STATE OF CALIFORNIA I CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Type of Dam Water is El Capitan Hydraulic fill /Earthfill 50.8 feet below Dam No. _8_-_ 7_ _ _ _ _ _ _ _ County . San Diego Type of Spillway spillway crest and Open channel with ogee side channel control 70.8 feet below dam crest. W.S .E. = 699.2 Weather Conditions Sunny and warm Nathan Grima, Erika Azcona, and Kurt Lewis of the City of San Diego Reason for Inspection Periodic Maintenance of a Jurisdictional Dam Contacts Made Important Observations, Recommendations or Action s Taken • The in the outlet tower, and the two valves were exercised without issue during this inspection. • The erosion repair with grouted riprap at the valve held up well under the valve releases during this inspection. • Vegetation control on the dam was generally satisfactory; however, shrubs growing along the waterline will need to be removed . • The seepage weir has again become inundated. Restore and maintain the function of the weir and resume weekly seepage readings for the . Also , increase to a weekly frequency the seepage readings of the combined flows from the dam and t • Complete the below recommended actions regarding spillway maintenance and repair. Conclusions From the known information and visual inspection, the dam , reservoir, and the appurtenances are judged safe below the spillway for continued use at or below the reservoir restriction elevation crest. Observations and Comments Dam The downstream and visible portion of the upstream faces , the crest, and the abutment contacts remain stable and in satisfactory condition with no indication of distress. The riprap cover appeared uniform and in good condition. The dam crest appeared level and uniform. The asphalt on the dam crest access road was worn and .rough with old cracking but was still serviceable. Vegetation control on the dam was generally satisfactory; however, shrubs growing along the waterline will needed to be removed . Nathan said CDC crews were scheduled to trim the vegetation along the dam groins and the shrubs would also be removed . There were rodent bait stations placed on the dam crest and there was no sign of rodent activity. The sinkholes on the downstream face are markE;ld with survey markers and are monitored annually. They remain unchanged. A DSOD Memorandum of Design Review dated July 18, 2013, recommends the dam 's certified maximum water storage level be restricted to Spillway The approach and side channel ogee crest were clear of debris. The rock and earth slide debris noted in previous reports remains in the right side of the side channel spillway basin. Due to heightened concern regarding spillway performance the following actions are recommended: Photos taken? Yes cc for DWR 1261 (Rev. 10/09) X No Owner/Book Inspected by Date of Inspection Date of Report (J Anna Kolakowski & 04/18/2017 6/23/2017 Sheet 1 --- of Ek,_ 8 INSPECTluN OF DAM AND RESERVOIR IN Ccr{TIFIED STATUS Name of Dam El Capitan Date of Inspection 04/18/2017 ~~~~~~~~~~ • Remove all debris from the spillway channel. The existing debris falling from the cliff above the spillway channel has caused damage that appears to have been repaired ; however, the remaining debris may be disguising damage underneath it, or it may cause damage if moved by high spillway flows . • Remove all vegetation , including roots, from the spillway joints and weepholes . The joints should be cleaned and resealed as needed • Inspect the spillway concrete and initiate any needed repairs. '• Remove all debris, the trees, and all other vegetation from the spillway plunge pool. Inspect and repair any damage to the plunge pool. • Remove all trees to ten feet, and all shrubs to five feet, away from the structural elements of the spillway, • The above recommended actions are not all inclusive. More action may be required as recommended by your engineering consultant and by a special letter from our office. Also, it is important this work be completed in a timely manner. • The approach and side channel ogee crest were clear of debris; however, the upstream approach area had what appeared to be shrubs or small trees growing in it. Recommend removing this vegetation before it becomes obstructive and before it becomes a habitat. The inspection : Access to operating the valves valves was exercised during this The outlet tower appeared in good condition appeared in new condition. all Two relatively new valves , and their respective diffusers, were both exercised without issue. The erosion repair with grouted riprap valve held up well under the valve releases during this inspection. at the The entire length of the was inspected and appeared well-aligned and in good condition with little seepage from the walls except that coming from high weepholes located at Sta.'s 7+50 and 8+00. All seepage appeared to be running clear. has been measured in the past at a v-notch weir near the Seepage from the The weir has again become inundated. Restore and downstream mouth of the maintain the function of the weir and resume seepage readings for the The pipeline in the bulkhead, appeared in satisfactory condition. Water pooled at the base of the near the downstream end and backed up into the Seepage The downstream face, groins, and toe of the dam were dry. DWR 1261 (rev. 10/09) Reportedly, combined seepage Sheet 2 of 8 INSPECTluN OF DAM AND RESERVOI R IN Name of Dam C1::~T I F I ED STATUS El Capitan Date of Inspection 04/18/2017 ~~~~~~~~~~ from the dam toe and are pumped and measured together through a meter on a monthly basis. Increase to a weekly frequency the seepage readings of the combined flows from the dam and l capture fluctuations and increases. Instr. Instrumentation consists of 69 survey monuments on both faces and the crest, 3 piezometers on the downstream slope (No. 