Laserfiche WebLink
STORhf\1'A7'ER SI'I'L' PI.AN <br />�fADISON CO�1h1UNITY CIIURCII <br />h1AY 26, 2006 <br />PAGE 12 <br />A maximum of 85% of thc rcquired `dead storage' may be provide in the `open water' <br />ccll. Thc 'opcn watcr' portion of thc dctcntion ponJ providcs 4.7G8 cf of `dcad storagc'. <br />This cooresponJs to approximatcly 30% of the dcaJ storagc rcyuirement. It has the <br />following clevations: <br />[3ottom of ccll = 374.0 <br />Top of'Dcad Sroragc' = 378.55 <br />Maximum Dcpth = 4.55 fcct <br />BMP RD.OS VEGETATGD TREATMENT CGLL <br />This cell will be scparated from the `open water' ccll by an ecology block wall extending <br />to an clevution 0.5 fcct above the bottom of 'live storage' elcvation (379). The bpen <br />water' ccll will overflow to thc vegetated trcatment ccll at Aie south �.; of the pond. Thc <br />wall at this point is sct at dic bottom of `live storage' elevation (378..,). <br />The volumc of die wet pond has hccn calculated using thc requirements of the CEM <br />Manual. Thc minimum volume can also not be Iess than 15 percent of the requircd dead <br />storagc, the volume of runoff from the 6 month storm event. <br />V,,,;� = 0.15 (5,954) = 893 cf <br />Thc `dcad storagc' volumc providcd in the vegctatcd trcatmcnt ccll is 1143 cf. The <br />average depth of the ccll is approximately 2 fect. This cooresponds to approximately 19% <br />of thc dcad storagc rcquiremcnt. It h�s the follo�ving cicvations: <br />Bottom of ccll = 376.0 <br />Top of'Dcad Storagc' = 373.55 <br />Maximum Depth = 2.55 feet <br />Thc tntal dcad storagc providcd by thc 72" manholc. 'opcn ���atcr' ccll and `vegctatcd <br />trcatmcnt' ccll is 6,024 cf. This exceeds thc rcquired 5�)54 ct� of storage of the developcd <br />6 month storni. <br />DETEN'I'ION B\IP <br />[3MP RD.06 �VL'TPOND <br />The drainagc design is based on the following standards. 'I'he dcveloped onsite runoR� <br />ratcs �vill bc dctaincd to thc Ciry of Evcrctt standards, %: thc 2 ycar ard matching the 10 <br />and 100 ycar. Thc lo�acr orificc conirols the t�vo year stomi event with the notch wcir <br />conirolling thc 10 S 100 ycar events to mcet thc discharge requirements. A 43.5°% <br />corccction factor has hccn applicd to thc li��c stor:�gc portion of this pond bascd on thc <br />basin impc:��ious co��cragc of approximatcly S3°%. Thc factor uf safcty has bcen applicd <br />Uy rcducing thc scctional arca of thc dctcntion pond by �13.5% prior to inputing thc data <br />inlo StonnshcdT`l Scc attachcd StonnShcdT" output in Appcndix C. <br />'I'lic dcsign f'ur thc dctcntion systcm is as follo�vs: <br />� o,,.�-y r,,�. eo�-�-�ry c��-rn � sia a-0:e�o�a�.aqe��ssr n+ra:o� ooeDWHlsrm <br />