STATE OF CALIFORNIA CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Grizzly Valley_ Darn No ?1-52 Plumes Type of com Earth Type or Spillway Concrete weir a_nd channel Water Is 10.85 feet below Spillway crest and 20. 85 feet below_ darn crest. Weather Conditions with cloudy skies. Water surface Elevation was STEM 15 feet. Contacts Made Michael Anderson and Vanesa Morones with DWR. Reason for Inspection Periodic_ Maintenance _Inspection. lm ortant Observations Recommendations or Actions Taken Conclusions From the known information and visual inspection. the darn. reservoir: and the appurtenances are judged safe for continued use. Observations and Comments psi The zone 3 shall material on the upstream and slopes contains andesite and granodiorlte. The andesite has shown to be very susceptible to freeze thaw deterioration. Evaluations concluded that this deterioration would not continue into the darn below about 3?feet, would remain cosmetic in nature, would not be the cause of any dam safety problems, and that future exploration excavations would be unnecessary. The visible portion of the upstream slope appeared to be stable. However. the riprap in some areas along the slope has deteriorated to the point where repairs are recommended. 08M plans on repairing these areas in question by 2018. The entirety of the slope was uniform and in satisfactory condition (see Photos 1 and 2). The abutments were stable and the groins and toe area were in satisfactory condition. The crest of the dam (Lake Davis Road) was level and in satisfactory condition (see Photo 3). The vegetation control was satisfactory. No rodent activity was observed. Sgillway The entrance area was clear of debris and in satisfactory condition (see Photo 4). The log?boom was in?place and in satisfactory condition. The spillway exit channel was clear of debris, and the concrete throughout was in satisfactory condition (see Photo 5). Outlet These valves reportedly performed without incident when they were last fully cycle In our presence on September 15. 2015 and during annual cycle on September 15. 2016. as 5w art/27426 Inspected by Alan Van Matte 1 Photos taken? Yes No Date of inspection 9/22/15 cc for Date of Report _10/28/20?1 DWR1261 {Re-v. Ioros) Sheet of 7 Name of Dam INSPECTION DAM AN. RESERVOIR IN CERTE ED STATUS Grizzly Valley Darn No. 1-52 Date of inspection 9/22/16 Observations and Comments Seepage DWR 1261 Photo 7). The outlet fall was clear of debris and in good condition. There was no visible seepage on the dam. The groins and toe area were dry. The seepage drains at the valve house headwall were obscured by weather covers that had been recently installed over the top of the drain outfalls. From what was visible, there did not appear to be any excessive seepage conditions present (see Photo 8). Monitored instrumentation at this dam consists of 7 embankment survey monuments thru 3 spillway crest monuments, 3 spillway bridge monuments, 1 internal settlement device at OW-4, 2 observation wells (OW-1 and 2 open standpipe piezometers (SP-2 and and 4 seepage points (LTD, LWH, RTD, and RWH). The latest Dam Safety Surveillance and Monitoring Report issued in May of 2016 includes data from January 2015 to December 2015. The survey monuments are surveyed at least once every three years and were last surveyed on September 15, 2015. The embankment survey monuments SM1 thru SM4 have been surveyed since1967 and embankment survey monuments SM5 thru 8M7 have been monitored since 1983. There have been no significant incremental vertical or horizontal movements throughout the data set. The largest total vertical movement of 2.52-inches (settlement) occurred at survey monument -and the lar est incremental vertical movement of 0.04-inches (settlement) occurred at monumentsh The largest total horizontal movement of 4.37- inches in the direction occurred at survey largest incremental horizontal movement of 0.39?inches occurred at monumen The spillway crest and spillway bridge monuments have been monitored since 1981. These monuments are surveyed at least once every 3 years. The graphs show that the maximum total and incremental movements have been within a range of 0.35?inches. These monuments have remained relatively stable throughout the dataset with no abnormal spikes and no alarming trends. The internal cross arm at OW-4 has been monitored since 1982. Vertical movements at the top and at joints 1 thru 7 are monitored at least once a year. The graphs show that the top and all of the joints have displayed similar movements over time, with total settlements of less than 0.85- inches. The incremental changes have been within 0.5?inches throughout