543 VIEW RIDGE DR 2022-03-14 - Laserfiche WebLink

1. PROJECT OVERVIEW This document is intended to provide engineering information necessary to support the SFR building permit application to the City of Everett for the proposed Single Family Residence (SFR) and concrete pad proposed on this lot. The site is located at 543 View Ridge Dr., Everett, WA 98203; refer to Figure 1 for a vicinity map. The parcel area is approximately 0.59 acres. The existing site consists of lawn, landscaping, an existing SFR and concrete driveway. The existing SFR will be demolished and portions of the driveway will be removed. The slope of the site, in the area of disturbance is moderate and averages approximately 11 percent. The proposed SFR will be set approximately 90 feet from the southern property line. The existing driveway takes access from the existing roadway to the south (View Ridge Dr.). This project proposes to construct less than 5,000 sf of new impervious surfaces. Therefore, minimum requirements 1-5 apply to all of the new impervious surfaces for this project along with all the disturbed pervious surfaces. However, due to the amount of removed and replaced impervious surfaces, this report will outline all Minimum requirements 1-9 and address each applicable section. This proposal does not meet any of the land -use criteria that require specific source control for the final use and a SWPPP has been prepared to address the runoff from the site during construction. Refer to Sections 4 and 5 for a detailed discussion. Figures 2 & 3 are provided to show the existing and developed basins and runoff conditions for the site. The runoff in the existing conditions will spread over the pervious, moderately sloped lawn to the northwest and drain towards the western property line. In the developed conditions the runoff from the new roof surfaces will be dispersed on -site via downspout splash blocks and a level spreader trench. The existing impervious surfaces that will remain in the developed conditions will be dispersed on -site via sheet flow. The general soil conditions for these properties were found to be medium sands. The drainage design has been laid out per the COE 2010 Stormwater Management Manual. The downstream system for this project is comprised of lawn, catch basins and ditches. During the site visit there were no signs of flooding or capacity issues within the observed downstream systems. Due to the size of this project Minimum requirements 1-5 apply to the proposed drainage design as noted above. Included on the following page is a copy of the MR flow chart out of the COE Drainage Manual showing how the applicable minimum requirements were determined. Pignataro SFR 15-1008 March 2016 Page 3 Revised June 2016