Q & A Library

Home > Info Center > Q & A Library

Questions and Answers about the Delta Conveyance Program

Use keywords to search the Q&A Library or sort by topics below.

Construction


  • What is the definition of “temporary” in terms of years?

    The term “temporary” in the CEQA document will be defined based on the resource area and the nature of the activity. As part of the initial EIR preparation, this term will be defined for each resource. Generally, for an EIR, “temporary impacts” range up to two years.


  • Who decides what a reasonable alternative is, what makes an alternative qualify as “reasonable” and to whom is the alternative deemed reasonable?

    DWR, as the lead agency under the California Environmental Quality Act (CEQA), will decide the range of reasonable alternatives for the environmental impact report (EIR).

    CEQA requires that an EIR include a detailed analysis of a range of reasonable alternatives to a proposed project. CEQA requires that an EIR evaluate alternatives to the proposed project that are potentially feasible and would attain most of the basic project objectives while avoiding or substantially lessening the project’s potential impacts. Likewise, the National Environmental Policy Act (NEPA) requires that a range of reasonable alternatives that meet the purpose and need statement of the action be analyzed at an equivalent level of detail in an environmental impact statement (EIS). Generally, a range of reasonable alternatives is analyzed to define the issues and provide a clear basis for choice among the options.

    CEQA requires that the lead agency consider alternatives that would avoid or substantially lessen any of the significant impacts of the proposed project. However, numerous alternatives that have slight variations are not necessarily required. The lead agency determines the alternatives to be analyzed in detail in an EIR. Section 15126.6[a] of the state CEQA Guidelines provides that:
    [a]n EIR shall describe a range of reasonable alternatives to the project, or to the location of the project, which would feasibly attain most of the basic objectives of the project but would avoid or substantially lessen any of the significant effects of the project, and evaluate the comparative merits of the alternatives. An EIR need not consider every conceivable alternative to a project. Rather it must consider a reasonable range of potentially feasible alternatives that will foster informed decision making and public participation. An EIR is not required to consider alternatives which are infeasible. The lead agency is responsible for selecting a range of project alternatives for examination and must publicly disclose its reasoning for selecting those alternatives. There is no ironclad rule governing the nature or scope of the alternatives to be discussed other than the rule of reason.

    The Council on Environmental Quality’s (CEQ) NEPA regulations states that the lead agency in an EIS shall “rigorously explore and objectively evaluate all reasonable alternatives, and for alternatives which were eliminated from detailed study, briefly discuss the reasons for their having been eliminated. Devote substantial treatment to each alternative considered in detail including the proposed action so that reviewers may evaluate their comparative merits. Include reasonable alternatives not within the jurisdiction of the lead agency” (CEQ NEPA Regulations 40 CFR 1502.114). In addition, CEQ has issued guidance on alternatives, stating, “For some proposals there may exist a very large or even an infinite number of possible reasonable alternatives…When there are potentially a very large number of alternatives, only a reasonable number of examples, covering the full spectrum of alternatives, must be analyzed and compared in the EIS…What constitutes a reasonable range of alternatives depends on the nature of the proposal and the facts in each case.” (See Council on Environmental Quality’s Forty Most Asked Questions Concerning CEQ’s National Environmental Policy Act Regulations; 2(a).)

    Under these principles, the EIR (and EIS) needs to describe and evaluate only those alternatives necessary to permit a reasonable choice and “to foster meaningful public participation and informed decision making” (State CEQA Guidelines Section 15126.6[f]). The EIR scoping process is used by the lead agency to gather input on alternatives to the proposed project. Ultimately, it is the responsibility of the CEQA lead agency to determine a reasonable range of alternatives to a proposed project for analysis in the EIR.


  • What are DWR plans for levee maintenance in regards to the intakes and flood protection?

    DCA is working with the U.S. Army Corps of Engineers (levee owner) to ensure that the construction of the intakes poses no additional flood risk. The current plan for keeping the levees intact during intake construction was presented during the January 22, 2020, presentation on intakes. To address this issue, the DCA prepared a construction sequence animation that showed how the levee and flood management protection would be maintained throughout the entire construction period. This material is available online at dcdca.org.


