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JUN 20 '95 13:59 C MORGRN RSSOC <br />FROMI�CITY OF E�R�TT g�p� ppT T0: 2063488234 <br />�}, . <br />.; <br />PI�fBL/C /YO�I►AfS <br />TO: <br />1�'1tODl: <br />DATE; <br />MF.MORANUUM <br />C�.trL¢s Mdrap�� <br />�Eirk-Biwel�A.. <br />Jane Zimmerman <br />)unc IS, 1995 <br />435 P02 <br />JLIN 19� 1995 10:35fiM p27g p,0; <br />�Qye �IZ <br />FaX- 3ya •E323� <br />3UBJRCT: Drninagc Calculation ltcvicw, Aroadway South Condominiutns <br />3Yetpond(�teq�p�; <br />'1'o dcmonstrltc that lhe wetpond mccts City staneinrds, the <br />be rauted through the po»d, and the peak starage during the s�includlnY li e and � <br />dcad storage, must be equnl to thc welponJ design valume. The wetpond dcaign sto�m <br />ix Ihe 6 month, 24-hour storm. If half of thc wetpond Jesign volume is provided as <br />dcad Ftorage, U�e other half of thc volume (24Qg cubic foet) must be backed up in l},e <br />pond Juring the wetpond dcslgn ak�rm. <br />When the b month, 24-hour st�rm is rcwtul through thc pond �s cucr�ntly dcslgneJ, <br />;nsufficicnt livc storage results. }iven when the ptlnury oNffee is reduced to tlx <br />minimum �powed 1 inch aia�, only 1922 cuhic fea� of atorage is obtaincd dunng tho 6 <br />rnnnlh, 24-hour storm. '1'hcrcPerc, the dexd storagc !n the pond rtwst be incrcer,ed by <br />4Ft6 cubfc fcct, Ro that the cambincd �►eak )ive storage during the stornt anci t1�e dcad <br />storage volume equal thc wctpond desi�n volumc of 48i6 cubic foet. <br />age- ve itBTl�e7etatlOtu}i1p of the pona iR n,�t ct�pged� by t}x addidon of deHd <br />storagc volume, swcanpary �rt8e� of 4.23 inclxx locrtcd 1d Wev�t[on 514.23 feet <br />would tlinw thc pond lo tnat both dcbendcm and wetpond requiroments. If the stagc• <br />live atoragc �f ihc pofxl is chet4;ed, routing ca)culations and orifice sizin� calculatiuns <br />will need to be ralone. The secondary m•iticc is placed at the meximum Ftorage <br />elcvaiion during the G month, 2q-hour storm and is aizcd so thot the combined <br />disch��rge f'rom Ihe primary and Fecondary orifices is cqual to the allowable disohar�e <br />(0.65 cfs) when lhe ponJ reachcs the overflow elevation. <br />���od� � <br />NOV 2 21995 <br />R <br />....... <br />CITY OF EVERETT <br />Bldq. Pormit Counter <br />