
City Permit No. 19-103025-00
King Co. Tax Parcel Number 416660-0600
30523 28th Ave SW
Federal Way, WA 98023
Section 12, Township 21N, Range 8 E
Of the Willamette Meridian
Prepared for:
Sergey Adzhigirey
32022 5TH Ave. S.W.
Federal Way, WA 98023
206-790-2911
sergey.adzhigirey@gmail.com
Dated:
April 28, 2020
Prepared by:
Jeffery S. Jones, Wetland Scientist & Wildlife Biologist
1.0 Project Description
The applicant is constructing a single-family residence and septic system on parcel 416660-0600,
see the site plan. The house will be located near 28th Avenue South. The property is under the
jurisdiction of Federal Way.
2.0 Site Address, Identification, and Directions
The street address is 30427 28th Ave SW Federal Way, WA 98023. The King County tax parcel
number is 416660-0600.
Directions from the Federal Way City Hall are as follows:
From South 333rd St;
Take a right onto 1st Way South (0.9 mi);
Take a left on SW 320th St (1.2mi);
Turn right onto 21st Ave SW (0.4 mi);
Turn left onto SW Dash Point Rd (1.0 mi);
Turn right onto 28th Ave SW (0.2 mi)
3.0 Analysis of Unpermitted Wetland and Buffer Impacts
During the construction of the foundation for a single-family residence, a trench was excavated
through wetland buffer and wetland. Excavated material was cast to the south side of the ditch
and resulting in 9-16 feet of impact. All of the buffer impacts and wetland impact will be
restored to a native plant community. The waterline will go around the wetland to the north and
thereby avoid being placed in and directly impacting the wetland. No trees will be planted over
the pipeline.
IMPACTS & RESTORATION AREAS
ON-SITE WETLAND RESTORATION 536 SF
ON-SITE WETLAND BUFFER 702 SF
ON-SITE WETLAND BUFFER 4,380 SF
OFF-SITE WETLAND BUFFER 1,955 SF
TOTAL WETLAND BUFFER RESTORATION 7,037 SF
WETLAND BUFFER
PERMANENT PIPELINE IMPACT 483 LINEAR FT
No trees were removed or killed by the excavation. Further, rerouting the waterline north of the
wetland will not result in the lose of any trees. Some side tree roots of big-leaf maple (Acer
macrophyllum) were cut by the excavator, but none of these were tap roots. Big-leaf maple area
hardy trees and difficult to kill. Root damage will not result in the mortality of any trees.
3.0 Analysis of Wetland and Buffer Impacts
The area that was impacted will be restored to its previous condition. There is still lush
vegetation near the trench and plants are likely to naturally re-establish themselves. However, a
complete replant of all impacted areas is planned.
Trench in Wetland Buffer
Trench at Building Envelope