the data set. lt should the crest of the dam (surveyed on September 22, 2011, October 3, 2013, and on September 24, 2015) remains above the design Elevation 5785-feet. The observation wells and standpipe piezometers are monitored? The reservoir has remained above Elevation 5760 since 1993 and the range of the reservoir elevation changes has remained within about 15 feet. The standpipe piezometers and SP-3) located?have experienced slightiy delayed and attenuated elevation changes about 5?feet) with respect to the reservoir elevation changes. The observation wells located ?have been relatively steady state throughout that time period. The hydrostatic pressure profiie shows a significant drop (about 20-feet) in the phreatic surface through the dam to the core, and an even more pronounced drop (about 90-feet) occurring across the chimney drain. The data shows that the shell has remained dry throughout the data set, which indicates the dam is performing satisfactorily. The left and right weep holes (4-inch) and the left and right toe drains (6-inch)? (rev. 10/09) Sheet 2 of 7 Name of Dam INSPECTION C. DAM AND RESERVOIR IN ED STATUS Grizzly Valley Dam No. 1-52 Date of inspection 9/22/16 Observations and Comments are monitored? Since 2006, the total flows have been less than 25 gpm. Since 1967, the average total seepage flow has remained at around 10 gpm. Peaks over 30 in the total seepage flow have occurred about once every ten years. These peaks have never exceeded 50 gpm. There were no abnormal spikes in the data set and there were no alarming trends. For a dam of this size, the historic seepage record indicates that it has performed satisfactorily. Data from the'lVlay 2016 Dam Safety Surveillance and Monitoring Report indicated that the dam performed satisfactorily during the January 2015 thru December 2015 time frame covered in the report. The instrumentation at this site is judged satisfactory. No additional instrumentation appears to be needed at this time. The are submitted annually and the next submittal is expected by May 2017. DSOD is working with to follow up on recommendations by the 2012 DSRB. Among the issues to be resolved are overtopping during the PMF. The seismic stability issues have been resolved. DWR 1261 (rev. 10/09) Sheet 3 of 7 INSPECTION DAM AND RESERVOIR IN CERT ED STATUS Name of Dam Grizzly Vane)! Dam No. 1-52 Date of Inspection I InletPhoto 2. A View of the slope as seen from the toe area. own 1261 (rev. 10:09) Sheet 9l22/16 4 of INSPECTION DAM AND RESERVOIR IN CERT ED STATUS Name of Darn Grizzly Valley Dam No. 1-52 Date of Inspection 9I22l?l 6 I 33? - Photo 3. A View of the crest of the darn (Lake Davis Road) as seen from the upstream outlet works control building. Photo 4. A View of the spillway entrance area. DWR1261 (rev. 10:09) Sheet 5 of 7 INSPECTION DAM AND RESERVOIR IN CERT. ED STATUS Name ofDam Grizzly Valley Dam No_ 1-32 Date of Inspection 9122/16 1. a. Any-3 . - ?Nim?n: .. -- . Photo 5. A View of the spillway exit channel looking Sheet 6 . of 7 INSPECTION DAM AND RESERVOIR IN CERT. ED STATUS Name: of Darn Dam No. 1?52 Date of Inspection gig/1 5 DWR1261 ?376 STATE OF CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Grizzly Valley Darn No. 1-52 County Plumas Type of Dam earthfill Type of Spillway Concrete weir and channel Water is 14.4 feet below spiliway crest and 24.4 feet below dam crest. ws 5761.1 feet Weather Conditions Cloudy and cool Contacts: Vanesa Morones, Kevin Wright, Joe Eades, and Jim Scarborough, Luis Sepulveda, Contacts Made Mike Anderson, Nick George, and Barbara Holbrook with DWR. Reason for Inspection Annual Inspection Important Observations, Recommendations or Actions Taken 9 Continue to remove vegetation along the upstream rock protection. 9 Install hoods over the toe drain and weep drain weir boxes to help determine how the siit is entering the boxes. ?will be tested for DSOD during the next inspection. Conclusions From the known information and visual inspection, the dam, reservoir, and the appurtenances are judged safe for continued use. Observations and Comments Qam The asphalt cracks along the crest road remain sealed for the most part; a few new cracks will be sealed, photograph 1. The embankment appeared to be stable. No signs of unusual stress were observed. No significant rodent activity was observed on the dam or abutments. Extensive rock weathering continues on the upstream and slopes, photographs 2, 3, and 4. The deterioration on the slope is but no repairs have been proposed, and no work is recommended at this time. The rock zone remains free draining at depth, in accordance with the original design parameters. The