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AA (11.111111113- .3.-391111. prepared 111 ?196133 3:331:11 1.3333103} 3111.12.11 3833,3333 Araciumng 7323. 33.33.1231 . 311.1313Acfet3' A31 311331211? 3 5'3 33 021361 ?sf 31139131333911 3?3 133.31.11.12 ?20 . . 120-- (11:30.1 {3113.8 03333131113 . -. II .- ?3 JUHA- 2.617 11-1-3 331$ DWR 1:151 11-11111; 111111111 5.1119113 "3 of . 5' Name of Darn INSPECTION 1.. DAM AND RESERVOIR EN CERT ED STATUS Robert W. Mathews [Dam No. 1013 Date of Inspection 31 June 2017 Observations and Comments Seepage Instr. (~584 sq mi) from the 120 square mile drainage area. The spillway capacity is ~87,000 which is just under the peak inflow. Total freeboard is 32 feet and the residual freeboard for the design storm is 6 feet. Freeboard is satisfactory. While an update hydrology review should be performed by DSOD, this is not considered a high priority item at this time because the dam has 32 feet of total freeboard, which is about 20% of the dam height, and is considered to be conservative. The owner has scheduled a detailed spillway inspection for 22 June 2017, which will be performed by the owner?s staff in conjunction with the owner?s consuiting engineers (GEI, CHD). i asked that a copy of the spiilway inspection report be sent to DSOD. Upstream control is provided by control is provided valves consisting of - valve Both the upstream (fully) and controls (partially) were cycled during the May 8, 2014 inspection and were found to be in satisfactory condition at that time. None of the controls were cycled during the inspection. Per the- gate operation log sheet, the upstream -gate was fully closed on 8 May 2017 for the annual inspection and maintenance of the penstock. After the completion the maintenance inspection, the-gate was fully opened on 11 May 2017. No abnormalities or deficiencies were noted. by discharge through and a valve. The face, groins, and abutments were dry and free of any indications of seepage. The seepage vault?, was accessed during the inspection. Seepage flow over the 90 degree v-notch weir was not measured daring this inspection, but instrumentation data shows measured flow is considered normal and within historic limits. The flow was clear with no evidence of fine sand particles in weir box. Instrumentation consists of the following: - Fourteen (14) survey monuments including three bench marks are installed along the crest and left abutment to monitor settlement and displacement of the embankment. Embankment survey monuments are monitored biannually. in addition, 28 monuments are installed on the spillway, 14 along the spillway walls, and 14 on the floor. They are surveyed biannually. - Eight (8) survey monuments installed in the left abutment to monitor displacement of the landslide that was first observed in February 1998. Landslide survey monuments are monitored biannuaily. . Eight (8) open well piezometers, four each located within the right and left abutments, installed to monitor hydrostatic pressures within the abutments. Piezometers are monitored weekly. - One (1) 90-degree v-notch seepage weir was installed to monitor the combined flow from seven foundation drains. The v?notch weir is monitored daily. - Two strong motion instruments are tocated on the dam crest; one located at the maximum section near Station 6+50 and other at the lower section near station 10+00. The most recent Dam Safety Surveiilance and Monitoring Report was received on 14 DWR1261 (rev. 10/09) Sheet 2 of 5 555555555 5.55% 5-55 55555555 35; 55.5% .55 555355 Name of Sam. 35.555 W. Math-5W5 Dam: No. 15.123 035:1 3'3 $15533 G55zawat?555 51:35 5525355555- 555123353?) 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"and piemmeter 5555555 55 mt: indicate "any 5555555 555.55. 535% piezmmertar are past ?rm-d5 am gamma}: {amending {aka 85555555, The mime-fa; grain-58:" wmmeni?? that, ?Ewing 535 di?-?jereme?- 55315595 ?55 maximzrm megs-wedpiamma??ar? depths ??f?pai'?d 55.5}? 15553 .rgasgiec?v??cifm ?52355 wan? mos-5m 55353-559; ?55115 had 5 very 3:535 diffem?oe 5f ft. imifcaz?i?g ?553 55 was exceeded. f-{awwerg 3551;551:551 grecgpita?an was: jam? aver-35" and the wake?" fave: refumed beicm-r its a?emards. 555553735 Weir Fifcsw: Sewage" pic-t- fQ-r 20-14 shears- thai weir ?ow is imam-cad 531515 ran-?33. and; ?555 51555505 ?che: year. The highest. 3551:2595 ?ow 410 gm was record-ed in march 2016- ?milewi?ng a large- event im the begin-?ing 0.15155 51mm. 5 85-52% 535555: Ens-trumems: NE) meagurabie 5513mm event has 5555555 during ?