Rheem Boulevard Sinkhole Emergency Project
Background. March 13, 2016
The winter rains of 2015-2016, with the widely publicized El Niño related conditions have saturated local soils and eroded aging infrastructure within the Town of Moraga. In the early afternoon of March 13, 2016, an unexpected 15’ wide by 20’ long by 15’ deep sinkhole developed at the Rheem Boulevard and Center Street intersection. Personnel from Moraga-Orinda Fire District, PG&E, and Town Staff were contacted to assist in evaluating the sinkhole location. Subsequently, the Town Emergency Field Operations Center was activated due to concerns of various utilities including a 4” gas line being exposed beneath the affected area of the sinkhole, and Contra Costa County Emergency Services was notified of the evolving situation.
As rains continued throughout the afternoon, a traffic signal pole, a PG&E electrical switch vault, and a portion of sidewalk fell into the expanding sinkhole. The collapse ruptured a 4” gas line that required immediate evacuation of two adjacent shopping centers, including a theater, and a shelter-in-place order was issued to surrounding residential areas. The gas line rupture affected 2,600 PG&E customers, requiring the mobilization of 200 PG&E workers to facilitate the shut off and restoration of gas service to each of these customers. Over sixty businesses were immediately closed and continue to be adversely affected by traffic detours through the two adjacent commercial centers. After the gas line was shut off, the PG&E customer service representatives revisited the affected properties to manually turn the gas back on, relight pilot lights, and inspect appliances.
The winterization work on the 96-inch storm drain pipe under the sinkhole is still performing well. Periodic inspections of the pipe are made when conditions allow. The surface work to protect the sinkhole and control surface water flows into the sinkhole are working well, the biggest challenge has been keeping the drainage grates clear of leaves. Agreements with affected utilities have been secured and work to obtain the required approvals to submit a final package to Caltrans for funding approval continue. Once all the approvals have been secured the Town will advertise the project for bids to hire a contractor for permanent repairs. The work is still expected to be completed by the end of this summer.
Pacific Gas and Electric has completed their gas line work at the intersection of Rheem Boulevard and Center Street. The work involved replacing a portion of the 4 inch steel gas line damaged by the sinkhole. PG&E will have their trenches repaved in the coming weeks as weather allows. The sinkhole has been winterized with a liner and several temporary drainage features to control surface water entering the area. The Town continues to work with Caltrans towards a permanent repair during the summer of 2017.
The inside of the existing 96-inch diameter metal pipe has been sealed and all voids filled with concrete. In the next few weeks, the contractor will install above ground erosion protection and storm water management facilities, which includes drain rock, plastic sheeting, sandbags, berm, temporary inlets and small pipe. Rheem Boulevard, with the existing intersection stop-controlled configuration, will remain open throughout the winter. Construction for permanent repairs is anticipated to begin mid-April, after the end of the rainy season.
Moraga, California – On July 1, 2016, the Town of Moraga was notified by Caltrans representatives that the Town’s application for funding assistance from the Federal Highway Administration (FHWA) for the initial emergency response and permanent repair of the sinkhole on Rheem Boulevard at Center Street was approved. The Town’s acceptance of FHWA financial assistance requires the Town to follow strict FHWA guidelines and approvals for each step of the process. The Town has been diligently working with Caltrans Office of Local Assistance, who administers the federal funds. Since July 1, approvals for the preliminary engineering and environmental phases of the project have been achieved.
Unfortunately, the Town’s original plan to award a contract for construction of the permanent repair work prior to the rainy season, which typically begins in mid-October, is no longer viable. The Town will move forward with our contingency “winterization” plan in the next few weeks to secure the work site, install storm water management and erosion protection measures, and patch any voids in the 96-inch culvert to allow Laguna Creek to pass through without creating further damage. Winterizing the site will allow for vehicles to continue safely traversing Rheem Boulevard and Center Street in its current lane configuration with one lane open in each direction. Without this work, the roadway would need to be closed during the rainy season. The Town’s contractor and inspectors will maintain and monitor the site for any changes or damage throughout the winter season while the storm water and erosion protection measures are in place.
The Town expects to receive authorization from Caltrans to bid the permanent repair work so that construction can begin next year after the rainy season, which traditionally ends in mid-April. The community will be notified prior to the beginning of any road closure or permanent repair work. Staff continues to work diligently to get Rheem Boulevard and the community back to normal. We anticipate lots of work ahead and appreciate your support. This update and all past updates can be found on the Town website’s dedicated Sinkhole webpage. Thank you for your continued patience.
When Contra Costa County was included in Governor Brown’s Proclamation of a State of Emergency on April 19, the Town became eligible to apply for FHWA financial assistance. Since the Rheem Boulevard sinkhole was on a “minor arterial” street, the state required the Town to seek federal assistance through FHWA before the Town could apply for any state assistance. Had the Town’s appeal to FHWA been unsuccessful, the Town would have then applied to the state for assistance.
