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Added impervious areas, roof, sidewalk,parking lot, and small portion of the landscaped <br /> area adjacent to the parking lot and the building, will enter underground storm drainage <br /> system via catch basins. Roof water will be collected with gutters and conveyed through <br /> downspouts and underground pipe to the detention vault. Storm water from parking lot <br /> and adjacent areas will be pre-treated and then secondary treated in StormFilters before <br /> released to the existing stream near the existing pipe. <br /> See Appendix D for the Developed Drainage Area Map of the area. <br /> SECTION III— OFFSITE ANALYSIS <br /> Field site visit was conduction on April 22nd. No severe problems were observed during <br /> the site visit. I did not observe any lack of capacity drainage problems, flooding or <br /> nuisance problems, overtopping, scouring,bank sloughing,or extensive sedimentation. I <br /> contacted owner living on the adjacent property to get help with past drainage problems. <br /> As described at Section II. of this report, precipitation enters the existing storm water <br /> conveyance system after sheet flowing into the wetland and wetland stream. The 48" <br /> concrete storm drain pipe conveys water across the Casino Road ROW to the north side <br /> of right-of-way. Drainage is then conveyed via same size pipe 500' to another heavy <br /> under brushed wetland area south of the HWY 526. Property west of this pipe is <br /> currently under the development. This flow is carried under highway 526 in northwest <br /> direction. <br /> Casino Road Office building will not aggravate the existing conveyance system since <br /> releases will be less than pre-development conditions. <br /> See Appendix E—Downstream Analysis Drainage Map and Photos. <br /> SECTION IV—ANALYSIS AND DESIGN OF REQUIRED EROSION <br /> AND SEDIMENT CONTROL BMPs <br /> Portion of the site is delineated as a wetland buffer area. Site will meet or exceed <br /> minimum requirements as described in Chapter 2 of the City of Everett Design and <br /> Construction Standard and Specification. Project will utilize a clearing and grading <br /> limits, silt fence, stabilized construction entrance, sediment trap, filter fabric protection <br /> for inlets, outfall protection, and temporary and permanent cover measures to protect <br /> disturbed areas. <br /> See Appendix F-Erosion and Sediment Control Plan. <br /> 3 <br />