deteriorating rock along the upstream slope is susceptible to wave erosion. As recommended by the 2012 DSRB, has developed a scope of work for placing additional rock. In the meantime, continued weed and brush control will help to slow the deterioration. Emerging vegetation is shown in photograph 5. Spillway The spillway remains in good condition, photographs 6 and 7. No significant concrete deterioration, evidence of uplift, deflections, or new cracking was observed. The minor concrete patches along the spillway floor remain sound. The bridge deck and supports appeared to be in satisfactory condition. The drains at the end of the chute were dry, as expected, but should be checked for blockages from time to time. The rock beyond the spillway flip bucket looked stable. This area should be watched for instability during and following significant spillway discharges. Outlet Inspected by WPennington (Alg Photos taken? Yes No Date of inspection 9/15/15 ?m cc for Owner/Book Date of Report 9/22/15 10", ?It DWR 1261 (Rev. 10/09) Sheet 1 of 9 1mm INSPECTION Lr? DAM AND RESERVOIR IN STATUS Name of Dam Grizzly Valley Dam No. 1?52 Observations and Comments Seepage Date of inspection 9/15/15 facility. Both were cycled on 8/22/13 and will be cycled for DSOD next year. Th line is not necessary for dam safety and was not In operation during the inspection. No seepage was observed on the slope of the dam, or along the groins. The toe drain weirs were dry, photograph 11, for example. The two weep drains are in close proximity to the toe drains. The right drain read 0.08 feet, about 2.1 gpm, and the left was dry. Ail four weirs typically have silt behind the weir plate. This material is thought to be entering from above, rather than through the drain pipes. The only way to test this theory is to install hoods over the weirs. This has been suggested in the past, but not implemented. anticipates that this will be done next season, which is satisfactory given that the weirs are monitored regularly. In addition to visual inspections, the monitoring program consists of seepage collection devices, 2 standpipe piezometers, 2 observation wells, survey monuments, an internal vertical movement device at OW-4, and a strong-motion accelerometer. ?piezometers SP- 2 and SP- 3 are located? The phreatic surface varies It In a narrow range in response to the reservoir level and remains within historic limits for a given reservoir level. Observation wells and OW- 4 monitor_ The phreatic surface remains just above the foundation at the toe of the chimney drain and below grade at the toe of the dam Seven survey monuments ?been installed, three along and four movement is monitored at SM-2, and The vertical movement at these locatIons appears to have stabilized within a small range. Horizontal deflection at continues a slow trend that reached 1.75 inches in 2014. SM-2 and remain stable within a narrow range. Monuments SM-5, and SM-7 are located_ All of these monuments show settlement attern with the most movement, about 2.5 inches, occurring at Horizontal movement at SM-4 has stabilized in recent years after moving about 4. Inc es owns ream, whiie the other three remain stable. The spillway bridge and crest monuments remain relatively stable Cumulative movement is negligible Settlement of the internal vertical movement device remains somewhat erratic. The recorded downward movement at joint 5 in 2013 was about 1. 5 inches, which would be unusual. These measurements were taken by a new person Verification measurements taken on 2/11/14 show that the movement was much less than the 2013 measurements indicated, and was within normal limits. Sheet 2 of 9 INSPECTION (Jr- DAM AND RESERVOIR IN STATUS Name of Dam Grizzly Vaiiey Darn No. 1-52 Date of Inspection 9/15/15 Observations and Comments Based on my field observations and my review of the 2014 data, the instrumented and visuai monitoring program appears to be adequate at this time, and the dam appears to be functioning normaliy. DWR 1261 (rev. 10/09) Sheet 3 of INSPECTION or DAM AND RESERVOIR IN STATUS Name of Dam Dam No. 1-52 Date of Inspection 1. The overall condition of the crest road is illustrated in the picture. The few unsealed cracks noted will be sealed as part of ordinary maintenance. 2. Typical conditions along the north and central sections of the upstream slope. The emerging vegetation Should be removed to slow the rock deterioration. DWR 1261 (rev. 10MB) Sheet 4 of INSPECTION Or DAM AND RESERVOIR IN CERTIHED STATUS Name of Darn Grizzly Valley Darn No. 1-52 Date of Inspection 9/15/15 3. The west side of the upstream slope is shown. The three trees that were in the vicinity of the arrow have been removed as requested. 