  • Do the conveyor belts go across the island?

    In order to reduce truck trips and roadway congestion, conveyor belts can be used to transport reusable tunnel material (RTM) from launch shaft sites to storage locations. RTM conveyance was discussed further at the February and March SEC meetings.


  • Regarding pile drivers: How many sites, are they all at once, how close, duration?

    Pile driving could be used at numerous locations of the Delta Conveyance program, including the intakes. The January 22, 2020, presentation on intakes described the potential need for pile driving at intake locations. The presentation included exhibits prepared by an acoustic engineer and quantified potential noise effects due to pile driving at the intake sites. It also addressed the potential for noise reduction with several construction methods. This material is available online at dcdca.org, and further information on pile driving for other components will be presented at upcoming meetings.


  • What are the specifics of the tunneling process, machinery used, material derived and its treatment?

    The February 12, 2020, meeting included a presentation that describes the specifics of the tunneling process.


  • Is there siting information available for burrow pits?

    SEC meetings 3-8 break the project up into individual components, each with their individual requirements for imported material. For components where a lot of import is needed, the presentations include potential import sites and invite Committee feedback to provide additional considerations.


  • How will the new levee affect the other Delta levees?

    The modified levees at the intake locations would be limited to short lengths on either side of the intake and would be designed to the most current U.S. Army Corps of Engineers (USACE) standards. The modified levees would be designed based upon numerical evaluations of hydraulic and geotechnical effects on other levees upstream and downstream of the new intake, including the levees across the river from the intake. Per the USACE permit requirements under the Clean Water Act, Section 408, the modified levees would be designed to not injure the function of the flood control project levees.


  • It was mentioned that there would be new barge routing and landing “overlay maps.” Do you know if they are available yet for either the proposed eastern route or the westerly (original route)?

    DCA is developing maps that indicate areas along the Delta waterways that could be used by different sized barges, areas that may not support barge traffic, and the relative potential for waterways to support construction and operation of barge landings to serve potential construction sites within the NOP corridors (which included the Central and Eastern corridors). The information will be used by DCA to determine the accessibility of potential tunnel launch shaft sites, as presented in the February 12, 2020, SEC meeting presentation.


  • What construction is going to be happening simultaneously throughout the whole project?

    At this point in the project, the sizes and locations of the facilities under the proposed project and the potential alternatives are being developed. As more information becomes defined, the construction schedules for facilities would be developed.


  • Will the other levees across from the proposed intake sites need to be raised, widened, etc.?

    Since water level impacts would not be expected to require levee modifications, impacts to the bank opposite the intakes would be evaluated using Hydrodynamic modeling to evaluate more localized erosive conditions along the levees. Given the results of similar modeling previously conducted, impacts on the opposite bank would be expected to be minimal.


  • What will be the impact of dewatering and excavation on aquifers?

    As described at the January 22, 2020, SEC meeting, the intake construction site would be surrounded by a slurry wall. Slurry walls would serve to isolate the site from surface water and groundwater to minimize the potential for seepage either into or out of the construction site. The construction activities would require minimum dewatering and would not affect short-term or long-term subsidence. Additionally, based upon the geological information available for the intake locations, it appears that there are adequate clay lenses below the excavations to isolate the site from surrounding groundwater.


  • What is seepage when tunnel segments are put together?

    We do not expect seepage from connecting tunnel segments due to the construction method. The tunnel segments are put together within the cylindrical steel shield of the TBM, and seepage is controlled by multiple wire brush seals as the segments are assembled together. The segments themselves are gasketed at all of the joints, essentially providing a completely sealed system.


  • How many tons of concrete will be poured on the launch shaft site pads?

