Laserfiche WebLink
This application contains calculations used to determine runoff volumes <br />• and flow rates for the 10-year, 24-hour precipitation event and <br />subsequent sediment volumes. The precipitation data were obtained from <br />the NOAA Atlas 2, Volume 3, for Colorado; soil types were obtained from <br />the Soils Map (Map 4). The design of the sedimentation pond is based on <br />worst case conditions. The worst case condition exists during and just <br />after an area has been disturbed and before any final revegetation of <br />the construction site is completed. <br />A non-clogging, dewatering device will be located at a lower elevation <br />on a maximum sediment storage volume. Dewatering will be achieved as <br />necessary to apply with the applicable state laws and regulations. <br />Sediment will be removed from the sedimentation pond when the volume of <br />sediment accumulates to not greater than 60 percent of the designed <br />sediment storage volume. Yearly measurements of sediment accumulations <br />will be conducted. The pond will be cleaned out when water levels are <br />• lowest, and the least amount of precipitation is expected. The removed <br />sediment may be used as topsoil or subsoil if it meets the suitability <br />criteria discussed under Section 2.04.9. <br />The detention time for the pond has been designed to be a minimum of 24 <br />hours to meet the applicable effluent limitations with respect to total <br />suspended solids. <br />The pond will be constructed so the minimum elevation at the top of the <br />settled embankment is at least one foot above the elevation of the <br />surface water in the pond when the emergency spillway is flowing at <br />design depth. <br />Peerless Resources has. designed and will construct and maintain the <br />sedimentation pond to prevent short-circuiting. As a general rule, the <br />inflow to the pond will be at the opposite end from the outflow area. <br />• The sedimentation pond embankment will be less than 10 feet in vertical <br />height from the toe of the centerline of the embankment to the bottom of <br />the emergency spillway. <br />4.05-6 <br />