4. The rock deterioration along the slope is clearly visible in this view looking upstream from the toe parking area. Both groins were dry and stable appearing. DWR 1261 (ta-V. 10t'09) Sheet 5 of 9 INSPECTION Or DAM AND RESERVOIR IN STATUS Name of Dam Grizzly Valley Dam No. 1-52 Date of Inspection 9/15/15 6. This view is looking at the spillway entrance. The training walls, entrance chute and bridge appeared to be stable. The concrete remains in satisfactory condition. DWR 1251 (rev. 10.309) Sheet 6 Of INSPECTION DAM AND RESERVOIR IN CERTIHED STATUS Name ofDam. Grizzly Valley NO- ?752. Date 7. Thu lower chute and walls were stable appearing and tho concrutc was in satisfactory condition. The minor mtches alum; chute ?oor wort: sound. Sheet 7_ of 9 INSPECTION (Jr- DAM AND RESERVOIR IN CERTI: IED STATUS Name omam Dam No. 1?52 Date of LJWR 1261 (rev, 10:09) Sheet 3 INSPECTION (Jr' DAM AND RESERVOIR IN STATUS Name Of Dam Dam No. L52 Dale of Inspection 9/15/15 DWR +251 (rev.10l09) Sheet 9 A of 42 STATE OF CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Darn Dam No. 1~52 County Plumas Type of Dam aa?wfill Water is 11.5_ feet spillway crest and 21.5 feet below dam crest. we -r 57?635 feet Weather Conditions?SLInr'fy and milcl - Primary contacts: David Sarkisian, Vanesa Morones, Kevin Wright, Joe Eades, John Rizzardo, Contacts Marie and Jim Scarborough with DWR. Reason for Inspection Important Observations, Recommendations or Actions Taken . Continue the removal of vegetation along the upstream rook protection. Conclusions From the known information and visual inspection. the dam, reservoir, and the appurtenances are judged safe for continued use. Observations and Comments . . Ena_m The asphalt cracks along the crest road remain sealed, photograph 1. The embankment appeared to be stable, photographs 1 through a. No significant rodent activity was observed. The rock slope protection along both sides of the darn continues to deteriorate. as seen in the photographs 2 through 6. 08M HQ is working on a riprap monitoring program and will address recommendations by the 2012 DSRB regarding replacement of deteriorated rock along the upstream slope. Removal of the weeds and willows growing along this slope, photograph 3 for example, should be continued to help manage the rock deterioration. The spillway remains in good condition, photographs 7. 8, and 9. No significant concrete deterioration, evidence of uplift, deflections, or new cracking was observed. The minor concrete patches along the spillway floor remain intact. The bridge deck and supports appeared to be in satisfactory condition. The drains at the end of the chute were dry. The rock beyond the spillway flip bucket looked stable. As previously mentioned, this area should be watched for instability during and following significant spillway discharges. Outlet All of the Intake valves were successfully Cycled by 08M staff following completion of the repair work. Last yearthey were all tested for a DSOD engineer. Inspected by WPennington J?hk Photos taken? YES ND Date of Inspection 10/2/14 go cc for Owner/Book? Date of Report ,10t29/14 rl-I JI It?ll own1astrnev.1oroa) Sheet I of INSPECTION O. JAM AN. RESERVOIR IN STATUS Name of Dam Grizzly Valley Dam No. 1-52 Date of inspection 10/2/14 Observations and Comments Seepage No seepage was observed on the slope of the dam, or along the groins. The two 6- inch toe drain weirs located at the wall of the outlet building were wet, but no flow was leaving the weir boxes. The right and left weep drains appeared to be flowing more than iast year, but flow was within historical levels. in addition to visual inspections, the monitoring program consists of seepage collection devices, 2 standpipe piezometers, 2 observation wells, survey monuments, an internal vertical movement device at and a strong~motion accelerometer. - piezometers SP-2 and are located on the crest ofthe dam. The phreatic surface varies within a narrow range in response to the reservoir level and remains within historic limits for a given reservoir level. Observation wells OW-1 and OW-4 monitor The phreatic surface remains just above the foundation at the toe of the chimney drain and below grade at the toe of the dam. Seven survey monuments have been installed, three along? and four movement is monitored at SM-2, and The vertical movement at these locations appears to have stabilized. Horizontal deflection at continues a slow trend that reached 1.75 inches in 2013. SM-2 and SM-3 remain stable. Monuments SM-4, SM-5, SM-B, and are located? All of these monuments show a steady settlement pattern, with the most movement, a