-358- rapcr?ng Ip?ried 33515:. - The {gimmi- Ensimmentatibn is; 55581255 35555355155 mm?inrim? dam W55 mgard 5551553125131. 9. 3 \v -. "Tha- upstream face: as view-ti {mm the 555355551555. pr?etectian: againsat Wave. fetch ems-Ear}. DWR 325-?; 555.1559; Sfieei- 3 5 .me?mmw??Xr . WX m. .. ?mgw?mm ?4me 2 mamm? 2.9. .33 mam Q. Smwmamsm ma?a. mm mm. .. gm. 1mg avm?mmg ?aw mua magma mm ?5.5.3 #03 ?mm any.? .mvgm?m?. - fa.- ??irlmfEm. ?.3;me .3 Em am 0.3 Em gamm?nw. 05m 35.3 $3 -. mm Name 0? Barn R?-ba? W, .- {gnu \n Mm E33141 Na. 4231 {res-x. 1015.9.) 13313 Damn? inspac?on 3-1 gum 2531i?? .. Shea? ML of STATE OF CALIFORNIA CALIFORNIA NATURAL RESOURCES AGENCY . I I - . DEPARTMENT OF WATER RESOURCES 1 DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 County Trinity Type of Dam Earth Type of Spillway Concrete weir and chute Water is I .6 feet spillway crest and 33.5 feet below the dam crest. Weather Conditions Clear and mild Contacts Made See ?Others? at the bottom of the report. Reason for Inspection Periodic Evaluation and FERC Part 12D Safety Inspection Important Observations, Recommendations or Actions Taken None of the controls were cycled during the inspection. Per the slide gate operation log sheet, the upstream slide gate was fully closed on May 2, 2016 for the annual maintenance of the penstock. it took 19 minutes to fully close the slide gate. After the completion the maintenance inspection, slide gate was fully opened again on May 5, 2016. No abnormalities or deficiencies were noted. Conclusions From the known information and the visual inspection, the dam, reservoir, and the appurtenances are judged satisfactory for continued use. Observations and Comments gm Both the upstream and faces of the embankment, crest, and the abutment contacts remain in satisfactory condition with no indication of surficial distress or instability. Riprap on the upstream and faces remains intact and provides protection against erosion without impeding inspection or monitoring for defects. The asphalt paved crest remains in excellent condition, with no noticeable cracks, or any indication of settlement or displacement. Vegetation control on the dam remains excellent as the entire dam and groins on both sides were free of any objectionable vegetation. No rodent burrowing activity was observed on the dam. The log boom, (Tuff boom -manufactured by Worthington Product Inc.) consisting of 67, ten feet booms including a boat gate section, was inspected by boat and was found to be in excellent condition. No large floating debris was noted along the log-boom. Inspection team including independent consultants, FERC and owner?s representatives inspected the left abutment land slide. This slide area consists of two shallow slides designated as South slide (located upstream of the dam) and North slide (located of the dam). Minor sloughing is continuously occurring during the rainy season. During heavy rains when slepes are completely saturated and have surface run off, there is a possibility of a major mud flow which may completely block the access road to the hydro power plant located on the toe of the dam. The owner will be developing a contingency plan to deal with this potential situation. This dam is a manned facility during the day and is closely monitored by the dam tender. Spillway The spillway approach, weir, chute, and exit channel were open and unobstructed. The existing crack near the top of the left wall of the spillway entrance channel remains sealed. The concrete of the spillway structure, including both walls and chute, remains in satisfactory condition. No evidence of distress or any noticeable deterioration was observed. All drain holes along the base Inspected by L. Singh {amt b/1t/6 Photos taken? Yes No Date of Inspection May 26, 2016 a co for Owner/Book Date of Report June 20, 2016 R65 411? ulti. own 1261 (Rev. 10/09) Sheet 1 of 7 UF DAM AND RESERVOIR IN IFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 26, 2016 Observations and Comments Outlet Seepage of the right spiilway wall were dry. The current design storm. prepared in 1960, is for a 1000 year return period producing 70,000 (~584 sq mi) from the 120 square mile drainage area. The spillway capacity is ~67.000 which is just underthe peak inflow of 70, 000 based on the 1960 hydrologic analysis. An update hydrology review is needed for this dam. However, this is not considered a high priority item at this time because the dam has 32 feet of total freeboard which is