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Home My WebLink About2020-10-29; Yarrow Drive Sinkhole and Emergency Sewer Repair Update; Gomez, PazTo the members of the: 1~f-1Tf COUNCIL DatJ~ CA _y_ CC _L CM 'l1 ACM ✓ DCM {3)Jl_ -- Oct. 29, 2020 To: From: 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 arks 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. Background 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 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 prope~ty 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. VB 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 hot yet aware of how much the regulatory fines or claims 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, 2020 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 To the members of the: CITY COUNCIL Date "tf1 /ia cA ✓cc ✓ cM..:::::,AcM ✓ocM {3) ✓ April 17, 2020 ATTACHMENT A Council Memorandum To: Honorable Mayor Hall and Members of the City Council From: Paz Gomez, Deputy City Manager, Public Works Via: Geoff Patnoe, Assistant City Manager {cityof . Carlsbad Memo ID# 2020068 Re: Yarrow Drive Sinkhole and Emergency ewer Main Break on April 12, 2020 This memorandum provides information on the Yarrow Drive sinkhole and emergency sewer main break that occurred on Sunday, April 12, 2020. Background Shortly after 12:00 pm on April 12, 2020, city staff from Police, Fire and Public Works Utilities Departments responded to a report of a sinkhole in a private pr9perty parking lot at 6300 Yarrow Drive. A van, either on or near the manhole, had fallen into a sinkhole which resulted in a palm tree falling on top of the van. It was determined that the cause may have been a collapsed sewer manhole along the Buena Outfall pipeline. This pipeline is owned by the Buena Sanitation District (Buena), located within its easement and shared with the City of Carlsbad for use through an agreement. Buena and City of Vista Public Works Department staffalso subsequently responded. · The sewage continued to flow through the hole and into the Buena Outfall pipeline. This pipeline conveys wastewater flow from Buena and the City of Carlsbad to the Encina Water Pollution Control Facility for treatment and disposal. Shortly before this occurrence, the McClellan-Palomar Airport weather station reported approximately 6.2 inches of rain over a ' ' ' 6-day period the week of April 6, 2020, including 2.88 inches received within a 24-hour period from midnight on April 9, 2020 t o midnight on April 10, 2020. Discussion Sewage flow continued down the pipeline and there was no sanitary sewer overflow (SSO) observed . Before the San Diego County Public Heal t h Order t o shelter in place related to the COVID-19 public health emergency, t he flow in the pipeline averaged 1.8 million gallons per day of sewage. Due to the rain events and the County Public Health Order to shelter in place1 the flow increased't o an average of approximately 3 million gallons per day of sewage. The pipeline is approximately 30 feet deep at t his locat ion, and P,umping was beyond the capability of both agencies' equipment. Outside services were immediately required to minimize the possibility of an SSO. An SSO would discharge untreated sewage int o Encinas Creek which outlets to the Pacific Ocean. Public Works Utilities Department 5950 El Camino Real / Carlsbad, CA 92008 / 760-438-2722 t 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 Main Extension project which is currently under construction 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 f;:icility. 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 lot 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 April 17, 2020 Page 3 operations budget 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: Celia 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 6200 · 1 l .•. ~ , I . . ______-,_----;;:-, ·--~ ~-:::.--r~, -\ ' 2271 1 ATTACHMENT B . . . . ' . -.. 1 "I ATTACHMENT C RESOLUTION NO. 2020-28 A RESOLUTION OF THE BOARD OF DIRECTORS OF THE BUENA SANITATION DISTRICT, APPROVING SETTLEMENT AGREEMENT AND RELEASE WITH RIF Ill-YARROW DRIVE LLC The Board of Directors of the Buena Sanitation District does resolve as follows: 1. Findings. The Board of Directors hereby finds and declares the following: A. On Sunday April 12, 2020, a sinkhole occurred at Buena Sanitation District's sewer manhole VB-4044.A0 on private property located at 6300 Yarrow Drive in Carlsbad. B. · The emergency repairs caused damage to existing private improvements on 6300 Yarrow Drive that are beyond the District's sewer easements. C. Permitting the owner to repair its private improvements will allow them to select the contractors of their choice, reducing the City's liability for claims if the repair work is not completed to owner's standards. Staff recommends a one-time payment of $330,097 to the owner of 6300 Yarrow Drive pursuant to a Settlement Agreement and Release. 2. Action. A. The Settlement Agreement And. Release With RIF Ill-Yarrow Drive LLC is approved, and Chairperson is authorized to execute the Agreement upon approval by the owner. 3. Adoption. PASSED AND ADOPTED at a meeting of the Board of Directors of the Buena Sanitation District held on October 13, 2020, by the following vote: AYES: NOES: Chairperson Ritter, Rigby, Franklin, Green, Contreras None ABSTAIN: None APPROVED AS TO FORM: 0AROLD PIEB APPROVED Darold Pieper 20201005082537 00091421 2 ATTEST: KATHY VALDEZ, CLERK OF THE BOARD By ~lt\~