Laserfiche WebLink
HYDROLOGIC CALCULATIONS <br />• <br />The attached hydrologic calculations follow the standard SCS method of <br />calculating runoff from a small drainage. Footnotes throughout the <br />hydrologic calculations indicate the references used to obtain certain <br />factors and other impertinent information used in the hydrologic <br />calculations. <br />Hydrologic calculations were performed in order to estimate the peak <br />flow from a 10-year, 24-hour event and the peak flow from a 25-year, <br />24-hour precipitation event. Calculations were also completed to <br />estimate the total runoff from the 10-year, 24-hour precipitation event. <br />The peak flow from the 25-year, 24-hour precipitation event was used in <br />the sizing of the emergency spillway from the sediment pond and the <br />estimate of total runoff volume from a 10-year, 24-hour precipitation <br />event was used in the sizing of the pond itself. <br />• SEDIMENT CALCULATIONS <br />Sediment calculations were performed in order to complete the sizing of <br />the sediment pond. The sediment calculations are fully annotated to <br />provide the reader with an understanding of the calculations. The <br />sediment calculations were performed to estimate the total sediment <br />yield from the site for a 3-year period. <br />HYDRAULIC CALCULATIONS <br />Hydraulic calculations were performed in order to size the sediment <br />pond, design the emergency spillway from the sediment pond and size <br />culverts C1 and C2. The hydraulic calculations are fully explained as <br />the reader proceeds through them with all assumptions listed and <br />justified. <br />The very flat lying topography of the site dictated that an insized <br />. sediment pond be established. Without the use of an insized pond it <br />would be impossible to collect the runoff in a reasonably small area <br />-2- <br />