about 20% of the dam height and is conservative. Both the upstream (fully) and controls (partially) were cycled during the May 8, 2014 inspection and were found to be in operable condition. None of the controls were cycled during this inspection. Per the slide gate operation log sheet (handed over during the inspection), the upstream slide gate was fully closed on May 2, 2016 during the annual maintenance of the penstock. it took 19 minutes to fully close the slide gate. After completing the maintenance inspection of the penstock, slide gate was fully opened again on May 5, 2016. No abnormalities or deficiencies were noted. The face, groins, and abutments were dry and free of any indications of seepage. The seepage vault, located upstream of the power house, was accessed during the inspection. Seepage flow over the 90 degree v-notch weir was measured to be 2.2 inch, or 0.183 feet. The flow was clear with no evidence of fine sand particles in weir box. This corresponds to ~16 and is considered normal and within historic limits. instrumentation consists of the following: Fourteen (14) survey monuments including three bench marks are installed along the crest and left abutment to monitor settlement and displacement of the embankment. Embankment survey monuments are monitored biannuaily. in addition, 28 monuments are installed on the spillway.14 along the spitlway walls, and 14 on the floor. They are surveyed biannuaily. - Eight (8) survey monuments installed in the left abutment to monitor displacement of the landslide that was first observed in February 1998. Landslide survey monuments are monitored biannually. - Eight (8) open well piezometers, four each located within the right and left abutmenis, installed to monitor hydrostatic pressures within the abutments. Piezometers are monitored weekly. One (1) 90-degree v-notch seepage weir was installed to monitor the combined flow from seven foundation drains. The v?notch weir is monitored daily. - Two strong motion instruments are located on the dam crest; one located at the maximum Sheet 2 of 7 INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 26, 2016 Observations and Comments Other section near Station 6+50 and other at the lower section near station 10+00. The most recent Dam Safety Surveillance and Monitoring Report was received on April 15, 2015. This submittal included an evaluation of the instrumentation data and summary of the visual observations by the owner. Embankment, Left Abutment, and Spiilway Monuments: Most recent survey included in this were performed by WEST SURVEYING CO. during September 18-19, 2013 and their survey report was reviewed by the owner?s engineer. Monuments located on the dam show no significant verticai movement on any of the monuments. Similarly, spitlway floor and wing walls monuments had very little horizontai or verticai displacement. Net displacement in either direction was well below the action levels. Observation Wells: A short term (2014) and long term (2009-14) plots consisting of rain fall, lake elevation, and piezometer elevation do not indicate any adverse trends. Most piezometer are following the past trends and generaliy responding to take eievation. Piezometer 6, located on the access road upstream of the embankment, is strongiy responding to the rainfall throughout the five year reporting period. Seepage Weir Flow: Seepage plot for 2014 shows that weir flow is strongly influenced by the rainfall and take elevation throughout the year. The highest seepage flow of approximately 225 was recorded in December 2014 right after the highest rainfall of about 11 inch in the beginning of the month. Strong Motion instruments: No measurable seismic event has occurred during the reporting period of 2014. The current instrumentation is judged adequate to monitor the dam with regards to the safety. The following listed persons attended the PFM discussion in owner?s office on 5/25/2016. All attendees except for Barry Vansickle and John Winzler participated in the inspection ofthe dam on the following day. 1. Brian Newell with Thavisak with John Friedenbach with Pat Kaspari with Dale Davidsen with Mario Palmero with Chris Merz with Ryan Chairez with Steve Marshaii with DWR1261 (rev. 10:09) Sheet 3 of 7 INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 26, 2016 Observations and Comments 10. John Winzler with 11. Charles Ahlgren with CARDNO 12. Paul Sorci with CARDNO 13. SAM LEE with FERC 14. Barry L. Vansickle with GHD 15. Bill Rettberg with GEI No additional PFM was identified during the PFMA discussion. All previous PFM were extensively discussed and they will remain listed in this current report with minor adjustments to their categories. . - 1. The log boom as Viewed from the boat. A boat gate section is located in the circled location. DWR1261(rev.10i09) Sheet 4 of 7 INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 26, 2016 2. A closer View of the log boom. DWR1261 (rev. 10109) Sheet 5 of INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 26, 2016 . 