's 1, 3, and 6 replaced with vibrating wire piezo's in 2000, No. 5 on the upstream side was abandoned when it was determined to be plugged), and 2 seepage monitoring points one each for the toe drain and the outlet . Instrumentation data submitted in the City of San Diego Dam Instrumentation Report Fiscal Year 2016 covering the period July 2006 to July 2016 is the subject of this review. The data consists of a plan view showing the locations of all the above mentioned instrumentation, 10-year plots of the survey monuments, and 1-year and 10-year plots of the piezometer, seepage , precipitation, and reservoir levels. The report summarizes that the recent reads of monuments continue to follow historical trends and the piezometer readings are following established trends. All monuments on the downstream side continue to follow established trends with mild seasonal fluctuations. Eight upstream monuments were accessed along El. 725 due to the low reservoir level and they also followed established trends . All other upstream monuments remained under water or were covered by Quagga mussels. Three piezometers in the downstream slope indicate saturation levels are normal; declining from the topmost to the bottommost. The highest saturation level is at feet below the restricted water surface elevation. Seepage from the toe of the dam and the l is conveyed to a sump covered by a storage shed (pump house) near the left base of the dam. The seepage was measured by a trapezoidal weir in the sump, but is now measured by a flow .meter located on the discharge side of the pump. The weir was again inundated during this inspection and the owner had discontinued the seepage readings; this ·was not discussed in their instrumentation report. The seepage plot shows the seepage to have been at about three gpm ; then it flattened at about one to two gpm. I recommend the owner restore and maintain the function of the weir and resume weekly seepage readings for the The combined seepage from the dam and the measured by the flow meter is responsive to the reservoir level and ranges from 15 to 150 gpm. Also , increase to a weekly frequency the seepage readings of the combined flows from the dam and The sinkholes on the downstream face are marked with survey markers and are monitored annually. They remain unchanged. The instrumentation at this dam is judged to be satisfactory and no new instrumentation is required at this time . DWR 1261 (rev. 10/09) Sheet 3 of 8 I INSPECTluN OF DAM AND RESERVOIR IN CcK.TIFIED STATUS Name of Dam _E_l_C _ a~ p_ ita _n ________ _ ____________ Dam 8-7 No. 04/18/2017 Date of Inspection ~~~~~~~~~~~~~~~~~- Photo 1. Rip rap covered upstream face . Photo 2. Partial view of the rip rap covered downstream face . DWR 1261 (rev. 10/09) Sheet 4 of 8 INSPECTluN OF DAM AND RESERVOIR IN C~tlT I F I ED STATUS Name of Dam El Capitan Dam No. Date of Inspection 8-7 04/18/2017 ~~~~~~~~~~~~~~~~- Photo 5. The dam crest as viewed from the left end . .· Photo 6. The spillway ogee crest. Recommend removal of the insipient woody vegetation in the spillway approach area . DWR 1261 (rev. 10/09) Sheet 6 of 8 INSPECTluN OF DAM AND RESERVOIR IN Ct:RTIFIED STATUS Name of Dam El Capitan Date of Inspection 04/18/2017 ----------~ .,. Photo 7. The spillway side channel with debris that has fallen into the basin from the cliff above. •. -. .. - ----: ·.--. - Photo 8. Repairs have been made to the spillway invert. DWR 1261 (rev. 10/09) Sheet 7 --- of 8 I INSPECTluN OF DAM AND RESERVOIR IN Ct:;r{TIFIED STATUS Name of Dam El Capitan Date of Inspection 04/18/2017 ~~~~~~~~~~~ , i ......:US....~JL~~~~~--L---~~~~~ Photo 9. Remove all vegetation including roots from the spillway joints and weepholes, and clear the plunge pool of all vegetation and debris. ~ Photo 10. The grouted rip rap erosion repair held up well to the valve exercise flows. DWR 1261 (rev. 10/09) 8 - of Sheet - - 8 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 El Capitan Type of Dam Hydraulic Fill / Earth 75.0 Water is below feet Water Surface Elevation - 678.0 Dam No. Type of Spillway 8-7 San Diego County Concrete-lined side channel with ogee crest 95.0 spillway crest and feet below dam crest. (gauge elev. 122.0, gauge zero= 553.0) Weather Conditions Sunny, clear, and cool - 60° F Contacts Made Nathan Grima, Assistant Engineer & Aleda Markham, Reservoir Keeper with the City of San Diego Reason for Inspection Periodic Maintenance Inspection of Jurisdictional Dam Important Observations, Recommendations, or Actions Taken • Additional vegetation removal along the downstream left groi.n is needed; see Photo 9 and the explanation included on Page 2 of this report. A clear and unobstructed line of sight along the entire length of the groin, from the toe up to the crest, should be maintained. • I requested that rodent burrows at the downstream left abutment be repaired, see Photo 12. Burrows and any small holes on or adjacent to the dam need to be collapsed and filled with gravel or compacted soil to prevent the damage from progressing. • Work to complete the energy dissipation project at the 48-inch blow-off valve should be complete by June. • A March 27, 2015 letter, from DSOD to the dam owner, acknowledged the City of San Diego's selfimposed reservoir restridion. DSOD concurs with the restriction and formally imposed a restriction that temporarily limits the maximum water surface elevation in the reservoir to below the crest of the spillway. The reservoir restriction will remain in effect until DSOD authorizes storage above this elevation. Conclusions From the known information and visual inspection, the dam, reservoir, and all appurtenances are judged safe for continued use at or below the restricted reservoir restriction below the spillway crest. Obse rvation s and Comments Dam The dam crest appeared level and well-aligned; there were no noticeable signs of concerning settlement or distortion. The weathered asphalt covering the dam crest has widespread, but normal, cracking along the entire length. Both the upstream and downstream slopes have rock Photqs taken? Copy for Yes x No Owner I File I Field Book DWR 1261 (Rev. 10/09) Inspected by R. Fessler Date of Inspection December 2, 2015 Date of Report April 26, 2016 cJ2k- 5lt~~ Sheet _1_ ~~ INSPECTION Name of Dam El Capitan ~:DAM AND RESERVOIR IN CER"t iED STATUS 8-7 Dam No. Date of Inspection December 2, 2015 ~~~~~~~~~~ Observations and Comments Dam (cont'd) protection facing that appeared uniform and stable; the placement and condition of the rip-rap protection remains satisfactory. There are two known depressions on the dam's downstream slope; referred to as the 'Old' and 'New' depressions. The older depression, first noticed in 2000, is on the left side of the dam at STA 103+50 and Elevation 710; the newer depression was discovered in 2012 and is on the right side of the dam at STA 107+00 and at an approximate elevation of 625. Both depressions are monitored during routine inspections by city staff and are surveyed to detect change. Each depression has remained stable since they were discovered and do not appear to be progressing. The abutment contacts appeared normal and stable and no signs of instability were observed at the downstream toe. Vegetation control was satisfactory over the majority of the dam's surface. There are mature oak trees with large limbs that overhang the embankment along the downstream left groin; this vegetation is very thick and visually obscuring. This vegetation was requested to be removed as part of my previous inspection. It was evident that a portion of the vegetation had been removed; however, the area remains visually obscured and additional removal is needed. Dense and/or visually obscuring vegetation within 5-feet and any woody vegetation or trees within 10-feet from the dam or any concrete structures should be removed to provide for unobstructed views and to prevent damage. A clear and unobstructed line of sight along the entire length of the groin, from the toe up to the crest, should be maintained. Rodent abatement measures were in-place at locations around the dam; damage to the embankment caused by burrowing rodents was not prevalent. There was, however, a small number of significant-sized burrows at the downstream left abutment that need to be repaired, see Photo 12. Rodent burrows and any small holes on or adjacent to the dam need to be collapsed and filled with gravel or compacted soil to prevent the damage from progressing. Spillway The spillway is located at the right abutment and consists of a large concrete-lined channel with an ogee weir crest. The spillway approach and side channel ogee crest remain unobstructed; a large deposit of soil and rubble, most of which resulted from a 2005 landslide, remains on the channel floor and on the right wall. The majority of the debris that was deposited in the channel was removed immediately following the slide. The amount of debris that remains in the channel does not present a dam safety concern at this time, as the material would likely be washed out the end of the channel in the event of high flows through the channel. I do, however, recommend that the remaining soil and rock be removed over time, to provide for adequate inspection and maintenance of the concrete surfaces. The sloped walls of the spillway channel remain well-aligned; the visible portion of the concrete surface in the spillway is aged but remains in good and serviceable condition. DWR 1261 (rev. 10/09) Sheet 2 of 10 INSPECTION Name of Dam F DAM AND RESERVOIR IN CER El Capitan IED STATUS 8-7 Dam No. Date of Inspection December 2, 2015 ~~~~~~~~~~ Observations and Comments Outlet The outlet tower has valves at the following elevations The exterior surface of the tower was examined the concrete surface is aged but remains in serviceable and acceptable condition. The outlet tower was not accessed during this inspection due in part to a The outlet tower should be accessed and inspected as part of the next regularly scheduled inspection. The valves have . None of the outlet components were operated during this inspection; both were independently operated and maintained by the owner six months prior to this inspection, in June 2015. The outlet controls appeared well-maintained and were reported to be in good working order. Recent independent operation of the outlet components by the owner and operation during a DSOD inspection is summarized in the following table. Independent Operation by Owner Operation Witnessed by DSOD Notes Valve February 2015 October 2014 Operated 100% Valve February 2015 October 2014 Operated 100% Outlet Component We accessed and inspected the entire length of the was in The concrete that lines the good condition throughout with no signs of significant cracking or deterioration observed. A small amount of seepage, that appeared clear, was present Seepage There were no obvious or unusual signs of seepage observed downstream of the dam, on the slope, in the abutment contacts, or along the downstream toe. Seepage is collected at two locations; seepage through the is measured at a V-notch weir at the l entrance and at a structure at the toe of the dam. Seepage from both locations is conveyed to a sump and is then pumped back into the distribution pipeline; a flow meter at the pump measures total seepage. Seepage measured in the outlet remains constant at +/- 6 gallons per minute; total seepage at the dam responds very closely to fluctuations in the reservoir's water surface elevation. Seepage flows observed were clear and remain within the historic range. Instrumentation Instrumentation at this dam consists of 69 survey monuments on both slopes of the dam and on the crest, 3 piezometers on the downstream slope, and 2 seepage measurement locations. The most recent submittal of instrumentation data for this dam was received by DSOD in December of 2015, in a report dated November 20, 2015. The monitoring period for the data included with this report is from July 2014 through June 2015. DWR 1261 (rev. 10/09) Sheet 3 of 10 INSPECTION Name of Dam .: DAM AND RESERVOIR IN CER"l El Capitan iED STATUS 8-7 Dam No. December 2, 2015 Date of Inspection ~~~~~~~~~~ Observations and Comments Instrumentation (cont'd) Survey Monuments Movement data provided for all of the survey monuments showed negligible movements in both the horizontal and vertical directions for the monitoring period; the elevation and deflection data reflect historic and acceptable trends for the