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Created in 1923 under state law, the Sanitation Districts of Los Angeles County ("Sanitation Districts") are a regional agency that manages the wastewater (sewage) and solid waste (refuse) needs of over 5.6 million people in 78 cities and unincorporated county areas. The Sanitation Districts consist of 24 independent special districts that share one staff under a joint powers agreement. Each district has a Board of Directors, which is comprised of the mayors or council members of the member cities and the Chair of the County Board of Supervisors.
1. What wastewater infrastructure does the Sanitation Districts manage?
The Sanitation Districts operate and maintain over 1,400 miles of sewers and 47 pumping plants that convey more than half the wastewater in Los Angeles County to 11 wastewater treatment plants. Approximately 400 million gallons of wastewater (sewage) are treated every day at these facilities. Ten of these facilities are located inland to support water recycling and are called water reclamation plants (WRPs). The WRPs produce highly treated water that is used for landscape irrigation and groundwater replenishment, among other uses. The Joint Water Pollution Control Plant (JWPCP), located in Carson, is the Sanitation Districts' largest facility with a treatment capacity of 400 million gallons per day (mgd). The JWPCP currently treats about 260 mgd and discharges treated water to the ocean through two tunnels and an outfall system.
2. What is the Joint Outfall System?
The Joint Outfall System (JOS) is a large sewer system that collects wastewater from 73 cities and unincorporated county areas in the Los Angeles basin and directs flow to one of seven wastewater treatment facilities. The JOS, which serves over 5 million people, is designed so that the inland WRPs remove the solids from the wastewater and return the solids to the sewer for centralized treatment at the JWPCP. This design reduces costs to ratepayers. Upstream flows that cannot be accepted at the WRPs (e.g., the WRP is running at capacity) are directed to the JWPCP. The treated water from the JWPCP is conveyed over six miles to Royal Palm Beach via two tunnels and is then discharged approximately 1.5 miles off the coast into the ocean through outfall pipes (perforated pipes on the seafloor). Because all solids and most of the JOS flow must pass through the JWPCP, the JWPCP and its effluent management system (tunnels and outfalls) are critical to the 5 million people served by the JOS.
3. What is the Clearwater Project?
In 2012, the Sanitation Districts Board of Directors approved a project to protect our local waterways by addressing aging infrastructure. Under the Clearwater Project, a new tunnel will be built to convey DOC # 4172934 Updated: 1/10/2018 Page 2 of 8 treated water from the JWPCP in Carson to existing ocean outfalls located at Royal Palms Beach in the Palos Verdes Peninsula. A multi-year master infrastructure (facilities) planning and environmental review effort that began in 2006 identified the need for a new tunnel in order to ensure the reliability of the JOS and provide sufficient system capacity through the year 2050.
4. Why a new tunnel?
During the aforementioned evaluation of the JOS, the following concerns were identified regarding the existing tunnels that convey treated water to the ocean:
(a) Insufficient flow capacity during large storms
During rainstorms, water enters the sewer system, causing higher than normal flows. The capacity of the existing tunnels was almost exceeded twice in the last two decades during major storms, most recently in January 2017.
(b) Risk of structural failure due to age
The existing tunnels, which were built in 1937 and 1958, cannot be taken out of service because they are needed to continuously carry flow.
(c) Risk of collapse due to an earthquake
The existing tunnels are not built to current seismic standards, yet they cross two earthquake faults.
The existing tunnels are an important part of the JOS and their reliability is critical to protecting public health and the environment. Structural failure or inadequate tunnel capacity would result in the diversion of (treated or untreated) wastewater to surrounding waterways or sewage overflows upstream, which could lead to environmental degradation for an extended period of time. The new Clearwater tunnel would prevent such emergencies and protect surrounding waterways by addressing the identified concerns.
5. What alternatives were evaluated during the planning process?
In 2006, the Sanitation Districts began a multi-year planning effort to identify improvements needed to maintain the reliability of the JOS and ensure sufficient capacity to serve a growing population through the year 2050. Many alternatives were evaluated during this master (facilities) planning effort, including reducing flows through conservation to enable access, inspection and repair of the existing tunnels; and treating most of the JOS flows at the upstream water reclamation plants. Each of these alternatives was found to be infeasible and it was concluded that a new tunnel is needed to reliably convey treated water from the JWPCP to the existing ocean outfalls.
Twenty-two different tunnel alignments were evaluated and over 500 public outreach meetings were held to solicit input. Based on this comprehensive effort, the tunnel alignment with the least environmental impacts and lowest cost was selected by the Sanitation Districts Board of Directors in 2012.