211;}. 4. Another View as seen towards the lower boundary of the slide with all uprooted trees. DWR 1261 (rev. 10/09) Sheet 6 0f . INSPECTION OF DAM AND RESERVOIR IN IFIED STATUS Name of Dam Robert W. Mathew Dam N0. 1013 Date of Inspection May 26, 2016 I I . 6. Spillway channel looking upstream. Sheet 7 of . . .. . 11111111311111 111111111111. 1113011113m 111111111111 DEPARTMENT 1131413111 TER: 3N $1 1111113112111 1:111 3111-15111 11:11 1311-1115 N1 1% N111 ., . . EQN {33?1? 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T1111- 13111'1'131111 ?es-11111 31131111. 131111111a=111111 111 111.61), 11.1 1111' 121' 111131) year 1911112111 11111111931 1:1:de111?31131; 7711,1191.) 111311 image-{111111 13.11 I I I 311111311 Nx?w- .13 :1 1311131119 113111-111? Yes 11. No 1.111111 1.11? 11111136311311 A131-r11-22 201.1 1" (11-11111 13111111111113111111 - Date 01118-11011 111311! .71 2111-5 4.x. . 1' 1 DWR "1 2131 151813)} INSPECTION DAM AND RESERVOIR IN ED STATUS Name of Darn Robert W. Mathew Dam No. 1013 Date of Inspection April 30, 2015 Observations and Comments (~584 sq mi) from the 120 square mile drainage area. The spillway capacity is ~67,000 which is just under the peak inflow of 70, 000 based on the 1960 hydroiogic analysis. An updated hydrology review is needed. A work request will be sent to the Design Engineering Branch. Outlet Upstream control is provided by a control is provided by valve and a Per May 6, 2015 email from Dale Davidsen, the penstock slide gate was fully cycled between 4/20/2015 and 4/23/2015 as a part of annual maintenance of the penstock. Per operation log attached with the email, the slide gate functioned normal with no abnormalities noted. None of the controls were cycled during the inspection because of the ongoing scheduled outage for the routine maintenance repair wor? Seepage The face, groins, and abutments were dry and free of any indications of seepage. Seepage flow over the 90 degree V-notch weir was measured to be 2.2 inch, or 0.183 feet. This corresponds to ~16 and is considered normal and within historic limits. As usUal, all drains along the left spillway walls were dry. instrumentation consists of the following: - Fourteen (14) survey monuments including three bench marks installed aiong the crest and left abutment to monitor settlement and displacement of the embankment. Embankment survey monuments are monitored biannually. in addition, 28 monuments are installed on the spillway,14 along the spillway walls, and 14 on the floor. They are surveyed biannually. 0 Eight (8) survey monuments installed in the left abutment to monitor displacement of the landslide that was first observed in February 1998. Landslide survey monuments are monitored biannually. Eight (8) open well piezometers, four each located within the rig ht and left abutments, installed to monitor hydrostatic pressures within the abutments. Piezorneters are monitored weekly. One (1) 90?degree v-notch seepage weir was installed to monitor the combined flow from seven foundation drains. The v?notch weir is monitored daily. Two strong motion instruments are located on the dam crest; one located at the maximum section near Station 6+50 and other at the lower section near station 10+00. The most recent Dam Safety Surveillance and Monitoring Report was received on April 2, 2014. This submittal included the evaluation of the surveillance and instrumentation data, and summary of the visual observations by the owner. This submittal was reviewed in the previous Sheet 2 of 4 im? EN Name. a? {33m Kmart 3534?. Math?w Dam Na. ?-30 3 3 {Essie m? af?x-?ii 3'8, 21815 and 'gii?sspem?an rep?mi, I I - K?x. .. . faaes i5 frag af- any abjectian'abie wmdy veg=etati0n.. 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L. . .922022332322322? 3'89 2" NO 2322223 02' 22.255323621220272; 5222-2233,! 22314 222?? 2,3, .29, CR 202 {312222232?2?802?222 - Date 0'2" 232222322222 23. 3302222 32,- '3 2322222 222:2. 