dam. Piezometers Piezometers 1, 3, and 6 (all on the downstream slope) are the only functional and active piezometers at the dam; Piezometer 5, on the upstream slope, is not functional and has not been read since 1998. The readings for the three piezometers remain constant and continue to respond to lower water levels in the reservoir during the reporting period. Seepage The vast majority of total seepage at the dam is from the measurement location at the toe, only a small fraction is from the . The amount of total seepage continued to drop throughout this monitoring period consistent with the water level in the reservoir. This behavior and the quantity appear to closely match historic and acceptable patterns. The instrumentation data reviewed indicates that the dam continues to perform adequately. The instrumentation program and monitoring frequency at this dam are currently judged to be adequate; no additional instrumentation is deemed necessary at this time. DWR 1261 (rev. 10/09) Sheet 4 of 10 INSPECTION _ ,: DAM AND RESERVOIR IN CER", Name of Dam El Capitan IED STATUS 8-7 Dam No. ~~~~~~~~~~~ December 2, 2015 Date of Inspection ~~~~~~~~~~~ Photo 1: View of dam crest, from left abutment Photo 2: View of upstream slope, from the right abutment DWR 1261 (rev. 10/09) Sheet 5 of 10 INSPECTION Name of Dam El Capitan ; DAM AND RESERVOIR IN CER'1• IED STATUS 8-7 Dam No. ~~~~~~~~~~- December 2, 2015 Date of Inspection ~~~~~~~~~~ Photo 3: View of downstream slope, from right side of toe DWR 1261 (rev. 10/09) Sheet 6 of 10 INSPECTION Name of Dam ,: DAM AND RESERVO IR IN CER'1 IED STATUS El Capitan 8-7 Dam No. ~~~~~~~~~~ Date of Inspection December 2, 2015 ~~~~~~~~~~ Photo 5: View of spillway weir and approach area Photo 6: View of spillway channel DWR 1261 (rev. 10/09) Sheet 7 of 10 INSPECTION Name of Dam ,: DAM AND RESERVOIR IN CER'1. El Capitan IED STATUS 8-7 Dam No. Date of Inspection December 2, 2015 ~~~~~~~~~~~- Additional vegetation removal needed Photo 11: View of outlet tower Fill witlt gravel and/or compacted gravel Photo 12: Example of rodent burrowing at downstream left abutment, repair needed DWR 1261 (rev. 10/09) Sheet 10 of 10 STATE OF CALIFORNIA CALIFORNIA NATURAL RESOURCES AGENCY DEPARTMENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS · El Name of Dam . Capitan 8-7 Dam No. San Diego County ~~~~~~~~~~~- Hydraulic Fill I Earth Type of Dam Type of Spillway Side Channel, Concrete-lined with Ogee Crest ~~~~~~~~~~~- 72.0 Water is below feet spillway crest and 92.0 feet below dam crest. Water Surface Elevation - 678.0 Weather Conditions Sunny and clear, 65 - 70° F Contacts Made Nathan Grima with the City of San Diego Reason for Inspection Periodic Maintenance Inspection of Jurisdictional Dam Im portant Observations, Recommendations, or Action s Taken 1. A letter to the dam owner will be sent detailing requirements of an interim reservoir restriction during which time a geotechnical exploration will be performed for the purpose of preparing an updated seismic stability evaluation for the dam. The restriction will require that the reservoir be maintained at or below below the spillway crest under normal operating conditions; temporary storage above is permitted for flood control purposes with a requirement that the water level in the reservoir be returned to the restricted elevation as soon as is practical. 2. In response to DSOD's recommendation to provide energy dissipation features at the valve, the owner has completed the design of a project that includes a buttressed headwall structure and grouted rip-rap downstream of the valve . Mr. Grima conveyed that work associated with this project was scheduled to commence in the near future. 3. There are very dense overhanging tree limbs and obscuring brush on the downstream slope in the area where the dam contacts the left abutment; this vegetation is in need of removal and this area should be maintained open and clear a minimum distance of ten feet beyond the footprint of the dam. 4. The valve arid the during this inspection . valve were both fully cycled without difficulty or incident Conclusions From the known information and visual inspection, the dam, reservoir, and all appurtenances are judged safe for continued use at or below the forthcoming reservoir restriction elevation of below the spillway crest. Observations and Comments Dam The dam crest appeared level and well-aligned, with no noticeable signs of concerning settlement or distortion. The asphalt surface covering the crest of the dam is weathered and has widespread, but normal, cracking along the entire length of the crest. Both the upstream and Date of Inspection (ZPf ?fi.,~fS 1111812014 Ja #2 1/1s Date of Report 03/10/2015 Inspected by Photos taken? Copy for Yes x No Owner I File I Field Book DWR 1261 (Rev. 10/09) R. Fessler Sheet 1 -- of 8 ·-~;{_y INSPECTION Name of Dam El Capitan DAM AND RESERVOIR IN CER..,.. '~ED STATUS 8-7 Dam No. Date of Inspection October 8, 2014 ~~~~~~~~~~ Observations and Comments downstream slopes are faced with rock protection. The visible portion of the upstream slope appeared uniform and stable; the placement and condition of the rip-rap protection remains satisfactory. The downstream slope also appeared to be in satisfactory condition; the rip-rap covered slope was uniform over the majority of the dam. There are two known depressions on the dam's downstream slope; the depressions are referred to as the 'Old' and 'New' depressions. The older depression was discovered in about 2000 and is on the left side of the dam at Sta. 103+50 and at an approximate elevation of 710. The newer depression was discovered recently in 2012 and is on the right side of the dam at Sta. 107+00 and at an approximate elevation of 625. Both depressions are monitored regularly for change and are surveyed two times a year, each of the two depressions have remained stable since they were discovered and do not appear to be progressing. The abutment contacts appeared normal and stable and no signs of instability were observed at the downstream toe. Vegetation control was satisfactory over the