STATE OF CALIFORNIA I 6 CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of I Darn Orovrlle Dam No. 1-48 County Butte Type of Dam earthfill Type ofSpillway Gated concrete weir and ungated conc. weir Water is 210 feet below spillway crest and 231 feet below darn crest. WS 691 ft Weather Conditions Sunny and warm Primary contacts Dave Sarkisian and Paul Dunlap from Bill Dickens and Joe Eades, Contacts Made OFD - and the 12 consulting board Reason for Inspection annual inspection Important Observations, Recommendations or Actions Taken 0 The inspection ofthe saddle dams was completed on 6/18/14. The inspection of the main dam was completed on 8/11-12/14. The inspections were held in conjunction with the 12 inspection. Members of the Board include Dr. Lelio Mejia, Dr. Paul Rizzo, Dr. Don Bruce, and Dr. Bob Wright. The members have been retained by until the next 5-year board. a As recommended in the previous 12 Report, .a plan for long?term monitoring ofthe phreatic surface within the dam embankment needs to be developed and implemented.? is working with DSOD to develop a course of action. a The river outlet system (RVOS) has been rehabilitated and tested for discharges up to 2,500 to provide the required cold water releases in a safe manner. The system is now operated and monitored remotely. A longer term project is being developed to increase the reservoir drawdown capacity for dam safety purposes. 0 Staff should continue to monitor the mid?slope seepage at the left side of the slope. The ground cover should be trimmed low to facilitate this activity. A means of monitoring the extent of the seepage area should be implemented. 0 Visual monitoring for movement of the irregular rock wave protection along the upstream slope should continue. Wave erosion appears to be disturbing the rock and causing it to move down slope in some areas. 0 Crest roadway paving is scheduled, but remains delayed due to higher priority work. a The remaining gate seal restoration work at the Flood Control Outlet is scheduled to start in October 2014. If conditions allow, the work will be completed by the end of the year,. Conclusions Based upon my information review and my inspection, the dam, reservoir, and appurtenances are judged safe for interim use pending restoration of adequate drawdown capacity, completion of Category 2 radial gate recommendations, and implementation of a long term monitoring program for monitoring the phreatic surface within the dam. Observations and Comments Da_m The crest roadway is shown in photograph 1. Repair of the surficial asphalt cracks has been delayed again due to higher priority work. The repairs to the shoulder of the crest are holding up well. The embankment, groins and abutments remain stable appearing and in satisfactory condition. See photographs 2 through 4. As noted during past inspections, the rock along the upper part of Inspected by WPennington Photos taken? Yes N0 Date of inspection 6/18 and cc for Owner/ Book Date of Report 9/18/14 u" DWR 1261 (Rev. 10/09) Sheet Name of Dam Oroville INSPECTION DAM AND RESERVOIR IN STATUS Dam No. 1-48 Date of Inspection 6/18 and 8/11?12/2014 Observations and Comments illwa the upstream slope remains uneven in some areas and should be visually monitored for signs of movement. Rodent and vegetation control appeared to be satisfactory. The inspection team walked the foundation galleries, the bypass tunnel, the S-block, and the Emergency Exit Tunnel. No new concrete cracks, or any significant offsets were observed along the galleries. As previously noted, mineral buildup continues at a number of crack and joint locations. An attempt should be made to clean the worst areas to allow better monitoring of flow and crack geometry. Conditions along the Emergency Exit Tunnel appeared to be unchanged. As previously requested, the drain system should be checked for blockages. Repairs are planned, but have been delayed. Bidwell Canyon Saddle Dam: The reservoir level remains well below both embankments. No signs of instability were observed, photographs 5 through 8. The graveled crest remains in good condition. Vegetation and rodent control remain satisfactory. Parish Camp Saddle Dam: The reservoir level well below the embankment. The graveled crest remains in good condition. No signs of instability were noted, photograph 9. Vegetation and rodent control remain satisfactory. The rock placed in the erosion gullies along both groins was intact and stable. Conditions along the upstream and sides of the Flood Control Outlet (FCO) appeared to be unchanged from recent inspections, photographs 10 and 11. The approach training walls remain stable and in good condition. No new spalling was observed along the roadway bridge bents. As noted during the last inspection, the diagonal crack on the left bridge abutment may have extended somewhat, but this could not be determined for sure due to the faded paint. The paint should be reapplied and observed regularly, as previously requested. The full length