12222252212222.2222 32.222222Fig.2 INSPECTION La. DAM AND RESERVDIR EN CERTI- ED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 8, 2014 Observations and Comments both walls and chute look satisfactory, and no indication of significant distress or deterioration was evident. drain holes along the base of the right spillway wall were dry. A medium size woody bush emerging along the right wall of the spillway, just upstream of the plunge pool, was requested to be removed. No significant erosion damage was noted around the piunge pool and the visible portion of the riprap along the left side of the plunge pool (power house side) remains intact. The current design storm, prepared in 1960, is for a 1000 year return period producing 70,000 (~584 sq mi) from the 120 square mile drainage area. The spillway capacity is ~67,000 which is just under the peak inflow of 70, 000 based on the 1960 hydrologic analysis. An updated hydrology by Design Branch is needed. However, it is not considered a high priority item at this time because the total freeboard of 32 feet is about 20% of the dam height and is conservative. Outlet Upstream control is provided by a Mr. Brian Newell fully cycled the upstrearr- gate during the inspection. He has been the dam caretaker for many years and is very familiar with the operation of the outlet controls. control is provided by valve and a valve. The partially cycled during the inspection and was found to be in operable condition. valve was Seepage The face, groins, and abutments were dry and free of any indications of seepage. Seepage flow over the 90 degree V?notch weir was measured to be 0.22? or 2.64?. This corresponds to ~26.15 and is considered normal and within historic limits. As usual, all drains along the left spillway walls were dry. instr. Instrumentation consists of the following: - Fourteen (14) survey monuments including three bench marks installed along the crest and left abutment to monitor settlement and displacement of the embankment. Embankment survey monuments are monitored biannually. In addition, 28 monuments are installed on the spillway,14 along the Spillway walls, and 14 on the floor. They are surveyed biannually. - Eight (8) survey monuments installed in the left abutment to monitor displacement of the landslide that was first observed in February 1998. Landslide survey monuments are monitored biannually. Sheet 2 of 5 INSPECTION DAM AND RESERVOIR lN CERT ED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection May 8, 2014 Observations and Comments Other - Eight (8) open weil piezometers, four each located within the right and left abutments, installed to monitor hydrostatic pressures within the abutments. Piezometers are monitored weekly. . One (1) 90?degree v?notch seepage weir was installed to monitor the combined flow from seven foundation drains. The v~notch weir is monitored daily. . Two strong motion instruments are located on the dam crest; one located at the maximum section near Station 6+50 and other at the lower section near station 10+00. The most recent Dam Safety Surveillance and Monitoring Report prepared On March 28, 2014 was received in DSOD office on April 2, 2014. The report includes the evaluation of the surveillance and instrumentation data and summary of the visual observations by the owner. Piezometer readings for the current reporting period of 2013 indicate that water elevations in most all eight piezometers generally fluctuated up and down in direct response to the precipitation received at the time and remained well below the threshoid/action level elevations. Weir flows show a pattern of increasing flow in response to rainfall. During the reporting period of 2013, flow varied between 6 and 48 and showed a direct correlation between seepage flow and precipitation. Overall, the seepage fiow remained within historic iimits. A Spillway Settlement and Wing Wall Monitoring Survey was performed in September 2013 and the data was compared with previous survey of October 12-13, 2011. No noticeable difference was observed between the surveys. Fifteen monitoring points along the top of the dam and adjacent left abutment were surveyed on September 18-19, 2013 and the results were compared with previous survey of 2011. A minimal difference in elevation was observed and most readings were falling within range of elevations shot in the previous years. Eight monitoring points on the west abutment slide were surveyed in September 18?19, 2013 and results were compared with previous survey of 2011. Maximum vertical