    At a tunnel launch shaft, a gantry style crane probably would be used for support of the tunneling operations, and a temporary concrete pad would be constructed around the shaft to allow for rails of the crane supports and to provide a work area. The concrete pad would be temporary and would be removed following construction. The concrete pad could be approximately 189,000 square feet and about 6 inches thick, or approximately 3,500 cubic yards. This amount of concrete would weigh approximately 7,100 tons.


  • When peat dirt is displaced, what mitigation efforts will be made to make sure the peat doesn’t increase the asthma problems in the Delta?

    Excavated soils, with or without peat, would need to be managed on-site to prevent particulate matter, including dust and peat material, from leaving the construction site boundary. At the tunnel shaft locations, the excavated material (approximately 600 cubic yards from the vertical shaft excavation) would be placed in areas to be managed to allow for testing prior to disposal or reuse. This will be analyzed in the environmental document, and any mitigation will be provided there. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Do you plan to rehabilitate the levees at launch sites and to what level in order to protect construction operations?

    The work areas at the tunnel launch sites would be placed on elevated pads to protect the site from the 200-year flood event, sea level rise and wind fetch with a specified freeboard height.


  • Are there going to be activities such as dewatering, power lines or pipelines between the launch shafts in addition to construction of the launch shaft sites?

    All construction between tunnel shafts is anticipated to be located at the TBM below the ground. Dewatering would not occur along the tunnel alignment between tunnel shafts. No pipelines would be constructed along the tunnel alignment between tunnel shafts. Power line alignments have not been developed at this time.


  • How many miles are between the Eastern Corridor’s Launch Site B to the Port of Stockton?

    The potential Launch Site B presented in the February 12, 2020, Stakeholder Engagement Committee meeting is approximately 3 to 4 miles from the Port of Stockton.


  • Has there been any analysis on how far away the top end of Launch Site B is from urban housing to the east and north?

    The screening process presented in the February 12, 2020, Stakeholder Engagement Committee meeting considered avoidance of construction within adopted city spheres of influence boundaries. The initial launch shaft sites were at least 1 mile from housing.


  • Will conveyor belts be moving RTM across farmland to the drying areas?

    Conveyors could be located either within a construction site or parallel to roads to minimize vehicle use. The specific uses for conveyors are currently being developed and will be discussed at future Stakeholder Engagement Committee meetings.


  • Is the build still anticipated to take 13 years?

    The preliminary construction schedule is currently estimated at 13 years. More detailed schedules are under development and would depend on identified tunnel drive lengths. Construction schedules will be discussed at future Stakeholder Engagement Committee meetings.


  • What is the anticipated labor load for each shift and the plan for caring for and feeding of those individuals?

    Labor estimates will be developed on a monthly basis for each construction site. In addition, use of centralized parking areas, mobile food trucks and centralized material consolidation centers are being considered as methods to reduce vehicle traffic during construction. These items will be discussed at future Stakeholder Engagement Committee meetings.


  • How close is this construction to residential areas?

    Specific construction sites are still being identified. However, based on the tunnel launch shaft areas presented at the Stakeholder Engagement Meeting on February 12, 2020, the tunnel launch shaft would be at least 1 mile from residential areas.


  • How will pockets of gas and water be avoided during tunneling?

    During the design phase, there will be an exploration program to identify and detect buried and/or abandoned water, natural gas and oil wells to allow for removal of the wells prior to tunnel construction. During construction, gas detection methods will be used for flammable gasses. The mechanisms used for tunnel liner construction would provide a sealed work area and protect the boring machine and workers from water intrusions.


  • What happens if you accidentally pierce a pocket of gas, oil or water during tunneling?

    During construction, gas detection methods will be used for flammable gasses. The potential condition for encountering a gas or oil pocket is covered under the Tunnel Safety Orders administered by Cal/OSHA. These laws dictate the safe working environment as well as the conditions that may require removal of workers from the tunnel until they are mitigated. One of the most typical mitigations required includes increasing the amount of ventilation to the affected area. The mechanisms used for tunnel liner construction would provide a sealed work area and protect the boring machine and workers from water intrusions.