out .5 inches, occurring at at the center of the embankment. Horizontal movement at SM-4 has stabilized in recent years after moving about 4.25 inches while the other three remain stable. The spillway bridge and crest monuments remain relatively stable. Cumulative movement is negligible. Settlement ofthe internal vertical movement device remains somewhat erratic. The recorded downward movement at joint 5 in 2013 was about 1.5 inches, which would be unusual. These measurements were taken by a new person. Verification measurements taken on 2/11/14 show that the movement was much less than the 2013 measurements indicated, and was within normal limits. Based on my field observations and my review of the 2013 data. The instrumented and visual monitoring program appears to be adequate at this time. The dam appears to be functioning normally Sheet 2 of 7 INSPECTION Ch .JAM AND RESERVOIR IN STATUS Name of Darn Grizzly Valley Dam No. 1-52 Date of Inspection 1012/1 4 2. Typical conditions along the upstream rock slope are shown. The darker rock is submerged for longer periods of time and, as a result, appears to have deteriorated less than the nermally exposed rock. Sheet 3 of 7 INSPECTION O. JAM AND RESERVOIR IN STATUS Name of Darn Grizzly Valley Dam No. 1?52 Date of Inspection 10l2f14 3. The occasional brush and weeds along the upstream slope should be removed on a regular basis to help control the rock breakdown. Eu a (?gag n2; n, 4'qu --.. II-- .. .rxr: 4. The left groin remains in satisfactory condition. The tree adjacent to the groin does not affect the dam or impede inspections. DWR1261trev.1Ui09) Sheet 4 of INSPECTION 0. .JAM AND RESERVOIR IN STATUS Name of Darn Grizzly Valley Dam No. 1-52 Date of Inspection 10f2f14 6. Rock breakdown remains an issue along the slope. Based on the results of a trenching program undertaken a number of years ago, the problem does not extend much beyond a depth of three to five feet. A plan for monitoring and repairing the rock along both slopes of the dam is under development. A rock assessment is included in the 2013 DWR 1261 (rev. Sheet 5 of 7 INSPECTION OI JAM AND RESERVOIR IN STATUS Name of Dam Grizzly Valley Darn No. 1-52 Date of Inspection ?'Cta?t -, .. 7. The spillway approach apron and crest structure are shown. The orange cylinder is part of the boat buoy line. The weeds in the approach area should be removed from time to time. 8. Two concrete patches are visible along the upstream edge of the spillway bridge. This was apparently done by a road crew. Sheet 6 of 7 INSPECTION O. JAM AND RESERVOIR IN STATUS Name of Dam Grizzlealley Darn No. 1-52 Date of Inspection 10/314 9. The spillway chute remains in satisfactory condition. No signs of instability or poor concrete were observed. DWR 1281 (rev. 10MB) Sheet 7 of 7 STATE OF CALIFORNIA CALIFORNFA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Grizzly Valley Dam No. 1?52 County Plumas Type of Dam earthfill Type of Spillway Concrete weir and channel Water is 6.5 feet spillway crest and 16.5 feet below dam crest. ws 5768.5 feet Weather Conditions Sunny and mild Primary contacts: David Sarkisian, Vanesa Morones, Kevin Wright, Joe Eades, Amber Orlof, and Contacts Made Jim Scarborough with DWR. Reason for Inspection Annuai Inspection Important Observations, Recommendations or Actions Taken Decommissioning and removal ofthe fish strainer system is still under consideration. Any contemplated changes to the outlet operation should be discussed with DSOD before implementation. a The outlet valves were successfully tested through full travel. Remove the trees located adjacent to the left side of the spillway approach apron. Conclusions From the known information and visual inspection, the dam, reservoir, and the appurtenances are judged safe for continued use. Observations and Comments 9m The asphalt cracks along the crest road remain sealed. The embankment appeared to be stable. See photographs 1 through 4. No significant rodent activity was observed. As mentioned in the past, the weeds and one willow growing along the upstream slope of the dam should be cleared to help manage rock deterioration. The rock slope protection along both sides of the dam continues to deteriorate, as seen in the photographs. This deterioration does not impact the function of the dam at this time, but consideration should be given to placing supplemental rock along the upstream slope if wave erosion becomes a problem. Spillway The spillway remains in good condition. See photographs 2 and 5. No significant concrete deterioration, evidence of uplift, deflections, or new cracking was observed. The minor concrete patches along the spillway floor remain intact. The bridge deck and supports appeared to be in satisfactory condition. The drains at the end of the chute were dry. The rock beyond the spillway flip bucket looked stable. As previously mentioned, this area should be watched for instability during and following significant spillway discharges. Outlet This line is not necessary for dam safety and was not in operation at the time of the inspection. 