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� - <br /> a <br /> � , <br /> • <br /> ': I <br /> Reid, Middleton b Associates, Inc. <br /> FILE N0. 02-85-094 Engineers • Surveyors • Plonners <br /> October 10, 1985 <br /> ' Revised Oct. 2�, 1985 <br /> 54bRM WATF.R DETENPION CAiw'Z)LATIONS F'JR <br /> SII,VER LA[� SELF SERVICE SRURAGE ADID CAFbVASE3 <br /> ' BY PUGFT WEST Q�RL�RATION � <br /> CPi'Y OF EVEREiT, W�IAX,�CN ' <br /> ; /1 h. S S.�L � [c�o� C�c <br /> ; �T Ur�ie.� � f /1 <br /> l� G pr �, ;, f �j L� �. • - �� }��c�� <br /> F.XT�TTIY� SITR Q2dDPPTCNR 5 0 �`iC eX . <br /> - - US" �i � �p' �`� <2 <br /> . I�,j r .r < « � � <br /> Area = 3.197 Acres � p �„Q � _�� ��� � . r (� <br /> P,esidential lot with grass field and woo�areas west of residence ��ooG���/. <br /> Fxisting runoff coefficient = 0.09(0.9) + 3.107(0.2) / 3.19; = 0.22 <br /> n = 450/1(60) + 10 min. = 17.5 n. �4 � �J� � <br /> intencity = i = 1.38 ir�/hr @ �,F�. Stocm E�erett Cur�e <br /> Q existing = c i A = 0.22 ( �j.38 ) 3.197 = 0�`97 c.f.s. C�P�,u � �/�°r,�r� <br /> hC/L' /i���U ✓�1 C/.0 �NCI 1 , <br /> a��P'ID Q���I�S � i l' -I-�Ci��t Z. ��n��/An '� �^ d� Cn"��-l�j� (- <br /> C�h��� A�+ � .� .- �. c I' r�/' /U�( `� a �iJ � 1 <br /> Area = 3.197 Acres ��� Y �; <br /> Prorated runoff coefficient"# Q.83 (2.45) + (0.8) 0.75 / 3.197 = 0.82 (�� p�fs c•; <br /> Design Storm = 25 year L� <br /> Required Detention = Qo = 0.97/ 0.82(3.2) = 0.35 <br /> T = -25 = 2706/0.35 = 62.93 <br /> Vs = (4329(62.93))/(62.93 +25)-(40(0.35)62.93 <br /> = 3098.19 - 881.02 = 2217.17 <br /> V total = 2217.17 (0.82) 3.2 = 5,817.85 cu.ft. <br /> Due to the lack of a defined stocm drainage channel to the south of this <br /> project and after a meeting with �n Mathias, City of E��erett. �is project. <br /> will discharge it's stocm water into the existing drainage way at the northwest <br /> corner of the project and contribute to the regional storm water detentioii <br /> syst�n fund for Faid basin. �e wntribution will be based on a ru.f.t, charge <br /> of $2.37 for the rtquired detention vol�ane for this project; <br /> = 5817.85 X 2.37 = $13,788.30 . <br /> 121 Sch Avenue Notth. Suice 200, Edmoncs, Woshington 98020 (206) 775-a434 <br />����. <br />