  • How are the tunnels ventilated?

    The equipment placed in the tunnel behind the TBM would include ventilation equipment, as will be discussed in upcoming Stakeholder Engagement Committee meetings.


  • How does tunneling operate in regards to potential for seismic issues due to the tunneling and the motion of the drives?

    The greatest ground motions in a seismic event would occur near the ground surface. At the depths of the TBM and tunnel, the structure would probably tend to move together with the surrounding ground and not be adversely affected by seismic forces.


  • New FAQ : QuestionHow does tunneling work in an unconsolidated soil type?

    The applied TBM face pressure would be balanced against the soil and groundwater pressure by the TBM operator.


  • What is the seismic vulnerability of the tunnel itself?

    The greatest ground motions in a seismic event would occur near the ground surface. At the depths of the TBM and tunnel, the structure would probably tend to move together with the surrounding ground and not be adversely affected by seismic forces.


  • How is the lining of the tunnel rated on seismic strength?

    The tunnel would be designed for seismic ground motions and forces generated using state-of-the-art seismic design modeling. Applicable engineering factors of safety for these dynamic forces would be used in the structural design.


  • Can members have a list of soil conditioners considered for use? What is the composition of soil conditioners?

    Many different types and brands of conditioners are used in tunneling based upon soil conditions present along the alignment. Conditioners are generally categorized as foams, polymers and bentonites. On recent projects, DCA consultants have observed the use of Soilax S products (available from the manufacturer Boraid Products), which are surfactants (i.e., detergents) and mixed with clean water as a foaming conditioner. Sometimes, a cellulose product, like Soilax C, is added into the conditioner mix to provide added strength to the soap bubbles, which helps when the conditioner is injected into certain soil formations. Thickening agents, such as polymers and a bentonite (a naturally occurring clay), are also used for different soil conditions. These include such products available from Mapei Products. These are just examples of some products that could be used. The construction specifications would require any conditioners to be inert (chemically inactive).


  • The ITR report notes there are no active fault crossings in the Delta conveyance alignment and that seismic demands are not extreme compared to other projects, and DCA indicated it agreed on that statement. Why are we building tunnels if seismic issues are not a concern?

    The ITR report’s note reflects the fact that the current tunnel corridors do not contain active faults and tunneling options themselves would not be uniquely affected by seismic considerations. It was not expressing any opinion regarding the need for or benefit of Delta Conveyance for providing increased seismic reliability to the State Water Project. On this point, in 2014 the U.S. Geological Survey (USGS) estimated that there was a 72% probability of a magnitude 6.7 or greater earthquake (a “major event”) occurring in the San Francisco Bay Area by 2043. Levees in portions of the Delta could be at risk of failure in the event of a “major event,” such as an earthquake of at least magnitude 6.7. If the levee failures occur in portions of the western, central or southern Delta, the reliability of freshwater SWP diversions at Clifton Court Forebay could be compromised.


  • Would tunnel segments still be lowered into the tunnel from launch shafts even if there was a maintenance shaft available?

    As currently proposed, the maintenance shaft sites would only be sized to remove the cutter head. The launch shaft sites would be sized to lift the segments into the tunnel, for tunnel boring machine trailing gear and for reusable tunnel material handling and storage. The large launch shaft site would only be required every 12 to 15 miles.


  • What is the power source for the tunnel cutter head?

    As currently proposed, a dedicated high-voltage power supply would be connected to the launch shaft sites to power the tunnel boring machine cutter head.


  • The Delta Conveyance program facilities, including tunnel shafts that are currently proposed to remain following construction, would be constructed at elevations greater than the 200-year flood event and projected sea level rise at year 2100 with considerations for freeboard and wind fetch waves.

    The Delta Conveyance program facilities, including tunnel shafts that are currently proposed to remain following construction, would be constructed at elevations greater than the 200-year flood event and projected sea level rise at year 2100 with considerations for freeboard and wind fetch waves.


