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HomeMy WebLinkAbout2021-04-21; Yarrow Drive Sinkhole and Emergency Sewer Main Break Update (District 2); Gomez, PazTo the members of the: ., ~I~ COUNCIL Date ~CA ✓cc / CM ✓ ACM ...IL. DCM {3) v April 22, 2021 Council Memorandum To: From: Via: Honorable Mayor Hall and Members of the City Council Paz Gomez, Deputy City Manager, Publi~ks Geoff Patnoe, Assistant City Manager ~ {city of Carlsbad Memo ID #2021083 Re: Yarrow Drive Sinkhole and Emergency Sewer Main Break Update (District 2} This memorandum provides an update to a previous memorandum dated Oct. 29, 2020, (Attachment A) regarding the Yarrow Drive sinkhole and emergency sewer main break that occurred on April 12, 2020. Background On April 12, 2020, city staff from the Police, Fire and Utilities Departments responded to a reported sinkhole in a private parking lot at 6300 Yarrow Drive. Rainfall around this time was well above average. The City of Carlsbad received approximately 3.45 inches of rain on April 10, 2020, and six inches over a six-day period beginning on April 8, 2020. A sinkhole formed over a sewer pipeline owned by the Buena Sanitation District (Buena), but located on private property in the City of Carlsbad. The pipeline conveys wastewater to the Encina Water Pollution Control Facility for treatment. Approximately 81.16% of the pipe's flow originates in the City of Vista and approximately 18.84% in the City of Carlsbad. A cost sharing and use agreement governs the two cities' use of the shared pipeline. As the owner, Buena took the lead on an emergency repair of the pipeline. City wastewater staff assisted Buena's staff and contractors, as needed, to complete the repairs and prevent any sewage spills. Previous memorandums discussed the construction repair tasks that were anticipated at the time of the initial emergency and provided an initial and updated cost estimate. The City of Carlsbad's share was estimated at $286,700 at the time of the Oct. 29, 2020, Council Memorandum. Buena was unsuccessful in obtaining Federal Emergency Management Agency (FEMA) emergency funding. Therefore, consistent with the cost sharing and use agreement, the City of Carlsbad wastewater budget will be responsible for a percentage of the total cost based upon the flow. Public Works Branch Utilities Department 5950 El Camino Real I Carlsbad, CA 92008 I 760-438-2722 t Council Memo -Yarrow Drive Sinkhole and Emergency Sewer Main Break Update (District 2) April 22, 2021 Page 2 Discussion All work has been completed and Buena recently provided the total cost for emergency repairs as shown in the below table: Contractor Description Cost Colich & Sons Emergency response and repair to manhole $499,350 VB4011.A0 TC Construction Repairs to manholes VB 4043.A0, VB 4044, $525,000 VB 4045, and VB 2046.A0 Charles King Co. Bypass pumps $99,990 HDR Condition assessment of manholes $31,414 Michael Baker, Int. Construction management $16,532 Vinje Middleton Soil technician $19,594 Koloa Pacific Construction Inc. Soil removal (unsuitable for backfill) $109,682 RIF Ill-Yarrow drive LLC Private property restoration $330,097 Total $1,631,659 City of Carlsbad's Share $307,405 Staff is working with Buena to better understand certain details of the invoices and costs; however, the city will likely contribute approximately $307,405 in emergency repair costs (approximately 18.84% of the total). The Utilities Department will place this item on a future City Council agenda for City Council approval of final agreed-upon costs. Next Steps In the next two months, staff will present this item for City Council approval of payment for the city's cost of the emergency repair. Attachment: A. Council Memorandum dated Oct. 29, 2020 cc: Scott Chadwick, City Manager Celia Brewer, City Attorney Laura Rocha, Deputy City Manager, Administrative Services Neil Gallucci, Police Chief Michael Calderwood, Fire Chief Robby Contreras, Assistant City Attorney Vicki Quiram, Utilities Director Ryan Green, Finance Director Kristina Ray, Community & Engagement Director To the members of the: ir,PT/ COUNCIL Dati~ CA .:L_ CC _J/. CM.JLACM~DCM (3)Jl Oct. 29, 2020 To: From: ATTACHMENT A Council Memorandum Via: Geoff Patnoe, Assistant City Manager , {cityof Carlsbad Memo ID #2020241 Re: Honorable Mayor Hall and Members of the City Council Paz Gomez, Deputy City Manager, Pub~ic orks Yarrow Drive Sinkhole and Emergency ewer Repair Update This memorandum provides an update to Council Memo ID# 2020068 dated April 17, 2020, (Attachment A) regarding the Yarrow Drive sinkhole and emergency sewer main break that occurred on April 12, 2020. Bac~ground On April 12, 2020, staff from the