Stormwater Surface Filtrationlinfiltration Facility Sizing Spreadsheet <br />.24 Hour Storm, NRCS Type 1A Rainfall Distribution <br />City of Eugene <br />Version-2.1 <br />Project Informatlon <br />Project Name: Oaklefgh Meadows Cohousing Date: 311112013 <br />Project Address: Oakielgh Lane Permit Number: <br />Bunene, OR 974 Catchment ID: Rain Garden 15 <br />Designer: Michael A Cox <br />Company: SSWgnaineeers Inc. <br />Instructions: <br />1. Complete this form for each drainage catchment in the project site that is to be sized per the Presumptive Approach. <br />2. Provide a distinctive Catchment ID for each facility coordinated with the site basin map• to correlate the appropriate <br />calculations with the facility. <br />3. The maximum drainage catchment to be modeled per the Presumptive Approach is 1 acre (43,560 SF) <br />4.For.infiltration facilities in Class A or: B soils where no infiltration testing has been'petfromed use an infiltration rate of 0.5 In/hr <br />For all facilities use a maximum soil infiltration rate of 2.5 in/hr for topsoil1growing medium. <br />Choose "Yes" from the dropdown boxes below next to the design standards requirements for this facility. <br />I Pollution Reduction (PR) Yes <br />Flow Control (FC) Yes- <br />Destination (DT) No. 'An infiltration facility must be chosen as the facility type to meet destination requirements <br />ISite Data -Post'Develo , rftent <br />Total Square Footage Impervious Area= 1592 sqft Total Square Footage Pervious Area= sgft <br />Impervious Area C1 98 Pervious Area CN= 85 <br />Total Square Footage of Drainage Area= 1592 sft Time of Concentration Post Development=E---5min <br />Weighted Average CN= 98 <br />Site Data Pre Development- (Data In this sectlon.ls only used if Flow Control is: required) <br />Pre-Development CN=L' `J Time of Concentration Pre-Development-- 10 min <br />Soil Data <br />Tested Soil Infiltration Rate= 2.5 in/hr (see Note 4) Destination Design= inlhr <br />Design Soil Infiltration Rate= 2.5 in/hr Soil Infiltration Rate <br />Design. Storms Used For. Calculations <br />Requirement <br />Rainfall De th Design Storm <br />Pollution Reduction <br />1.41inches I <br />WaterQuality <br />Flow Control <br />3.61 inches <br />Flood Control <br />Destination <br />3-61inches <br />Flood Control <br />LEacility-Data-... . . - - • -I <br />' Facility Type=1 <br />Filtration Rain Garden <br />Facility Surface Area=1 <br />1471sgft <br />Surface Width=) <br />7 <br />ft <br />Facility Surface Perimeter=1 <br />56 ft <br />.Surface Length= <br />21 <br />ft <br />Facility Bottom Area=1 <br />72 sgft <br />Facility Side Slopes= <br />-3 <br />to 1 _ <br />Facility Bottom Perimeter=1 <br />44 ft <br />Max. Ponding Depth <br />1 <br />in Stormwater Facility= <br />6 <br />in. <br />Basin Volume= <br />57.0 cf <br />I Depth of Growing Medium (Soil)= <br />18 <br />in <br />Ratio of Facility Area to Impervious Area= 0.092 <br />Y <br />607 <br />3/11!201.3-10.57 AM 1 <br />