North County Transit District (NCTD) and the San Diego Association of Governments (SANDAG) are recommending a series of expedited actions to stabilize sections of track on the Del Mar Bluffs, which have been subjected to reduced speeds and emergency repairs due to drainage challenges.
The tracks on NCTD’s right-of-way experienced erosion washouts at two locations on the Del Mar Bluffs on Nov. 28 and Nov. 29. A temporary fix was completed on Nov. 30 at the southernmost erosion point, while the second location requires additional engineering analysis. Reinforced concrete piles had previously been installed at the location of the second washout to prevent the track bed from sliding. NCTD and SANDAG said a fix to the second location will be completed by Jan. 11-12, 2020, when the section of track will be shut down for previously scheduled work. NCTD says it will have an inspector on site, around the clock to monitor the track on the Del Mar Bluffs until repairs are complete to ensure safety for passengers and train crews.
“This event highlights the fragile nature and lack of resiliency of the Del Mar Bluffs. It is critical that we advance projects to stabilize the Bluffs for the next 20 to 30 years so that the region can determine and implement a permanent solution,” said NCTD Executive Director Matthew Tucker. “Over the last few years, we have all seen the impacts of sea level rise and we should expect that we will continue to see more weather-related events like this most recent rainstorm moving forward.”
NCTD’s consultants, Jacobs Engineering and Leighton Consulting, Inc., determined in separate field inspection reports that insufficient drainage contributed to the washouts and recommended a focus on maintaining the drainage systems be a top focus.
The Jacobs report notes several immediate contributions to the washouts including the following:
- Excessive stormwater run-on from the city of Del Mar’s residential streets and adjacent properties.
- Existing drainage facilities (earthen swale drainage ditches) to include culvert clean outs, stormwater overflow not channeled correctly built up and overflowed the main track at MP 244.25 (just south of 13th Street) causing erosion on the west side of the Cast-In-Drilled-Hole (CIDH) piles.
- Debris was observed on the ends of the ties and evidence of the drainage overflowing the track adjacent to the CIDH piles.
- Drainage channels were completely silted in at this location as well. Excessive silt was a result of overwhelmed inlets from heavy rain and excessive city of Del Mar run-on stormwater that mobilized right-of-way sediment and sediment migrated further, blocking inlets and filling in earthen trackside ditches.
“Drainage is of the first and most important in track maintenance safety,” Jacobs wrote in its report conclusion. “Proper monitoring of all drainage facilities on the railroad should always be at the top of the track maintenance list.”
“Continuous maintenance of all drainage facilities along Del Mar Bluffs should be considered one of the highest priorities especially since we have the ability to control maintenance within the railroad right of way,” Leighton Consulting wrote in its report.
NCTD said that in addition to the enhanced inspection protocols, it plans to procure supplemental resources to assist in managing the challenges on the Del Mar Bluffs.
Tucker and SANDAG Executive Director Hasan Ikhrata have requested actions they would like to see taken to support advancing projects that will secure track on the Del Mar Bluffs including:
- Providing immediate funding of $5 million to support emergency repairs.
- Fully funding the Del Mar Bluffs Stabilization 5 Project in Fiscal Year 21, which is estimated to cost $24 to $30 million to evaluate the seismic and static stabilization needs, drainage facilities, the addition of pilings and tie backs, replacement of old drainage structures and localized lagging as bluff retreat accelerates.
- Fully funding the Del Mar Bluff Stabilization 6 Project over FY22 and FY23, estimated to cost between $70 and $80 million, and will support the design and construction of additional stabilization measures, including bluff toe protection, bluff face stabilization and lagging installation, while taking into consideration local coastal access.
- Ensure a streamlined regulatory approval process that recognizes that Projects 5 and 6 will secure the bluffs for the next 20 to 30 years and will allow federal, state and local stakeholders to determine and implement the long-term plan for the region. Tucker and Ikhrata warn that if the environmental process is not streamlined, then the project implementation timeline could increase by three to four years.
Of the projects mentioned above, $6 million has been provided from the Department of Natural Resources for the Del Mar Bluffs Stabilization 5 Project. NCTD and SANDAG development of the projects can proceed assuming California commits to providing $100 million “to complete the necessary repairs for this critical transportation link.”