majority of the dam's surface and in areas directly adjacent to the dam. There was, however, thick and obscuring vegetation including very large and dense limbs growing down from mature oak trees to the left of the dam, on the downstream side, in the area where the dam contacts the left abutment. The amount of vegetation present does not allow adequate access to this area or for an unobstructed view of the groin. I discussed with Mr. Grima the need to have the limbs pruned and the vegetation removed and maintained open and clear; all obscuring vegetation should be cleared in an area that extends at least ten feet beyond the footprint of the dam. Rodent abatement devices were present on and around the dam and there was no evidence of significant damage to the embankment caused by burrowing rodents. Spillway The spillway for the dam is located at the right abutment and consists of a large concrete-lined channel with an ogee weir crest. The spillway approach and side channel ogee crest were both unobstructed and clear of debris; a large deposit of soil and boulders, most of which resulted from a landslide that occurred in 2005, remains on the channel floor and on the right wall. The majority of the debris that was deposited in the channel was removed in the years following the slide. The amount of debris that remains in the channel does not pose a dam safety concern at this time, as the material would likely be washed out the end of the channel in the event of high flows through the channel. I do, however, recommend that the process of removing the soil and rock be resumed and completed over time as resources and finances allow, to provide for adequate inspection and maintenance of the concrete surfaces and to restore the original hydraulic capacity of the channel. The sloped walls of the spillway channel remain well-aligned; the visible portion of the concrete surface in the spillway is aged but remains in good and serviceable condition. DWR 1261 (rev. 10/09) Sheet 2 of 8 INSPECTION Name of Dam DAM AND RESERVOIR IN CER-r 'IED STATUS El Capitan 8-7 Dam No. October 8, 2014 Date of Inspection ~~~~~~~~~~ Observations and Comments Outlet The cylindrical wet tower has valves at the following elevations We inspected the exterior surface of the outlet tower ; the concrete surface is aged but remains in satisfactory and serviceable condition. appeared new and were reportedly replaced in the recent past. Staff members from the City's Operation Division accessed tower and demonstrated the operability of The valves were both fully exercised during this inspection, with no difficulties or issues encountered. These two valves were recently rehabilitated; valves equipped with energy dissipating diffusers replaced the former valves. Each of the valves was fully opened and then closed using the controls. The outlet controls appeared well-maintained and were reported to be in good working order. Recent independent operation of the outlet components by the owner and operation during a DSOD inspection is summarized in the following table. Independent Operation by Owner Operation Witnessed byDSOD Notes Valve October 2014 October 2014 * Operated 100% Valve October 2014 October 2014 * Operated 100% October 2014 October 2014 - Outlet Component We accessed and inspected the entire length of the The concrete good condition throughout with no signs of significant cracking or deterioration observed. minimal amount of clear seepage was present Seepage A There were no obvious or unusual signs of seepage observed downstream of the dam, on the slope, in the abutment contacts, or along the downstream toe. Seepage is collected and measured at two locations: seepage through the is collected and measured using a V-notch weir at the seepage is also collected in a structure at the toe of the dam. Seepage from both locations is conveyed to a sump and is then pumped back into the distribution pipeline; a flow meter at the pump measures total seepage. Seepage measured in the remains essentially constant at 6-7 gallons per minute; total seepage at the dam appears to respond consistently with variations in the reservoir's water surface elevation. Seepage flows were clear and remain within the historic range. DWR 1261 (rev. 10/09) Sheet 3 of 8 INSPECTION Name of Dam El Capitan . DAM AND RESERVOIR IN CER...- ·~ED STATUS 8-7 Dam No. Date of Inspection October 8, 2014 ~~~~~~~~~~ Observations and Comments lnstrumEntation Instrumentation at this dam consists of 69 survey monuments on both slopes of the dam and on the crest, 3 piezometers on the downstream slope, and 2 seepage measurement locations. The current submittal of instrumentation data for this dam was submitted to DSOD in September of 2014, in a report dated 9/9/2014. The monitoring period for the data included with this report was the City of San Diego's Fiscal Year 2014, or July 2013 through June 2014. Survey Monuments Movement data provided for all of the survey monuments showed negligible movements in both the horizontal and vertical directions for the monitoring period; the elevation and deflection data reflect historic trends for the dam. Piezometers Piezometers 1, 3, and 6 (all on the downstream slope) are the only functional and active piezometers at the dam; Piezometer 5, on the upstream slope, is not functional and has not been read since 1998. The readings for all three active piezometers remain very constant and appear to have responded closely to a slight drop in the reservoir's water surface elevation during the reporting period. Seepage for El Capitan dam is collected and measured at two locations, one at the and the other at the toe of the dam. Seepage through the is measured using a V-notch weir and remains constant between 6 and 7 gallons per minute. Combined seepage is also measured with a flow meter where it is pumped into the water distribution pipeline. The total seepage for this monitoring period closely matches historic and expected patterns; the quantity of seepage excluding seepage from the responds closely and in response to variations in the reservoir's water surface