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22. I( suitable soils eaist on the site, .inderground in(iltration systems (e.g., inliilration trenches) or <br />surface stormwaler infiliralion systems (e.g., splash blocks, pervious pavers, or sur`ace <br />ponding areas andlor swales) may be i�sed to avoid creating hydraulir.allyconnr.r.ted <br />impervious area from a stormwater detention standpoint. Section 3-2.2 of the Citys <br />Stormwater Management Manual lists sile and design criteria that mi�st be met, <br />23 From a stormwater dete�tion star�dpoint, for an impervious area to be considered <br />hydraulically disconnected, stormwater runoit from the 100-year, 24-hour stonn must be fully <br />retained andlor infillrated — without resulling in significant potenlial (or adverse effects from <br />Ihe infilirated water (such as slope saturation or migration to cra�.vlspaces and/or basements� <br />However, if the on-site soils cannot support full infillration of thc 100-year, 24-hour storm, <br />partial infiltralion may slill be feasible to meet allowable stormwater release requireinents <br />?4 On-site detention is required per City slandards Detention must �e calcuiated for sitr. <br />vegetative conditions prior to the most recent clearing and grading activity on the site. <br />Nilural wellands may nol be used lo moet detention rzquirements (or st�rm watcr. In <br />addilion, storm water delention is generally nol allowed in weQands crealed (or mitiyation. <br />However, with certain types of mitigatior weUands, a restricled outlet and flucluating water <br />table is a desired and designed feature of the wetland. Detention c' clean or treated storm <br />water runo(f may be permissible under these circumstances. <br />2; All storm water facilities shall be designed in accordance with applicable G�;y standards <br />nndlor design policies <br />2f An NPDES (National Pollutant Discharye Elimination System) pemiit, 2dminislered by <br />1Nashinyton Stale.'s Department of Ecology, will be required for clearing and gradiny activ�,ies <br />on this site if the sile area disturbed by land alteration activities is greater than or equal ro onc <br />�icre. <br />2 J Per City policies, due to the proximity of the site to environmentaily sensitive areas, seasonal <br />hmitations may be placed on land alteration activities. Land alteration activities are detined in <br />the Cily's Desiqn and Consiruction Standards and Specificalions as clearing, grubbing, <br />excavalion, filliny, grading, and stockpiling. Determination of the exact seasonal limitation <br />period requires site-speci(ic iniormation generally not available until ihe projecl design slaye. <br />However, preliminary analysis usin� the information availablc at Ihis time indicates ihal I�nd <br />alter�lion activities on lhe project sde may be restricted to 1he period belv�een April 1 and <br />October 1, <br />� 8 A specially designated area will be required (or washing oi cars by residents of the projec?. <br />ihe area must be hydrologically isolated from the resl oi the site, be covered, and wash <br />�v�ter from the area must drain to the sanitary sewer aiter being routed lhrou�h a baffle-,.�;,e <br />oil!waler separator designed to City standards. Signs must be posted on the site•limitinp car <br />�vashing to the designated area only. The project covenants musl contain a clause that <br />��rohibits car washing on the site outside of the specially designated area. If units are to be <br />renled, tho covenant shall state Ihal a clause reslncting vehide washing on the site (o ihe <br />designated area only will be written inlo ihe tenant leases andlor rental agreements. In <br />:�ddilion, a note stating that car washing is only permissible in the designated area must t�e <br />mc'�,�dad on the slorm drainage plans_ <br />