If all requested funding is deemed eligible, the Town will be reimbursed 100% for approximately $545,700 for “Emergency Opening (EO)” work. This covers the work the Town has done to date including the emergency response, road closure, traffic control, erosion protection, fencing, traffic signal, and other work associated with the gas line rupture, engineering, and construction management.
For work required to make repairs for “Permanent Restoration (PR)” of the sinkhole, the Town is eligible to receive 88.53% of eligible costs from the FHWA. The current estimate for the total cost associated with PR work is $2,948,125, which would split the costs between FHWA at $2,609,975 and the Town’s portion at $338,150 if all estimated costs are deemed eligible. The Town’s acceptance of FHWA financial assistance requires the Town to follow FHWA guidelines and approvals for each step of the process. The Town’s original plan to award a contract for construction will now be delayed to meet the FHWA guidelines, which will shorten the available construction time prior to the rainy season that typically begins in mid-October. If the PR work cannot be completed during this construction season, the Town will implement plans to secure the work site and divert the storm water over the course of the winter until the project can resume.
The Town will keep the public and its business community updated through About Town, Nextdoor, and Nixle.
The Town staff is extremely thankful for the support from Senator Glazer and Assemblywoman Baker and their staffs throughout this process and for all of the community support and patience shown thus far. The Town is working diligently to get Rheem Boulevard and the community back to normal, anticipating lots of work ahead. Thank you for your continued patience.
Rheem Boulevard is now open with one lane in each direction. Based on results from tests conducted along the alignment of the existing 96-inch diameter corrugated metal pipe (CMP), the Town’s consultants have determined that the Rheem Boulevard and Center Street intersection is safe for vehicles. The two westbound (downhill) lanes of Rheem Boulevard now require the right lane to turn right only and the left lane to go straight or turn left. Eastbound traffic (from Orinda) is defined by delineators creating one lane and the speed limit has been reduced to 25 MPH. The intersection of Rheem Boulevard at Center Street is now controlled by stop signs in all directions. Previous detours through the adjacent shopping centers are no longer required. Please drive slowly and be attentive to other vehicles and pedestrians at all times. This change will continue until repair work begins on the sinkhole. Please remember all businesses are open and need your support. Visit Rheem Boulevard Re-opened to see the graphic of the new traffic pattern. The Town thanks everyone for their patience and understanding throughout this process.
Preparing for the repair is progressing on schedule with the 65% design submittal and contractor prequalification documents complete. After the bid documents are complete and bid proposals are received, the Public Works Director/Town Engineer will make a recommendation to the Town Council on June 8 to award a construction contract and begin construction of the repair project. Construction is anticipated to take 2 to 3 months and be completed before the beginning of the next rainy season, October 15. For those interested in the April 27 Town Council presentation on the cause and repair alternatives, the video link can be viewed from the Sinkhole webpage.
The Town has engaged the Federal Highway Administration (FHWA) through the California Department of Transportation (Caltrans), has submitted initial required documents to start the disaster process, and must now wait for the next steps necessary for possible financial assistance to fund the estimated $3.3 in million repair costs. This update and all past updates can be found on the Town website’s dedicated Sinkhole webpage. Thank you for your continued patience.
The sinkhole collapse was preceded by 8 days of rain, where water from a variety of sources found its way to the sinkhole location, eroding the soil around the 96-inch CMP and washing it into the offsets in the pipe joints, creating voids beneath the sidewalk, which eventually gave way, creating the sinkhole in its condition today.
The Town’s consultants immediately began working on the design and will finalize the plans and specifications in the coming weeks. On June 8, the Public Works Director/Town Engineer will make a recommendation to the Town Council to award a construction contract and begin construction of the repair project. Construction is anticipated to take 2 to 3 months and be completed before the beginning of the next rainy season, October 15.
The Town is still working with state and federal agencies to address possible financial assistance for the needed repairs. This update and all past updates can be found on the Town website’s dedicated Sinkhole webpage. Thank you for your continued patience.
GOVERNOR DECLARES A STATE OF EMERGENCY
April 19, 2016, the Honorable Governor Edmund G. Brown Jr. issued a proclamation declaring storm-related damage to roads and highways as a State of Emergency. The proclamation names Contra Costa County and several other counties which will cover Moraga’s sinkhole and assist the Town of Moraga with qualifying for financial assistance to help fund necessary repairs.
On behalf of my fellow Councilmembers, Town staff, and our entire community, I want to thank Governor Brown for the quick response to our emergency situation and for his willingness to assist us in our time of need. The emergence of the sinkhole on March 13, 2016, and resulting gas line rupture, forced an emergency evacuation of all area businesses, caused the loss of gas service to 2,600 PG&E customers, and continues to harm our local business community. The initial response and ongoing costs associated with the sinkhole have taxed our resources and the current repair estimate of $3.5 million would be devastating to the Town’s financial stability. The Governor’s Declaration has provided hope and renewed optimism for making it through this emergency.