elevation. Seepage quantities and patterns for both the and dam remain with historic and acceptable limits. Seepage The instrumentation program at this dam indicates that the dam is performing satisfactorily and the monitoring frequency is currently judged to be adequate; no additional instrumentation is needed at this time. Other An October 1, 2014 letter from the owner detailed a self-imposed reservoir restriction. The reason for the restriction is that there are questions about the seismic stability of the dam. The owner is currently working on a geotechnical exploration program which will then be followed by an updated stability evaluation. On March 17, 2015 Ms. Yana Balotsky was called and informed that DSOD would be sending a letter formally adopting the interim restriction. DWR 1261 (rev. 10/09) Sheet 4 of 8 INSPECTION! Name of Dam El Capitan . DAM AND RESERVOIR IN CERr ,ED STATUS 8-7 Dam No. ~~~~~~~~~~~~ Date of Inspection October 8, 2014 ~~~~~~~~~~~- Photo 1: View of dam crest, from left abutment Photo 2: View of upstream slope, from right abutment DWR 1261 (rev. 10/09) Sheet 5 of 8 INSPECTION' Name of Dam El Capitan . DAM AND RESERVOIR IN CERi lED STATUS 8-7 Dam No. ~~~~~~~~~~ October 8, 2014 Date of Inspection ~~~~~~~~~- Photo 3: View of downstream slope, from toe Photo 4: View of left downstream abutment contact (note vegetation) DWR 1261 (rev. 10/09) Sheet 6 of 8 INSPECTION Name of Dam : DAM AND RESERVOIR IN CER El Capitan 'IED STATUS 8-7 Dam No. ~~~~~~~~~~~~ Date of Inspection October 8, 2014 ~~~~~~~'--~~~~ Photo 5: View of spillway channel approach Photo 6: View of spillway channel DWR 1261 (rev. 10/09) Sheet 7 of 8 FILE 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 Type of Dam Water is El Capitan Hydraulic fill /Earthfill 49.2 feet below -~~~~~~~~~~ Dam No. 8-7 Type of Spillway County San Diego Open channel with ogee side channel control 69 .2 feet below dam crest. ~~~~~~~~~ spillway crest and Weather Conditions Sunny and warm Contacts Made Yana Balotsky and Nathan Grima of the City of San Diego Reason for Inspection Periodic Maintenance Important Observations, Recommendations or Actions Taken • A DSOD Memorandum of Design Review dated July 18, 2013, recommends the dam's certified maximum water storage level be restricted to a lower level, · • Recommend installation of erosion resistant buttressing at the valve. Conclusions From the known information and visual inspection, the dam, reservoir, and the appurtenances are judged safe for continued use pending implementation of a reservoir restriction as an interim risk reduction measure . Observations and Comments Dam The downstream and visible portion of the upstream faces, the crest, and the abutment contacts remain stable and in satisfactory condition with no indication of distress. The riprap cover appeared uniform and in good condition. The dam crest appeared level and uniform. Vegetation control was excellent. There were rodent bait stations placed on the dam crest and there was no sign of rodent activity. The sinkholes on the downstream face are marked with survey markers and are monitored annually. They remain unchanged. Spillway The approach, side channel ogee crest, and exit channel of the spillway were clear of debris. The rock and earth slide debris noted in previous reports remains in the right side channel though some effort has been applied to remove a portion of it. There is environmental concern that the debris will choke the stream bed if flows pass through the spillway; however, the sl ide debris does not appear to create a concerning blockage to the spillway capacity at this time as most of it will likely wash away if the flows become large .. A very large boulder is perched to fall from the abutment into the spillway which may cause some damage to the spillway concrete. The spillway concrete appeared in generally good condition. Outlet This inspection was scheduled around witnessing the first exercise of the new valves under full reservoir pressure. The new valves had already been proof exercised (see Inspection Report dated 04/22/2013). The valves could now be exercised under full reservoir head because the reservoir lower stratum had become anoxic and therefore inhospitable to the Quagga Mussel. The City closed the valves that had been open with the valve remained open . They called the Alvarado WTP to resume drafting water from the reservoir to remove the Quagga infested water in the pipeline. Both new valves were subsequently smoothly and easily operated by full cycle opened and closed . The r was easily operated by l to 100% opened was connected to the valve via a three to and was closed again. The four foot long pipe spool and was easily operated by full cycle opened and closed. A Kolakowski ~ Photos taken? Yes cc for DWR 1261 (Rev. 10/09) X No Owner/Book Inspected by Anna Date of Inspection _ __ _1 _1_/_18_/_2_0_1_3_ _ __ Date of Report 3/24/2014 Sheet 1 -- of 6 INSPECTION Name of Dam vr DAM AND RESERVOIR IN CERT1r 1ED STATUS El Capitan Date of Inspection 11 /18/2013 ~~~~~~~~~~ great deal of erosion occurred during the 48-inch plug valve operation. Yana said they would need to go through the environmental process and then will design either riprap or concrete backfill. The outlet tower appeared in good condition by inspection from the shore. Access The entire length of the was inspected and appeared well-aligned and in good condition with little seepage from the walls except that coming from high weepholes located at Sta.'s 7+50 and 8+00. All seepage appeared to be running clear. Reportedly most of the seepage that is measured from the appeared in satisfactory condition . Water pooled at the near the downstream end backing up to about Sta. 10+30. base of the Seepage The downstream face, groins, and toe of the dam were dry. The weir was running clear. The cipoletti weir measured 0.12' which is well within past historical limits. Instr. Instrumentation consists of 69 survey monuments on both faces and the crest, 3 piezometers on the downstream slope (No.'s 1, 3, and 6 replaced with vibrating wire piezo's in 2000, No. 5 on