of the FCO discharge chute was inspected. Conditions appeared to be normal. The walls were well aligned and appeared to be stable. See photographs 12 and 13. The chute and the dentates remain in satisfactory condition, photograph 14, for example. The emergency spillway remains in satisfactory condition, photograph 10. No signs of instability or concrete problems were observed. will review the sliding and overturning stability of this structure. The service (upper) deck remains in satisfactory condition. Nothing unusual was observed along the radial gate hoist deck. The radial gates were inspected by looking down from the hoist deck and by observation from accessible locations along the trunnion deck and spillway chute. Gate 5 was blocked open for access to the chute floor. No problems were observed during a cursory inspection of the radial gates and trunnions. The gates appeared to be in satisfactory condition. As noted in the past, the usual detritus was observed along gate members. See photograph 16, for example. Regular maintenance is needed to keep these areas clean. DWRi261(rev.10l09) Sheet 2 of 15 Name of Darn Oroville INSPECTION DAM AND RESERVOIR IN STATUS 1-48 Dam No. 6/18 and 8/11-12/2014 Date of Inspection Observations and Comments Outlet Seepage DWR 1261 (rev. 10109) The remaining gate seal restoration work at the FCO is scheduled to begin in October 2014. If conditions allow, the work will be completed by the end of the year. A number of Category 2 recommendations resulted from the September 2012 radial gate inspection by the HDR. Inc. The recommendations will be scheduled and completed on a priority basis. This approach is satisfactory to DSOD. Photograph 15 shows the trunnion deck. The tendon anchors are about 50?years old and could experience problems in the future based on the history of tendon breakage at dams of similar age and construction. The Board expressed concern about this and will make strong recommendations about the need to carefully monitor and test the tendons using the latest tools. Ultrasonic testing of the anchor rods has resumed. At the suggestion of the Board, more informative testing methods are actively being pursued by The river outlet system (RVOS) was recently rehabilitated and tested for discharges up to 2,500 to provide the required cold water stream releases in a safe manner photograph 17. The system is now operated and monitored remotely. Cameras have been installed at key locations. A longer term project is being developed to increase the reservoir drawdown capacity for dam safety purposes. Oroville Dam: Flow thru the toe weir was normal for the reservoir level. The seepage flow in the galleries was within historical trends and remains relatively low due to the sustained low reservoir level. Measurement weirs located along the gallery gutters can be used to the check the flow over a specific reach of a gallery. Seepage within the emergency exit tunnel appeared to be normal. As previously requested, the drain pipe system should be cleared and repaired. Paul Dunlap mentioned that repairs are planned. During the July 2013 DSOD inspection, the team noted a small spring in a tree lined channel located from the right groin. The area around the small undercut pool was wet for a short distance. As the reservoir rises next season, the location should be watched to see if the reservoir influences the flow. The long established wet area at mid-slope on the left end of the dam was surface dry. A means of monitoring the extent of the seepage area should be implemented so that year to year changes can be recorded. in addition, the ground cover in this area should be kept low to facilitate the monitoring process. - Bidwell Canyon Saddle Dam: The lake level was well below the embankments. The toe drain outfall at the west embankment was dry, as expected. The foundation seepage that migrates from Miners Ranch Reservoir to a seepage area upstream from the south embankment was minimal. Parish Camp Saddle Dam: The lake level was well below the embankment. As expected, no seepage was observed. Sheet 4 of i Name of Dam Oroville INSPECTION DAM AND RESERVOIR IN STATUS Dam No. 1-48 Date of Inspection 6/18 and 8/11-12/2014 Observations and Comments Instr. The latest monitoring data on file is the December 2013 which covers the period from 10/1/12 to 9/30/13. The following comments are provided. Oroville Dam embankment: House remains in satisfactory condition. Three active piezometers are thought to be functional. These are P-37(upstream transition), and They will be read until they no longer function. The last FERC Part Report states that .a plan for long-term monitoring of the phreatic surface within the dam embankment needs to be developed and implemented.? is working with DSOD to develop a course of action. The Board is very interested in this issue and will comment formally. Survey monuments are located on the upstream and slopes and along the crest of the dam. Crest settlement remains minimal. The maximum