Since the Clearwater Project was approved, a large recycled water project with the Metropolitan Water District of Southern California (MWD) has been proposed at the JWPCP. In 2016, the Sanitation Districts conducted a technical review of the Clearwater Project to determine if a new tunnel would still be needed if this recycled water project were implemented. The technical review determined that a new tunnel would still be necessary to reliably protect public safety and the environment.
In 2017, the Los Angeles County Department of Public Works conducted an independent review of the Sanitation Districts 2016 technical review and concurred with the determination that the new tunnel is still needed.
6. What is the construction schedule?
7. How will tunnel construction affect my home, my community, and me?
The Sanitation Districts will construct the tunnel utilizing a state-of-the-art, balanced pressure, tunnel boring machine (TBM). This multi-million dollar system will be specifically built for this project. The new tunnel will mostly be located within public right-of-way (e.g., under streets) and will not pass under any homes. The tunnel will be 30 to 450 feet deep and will produce no noticeable vibration or noise. Tunnel construction will be closely monitored using an extensive vibration and settlement detection system installed along the tunnel alignment. Tunneling will be slowed or stopped if vibration or settlement approaches noticeable levels. The most visible element of the project will be the access shaft at the JWPCP in Carson, which is needed to lower the TBM and construction material into the ground, remove soil from the underground excavation, and provide labor access during construction. The access shaft site will be screened with barriers to minimize visual and noise impacts. A smaller exit shaft is needed at Royal Palms Beach to remove the TBM and connect the new tunnel to the existing ocean outfalls.
The EIR/EIS assessed potential impacts of the project and identified mitigation measures to avoid significant impacts. The Sanitation Districts will implement these measures, such as requiring all on-road heavy-duty diesel trucks used during construction with a gross vehicle weight rating greater than 14,000 pounds to be powered by a 2007 model year engine or newer, or be equipped with a particulate matter trap.
8. What street(s) will the tunnel go under?
The alignment for the new tunnel follows public rights-of-way (e.g., streets) as much as possible to avoid going underneath homes and businesses.
The tunnel will start under the west side of the JWPCP, then under Figueroa Street, Harbor Regional Park, North Gaffey Street, Capitol Drive, Western Avenue (through South Dodson Avenue), and end at Royal Palms Beach. The tunnel must pass under commercial property to make the turn from Gaffey to Capitol and from Capitol to Western.
Because the tunnel will be constructed approximately 30 to 450 feet below ground, street level impacts are anticipated to be imperceptible. As a protection measure, an extensive monitoring system will be installed along the alignment to closely monitor for a variety of parameters including vibration and settlement.
9. Will the new tunnel result in more air pollution in the Harbor area?
Once constructed, the project will result in no air emissions. While the Clearwater Project will result in increased air emissions during construction, mitigation measures will be implemented to minimize these impacts. Mitigation measures include the use of cleaner engines for off-road construction equipment and on-road trucks, and routing construction trucks away from congested streets or sensitive receptor areas where feasible.
10. Will the new tunnel result in significantly more local traffic?
Once constructed, the project will have no impact on traffic. During construction, the project will require traffic trips for workers, supplies and soil removed from tunneling. The impact of this traffic was analyzed in the EIR/EIS and found to be less than significant. Nonetheless, the Districts and their contractor will work with the local cities on a traffic plan to minimize the impact to the community.
11. What is the risk of settlement or damage to buildings during tunneling?
Today's modern tunnel boring machines (TBMs) are sophisticated machines that provide a very controlled tunneling process. TBMs are used worldwide to tunnel under urban areas. These machines work by placing the outer wall of the tunnel (ring) in 5-foot segments before digging the next five feet. This construct-as-you-go approach provides immediate support to the surrounding soil. Throughout tunneling, settlement will be monitored and changes in the tunneling operation will be made if settlement approaches a threshold that ensures no damage. For most of the Palos Verdes Peninsula, tunneling will occur deep below the surface.
12. What types of geotechnical monitoring instruments will be used along the tunnel alignment?
Over 1,000 monitoring points will be installed along the tunnel alignment to ensure safe tunneling. This extensive geotechnical monitoring program includes the following:
Ground Surface Monitoring Points (GMPs) - GMPs are reference points installed at the ground surface to directly monitor for any ground deformation or settlement. These monitoring points are installed every 300 to 1000 feet along the alignment.
