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STORMWATER SITE PLAN <br />EVERETT COMMUNITY COLLEGE HOUSING - BROADWAY <br />SEPTEMBER 11, 2015 <br />PAGE 3 <br />OPERATIONS AND MAINTENANCE <br />Maintenance requirements taken from the CESMM Manual are provided in Appendix C of this <br />report. <br />EXISTING CONDITIONS SUMMARY <br />DESCRIPTION <br />The 0.35 ac site currently contains 3 single family homes, 2 garages, walks and landscaping. The <br />site slopes generally to the east from elevation 128 at the southwest corner at the alley to <br />elevation 118 at the back of sidewalk at the northeast property corner. See Figure 2: Existing <br />Site Map for more information. <br />SOILS DESCRIPTION <br />A geotechnical report has been prepared for the site by PanGeo Inc. The site typically has <br />about a foot of topsoil underlain by medium to very dense brown silty fine to medium sand <br />with gravel. Three borings were made to a refusal depth of 6.5-8 feet with no groundwater <br />seepage. Their report is included as Appendix A. <br />EXISTING BASIN <br />The existing basin consists of 0.35 acres and contains the following surfaces: <br />Impervious Roofs and Drives: 0.19 ac <br />Pervious Lawn on Till: 0.16 ac <br />Flow generally leaves the site as sheet flow and enters the storm system in the surrounding <br />streets. <br />UPSTREAM ANALYSIS <br />The alley intercepts upstream flow and directs it to the north. To the south, north and east; the <br />site is higher than the surrounding properties. <br />DOWNSTREAM ANALYSIS <br />Runoff from the site leaves as sheetflow to the north, east and south and enters the storm <br />drainage systems in Broadway Ave and 10th St. These systems are connected to the combined <br />sewer system. <br />Per discussion with City of Everett staff, this area has no know capacity issues such as <br />basement flooding. <br />I'��\1'i,ik I'injrcl.��'llli IS-UU K��i- 13ruud���a�'('I��I)O('Sl�ui lin,ud��:i�' I)iainurr I?-17U�h�c <br />