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r Mr.Mike Gaffron Re:Orono Villas <br /> Page 5 ' 13 November 2006 <br /> ' Lance Hoff Memo of 16 August 2006 ° <br /> 1. The proposed site meets existing flow rates for the 2-yr, �0-yr, and 100-yr, <br /> 24-hour storm events. The table below summarizes our modeling � <br /> results. � <br /> Storm Return Period . <br /> Condition 2_yr 10-yr 100-yr <br /> � Existing 1.3 4.7 10.4 <br /> � . Proposed 1.3 4.2 8.2 . <br /> 2. The proposed pond has sufficient wet volume to treat runoff from the <br /> 2.5", 24 hour Storm. <br /> � 3. A spot elevation or contour for the pond top of berm should be shown <br /> on the grading plan. The pond should provide flood storage up to an <br /> elevation of 959.5 as shown in the developer's submitted model. <br /> The top of berm has been revised to 959.5, see sheet C3.9. <br /> 4. A pond outlet detail should be provided. The pond outlet should. <br /> provide skimming up to the 10-yr event. Low flow control is not <br /> necessary for this site. , . <br /> A pond outlet detail has been provided, see sheet C4.9. <br /> 5. The pond EOF elevation and location should be shown on the grading � <br /> plan. The pond EOF should be located at or above the 100-yr HWL. <br /> The pond EOF elevation and location has been provided, see sheet <br /> C3.9. The pond EOF elevation is 0.9-feet above the 100 year HWL. <br /> 6. 2' of freeboard should be maintained for the townhome adjacent the <br /> northwest rain garden (B.F. 1). � <br /> 2'of freeboard has been provided far all townhomes adjacent to � <br /> rain gardens, see sheets C3.9. � <br /> 100 NORTH SIXTH STREET SUITE 800C MINNEAPOLIS,MN 55403 <br /> OFFICE: 612.252.9070 FAX:612.252.9077 www.landform.net <br />