the upstream side was abandoned when it was determined to be plugged), and 2 seepage monitoring points one each for the toe drain and the . Instrumentation data submitted in the City of San Diego Dam Instrumentation Report Fiscal Year 2013 covering the period July 2003 to July 2013 was reviewed prior to this inspection. The data consists of a plan view showing the locations of all the above mentioned instrumentation, 10-year plots of the survey monuments, and 1-year and 10-year plots of the piezometer, seepage, precipitation, and reservoir levels. The report summarizes that the recent reads of monuments continue to follow historical trends and the piezometer readings are following established trends . All monuments on the downstream side continue to follow established trends . Eight upstream monuments were accessed along El. 725 due to the low reservoir level and they also followed established trends . All other upstream monuments remained under water. Seepage from the toe of the dam and the is conveyed to a sump near the left base of the dam. The seepage was measured by a trapezoidal weir in the sump, but is now measured by a flow meter located on the discharge side of the pump. The owner has repaired the drainage for the weir and it was running clear. They continue to read the seepage separately. They report the seepage is following established trends. My review of the data confirms the above summary with added comment that the weir seepage is responsive to reservoir level, and the monument readings are generally within plus or minus a tenth of a foot. The sinkholes on the downstream face are marked with survey markers and are monitored annually. They remain unchanged. The lake level in the past ten years has seldom been above El. 725, though the certified lake level (at the spillway elevation) is El. 750. There has not been much change in the piezometric levels in the reported 10-year span . Piezometers #3 and #6 are mildly responsive to the reservoir level. Piezometer #1 , the furthest downstream from the crest, has been fairly constant. A DSOD Memorandum of Design Review dated July 18, 2013, recommends the dam's certified maximum water storage level be restricted to a lower level, DWR 1261 (rev. 10/09) Sheet 2 of 6 ( INSPECTION Name of Dam I vr- DAM AND RESERVOIR IN CERT 1r1ED STATUS El Capitan Dam No. Date of Inspection 8-7 11/18/2013 ~~~~~~~~~~~~~~~~- ~:··; ~.\~~r.. . -~:·.~!.!.f.~.jl ~- ~.:;-·; ··. - :. : ;;.,;\~*'! :'.:._:";'"}.. , I Photo 2. Visible portion of the upstream slope. Photo 3. Side channel spillway with ogee control section . Note the debris gathering in the side channel from the slope above. DWR 1261 (rev. 10/09) Sheet 4 of 6 STATE OF CALIFORNIA CALIFORNIA NATURAL RESOURCES AGENCY DEPARTM ENT OF WATER RESOURCES DIVISION OF SAFETY OF DAMS FILE INSPECTION OF DAM AND RESERVOIR IN CERTIFIED STATUS Name of Dam Type of Dam _E_I_C_a~pi_ta_n_ _ __ __ _ _ Dam No. 8-7 County _S_a_n_D_i_e~g_o_ _ _ __ _ Hydraulic/Rockfill Embankment Type of Spillway Side Channel Control with Open Channel 32.88 feet below spillway crest and 52.88 feet below dam crest. Water is Water Elevation :717.12 MSL, or at gauge 164.12 Weather Conditions Partly Cloudy and Cool. Contacts Made Nathan Grima and Aleda Markham with the City of San Diego Reason for Inspection Periodic Maintenance Inspection Important Observations, Recommendations or Actions Taken 1. Rodent control measures had been increased as requested during the previous inspection. 2. Replace the missing lids to crest monuments No. 9 and No. 10. 3. Remove the woody vegetation that is growing in the spillway's invert panel joints. 4. Include the Old and New Depression areas on the instrumentation's submittal plan sheet. Conclusions From the known information and visual inspection, the dam, reservoir, and the appurtenances are judged safe for continued use. Observations and Comments Dam Spillway Photos taken? cc for The chip seal paved crest was level, well-aligned, and in satisfactory condition . The pavement had moderate distress in the form of cracking, but appeared in serviceable condition. The metal caps to crest monuments No. 9 and No. 10 were missing and need to be replaced . The upstream face of the dam was inspected by boat and the downstream face was inspected from the crest, benches, and downstream toe. The visible portion of the upstream face and the downstream face appeared uniform with no sign of distress or structural instability. Two areas located on the downstream slope have been delineated as depression areas and are named the Old Depression and the New Depression. Numbers that have been painted on selected riprap are surveyed and reported on in the instrumentation submittals. The Old Depression is located near El. 710 towards the left abutment and the New Depression is located near El. 620 towards the right abutment and downstream toe. I would have not noted the minor depressions if Mr. Grima had not pointed them out. The Old Depression (Photos 2 & 3) is the more pronounced of the two and I could not detect a depression in the New Depression area. The readings for the New Depression were initiated in June of 2012. A sinkhole located between toe wall drains No. 2 and No. 3 and just below the riprap lined portion of the downstream slope of the downstream toe was observed (Photo 4). According to Mr. Grima and Ms. Markham , the sinkhole was created from pumped water during the project to restore the two flooded seepage weirs. This area appeared stable and dry and I requested this area repaired, to which Mr. Grima agreed. The groins.appeared normal and the abutments stable. Vegetation control was excellent. No concerning rodent activity was noted during this inspection. Rodent bait stations had been placed at the crest to increase rodent control measures as requested during the previous inspection. The approach, side channel crest, and exit channel were clear of concerning debris. The concrete that comprised the ogee crest, slab invert and channel walls appeared in serviceable condition with no sign of instability or distress. There was minor rock and earth slide debris littered in the spillway channel and the concrete patches that have been repaired from prior rock Inspected by Bill Vogler ~\/ r,jtr( IJ Yes_x_ No Date of Inspection 01/18/2013 ~/< Owner/Field Book/File Copy Date of Report _0_5_/0_2_/2_0_1_3_~---~-- DWR 1261 (Rev. 10/09) t,/t-4/11X=S ~ G l ZJ.