Answer Happy

Lake Cushetunk 1: You are the project engineering on the Lake Cushetunk Dam's annual regular inspection during the examination of the main spillway and outlet works the dive inspector indicated that silt in front of the spillway has reach a depth of approximately (3) three feet possible from the repeated last winter storms that hit this area (see below a portion of the inspection report). Before finalizing the report and sending it to the NJDEP Dam Safety Section you speak with the dam owner Scott Jesseman the Director of Public Work, Readington Township about hydro-jetting and flushing the silt through the sluice gate. You prepare a cost proposal which he rejects due to the high cost and requests that you prepare an analysis of why we need to even worry about the silt and present it to Town Council and the Township engineer for their review. Prepare a concise two paragraph report explaining your calculations of the additional force caused by silt that has settled on the lake bottom. Assuming that silt is equivalent to a liquid of density p,=110mb/n and considering a 1-ft-wide section of dam, determine the percentage increase in the force acting on the dam face for a silt accumulation of depth 3 feet. Note: Gravite is already included in pgwater = 62.4 lbs/ft³ &pg=110 lbs/ft³ 10-13 NOV of Concrete Spliwy 1310 NOV Veter. D Stewight 30 out Flow for Apron EL143 Concrete Footing htt
Inspection of Lake Cushetunk Dam NJ INSPECTION YEAR: 2017 EXAMINATION OF SPILLWAYS AND OUTLET WORKS TYPE(S) AND DESCRIPTION OF SPILLWAY(S) Primary: Two 25 long concrete gravity ogee-shaped spillway separated by 5-6 wide central concrete pier. See photos #P24, P43,44 & VS Secondary (auxiliary): Concrete covered ogre earth embankment. See photo #P16, P23, P25-27 & V4 Emergency: Other: LOW LEVEL OUTLET/SLUICE GATE Description: 30" corrugated metal pipe cast into the concrete of the main spillway with invert at elevation 125". The outflow is controlled by a cast iron sluice gate bolted to the upstream face of the concrete spillway and operated by a stem and wheel house on the pedestal above. See Photos # P65-66, and video #V6 Condition: steel stem is in satisfactory condition. The epoxy coating applied in 2007 has maintained good protective value to the solid steel stem, the connecting bolts & nuts are showing signs of deterioration and should be removed. inspected, & replaced if required. The original cast iron sluice gate is in good condition and is operating and functioning properly. During the underwater inspection the dive inspector probed and estimated the depth of silt along the face of the concrete spillway to be between 2-3 feet in depth and deeper in some locations See photos #P12 & V8