I also extend our sincerest thanks and appreciation to both Senator Steve Glazer and Assemblywoman Catharine Baker for reaching out to our staff with offers of assistance soon after the sinkhole occurred. It is most gratifying to see elected officials, and their incredibly competent staffs, respond quickly and collaboratively to assist and guide in emergency situations. The Town of Moraga and the State of California are fortunate to have both in our service.
Mayor, Town of Moraga
The Town’s consultants are continuing their investigation to complete a forensics study to determine the cause of the sinkhole and mode of failure. Methods of investigation involve reviewing previous data, site reconnaissance, subsurface exploration, and laboratory testing. Simultaneously, the repair alternatives and cost-benefit analysis is continuing in its development. In the upcoming week, two test pits will be dug to determine the exact alignment of the damaged 96-inch storm drain corrugated metal pipe that is buried approximately 23 feet deep in the ground. Additionally, a core sample of soil will be extracted to characterize the fill material above and below the pipe. Repair options such as open cut, trenchless, and daylighting are being explored and each will be evaluated based on costs, schedule, risk, and other factors. Town staff will present the results of the forensics study and a repair recommendation to Town Council tentatively on April 27, 2016. While these studies are being conducted, the Town continues to coordinate with PG&E and their plans to provide reliable gas and electricity to businesses affected by the sinkhole. Although affected businesses are currently being provided electrical services through a temporary tie-in, PG&E is working on a plan to address anticipated increased electrical demands of the summer that the temporary tie-in cannot support. In regards to gas services, PG&E will begin work as early as Friday, weather dependent, to switch out the temporary mobile Compressed Natural Gas units by installing a bypass gas line to affected businesses. It is anticipated that work to complete the bypass line will not affect the current detour route through the Rheem Shopping Center. On April 4, 2016, Senator Glazer and Assemblywoman Baker sent a letter to Governor Brown and California Office of Emergency Services (Cal OES) Director Ghilarducci supporting the Town’s State request for financial assistance. Cal OES responded that they will be sending a representative to visit and investigate the sinkhole. The Town hopes to learn more about what Cal OES programs may be available to assist businesses negatively affected by the sinkhole. This update and all past updates can be found on the Town website’s dedicated Sinkhole webpage. Thank you for your continued patience.
On March 24, 2016, conditions finally permitted safe inspection of the sinkhole and revealed that the scope of the repair was far beyond what was initially anticipated, as well as the Town’s ability to pay for it. Town-owned infrastructure associated with the sinkhole that has been identified as damaged to date includes, but is not limited to, the following: approximately 125 linear feet of the 96” storm drain corrugated metal pipe, 20 linear feet of the 27” storm drain reinforced concrete pipe and a storm drain inlet structure; a traffic signal pole with mounted streetlight; concrete sidewalk, curb and gutter, and pedestrian curb ramp; and roadway pavement, striping, and pavement markings. The revised preliminary estimate to repair the damage is $3.5 million, which also includes costs associated with the work required to backfill the cavity and restore the roadway. During the investigation, the Town’s consultants reviewed the condition of the interior of the 96” storm drain corrugated metal pipe and have deemed the Rheem Boulevard and Center Street intersection as unsafe for vehicular traffic. Vehicles shall continue using the alternative routes provided to detour around the road closure. The Town asks all motorists to be alert, cautious, and drive slowly through the detour areas without disturbing existing traffic control devices. Please remember that the shopping centers are open for business and drivers should look for, and yield to, pedestrians. On March 29, 2016, the Town sent a letter to Governor Brown and Director Ghilarducci of California Office of Emergency Services to request financial disaster assistance. In the meantime, the project team is continuing its investigation to complete a forensics study and determine the mode of failure and cause of the sinkhole. On a parallel track, a repair alternatives and cost-benefit analysis is being developed and is tentatively scheduled to be presented to Town Council on April 27, 2016. This update and all past updates can be found on the Town website’s dedicated Sinkhole webpage. Thank you for your continued patience.
Since the last update on Friday, March 18, the Town's contractor focused on securing the site for the expected rain this past weekend. Since the weather cleared up, the investigation of the cause resumed. This week the Town's surveyor completed a survey of the entire site including locating property lines, utilities, and storm drains. The Town continues to monitor the traffic control and detour routes and will make minor adjustments as needed to help with the traffic flow. The Town will provide weekly updates unless something occurs that will create an immediate impact on the community.