<-/( S' 5 Sheet ~ of INSPECTION OF DAM AND RESERVOIR IN CERTlh~D STATUS Date of Inspection 01/18/2013 ~~~~~~~~~~ Observations and Comments slides appeared intact. The rock slides are a longstanding condition, originating from the cut slope to the north that frequently dumps debris into the channel. The debris does not appear to affect the function of the spillway. Woody vegetation is becoming established in the invert's panel joints (Photo 5) and this vegetation needs to be removed. The outlet tower was inspected near the top of the tower. The concrete comprising the tower appeared in satisfactory condition with no sign of distress or instability. A single r valves and the performed adequately when it was partially operated during the inspection. Valves #2 and #3 were open during this inspection. The valves consist of a new valves that release water into the San Diego River's streambed. They were operated on April 22, 2013 during a proof of exercise by the Contractor, which was inspected by Anna Kolakowski. The was inspected after City staff completed a confined space entry permit and gas monitors were carried by the staff. The two pipes located at the appeared in satisfactory condition. liner appeared well-aligned and in good condition with no evidence of distress or instability. 'eepage There were no sign of seepage on the downstream face, groin, or downstream toes areas. The 12-inch trapezoidal (Cipolleti) weir had a measurement of 0.1-ft (48 gpm). The seepage water is now pumped and reclaimed back into the reservoir and the flow meter connected to the pump had a reading of 67 gpm, which is equivalent to 0.125-ft to a Cipolleti weir. The seepage at the entrance to the at the 90 degree V-notch weir was flowing clearly at approximately 1.2 gpm. The seepage from the pipes connected through the had slow to steady drip conditions. These seepage conditions are considered normal for the reservoir's water elevation during this inspection. Instrumentation at this dam consists of 79 survey monuments, four piezometers, and 2 seepage points, reservoir water level, and rain gauge data. The most current instrumentation report, dated October 24, 2012, contains data for the past 1O years from July 2002 through July 2012. There are three functioning piezometers and the fourth piezometer, Piezometer 5 located on the upstream portion of the embankment, was abandoned in 1991. The piezometers have reported nearly constant levels during the 10-year plotting period. They appear to be slightly influenced by the reservoir's water elevation level and do not appear to be influenced by precipitation events. No adverse trends or abnormal behavior is indicated by the piezometer data. The measurements of the survey monuments continue display small oscillatory and insignificant movements in the both the vertical and horizontal directions during the 10-year plotting period. The readings of the upstream monuments have been discontinued. The survey data does not indicate any adverse trends or conditions. Two areas of depression are measured by survey by taking elevation readings from selected riprap that are painted with numbers. The Old Depression is located near El. 710 towards the left abutment and measurements are taken from eight rocks that encircle the depressed area. The 10-year plot indicates no movement and the depressed area appears stable. The New DWR 1261 (rev. 10/09) Sheet 2 of 5 INSPECTION OF DAM AND RESERVOIR IN CERT1 ED STATUS Name of Dam El Capitan Dam No. Date of Inspection _8_-_7_ _ _ _ __ _ __ 01 /18/2013 ---------~ Observations and Comments Depression is located near El. 620 towards the right abutment and downstream toe and measurements are taken from eight rocks that encircle the depression. The readings had been initiated in June of 2012 and two measurements had been taken for the report. The two areas of depression should be shown on the submittal's instrumentation plan sheet. The 12-inch trapezoidal weir measures seepage from the three toe wall drains and the 90degree V-notch weir measures seepage from the . The City has completed a project to restore the two traditionally flooded weirs to normal operating condition by pumping the water back into the reservoir. The seepage at the trapezoidal weir is now measured by a flow meter connected to the pump. The seepage readings have now been resumed and subsequent submittals will include the seepage data. The 10-year seepage plot indicates the trapezoidal weir is directly influenced by the reservoirs water elevation. The resumption of the readings in July of 2011 continues to confirm this trend with no abnormal conditions noted . The instrumentation indicates that the dam is performing in a satisfactory manner and the instrumentation at this dam is judged satisfactory. Photo 1. A view of the crest of the dam as seen from the left abutment. DWR 1261 (rev. 10/09) Sheet 3 of 5 INSPECTION (Jf DAM AND RESERVOIR IN CERT Name of Dam El Capitan .:D STATUS Dam No. _8_-7 _ _ _ _ _ _ _ _ __ Date of Inspection 01 /18/2013 ---------- Photo 2. The red arrow points to the approximate location of the Old Depression area located on the downstream slope of the dam. Photo 3. A close up view of the Old Depression. Note the rocks painted with their respective numbers for survey recording . DWR 1261 (rev. 10/09) Sheet 4 of 5 INSPECTION OF DAM AND RESERVOIR IN CERl\ Name of Dam El Capitan 2D STATUS Dam No. --=8_-7 _ _ _ _ _ _ _ _ __ Date of lnspection_0_1_/1_8_/2_0_1_3_ _ _ _ __ Photo 4. A sinkhole was observed at the downstream toe and is reportedly a result of pumped water from the recent project to restore the two flooded seepage weirs. Photo 5. The woody vegetation that is growing in the spillway's invert panel joints near the exit needs to be removed. DWR 1261 (rev. 10/09) Sheet 5 of 5