  • If heavy concrete is put on top of these soils, how will the sites be stable?

    As currently proposed, the shaft would be constructed with a diaphragm wall or concrete shell that would extend to the bottom of the tunnel where there are structurally competent soils; therefore, the tunnel shaft would not be expected to settle. The soil on top of the ground at the shaft locations would be treated with ground improvement methods as necessary to stabilize the site for equipment and the shaft pads.


  • Are the maintenance and retrieval shafts being kept or filled after construction of the project?

    Decisions about the post-construction design have not been completed. There are many considerations currently being discussed, including not removing the shafts to allow for access into the tunnel and minimize truck traffic to remove the soil used to form the tunnel shaft pad. If the shaft pads were removed, concrete or other structures would be used to cap the shaft at the ground surface.


  • What flood standard is being used to determine the height of the shaft pads compared to what DWR has analyzed in the fourth climate change assessment for storm surge and downstream flood risk?

    Over the lifetime of the Delta Conveyance program, the facilities would be designed for the 200-year flood event, projected sea level rise for year 2100, freeboard criteria and wind fetch waves. The sea level rise would consider the Ocean Protection Council’s guidance. The criteria do not require that the facilities need to be initially designed for the year 2100 sea level rise, but they must be designed to be adaptable over time to protect the facilities with sea level rise.


  • The ITR report sought to determine if CEQA could have an approach for the unknowns. How can that comment be assimilated? The Big Bertha TBM used on the Alaska Way Viaduct got stuck 1,000 feet into the tunnel drive. How is that type of possibility going to be addressed from the engineering point of view?

    During the ITR team review, it was discussed that use of maintenance shafts approximately every 5 miles with full maintenance procedures at those shafts would substantially reduce the probability of failure between shafts. In addition, it is understood that tunnel boring machine technology is continually evolving and many of the maintenance procedures can be completed from within the tunnel. The ITR team documented one case study that included a main bearing being replaced from inside the tunnel. Technology will continue to change significantly five years from now when the Delta Conveyance program is projected to be under construction. During the design phase, additional ITR reviews will be conducted to incorporate new technologies. DCA is being conservative in planning full maintenance shafts every 5 miles in order to avoid the need for an emergency shaft.


  • Why all of this for one region?

    With these new proposed intake locations, the State Water Project would have greater flexibility to adapt to climate change, manage rising sea levels, function in the event of a natural disaster and safely move water during high flow events. This project could deliver water to a broad geographic area to State Water Project contractors and, potentially, Central Valley Project contractors.


  • Where will water pumped in the dewatering process go?

    The dewatering water would be tested to determine if on-site treatment would be required prior to reuse or removal from the site. The treatment could range from removal of sediment to removal of other constituents. The treated water would be considered for on-site reuse, including use for dust control or mixing with slurry, grout or cement materials. At this time, the volume of dewatering flows and water supplies has not been calculated for each construction site. Therefore, the need for off-site disposal of dewatering flows is not known. However, the dewatering flows would not be discharged to local drainages and stormwater facilities in a manner that would reduce capacity for continued use of these existing facilities by local lands or cause a rise in groundwater and seepage problems on lands adjacent to the drainages.


  • How will you overcome the challenge of not disrupting reclamation districts’ routine levee maintenance during periods of high flood? How will we mitigate for the required seasonal and annual inspections to ensure reclamation districts are able to keep the community safe?

    Reclamation districts (RDs) have important requirements for maintenance, monitoring and flood fighting. These efforts will need to continue during construction and operation of the Delta Conveyance facilities. During design, DCA will coordinate with potentially affected RDs to understand their typical processes and annual schedules to minimize disruptions. DCA will also work closely with the RDs to develop strategies and contingencies for high-water conditions to ensure their ability to maintain, monitor and implement flood-fight activities during construction and operations.


  • Is there is a document that compares WaterFix to the new proposed project and highlights the key differences from the administration’s perspective and why those changes are being made?