Police, Fire and Public Works Utilities Departments responded to a reported sinkhole in a private parking lot at 6300 Yarrow Drive (Attachment B). Rainfall around this time was well above average, as the City of Carlsbad received approximately 3.45 inches of rain on April 10, 2020, and 6 inches over a six-day period beginning on April 8, 2020. The sinkhole formed over a sewer pipeline located on private property in the City of Carlsbad, which is owned by the Buena Sanitation District (Buena). The pipeline conveys wastewater to the Encina Water Pollution Control Facility for treatment. Approximately 81% of the pipe's flow originates in the City of Vista and approximately 19% in the City of Carlsbad. A cost-sharing and use agreement governs the two cities' use of the shared pipeline. As the owner, Buena took the lead on the emergency repair of the pipeline. City of Carlsbad wastewater staff assisted Buena's staff and contractors as needed to complete the repairs and prevent any sewage spills. Discussion The memo on April 17, 2020, discussed the construction repair tasks that were known to be needed at that time. However, the depth of the pipeline and manhole was found to be approximately 30 feet, and additional problems with Buena's pipeline and manholes arose during construction, causing the emergency repair to be more complicated than expected. Additional work that was initially unanticipated included gradually sloping the excavation to reach the 30-foot bottom of the manholes, continuing to bypass the sewage, constructing a new manhole base, installing manhole risers to the grade in the.deep excavation, backfilling the excavation, replacing one additional manhole, rehabilitating another manhole and Public Works Branch Utilities Department 5950 El Camino Real I Carlsbad, CA 92008 I 760-438-2722 t , I i ii I I I' I Council Memo -Yarrow Drive Sinkhole and Emergency Sewer Repair Update Oct. 29, 2020 Page 2 replacing sections of pipe. Furthermore, the sinkhole damaged the loading dock, parking lot, irrigation and landscaping on the private property. Buena negotiated a settlement agreement (agreement) of $330,097 to compensate the property owner for such damages and allowed the owner to have direct control of the repairs to the private property. The Buena Board of Directors' Resolution approving this agreement is attached as reference (Attachment C). Buena initially estimated costs to complete the emergency repair at $575,000. With the additional work as described above, the unaudited cost estimate for the repair totais $1,521,587 and is summarized in the following table: Contractor Contract Value Description Colich & Sons, LP $500,000 Replace MH No. VB 4044.A0 and sewer bypass TC Construction $525,000 Replace MH No. va 4045 and rehabilitate VB 4044 Charles King $99,990 Sewer bypass VB 4045 and VB 4044 HDR $30,000 Condition assessment of manholes MBI $16,500 Construction management Vinje Middleton $20,000 Soil technician Private Property $330;097 Damage paid to owner -see Attachment C, Buena Board of Directors Resolution No. 2020-28 Total $1,521,587 City of Carlsbad's Share $286,700 Approximate estimate Based on usage flow, the City of Carlsbad's share of this cost of $1,521,587 is 18.84%, or approximately $286,700, in accordance with Agreement 18200-R, Section 12, Major Repair and Reconstruction and Replacement. Though the estimates are unaudited, we do not expect them to change significantly from this point forward. To help fund this repair, Buena requested Federal Emergency Management Agency (FEMA) emergency funding but was not successful. Therefore, the City of Carlsbad wastewater budget will be responsible for the city's share of the total cost. When the final cost is determined, staff will return to City Council to request additional appropriation to cover these costs. As previously discussed, there was significant rainfall surrounding this event. During the event, the same Buena pipeline exceeded capacity downstream on Palomar Oaks Way. The pipeline surcharged, spilled sewage and backed up into two nearby private buildings in the City of Carlsbad. Staff from the. Cities of Vista and Carlsbad responded with vactor trucks to address the issue. City of Carlsbad staff reported the spill to appropriate regulatory agencies and posted signs the next day. Staff is not yet aware of how much the regulatory fines or cl.aims from the affected buildings will be or which agency will be deemed responsible for Council Memo -Yarrow Drive Sinkhole and Emergency Sewer Repair Update Oct. 29, 2020 Page 3 the sanitary sewer overflow. These costs are not included in the·above estimates. Next Steps Staff will update City Council when the total