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<br />2 <br /> <br />Weekly - Monitoring of seepage. <br /> <br />Monthly - Thorough visual inspection. Gathering, <br />immediately plotting, and interpreting observation <br />well and piezometer data. <br /> <br />Anr.-Jally - Reading horizontal and vertical control <br />monuments (more frequently if necessary). <br /> <br />Test operation of outlet and spillway mechanical <br />components. <br /> <br />Routine maintenance as required. <br /> <br />MODERATE HAZARD DAMS - Failure of the <br />dam would cause extensive property damage but is not <br />expected to cause loss of human life. <br /> <br />Weekly - Surveillance by the owner or caretaker. <br />Monitoring of seepage. <br /> <br />Monthly - Thorough visual inspection whon stDrage <br />is in excess of one-half the maximum gage rod reading. <br />Gathering, plotting and interpreting obser- <br />vation well and piezometer data when storage is in <br />excess of one-half the maximum gage rod reading. <br /> <br />Annually - Test operation of outlet and spillway <br />mechanical components. <br /> <br />Reading of horizontal and vertical control monuments <br />after a satisfactory performance record has been <br />established for the dam. <br /> <br />Routine maintenance as required. <br /> <br />LOW HAZARD DAMS - Failure would cause little <br />damage beyond the loss of the dam structure itself. <br /> <br />Monthly - Surveillance by the owner or caretaker. <br />Monitoring of seepage when storage is in excess of <br />one-half the maximum gage rod reading. <br />Gathering, plotting, and interpreting observation well <br />and piezometer data when storage is in excess of ooc- <br />half the maximum gage rod reading. <br /> <br />Annually - Thorough visual inspection. (If the reser- <br />voir is full all year, visual inspection should be done <br />quarterly.) Testing operation of the outlet works. <br /> <br />Every Five Years - Reading of horizontal and vertical <br />control monuments after a satisfactory performance <br />record has been established. <br /> <br />Routine maintenance as required. <br /> <br />1.4 CRITICAL CONDITIONS <br /> <br />Floods <br />When floods caused by severe rainstorms, or excessive <br />snowmelt runoff are predicted, the spillways of all <br />dams should be inspected to detect any areas that will <br />need special protection while passing the flood flows. <br />During the flood and after flows subside, the spillway <br />should be inspected to identify any damage needing <br />repair. <br /> <br />Windstorm <br />High winds can cause damaging wave action. The <br />upstream slope must be monitored during severe wind- <br />storms to allow prompt repair of damaged areas. Tho- <br />rough inspection when the storm subsides will allow <br />required' maintenance to be identified and prompt <br />repairs initiated. <br /> <br />Earthquake <br />If the effects of an earthq uake are identified in th, <br />of the dam site or if tremors have been reportee, <br />dam should be thoroughly inspected immediatel: <br />at weekly intervals for four to six weeks afte <br />quake. Conditions triggered by an earthquak< <br />often take sev~ral weeks to appear. <br /> <br /> <br />'i-~ <br /> <br />PHOTO 1.4-] <br />RUNOFF DAMAGE I <br />FLOWS ERODING UNPROTECTED SPILLWAY CHANNEL. Sail <br />bags and plastic sheet placed on right side to divert flow. Note full out <br />discharge to minimize flow through spillway. I <br />1 <br /> <br /> <br />PHOTO 1.4-2 <br />WINDSTORM DAMAGE <br />Large cavern eroded into embankment after wave action destroyed concrete <br />protective coating on the upstream face. <br />