    In July 2017, DWR approved a conveyance project in the Delta involving two tunnels referred to as “California WaterFix.” In his State of the State address delivered February 12, 2019, Governor Newsom announced that he does not “support WaterFix as currently configured” but does “support a single tunnel.” On April 29, 2019, Governor Newsom issued Executive Order N-10-19, directing several agencies to (among other things) “inventory and assess…[c]urrent planning to modernize conveyance through the Bay Delta with a new single tunnel project.” The governor’s announcement and executive order led to DWR’s withdrawal of all approvals and environmental compliance documentation associated with California WaterFix. The current CEQA process being completed by DWR will, as appropriate, use relevant information from the past environmental planning process for California WaterFix, but the proposed project will include new alternatives and undergo a new standalone environmental analysis leading to issuance of a new EIR. It would be difficult to compare the California WaterFix alternatives to the new EIR alternatives because they are different projects and, due to the time lapse, some analysis may be updated and utilize different assumptions used in the current CEQA process as compared to previous analyses.


  • How much peat dirt will be displaced in the process of excavating?

    Excavated soils, with or without peat, would need to be managed on-site to prevent particulate matter, including dust and peat material, from leaving the construction site boundary. At the tunnel shaft locations, the excavated material (approximately 600 cubic yards from the vertical shaft excavation) would be placed in areas to be managed to allow for testing prior to disposal or reuse. This will be analyzed in the environmental document, and any mitigation will be provided there. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • How many launch shaft pads are being proposed?

    The potential tunnel alignments and shaft locations in the Central and Eastern Corridor are still being developed. At this time, it appears that two tunnel launch shafts would be located within the footprint of the Southern Forebay and two to three tunnel launch shafts per corridor would be located to the north of the Southern Forebay.


  • Has a tunneling project with this magnitude, soil condition, length, etc. ever been performed anywhere?

    There are many places in the world where tunnels with similar features referenced have been constructed or are under construction, including tunnels at the Port of Miami, Hong Kong (China), Madrid (Spain) and Turkey.


  • What is the fish screen noise in decibels?

    Specific decibel levels are not known for the screen cleaner mechanism. DCA anticipates further studies and analysis by acousticians.


  • Will acousticians conduct on-the-ground surveys in the actual Delta?

    DCA may consider on-site acoustical surveys near potential construction sites to develop site-specific noise reduction methods. These types of surveys would not be conducted until specific construction sites and methods have been developed.


  • How much noise will be produced by the shaft boring process?

    The shaft construction process would require a large crane or milling machine for the slurry panel excavation or panel excavator if cutter soil mix panels were used. A second crane would be required to support operations for the panel construction (e.g., lifting the steel rebar reinforcing cages into the panel excavations). Based on current information, the loudest construction noise would generally be related to the motor noise from these two pieces of equipment.

Cultural/Historical


  • Can we add to Map 8: historical sites, cultural resources and Indian burial grounds?

    Public disclosure of the locations of archaeological resources and tribal cultural resources, including human remains, may make those resources vulnerable to theft and vandalism as well as be in violation of both federal and state laws. Because of this, these resources cannot be mapped for, or shared with, the public. Federal regulations include, but are not limited to, Section 304 of the National Historic Preservation Act (54 United States Code [USC] § 307103) and the Archaeological Resources Protection Act (16 USC § 470h). State regulations include, but are not limited to, California Government Code Section 6250 et seq. and Section 6254 et seq. Other state regulations such as Public Resources Code Section 5097 et seq. and Health and Safety Code Section 7050 et seq. cover the unanticipated discovery and treatment of human remains.


  • Is there a map reflecting the history of settlement of Native peoples?

    DWR, as the CEQA lead agency, will conduct a CEQA analysis on the proposed Delta Conveyance program that includes analyzing potential impacts to cultural and tribal cultural resources, including descriptions of the settlement of Native peoples in the project study area. However, DWR does not have a map of these settlements at this time.


  • What is the process in place for any undocumented cultural sites that might be discovered during construction?