Utility Monitoring Points (UMPs) - UMPs consists of fixed vertical rods that touch an existing subsurface utility to detect any movement. UMPs are spaced every 25 to 100 feet along the stretch of the utility that overlies the tunnel alignment.
Multiple Position Extensometer (MPX) - The MPX monitors for settlement at multiple depths below the ground surface to provide an early-warning system for potential settlement near the surface that could impact surface structures and buried utilities. MPX detectors will be installed every 10 to 50 feet vertically from the top of tunnel to the ground surface. The MPX detectors are installed along the tunnel alignment at a specified distance apart.
Displacement Monitoring Points (DMPs) - Monuments or other fixed points are used as references during monitoring to detect any ground movement.
Vibrating Wire Piezometers (VMPs) - VMPs track any changes to groundwater levels during excavation. This information assists the operator of the TBM in selecting the right pressure at the front of the tunneling machine.
Inclinometers - These instruments measure lateral ground movement and are installed near the surface.
Vibration Monitoring - Instruments will be placed in locations near residents to detect any ground-borne vibration and noise from tunneling activity.
In addition, pre- and post-construction inspections will be done to compare conditions before, during, and after tunneling. This data will help in determining the changes, if any, from the project.
13. What assurances/guarantees can the Sanitation Districts provide regarding the potential for property damage due to tunneling activities?
As a public agency, we are responsible for any damage caused by our construction projects. For the Clearwater Project, $7 million will be invested in the geotechnical monitoring system described above to ensure safe tunneling. Although no perceptible surface impacts are expected, we will establish a claims submittal process as an additional assurance for the community.
14. In the Palos Verdes Peninsula, we have active landslides and our homes and roads are continuously at risk. How can you guarantee that this construction will not trigger another event or make an existing situation worse?
The vibration from this tunneling is expected to be less than the vibration from a large truck driving down the street. Further, it is important to note that the geology and circumstances that led to the landslide at White Point are not present at Royal Palms Beach. For a landslide to occur, all of the following factors are required:
Unfavorable bedding - This condition occurs when the thin layers that separate the rock layers, called bedding planes, are angled or tilted downward towards the ocean.
Weak bedding plane - A weak bedding plane occurs when the bedding plane is made of weak material, such as bentonite clay.
Wetted bedding plane - This condition occurs when water has passed through the rock formation and wetted the bedding planes. In the case of bentonite clay, water turns the clay into a slippery surface.
Landslides can also occur without a wetted bedding plane if the base of a bluff is undermined, such as erosion caused by ocean waves. All of these factors were identified as causes of the White Point Landslide by the City of Los Angeles' geotechnical consultant. At Royal Palms Beach, the bedding planes are angled more favorably and are highly folded, making the geology stable. Additionally, the bottom of the bluff is protected from erosion caused by ocean waves.
15. How can the Sanitation Districts assure that vibration/settlement from tunneling will not impact old utilities in the area that may be transporting hazardous materials along North Gaffey? Some of the utilities/pipelines were installed decades ago and an exact location may not be known.
The Sanitation Districts have contacted all the local governments and utility companies along the tunnel alignment regarding utility lines. Engineering drawings for the tunnel design were shared with these entities and their feedback was incorporated.
The tunnel are placed about 50 feet deep in this area, which is much deeper than utility lines. As noted above in response 7, all utility lines will be monitored for settlement and if settlement reaches a strict (and very protective threshold), the tunneling operation will be modified or tunneling will stop. Any old utility lines that are unknown to utility providers and the city are very likely to be abandoned and not carrying anything. Nonetheless, the settlement monitoring for known utilities will also limit settlement to unknown utilities and the strict protective threshold will prevent damage.
16. Will a landslide similar to White Point happen at Royal Palms Beach due to tunneling?
See response 14. Additionally, the existing two tunnels were excavated at Royal Palms Beach without triggering landslides. These tunnels were constructed in the late 1930s and 1950s by blasting through bedrock. Today's tunnel boring machines produce little to no vibration at the ground surface and much less energy that might trigger a landslide than the blasting techniques used previously.
The tunnel boring machine will take about two weeks to cover the last 600 feet between Paseo del Mar and the work site on the Royal Palms Beach. Tunneling will occur 30 feet below the bottom of the bluff, so the bluff itself will not be undermined.
As a safeguard, extensive instrumentation will be used to monitor for any land movement and vibration during tunneling. Various measures can be taken if necessary, including slowing the rate of tunneling and grouting the ground ahead of the cutting face.
