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CONCEPT ARCHITECTURE, LLC
1712 Pacific Avenue Suite 107, Everett, WA 98201
1005 Terminal Way Suite 245 Reno, NV 89502
ConceptArchitecture.com
UPSTREAM FLOW / WATER ROUTING QUESTION
Project: 4th Dimension Building
Site Location: 4502 NE 4th Street, Renton, WA
APN 1023059068
Item A –
The upstream basin has been analyzed using the Renton GIS to determine tributary areas. The
calculation of upstream flows was performed in accordance with standard practice and by
direction provided by the City for modeling upstream detention systems. This is all documented
in the TIR. We feel the numbers generated are suitable for the flow calculations performed for
the TIR in regards to backwater and flood storage.
We reviewed the site and its immediate vicinity for critical areas (wetlands, streams, and their
associated buffers) per the City of Renton Code Requirements. We have also prepared a TIR
analysis to model if anticipated development of the project site would significantly alter
downstream flow regimes. As part of the TIR model, an assessment of land use cover was
assessed for the watershed basin. It was determined that no adverse impacts to stream flows
would result from the project. Additional stormwater generated from site development would be
directed to stormwater facilities where it would be treated and discharged accordingly.
Any additional study would seem to be informational only and not necessary to the analysis and
design of the project from an engineering or wetland stand point.