displacement ranged from 0.004? to 0035? feet between two consecutive surveys. Also, no appreciable horizontal movement has been observed at monitoring stations within the reporting period of 2011 and 2013. The instrumentation data review indicates that there is no significant hazard to either the embankment or left abutment and the existing instrumentation array appears adequate to monitor conditions at the dam. We also briefly inspected the left abutment slide area which encompasses two localized shallow slides within the periphery of what is thought to be a dormant deep-seated slide. The localized shallow slides are designated as the north and south slides. Numerous dead trees dislocated by the north slide are still lying there. From visual observations, we were not able to identify any fresh movement because the majority of the area is covered with relatively young vegetation. Per the current the owner's engineer Patrick Kaspari along with a certified engineering Sheet 3 of 5 EAEE SE EE {-23 Name {Nisan-2' Egbert Mai-haw Earn Na Ema May 2-834 . 3mg {Em-mman?s; ?geaiagigt and the awaer?s: 0mm rmremnta?va? .?mpzaeted Ea Rafi: abu?ime: 3: wide: is": Em} REE-13.. ?{th gm: (if We ops-aim a mming?ngy {3:337 mantis it": ?g?m?apmi fir}- az?dmsg this: Mi; Ep-i-anfs-?ia haw-s33 Ef?f?ss-ia?a? ?uwewr :take- a {wk ih-e ??de during raw->2 may merfmm mama? the diar?- Bria-z": Newe?i basing madam tame-3r,- visit-as That: $33-st is?ciaig moire: Emmy as mam ?was; are {Bahia} ins-gamma; . \?mm . A generai View of {he and pariiai' dowmt'rea which 3:55.031 ma right aba?ment, :3 .. n. . The: dam face View as seen. is shown wi?i?im frag red ?ne. mama-126'; {item 'iEifQQ) Shea: mi if: '33333333337?3333333'333 3333333333 31333333 333 31333313733 E333 333333333333 Karma {53? 33am- 333333333 W1 3V333336W {ham Na. *3 {3'33 33333330 ins-igneciion 33:33}! 8, 233333 2? ,1 x/ my . 33:23 @313 aim-33333323333333 $3996, This: 'L?'Wf?i?ij" manimm 3:13-93 cut $3339.54. 33:32" an}; 33ng 33391333 a? r9333: which icsasea and p?iemiia?y 3-333 the 53333333333: waif, IIJWR (rev. 3.33.393} 3' - if? z; - 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 Robert W. Mathew Darn No. 1013 County Trinity Type of Dam Earth Type of Spillway Concrete weir and chute Water is 5 feet feet below spiliway crest and 37 feet below the dam crest. Weather Conditions Light rainfall at the time Contacts Made Brian Newell and Dale Davidsen during the inspection. Reason for Inspection Periodic Evaluation Important Observations, Recommendations or Actions Taken The valve was partially cycled during the inspection and was found to be in working condition. There are no prior outstanding administrative requirements requested of the owner. Conclusions From the known information and the visual inspection, the dam, reservoir, and the appurtenances are judged satisfactory for continued use. Observations and Comments Dam Similar to previous inspections, the visible portions of the upstream and faces, the crest, and the abutment contacts remain in satisfactory condition with no indication of surficial distress or instability. The upstream face remains well protected with riprap which provides protection against erosion without impeding inspection or monitoring for defects. The asphalt paved crest remains in good condition with no indication of settlement or displacement. Vegetation control on the dam remains very good as both sides of the embankment and groins were free of any undesirable woody vegetation. Rodent controi is also satisfactory, and no significant indications of rodent activity were observed. No visible evidence of movement at the left abutment landslide was noted. The dam being a manned facility during the day is closely monitored by the owner. Spillway The spillway approach, weir, chute, and exit channel were open and unobstructed. The log boom remains in place approximately 1,500 feet upstream of the dam. The crack near the top of the left wall of the spillway entrance channel noted in the previous report appears unchanged. The concrete invert and walls of the remaining portions of the spillway chute are in satisfactory condition, and no indication of significant distress or deterioration was observed. The current design storm, prepared in 1960, is for a 1000 year return period producing 70,000 (~584 sq mi) from the 120 square mile drainage area. The spiilway capacity is ~67,000 which is just under the peak inflow of 70, 000 based on the 1960 hydrologic analysis. An updated hydrology by Design Branch is needed. However, it is not considered a high prionty item at this time because the total freeboard of 32 feet is about 20% of the dam height and is . . Inspected by L. 7! 