movement being about 9-inches at station 53+00 since 1969. Settlement and displacement along the upstream and slopes remains normal and appears to be stabilizing. Bidwell Canyon Saddle Darn: Settlements and deflections remain small and normal. Parish Camp Saddle Dam: Settlements and deflections remain small and normal. The instrument program for Oroville Dam is satisfactory on an interim basis, pending completion of a program to monitor the embankment phreatic surface. The saddle dam instrument program remains satisfactory. Based on my field inspection, my discussions with field staff, and my review of the available data, Oroville Dam, and the saddle dams, appear to be functioning normally. Sheet 4 of 15 DAM AND RESERVOIR IN STATUS Name of Dam Oroville Dam No. ?1?48 Date of Inspection 6/18 and 8/11-12/2014 4 xmfx?iw??, 73.33?? 2. The right side of the dam and the shoulder of the crest are shown. Conditions were normal. DWR 1261 (rev. 10f09) Sheet of '15 INSPECTION DAM AND RESERVOIR IN CERT STATUS NameofDam Oroville Dam No. 1-48 Date of Inspection 6/18 and 8/11-12/2014 3. The left side of the dam and the parking for the right gallery entrance, arrow, are shown. Conditions were normal. 4. This View shows the typical conditions along the upstream side of the dam as seen from the left abutment. Conditions were normal. Sheet 6 of 15 INSPECTION DAM AND RESERVOIR IN CERT Name of Dam Oroville Dam No. ED STATUS 1?48 Date of Inspection 6/18 and 8/11-12/2014 5. Bidwell Bar Saddle Dam west embankment - The stable appearing rock along the upstream slope was in good condition. Photograph 6/18/14 6. Bidwell Bar Saddle Dam west embankment - The side of the embankment and the crest road Photograph 6/18/14 were in good condition. DWR 1261 (rev. 10109) Sheet of 15 DAM AND RESERVOIR IN ED STATUS Name ofDam Oroville Dam No. 1-48 Date of Inspection 6/18 and 8/11-12/2014 7. Bidwell Bar Saddle Dam south embankment - The upstream rock slope protection and crest road were in good condition. Photograph 6/18/14 8. Bidwell Bar Saddle Dam south embankment - The slope of the south embankment was also in good condition. The low grass cover does not impede the inspection process. Photograph 6/18/14 Sheet 8 of 15 INSPECTION DAM AND RESERVOIR IN ED STATUS NameofDam Oroville Darn No. 1-48 Date of Inspection 6/18 and 8/11-12/2014 9. The Parish Camp Saddle Dam is shown looking towards the left abutment. The crest and slopes were in good condition. . Photograph 6/18/14 DWR1261 (rev.10f09) Sheet of i INSPECTION DAM AND RESERVOIR IN CERT ED STATUS Name ofDam Oroville Dam 1-48 Date of Inspection 6/18 and 8/11-12/2014 I: i "\10. The Flood Control Outlet Structure, the inlet training walls, and the emergency spillway were in satisfactory condition. No signs of instability or overstress were observed. The slopes of the inlet channel appeared to be stable. DWR1261 (rev. 10/09) Sheet 10 of 15 INSPECTION DAM AND RESERVOIR IN ED STATUS Name of Dam Oroviile Dam No_ 1-48 Date of Inspection 6/18 and 8/11-12/2014 11. Conditions along the side of the Flood Control Outlet Structure appeared to be unchanged from recent inspections. No signs of instability or overstress were observed. Sheet 11 of 15 INSPECTION DAM AND RESERVOIR IN ED STATUS NameofDam Oroville Dam No. 1-48 Date of Inspection 6/18 and 8/11-12/2014 12. The FCC channel appeared to be in satisfactory condition. The walls were well aligned and the patches along the chute floor remain intact. 13. This View is looking upstream along the FCO channel from the dentates. Dark, vertical stains along the walls indicate the location of the drain outfalls. DWR 1261 (rev. 10/09) Sheet 12 of 15 INSPECTION DAM AND RESERVOIR IN ED STATUS NameofDam Oroviile Dam No, 1-48 Date of Inspection 6/14. The Boards members from left to right are Dr. Paul Rizzo, Dr. Don Bruce, Dr. Bob Wright, and Dr. Leiio Mejia. They are standing at the dentates for the FCO chute. Note the concrete patch to the right of the Board members. Patching of the dentates is sometime required after significant releases. Sheet 13 of 15 INSPECTION DAM AND RESERVOIR IN CERT ED STATUS Name of Darn Oroville Dam No. 1?48 Date of Inspection 6/18 and 8/11-12/2014 15. The trunnion deck is shown in this View looking right. The deck area was recently cleaned. Nothing unusual was observed. The Board members are concerned that the trunnion anchors are reaching their service life. Recommendations concerning this issue are expected. ll - 16. The usual accumulation of detritus was visible at the bottom of the radial gates, arrow. This material tends to cause corrosion and should be removed regularly. Sheet 14 of 15 INSPECTION DAM AND RESERVOIR IN CERT ED STATUS Name of Dam Oroville Dam No, 1-48 Date of inspection 6/18 and 8/11-12/2014 17. Dr. Mejia is in front of the access door for the two H-B valves in the RVOS chamber. The new pressure relief wall to the right of Dr. Majia is covered by a catch net. The motor and drive shaft for the left valve operator are at the arrow. Sheet 15 of 15