costs of the emergency repair and sanitary sewer overflow are finalized and request additional appropriation to cover these costs. Attachments: A. Council Memo ID# 2020068 dated April 17, 2()20 B. Location Map C. Board of Directors of Buena Sanitation District Resolution No. 2020-28 cc: Scott Chadwick, City Manager Celia Brewer, City Attorney Laura Rocha, Deputy City Manager, Administrative Services Neil Gallucci, Police Chief Michael Calderwood, Fire Chief Cindie McMahon, Assistant City Attorney Robby Contreras, Assistant City Attorney Vicki Quiram, Utilities Director Kevin Branca, Finance Director Kristina Ray, Community & Engagement Director Ryan Green, Assistant Finance Director Honorable Mayor Hall and Members of the City Council April 17, 2020 - Page 2 Buena took the lead on the project; however, City of Carlsbad Utilities staff has continuously worked with Buena staff and the contractor to prevent the spilling of sewage. Carlsbad Police and Fire Departments were on-site whenever needed. Buena staff contacted Colich & Sons, LP (Colich), a company they already had under contract to build the Buena Outfall Force l'y'lain Extension project which is currently under const_ruction along Palomar Airport Road, to repair the manhole and backfill the sinkhole. Colich's construction crew and equipment were already mobilized in the area and were best situated to c;1ssist and minimize the possibility of an SSO. In addition, Buena contacted Michael Baker, Inc. (MBI) to assist with construction management and inspection for Colich's work. The business located at this building, Spectrum Assembly, Inc., provides an essential service. Since April 13, 2020, approximately 150 employees have continued to work at the facility. Staff has continually kept in conta.ct with the property manager and the business owner to keep them updated on status. Since beginning·work on April 12, 2020, Colich has expended approximately $200,000 bypassing the sewage with emergency diesel pumps, excavating and removing the unsuitable soils and exposing the manhole base. The soil was found to be extremely saturated and unstable, and the excavation could not be shored. Colich had to excavate a larger hole in order to safely repair the manhole. Colich's remaining work includes continuing to bypass the sewage, constructing a new manhole base, installing manhole risers to the grade in the deep excavation of over 30 feet,· backfilling the excavation and moving on to restoration of the surface,. irrigation and lights to the, parking tot of the private property owner. Buena has estimated the total cost to complete the emergency repair to the manhole at $575,000. They are executing an emergency contract with Colich in an amount not to exceed $500,000 for services to repair the manhole and backfill the sinkhole. In addition, they are executing an emergency contract with MBI in an amount not to exceed $50,000 for construction management and inspection services. Buena has also issued a task order for $25,000 With Vinje Middleton Engineering, Inc. (Vinje) for professional geotechnical · engineering, materials testing and construction inspection. The adjacent manholes that are being utilized for the bypasses also need repair or replacement, which could cost up to an additional $150,000. Buena will be submitting this project for possible Federal Emergency Management Agency (FEMA) emergency funding. Under the city's agreement with Buena for use of this pipeline and after determination of availability of FEMA emergency funding, the Carlsbad wastewater Honorable Mayor' Hall and Members.of the City Council Aprif ·17, 2020 Page 3 operations bud$et may be responsible for a percentage of the total repairs on both projects based on usage flow which is currently estimated at 15-20%. As noted earlier, there was significant rainfall on April 10, 2020. That day, the same Buena pipeline was over its full capacity in a downstream section on Palomar Oaks Way, which surcharged, spilled sewage and affected two nearby buildings. Staff responded with vactor trucks to address the issue. The spill was reported to appropriate agencies and signs were posted the next day . . Next Steps Utilities crews will continue to assist Buena on-site as needed and will continue to do so until project completion, which is expected to be in approximately two weeks. Staff will return to City Council with cost-sharing information as soon as cost of repairs are finalized. cc: Ce_lia Brewer, "City Attorney Neil Gallucci~ Police Chief Michael Calderwood, Fire Chief Cindie McMahon, Assistant City Attorney Vicki Quiram, Utilities Director Kristina Ray, Community and Engagement Director Ii Ii f ,I 1: 11 11 11 I, ii I!