3"Li/i} Photos taken? Yes N0 Date June 25, 2013 ccfor Owner/Book Date of Report July 18, 20130 4W Sheet 1 of? INSPECTEON OF OAM AND RESERVOIR lN CERTIFEED STATUS Name of Dam Robert W. Mathew Dam No. 1013 Date of Inspection June 25, 2013 Observations and Comments conservative. Outlet Upstream control is provided by valves valve was control is provided by consisting of a valve and a valve. partially cycled during the inspection and was found to be in operable condition. The upstream -gate was not cycled during the inspection. it is frequently operated as a part of the normal reservoir operation. lVlr. Newell provide me the operation log which showed that the- gate was cycled on 5/7/2013 as part of the owner?s annual maintenance of the penstock. Seepage The face, groins, and abutments were dry and free of any indications of seepage. Seepage flow over the 90 degree V-notch weir was measured to be This correSponds to ~16 and is considered normal and within historic limits. The six PVC pipe drains, which daylight at varying heights along the left spillway wall, were dry. instr Instrumentation consists of the following: - Fourteen (14) survey monuments including three bench marks installed along the crest and left abutment to monitor settlement and displacement of the embankment. Embankment survey monuments are monitored annually. - Eight (8) survey monuments installed in the left abutment to monitor displacement of the landslide first observed in February 1998. Landslide survey monuments are monitored annually. Eight (8) open well piezometers, four each located within the right and left abutments, installed to monitor hydrostatic pressures within the abutments. Piezometers are monitored weekly. . One (1) 90-degree v?notch seepage weir installed to monitor the combined flow from seven foundation drains. The v?notch weir is monitored daily. - Three (3) triaxial strong. motion earthquake recorders; two on the dam crest and one founded in rock on the right abutment. Submission of data from the recorders to DSOD on a routine basis is not a current requirement. The most recent Dam Safety Surveillance and Monitoring Report was transmitted on March 29, 2013. The report includes the evaluation of the surveillance and instrumentation data and summary of the visual observations by the owner. Piezometer plots for the current reporting period and 2007?12 long term plots indicate that water elevations in most piezometers generally responded to the precipitation received at the time and remained well below the threshold/action level elevations. Sheet 2 of 4 EN N?ixi? Mama-cf Dam Kmart Mathew {Is-am. ?3 0353' Bate:- ?2221? irzsgaexixioh JUNE- 25 35733- . aha-axxzaxxmg mix-xx W?eix ?aws; shew a pax?fem {ifZS-msreaa?ng ?aw in {@smnm faxinfaxxi. {Ewing the re?uxing ga?'mx {33" am: ?aw Vezriaxx anti 3'88: and, shawaci ax- dir?cx carraiaxim ax? sewage. ?aw- and Quantity afraihfa?x. Swarm-32', smxx?ue flaw rsxmai-smd Within his-term iimx?s. xxsx?xxexyix?xg may: prepara? by F?i?ix?: West Summing Sax} ?'m?uaxed in ?ux: cums-2m repair Maia-x waiters-x Gama-y on x?ha {jam was; in Rama?; {if xh? data was mt indicate 3x113; m?ceaizxe mangaxx am differsxmex in cw fax} within xhxe' saxmaxad armr- ?Eta? mag-3x: remema and .ix?xmitmi'ng Survey. wag pexfm?mefi in "32413:, 201"! and mere-x Fesxxiitxx ware? dis?usaed in the pravlizmsx rainy: new ?uway' haw mien ?axf?m?xe? during ?ve muffs-gm. remixing perimcx NC: new 'Surxi-ey have men perfmmeci farms: wax-x a-buxm-es?. sti?e- :duri-ng the garment Tamra-?g periad. Tm?: previws starve-3a gag-{farmed in (mailman: 1 were? (Sigma-?aged in the aariier remark? The next survey- are due in "the fax 2x313. apex: wen piezamex?xx at ie?fx abutment wixi aim be mad at that ?xxme-tc dates: any g'mund water Tm: is?xsxrumentaxim data raview inciicaxaa that them is no Signifiaan?t hazard in aifher the: Exi?rxbar?xi?r?a'em' 2:35;: abutment. and ?the wax-axing array appear-:3 aim-gums. xx} man-its? candi-Eionss at the dam 1.. A gamma}. View af- xhzes- gaff, abuxmenx as wen axang the access mad. N6 Vixibie- ?iign afar-1y fresh nix-memenx is; exiixierxx; mm 1251 (my. mm} . Shem 3- cf 4? mpg-mam W: mamvm gm mmaF-sm yaw Name. (if Dam. Rama-rt W. Mathew Dam N95 2, ?3261 {rem-10109; mm Date Of {nspeci?bra 432153.225, 3013' ?633?: i" 'To. . R. - 3% 52.3? v? 5? . if; \bxk? \x