17. Will you shore up the slope at Royal Palms Beach?
Based on our geotechnical engineering investigation, shoring of the bluffs is not necessary.
18. Will noise be reflected off the construction sound wall towards the neighborhoods above the bluff?
The Sanitation Districts assessed noise and other impacts associated with the project in the EIR/EIS and adopted mitigation measures to prevent significant impacts from occurring. The Sanitation Districts have committed to implementing a sound wall at Royal Palms Beach and the selected contractor will design a wall that accounts for potential sound reflection to ensure that the neighborhoods above the bluff do not experience significant noise impacts during construction.
19. What will be the trucking activity out of Royal Palms? What roads will they follow with heavy trucks?
During construction, trucks and construction worker vehicles would utilize the only access to Royal Palms Beach, the two-lane Kay Fiorentino from West Paseo Del Mar. From there, the truck route studied in the EIR/EIS was along Western to 9th Street and Gaffey. The Sanitation Districts will develop a specific traffic plan that meets the requirements of local jurisdictions. As discussed in the EIR/EIS, the surrounding roadways can safely accommodate the additional daily truck and worker commute trips with little to no traffic delay. At Royal Palms Beach, there will be an average of 10 truck trips per day, which will result in 1 to 4 truck trips per hour during the day.
20. Will streets be affected by construction?
The project will involve very limited work in the streets to install the geotechnical monitoring system. Otherwise, street impacts will be limited to vehicles carrying workers and construction materials as discussed in response 10.
21. Will there be any road closures?
No road closures are needed.
22. Given that work at Royal Palms won't begin until 2022 and the EIR was completed in 2012, should a new traffic study be completed?
The EIR analysis concluded that traffic impacts near Royal Palms Beach would be very limited (less than significant). It is unlikely that a different conclusion would be reached from a new study. However, additional studies could be performed in advance of the work at Royal Palms Beach.
23. Have you done another traffic study since the EIR?
An additional analysis was performed in May 2012 (before the Final EIR certification) to account for changes in traffic after the White Point landslide. This analysis concluded that the traffic impacts after the slide would be consistent with the impacts in the original traffic analysis and that the impacts at the analyzed intersections would be less than significant. As noted in Response 22, if necessary, additional studies can be performed in advance of the work at Royal Palms Beach.
24. What is the budget for the project?
Approximately $700 million, which includes design and construction management costs.
25. How are you funding this project?
The Clearwater Project will be funded through the use of existing capital reserves and annual service charges collected from residents and businesses that use the sewerage system.
26. Will recycling 100% of the treated wastewater at JWPCP be a way to not build a new tunnel?
In 2016, we recycled over 32 billion gallons of recycled water, which is enough water to supply the cities of Long Beach and Cerritos for an entire year. We continue to look for new opportunities to partner with water purveyors on recycling projects. The Sanitation Districts are currently involved in two large water recycling projects. In partnership with the Water Replenishment District of Southern California, approximately 21,000 acre-feet per year (AFY) of treated water from the San Jose Creek WRP will receive advanced treatment and be used to replenish groundwater supplies. This is enough water to supply the cities of Manhattan Beach and El Segundo. This project is in construction. The Sanitation Districts have also partnered with the Metropolitan Water District of Southern California (MWD) to explore building a water purification facility at the JWPCP that would produce 168,000 AFY of highly purified water (enough for 335,000 homes). This project is currently in the demonstration stage.
While these projects help support water reliability for the county, a reliable tunnel and outfall system is still be needed for times when water purification facilities are out of service for maintenance or recycled water is not needed (e.g., after weeks of rainy weather). Also, during large storms when flows into treatment plants increase, the potential recycling project would handle less than half the flow treated at the JWPCP and the remainder would need to be discharged to the ocean. In summary, the new tunnel is needed to provide a safe, reliable wastewater treatment system regardless of the implementation of a large water recycling project and additional improvements in water conservation.
27. Will water conservation efforts reduce the need for additional effluent management capacity?
Over the past decade, water conservation efforts have delayed the need for additional facilities, and to some extent, it is anticipated that this trend will continue into the future. The Sanitation Districts recognize the environmental and economic benefits of water conservation and support the efforts of water supply agencies to increase conservation. The Clearwater MFP assesses the overall impact of water conservation on flow projections. While conservation has reduced wastewater flows and additional conservation may further reduce wastewater flows, large peak flows are still a concern as are the age of the existing tunnels and the seismic vulnerability of the existing tunnels. Thus, a new tunnel is still needed even with ongoing conservation efforts.