    DWR routinely includes a set of best management practices in construction contracts to address the potential for unanticipated discovery of archaeological materials. The environmental analysis will discuss the potential for impacts and will define mitigation measures aimed at reducing the potential for cultural resources to be disturbed or destroyed. This includes a measure that addresses the potential for “unanticipated discoveries” during construction, including specific requirements for tribal consultation, pre-construction awareness training, and requirements for stopping work in the vicinity of such discoveries until such time that a professional archaeologist is able to assess the discovery and work with DWR, in coordination with the appropriate regulatory and/or tribal authorities, to develop a plan for appropriate treatment. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Can members have a detailed map identifying groundwater and aquifers in the Delta?

    At this time, DCA does not have knowledge of detailed maps of the groundwater aquifers in the Delta that extend across county boundaries to form a uniform map or dataset. Agencies within Contra Costa, Sacramento, San Joaquin, Solano and Yolo counties are currently preparing groundwater management plans in accordance with the California Sustainable Groundwater Management Act. Information from those efforts may be available in the future to prepare a uniform map.

Environmental


  • Will there be real-time disclosure of existing issues discovered during soil testing or field work?

    “The actual draft and final soil testing results will be initially shared with property owners. If the property owners wish to disclose the information prior to publication of the geotechnical report, that information may be provided by the property owners. The geotechnical report will include the results of the soil testing.

    If any hazardous materials or other environmental hazards are encountered during the field work, property owners will be notified, and notification of federal, state and local agencies in accordance with applicable laws and policies will be coordinated with the property owners.”


  • Are you going to coordinate markers on each soil collection point so levee impacts can be tracked by RDs?

    Yes. The exploration locations will be documented with survey coordinates using current datums, and a metallic pin will also be buried in the top of the wet backfill grout at each exploration to allow for future locating with metal detection equipment.


  • Will you be identifying and protecting native plant species around the Clifton Court Forebay used for tribal medicinal practices?

    DWR, as the CEQA lead agency, will conduct a CEQA analysis on the proposed Delta Conveyance program that includes analyzing potential impacts to biological, cultural and tribal cultural resources, among many other resource areas. To analyze potential impacts to biological resources, an evaluation of the project study area, including Clifton Court Forebay, will be conducted to identify plant communities and determine if existing conditions provide habitat for any special-status plant or wildlife species or are the location of any tribal cultural resources. As part of the cultural and tribal cultural resources review, DWR will be providing tribes the opportunity, through consultation as required under AB 52 and DWR’s own Tribal Engagement Policy, to share information concerning native plant species that are used for tribal medicinal practices and potential measures for avoidance or mitigation. Cultural resources work will be initiated consistent with release of the Notice of Preparation. DWR has initiated pre-AB 52 discussions with the tribes with potential ancestral territories in the Delta.


  • What possible impact will the project have on the Park District’s several properties in the South-Central Delta that are under irrigation leases?

    At this time the corridors shown in the NOP do not appear to include East Bay Regional Park District parks. The Central Corridor does include the land with the Contra Costa Water District intake along Old River; however, the future facilities would not be constructed in that parcel. If the irrigation leases are located on nonpark lands, please indicate where those properties are located for further analyses.


  • Can members have access to the recent geotechnical data collected?

    The geotechnical data currently being evaluated consist of project-specific data collected over the past years by DWR, supplemented by historic data from other agencies. The project data has been compiled and issued as part of the administrative record for prior environmental permitting for the California WaterFix project. The majority of the supplemental agency data are publicly available through Caltrans and the California State Water Resources Control Board. Water well data compiled by DWR is confidential and therefore cannot be shared. There are other limited data provided by specific agencies that are also subject to confidentiality requirements and therefore cannot be shared.


  • What are the calculations on the volume of sediment for these flows and for high water events?

    Sediment removal quantity calculations at the intakes would be dependent on total diversion amounts, which will be developed as DWR completes operational modeling for the EIR. Therefore, total annual amounts of sediment that could be removed at the intakes are unknown at this time. Based upon previous studies for intakes in this portion of the Sacramento River, sediment quantities removed at the intakes could range up to 10,000 cubic yards in a month with peak diversion flows.


