Laserfiche WebLink
Sedimentation Pond 004. Sedimentation Pond 004 was surveyed in 1990 for sediment <br />accumulation during the scheduled sedimentation pond surveys. The survey infarmat ion was <br />utilized to develop a contour map. This contour map was used to calculate the sediment <br />storage beneath the principle spillway. The sediment storage rapacity then was compared <br />to the previous survey conducted in 1987. The results are as follows: <br />POND 004 <br /> 1987 Survey 1990 Survey <br /> Capacity Cumulative Capacity Capacity Cumulative Capacity <br /> Elevation (AC-FU (AC-FU (AC-Ft) (AC-FU <br /> <br /> 6936.0 0 0 0.0 0.0 <br /> 6937.0 0.05 0.05 0.03 0.03 <br /> 6938.0 0.23 0.28 0.15 0.18 <br /> 6939.0 0.44 0.72 0.36 0.54 <br /> 6940.0 0.65 1.37 0.62 1.16 <br /> 6941.0 0.85 2.22 0.93 2.10 <br />• 6942.0 <br />6943 <br />0 1.05 <br />1 <br />29 3.27 <br />4 <br />56 1.22 <br />1 <br />49 3.32 <br />4 <br />81 <br /> . . . . . <br /> 6944.0 1.61 6.17 1.75 6.56 <br /> 6945.2 2.50 8.67 2.45 9.01 <br /> Principal Soillway <br /> <br /> 6946.0 2.07 10.74 2.03 11.05 <br /> 6947.0 2.99 13.73 - - <br /> 6448.0 3.30 17.03 - - <br />Sedimentation Pond 004 wes retrofitted with a 6" CMP reducer on the 36" CNP principal <br />spillway (see design Appendix 7-bc, Tab 7, Volume 5) in 1986. Calculations showed Pond <br />004 to have an available sedimentation storage of 9.96 ac-ft below the principal spillway <br />elevation of 6945.2. <br />Sediment inflow into the pond was based on the MUSLE. The rate was calculated at 4.28 <br />ac-ft/10yr-24hr storm, or a total design capacity of 2.3 storms (NUSLE's). <br />• <br />7 <br />