Laserfiche WebLink
V. Design Calculation Summary <br />See Appendix C for calculations <br />Table — Runoff Rate <br />Rainfall Event <br />(Type 11 24-hr) <br />Existing <br />(cfs) <br />Proposed <br />(cfs) <br />2 -year <br />3.58 <br />2.52 <br />10 -year <br />7.64 <br />6.83 <br />100 -year <br />13.91 <br />11.45 <br />Table — Filtration Volume <br />BMP <br />Filtration Volume <br />(cf) <br />Central Pond <br />6,635 <br />Parking Lot Islands <br />1,595 <br />Underground <br />Filtration System <br />2,710 <br />Total Provided <br />10,940 <br />Total Required <br />7,840 <br />Table — High Water Levels <br />BMP <br />Bottom <br />HWL <br />Central Pond <br />930.0 <br />933.4 <br />Underground <br />Filtration System <br />920.6 <br />924.4 <br />VI. Construction Discussion <br />Temporary sediment basins will be constructed to treat construction runoff. The basins will be <br />located at the location of the new proposed basin at the center of the site, and the snow melt <br />area northeast of the bus turnaround. Final elevation and construction of the sediment basins <br />will be determine after on -site inspection for existing containments are completed and <br />recommendations provided for their design. If unsuitable soils are encountered in identified <br />infiltration areas, they will be replaced with engineered soils. <br />Temporary erosion and sediment control measures are included in the design plans to minimize <br />construction impacts and meet the NPDES Construction Storm Water Permit requirements. <br />Hwy 36 and Rice Street Park and Ride <br />Storm Water Narrative — 90% Review Set <br />8/5/2011 <br />34 <br />Page 1 6 <br />