0 Inspected by WPennington Aw Photos taken? YES N0 Date of inspection 8/22/13 cc for Owner/Book Date of Report 9&0? 3 . (.Qilygofq/30g/3 DWR 1261 (Rev. 10/09) Sheet INSPECTION C. DAM AND RESERVOIR IN CERTI: IED STATUS Name of Dam Valley Dam No. 1-52 Date of Inspection 8/22/13 Observations and Comments Seegage All of the outlet valves, except those on the-line, were tested through full travel and were found to operate satisfactorily. As mentioned before, has stopped using the fish strainer system. See photograph 4. This structure may be removed in the future. Any changes to the configuration or operation of the outlet should be discussed with DSOD prior to implementation. No seepage was observed on the slope of the dam, or along the groins. The two 6- inch toe drain weirs located at the wall of the outlet building were dry. The right and left weep drains were flowing <2 each. As previously mentioned, the weir boxes should be cleared of fines and checked later to see if fines are coming from the drains. is planning to install hoods over the weir boxes to prevent fugitive sand and debris from entering. The instrumented and visual monitoring program appears to be adequate at this time. Conditions appearto be normal based on my field observations and my review of the 2012 data. The instrumentation suite consists of seepage monitoring devices, 2 standpipe piezometers, 2 observation wells, survey monuments, an internal vertical movement device at OW-4, and a strong- motion accelerometer. Standpipe piezometers and are located?The phreatic surface varies within a narrow range in response to the reservoir level and remains within historic limits for a given reservoir level. Observation wells and monitor the See photograph 8. They show that the phreatic surface is just above the foundation at the toe of the chimney drain and below grade at the toe of the dam. This indicates that the chimney drain is effective in keeping the shell unsaturated. Seven survey monuments have been installed, three along the ?and four The maximum vertical movement has been about 2.3 inches at SM-4 near and 1.75 inches at SM-_on the upstream slope. All of the vertical movement appears to be stabilizing. Horizontal movement also appears to be stabilizing. However, SM-4 moved about 4.3 inches before showing signs of stabilization. Settlement of the internal vertical movement device remains erratic, but within a narrow range at all joints. The spillway bridge and crest monuments remain relatively stable. Cumulative movement is negligible. Sheet 2 of 6 INSPECTION L. DAM AND RESERVOIR IN CERTI. .ED STATUS Name of Dam Grizzly Valley Darn No. 1-52 Date of Inspection 8I22f13 . - ?515: ?hag; 1. The upstream slepe appeared to be Stable. The ongoing deterioration of the rock is evident. At some point, it may be necessary to add supplemental rock to protect the slope. 2. The right side of the upstream slope and spillway approach are shown. The trees at right are growing on the reservoir ?oor, not on the dam, but consideration should be given to removing them so they don't block the spillway if they get uprooted during a large storm. DWR (rev. toms) Sheet 3 of 5 INSPECTION L. DAM AND RESERVOIR IN CERTI. .ED STATUS Name of Darn Grizzly Valley Dam No. 1-52 Date of Inspection 8/2313 7 If . i' 4H db. 153%??er 3"",The face of the dam and most of the right groin are shown. The ongoing rock deterioration is Visible. Past work has Shown that the deterioration is limited in depth and is not expected to impact the drainage properties of the embankment. Sheet 4 of 6 INSPECTION L. DAM AND RESERVOIR IN CERTI. .150 STATUS Name of Dam Grizzly Valley Dam No. 1-52 Date of Inspection 8/22fix?. ?ii'v?ili'ilsii rill -- I . . I?d. . cilia slalir'l! 5. This View is looking upstream along the apillway chute. The concrete was in satisfactory condition. No signs: oi'ina?iahility were obaerved. The drains at the end oilhe chute were dry, but may need to be cleared. The pipe at right is a siphon that was installed a number ol?yeara ago for ?shery releases. It would not impact spillway operation. DWR 1261 (rev. 10f09) Sheet 5 of INSPECTION L. DAM AND RESERVOIR IN CERTI. .ED STATUS Name of Dam Dam No. Date of Inspemion 8/2313 DWR 12131 (rev. 10101311 Sheet 6 of