2507 HOWARD AVE 2016-01-01 MF Import

E'I'ORMWATC•R SITF PL:1N DECEh1BER 19.2005 N[W C�N'I'URl'VILI.AGG PAGE 5 III: OFFSITE ANALYSIS DO�VNSTREA�i INVESTIGATIQN � Infiltratiun is proposed for the redevelopmcnt area. As such, no runoff is expected io leave the that arca.No runoff will be added to the downstrcam system and no speciti: off-site analysis was performcd. An overflow is provided from thc intiltration system to the existing storm drainaee system tor the southeast multi-family devclopmcnt. "I'his will allow a safc ovcrflow unde; unGsually intensc storms. The City of Evcrett drainage inventory maps show the existing srorm system and the off- site connection. A copy of d�is map is included for refcrence in Appendix A. POTE:V'CIAL PROBLEMS AND DOWNSTREAM h11TIGATION r W iP.i no additional runoff being directed to the downstream system, no mitigatioin ;s propused bcyond thc usc of inYiltraton as a stormwatcr quartity control. There is an existing catchbasin diat collects runoff from die northeast multi-family structure. This catchbasin was insta.�ed many ycars ago. apparenHy as a dry well. The City of Everett has noted tnat this system no longcr functions adequately. Given the local topography,the catchbasin lies at a lower elevation Uian any of the other on-site storm systems and canr.ot be raised due ro the cxisting strucWre and parking :re�i that will remain. �ye propose to install a new intiltration system to the wcst ot'dtis structure to handle �vnof£ The desibm of this system is detailed under the ANALYSIS AND DESIGN OF RUNOFF CONTROL BMP'S section latcr in this repoR. i � � J?Nous�ng noce`oroaanap 6e�eu Hcas�rg G�255'o�a�na�e:sSP Hex Ce•nury OOG DWH/Sfrt1 I �