HomeMy WebLinkAboutRS_25103 Impacts Analysis (2)September 7, 2025
Altaf Gilani
Ultima Homes LLC
17912 NE 27th St
Redmond, Washington, 98052
RE: Renton Highlands Short Plat – Impacts Analysis
Parcel #1123059068
SWC Job#25-103
The Renton Highlands Short Plat project is a 6 lot plat with associated
infrastructure. The City requires Pasco Place SE, which abuts the south
end of the site to be extended into the site. This will require filling of
Wetland A completely to construct the road. Wetland B, a small low
function Category IV wetland which is 469sf in size is also proposed to be
filled. This wetland is of very low function, yet the wetland and its
associated buffer greatly reduce the available area for development on the
site.
These two small, Category IV wetlands with a total area of 991sf area
proposed to be mitigated off-site using credits from the King County
Mitigation Reserves Program.
The City has indicated use of the King County Mitigation Reserves
Program credit purchase is suitable for mitigation as long as the
mitigation site is within the same drainage basin.
The Sazei Design Group Drainage study prepared for the site found that
the site does in fact drain to the south into the Cedar River Drainage
Basin (see following drainage basin image). This includes both of the
wetland to be filled.
Sewall Wetland Consulting, Inc.
PO Box 880 Phone: 253-859-0515
Fall City, WA 98024
Ultima/#25-103
Sewall Wetland Consulting, Inc.
September 7, 2025
Page 2
Above: Drainage Basin Map from Sazei Drainage study of the site showing
the site drain into two sub-basins to the south which go to the Cedar River
Drainage.
Conversations with Megan Webb of King County Mitigation Reserves
Program In-Lieu Fee Mitigation Program indicate that credits area
available for this project in their “Rainbow Bend Mitigation Project” in the
Cedar River service area. This Mitigation “bank” is in the same drainage
basin as the site. Therefore, the use of credits from this bank is
appropriate and the most efficient use of mitigating for these two, small
low function wetlands.
Ultima/#25-103
Sewall Wetland Consulting, Inc.
September 7, 2025
Page 3
The attached In-Lieu Fee Use Plan and associated Credit/Debit
scoresheet and debit calculator spreadsheet was prepared to calculate
the functional mitigation needed.
The KC MRP will provide mitigation credits under this In-Lieu Fee Use
Plan as depicted below which were calculated using the methodology
described in WADOE 2012 “Calculating Debits and Credits for
Compensatory Mitigation for Wetlands in Western Washington”. The
credits have been calculated using the WADOE Spreadsheet and the
credit calculation is as follows:
These have been reviewed by KC MRP and they have calculated the
project will need to purchase credits from the bank to compensate for the
proposed impacts.
If you have any questions in regards to this repo rt or need additional
information, please feel free to contact me at (253) 859-0515 or at
esewall@sewallwc.com .
Sincerely,
Sewall Wetland Consulting, Inc.
Ed Sewall
Senior Wetlands Ecologist PWS #212
Attached: In -Lieu Fee Use Plan
Credit/Debit Score sheets
Debit Calculation Spreadsheet
Ultima/#25-103
Sewall Wetland Consulting, Inc.
September 7, 2025
Page 4