Since the last update the sinkhole has been opened up for safety reasons to allow staff, consultants and PG&E into the hole for inspections. This involved cutting the side slopes of the sinkhole back to a safe angle to prevent the walls from caving in on workers. To provide safe access the traffic signal pole and concrete foundation were removed along with the PG&E electric switch vault and other debris.
The Town has confirmed there is a “spaghetti bowl” of utilities in the hole, including, but not limited to: a 96” storm drain corrugated metal pipe; a 27” storm drain reinforced concrete pipe; a bank of Comcast conduits filled with fiber optic lines; traffic signal electric lines; AT&T fiber lines; PG&E electric lines; a 4” PG&E steel natural gas line, and two unclaimed utility pipes. Adjacent to the hole are a 15” Central San sewer vitrified clay pipe line and an EBMUD 12” water line. The Town’s contractor has made every effort to protect these utilities in place to ensure service is maintained, but the presence of the utilities moving forward will complicate the repair process.
Work crews are also making preparations for the rain that is forecasted for the upcoming weekend. They are working to divert and channel runoff away from the sinkhole to prevent additional damage. Depending upon the amount of rain and runoff that the Town receives, repair work may be delayed. Engineers are still in the investigation phase with an unknown start date for repair work to begin.
The site is now secured with temporary fencing and the public is asked to avoid the area. The traffic plan has been adjusted to improve traffic flow with additional signage placed in the two adjacent shopping centers. It continues to be monitored and seems to be working well. The Town continues to ask all motorists to be alert, cautious, and drive slowly through the detour areas. Please remember that the shopping centers are open for business and drivers should look for, and yield to, pedestrians. Thank you for your patience.
The Town has assembled an experienced team of experts to work with Public Works staff to address and repair the sinkhole. Currently, the Town’s contractor is stabilizing the Rheem Boulevard sinkhole for safety. This needs to be done before the PG&E electric box in the sinkhole can be de-powered and rendered safe for removal. This involves cutting the side slopes of the sinkhole back to a safe angle to prevent the walls from caving in on workers. Once the electrical hazard is cleared, the process to identify the actual cause of the sinkhole can begin.
The ruptured 4” gas line in the sinkhole was capped after the leak was stopped early Monday morning. For the 37 businesses in the area of the sinkhole that cannot have normal service connected, PG&E is providing with a portable gas delivery system. PG&E plans to install a new gas line that will bypass the current broken line in the sinkhole. This project will not affect the sinkhole repair work.
The traffic signal was removed from the hole this morning and will be salvaged for re-use. The existing signal at Rheem Boulevard and Moraga Road has been repowered with a temporary generator and is now functioning, which will help the traffic flow through the intersection. Access to and from Rheem Boulevard is being provided via alternate routes through the two adjacent shopping centers. Please drive safely and slowly through this area. The business community has been very accommodating and the Town appreciates their assistance.
At a special Town Council meeting on march 16, 2016, the Council ratified the proclamation declaring a State of Local Emergency that was issued on Monday due to the sinkhole and natural gas pipe rupture. Ratification of the proclamation will allow the Town to expedite the procurement of repair services and supplies to promptly repair the sinkhole.
The Town thanks you for your patience. More information will be posted as it becomes available.
PG&E is completing their immediate gas line work at the site of the sinkhole this morning. The Town’s engineers and construction crew have begun their investigation into the cause of the sinkhole today and are developing a plan to address that cause and repair the damage that was done. As of today, we do not have an estimate for the full re-opening of Rheem Boulevard; however, the Town is continuing to develop and refine a traffic plan to ease the impact on Moraga residents and businesses. PG&E is in the process of restoring gas service to residents affected by the outage. PG&E has implemented an interim plan to restore gas and electric service to those businesses that have temporary power and gas service.
The Town of Moraga and PG&E are continuing to work to repair the damage caused by recent sinkhole at Rheem Blvd. and Center Street. Beginning at around 1:00 PM today PG&E will be venting the small amounts of natural gas as the broken line is repressurized. There are approximately 25 vent sites in the Rheem Valley area that will be staffed with PG&E personnel. Residents may smell the odor of natural gas between 1:00 and 3:00 PM today. The natural gas odor will quickly dissipate and will not be harmful. However, If you have concerns about strong odors of natural gas or electrical issues caused by the storm damage or if you need additional information please contact PG&E at 800-743-5003 or visit the PG&E outage website.
Town Actions & Information
- Rheem Boulevard Reopened - Map. Note: This is a preview. See map for implementation date.
- Video clip: Presentation to Town Council on Cause of Sinkhole & Repair Alternatives
- Governor's Proclamation of a State of Emergency
- 04/18/2016 Detour Map
- 03/16/2016 Town Council Special Meeting Agenda
- Resolution 24-2016 Ratifying Declaration of Local Emergency
- 03/14/2016 Declaration of Emergency
- 03/30/2016 Letter to the Governor Brown
- How Does the Emergency Relief Program Work?