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1. PROJECT OVERVIEW <br /> This document is intended to provide engineering information necessary to support the <br /> building permit application to the City of Everett for the proposed Single-Family Residence <br /> and driveway on this lot. The site is located at the corner of Zillah St and S. 1st Ave, <br /> Everett, WA 98203; refer to Figure 1 for a vicinity map. The project site consists of one lot <br /> with parcel number 00500302700100. The lot is approximately 0.16 acres. The existing <br /> site consists of mostly brush and a couple deciduous trees. The slope of the site is <br /> moderate and averages approximately 10 percent down to the east. <br /> This project proposes to construct a SFR on the existing lot with driveway. The driveway <br /> will take access from the existing alley to the west. The City is requiring frontage <br /> improvements along 1st, Zillah and in the Alley. Since the property to the south is also <br /> being developed at this time some of the work from that project will include a portion of <br /> this projects frontage like the required alley improvements. Refer to the permit set for the <br /> Zillah Lot 2 application. <br /> This project proposes to construct approximately 2,310 sf of impervious surfaces on-site, <br /> however the off-site improvements total approximately 4,998 sf of new plus replaced <br /> impervious surfaces. Therefore, this project proposes to construct approximately 7,218 sf <br /> of new plus replaced impervious surfaces, including off-site and on-site. <br /> This project proposes to construct more than 5,000 sf of new and replaced impervious <br /> surfaces, including roof, driveway and off-site improvements, such as sidewalk and paving <br /> the existing gravel surfaces. Therefore, Minimum Requirements 1-9 apply to all of the <br /> -new—and—replaced—impervious—surfaces—for—this projeet—along with all the- converted <br /> vegetated areas. The proposed impervious surfaces will either be infiltrated on-site. This <br /> proposal does not meet any of the land-use criteria that require specific source control for <br /> the final use and a SWPPP has been prepared to address the r-unoff from the site during <br /> construction. Refer to Sections 4 and 5 for a detailed discussion. <br /> Figures 2 & 3 are provided to show the existing and developed basins and runoff <br /> conditions for the project site. The runoff in the existing conditions will spread over the <br /> pervious surfaces on-site and drain toward the east property line to S. 1st Ave. In the <br /> developed conditions, all of the runoff from new and replaced impervious surfaces will be <br /> infiltrated on-site. Drainage from the road improvements will be collected within a <br /> vegetated planter strip/swale and then conveyed south within 1st to an existing CB and <br /> piped conveyance system. The drainage design has been laid out per the DOE 2014 <br /> Stormwater Management Manual for Western Washington (SWMMWW), as well as Vol. 1, <br /> Section 4 of the City of Everett's current Design and Construction Standards and <br /> Specifications for Development manual. <br /> A geotechnical investigation was performed on this site by Nelson Geotechnical <br /> Associates, Inc. The general soil conditions for the site were found to be glacial till. Refer <br /> to Geotech report for further analysis of soils. See Appendix B. <br /> Due to the size of this project Minimum requirements 1-9 apply to the proposed drainage <br /> design as noted above. <br /> Zillah Lot 1 SFR 18-0605 <br /> Aug.2019 Page 3 <br />