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HomeMy WebLinkAboutPermit Correspondence 2005-7-31 ,... Jul 3t/200\ 9:27PM ~()iLc(X)'6" - OC) C\ I ~ Date: 07/31/05 Invoice No. 259 Remit Payment 10: Ronald J. Derrick, P.E. 420 NW Maxine Avenue Corvallis, Oregon 97330 Ph. 541-913-0220 Fax. 541-753-0938 Mr. Stu Meyers 1620 Kellogg Road Springfield, Oregon 5+YI)f-t5?"? ~ ~ Uuanlltv Unit l,;OSl . Uescnollon ot ~envces l,;ost 1 $100,00 Infiltration Basin Design 1620 Kellogg $100,00 Totllllnvoice.,..,....... $100,00 Thank You for Your Businesslll J' rI~5 l/' " Jul 31 2005 9:27PM .LASERJET FAX . p.2 Rone/d J. DerrIck, P.e. 420 NW Maxine Avenue Corvallis, Oregon 97330 Ph. 541.913.0220 Fax 541-758-8563 July 31,2005 Mr. Stu Meyers 1620 Kellogg Road Springfield, Oregon via Facsimile RE: INFILTRATION BASIN DESIGN 1620 KELLOGG ROAD SPRINGFIELD. OREGON Based on my June 17, 2005 on-site infiltration testing and the data analysis presented in the accompanying June 20, 2005 report. the following infiltration data and system design for disposal of roof drainage off the existing residence on the property is presented herein. The measured on-site vertical hydraulic conductivity at 1620 Kellogg Road is 0,3 ftlhr which calculates to a rate of infiltration of 25 gallonsJhourisquare foot with a 2 foot hydraulic head. The roof area of the existing residence is 1,078 square feet and the 5 year, 24 hour storm event will produce 3,6 inches of rainfall. The calculated amount of drainage water produced is 323 cubic feet = 2,419 gallons'in 24 hours. The infillration area required to dispose of this volume of water is 4 square feet, applying a safety factor of 2, the required infiltration area is 8 square feet. A 3 foot squafe infiltration basin is recommended and the basin shall be a minimum of 5 feet deep with a foot of topsoil cover and shall be located at least 5 feet laterally from structural foundations, The storage volume of a 3'x3'x4' deep basin filled with rounded drain rock is estimated to be 94 gallons of water. The infiltration pit shall be constructed as shown on the attached detail. Limitations This rep'ort was prepared solely for the Owner and engineerfdesigner for the design of the . project. The .opinions and recommendations contained within the report are not intended to be nor should they be construed to represent a warranty of subsurface conditions, but are intended to assist in the planning and design processes, This report pertains to the material testedlinspected only. Information contained herein is not to be reproduced, except in full, without prior authorization form this office, This report does not express any opinions nor does it make any conclusions regarding any environm~!IH11 concerns of in-ground storm water disposal. 'r~,'J>- '. ' . ~~ /~-" ~ Ronald J. Derrick, E Sincerely. ,-,,,.. " ..; .~, Jul 31 2005 9:27PM . , .LASERJET FAX -:.--e p.3 Notes: Minimum depth of Il1fIltratlon Pills 5 feel Fill pit with open graded round drain rock (314" or larger) Wrap drain rock In flllerfabrlc (Mlratl140N or equivalent) Inllno clllanout or debris trap , 12 Inches of Topsoil .-- .r~- ..;.;,,:....... ,r;l:!;i:::,i"~" . .----... . .... ~f.~;..;: " ' ,~:4'~ ::f:' > :~f: ",r... .,,"" Id ':~':: ::::'~;!~:~~.::! ,'. 5 Feet ............ ~ WI WI ~....... ~....,.. w.~' . ... w..... .:....... ..' .w......,... .........' ..,...,..,.......,......... .......,............... . . . . . . .. . . .' I.>' ............. ...w w" Tight line drain pipe from surface Inlets st 2% min, slope 3 Feet Infiltration Pit Construction Detail Not to Scale FIGURE 1 INFILTRATION BASIN DETAIL 1620 KELLOGG ROAD, SPRINGFIELD OREGON J