  • Is there any correlation with outside bends and in-migration and out-migration of fish?

    See attached response.


  • Can SEC members get answers to questions about the river bends from fish biologists, since there is a difference of opinion within the fish biology community?

    DWR intends to consider and document analyses and other relevant biological information supporting the assessment of siting, constructing and operating intake facilities on the Sacramento River in the EIR. Input from fish biologists, as well as other relevant experts, and evaluation of alternatives using best available science, will be key components of the environmental planning process going forward.


  • Will the impact analysis of the fish screen brushing on the food web be performed to a microscopic level?

    DWR plans to assess changes to primary and secondary productivity resulting from new operations as part of the analysis in the EIR. Operations and maintenance of the fish screens would be intended to minimize the buildup of biological material on the screen itself. If additional needs or details with regard to finer-scale food web changes associated with the project are identified through the scoping process or the effects analysis, those will be considered as well. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Is there any consideration given to any type of unexpected wildlife that gets stuck in the sedimentation basin, such as monitoring of eggs?

    The DCA intake analyses to date have focused on development of the fish screen configuration. Operational issues, including those related to wildlife management and protection, would be evaluated as part of the EIR. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • How will this facility be ensured to not kill Delta smelt, as has been reported to be happening at Clifton Court Forebay?

    The proposed intakes will include fish screens specifically designed to exclude Delta smelt from entering the system prior to diversion using state-of-the-art fish screening meeting all regulatory requirements for Delta smelt as developed by the U.S. Fish and Wildlife Service and California Department of Fish and Wildlife. Clifton Court Forebay is configured in a manner that fish screens cannot be installed at the existing inflow location to Clifton Court Forebay.


  • Is it possible to incorporate a riparian zone into the design of an intake facility, and would that be easier with the cylindrical tee screen or vertical flat plate type?

    It could be possible to provide some type of vegetation at portions of the intake locations following construction. Riparian habitat disturbed upstream and downstream of the intake during construction could be replaced in accordance with USACE and DWR criteria. Other areas on the intake site could also be considered for habitat plantings. Upland habitat could be considered between the intake structure and the highway at the same elevation as the top of the levee. Irrigation could be provided to help facilitate the diversity of plants. These concepts would be independent of the type of intake screens.


  • Will there be real-time disclosure with water quality issues found during construction?

    The State Water Resources Control Board or Central Valley Regional Water Quality Control Board will issue a Stormwater Pollution Prevention Plan permit to regulate water quality of stormwater and nonstormwater runoff from the construction sites. It is also possible that these regulatory agencies would issue a National Pollution Discharge Elimination System permit to regulate nonstormwater runoff from the construction sites. These permits would include monitoring and reporting requirements, such as the collecting and analyzing water samples of runoff from the construction site and in the receiving water body. The results of these analyses would be submitted to the regulatory agencies and could be posted to a publicly available website.


  • Will there be some information provided to the committee regarding hydraulic impacts such as water surface elevations and velocity?

    DWR will perform hydraulic and hydrodynamic modeling for the proposed project and alternatives as part of the CEQA analysis. Modeling will be used to estimate changes in velocity and elevation in the waterways at intake locations and other locations in the Delta under different hydrologic conditions. This information will be presented as part of the CEQA process. DWR is planning a separate public outreach process related to CEQA to discuss this and other issues addressed by the EIR.


  • Why were Southern California reservoirs full when Northern California reservoirs were empty during the last drought?

    See attached response.


  • My concerns include water quality, water levels rising and falling and how that will affect fish and plants.

    DWR will assess potential impacts to fish and wildlife (including plants) and associated habitat during future environmental compliance activities, including the CEQA environmental review process. This includes potential changes in water quality conditions as well as potential changes in surface water elevations and associated effects. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • What effect will restoration plans and mitigation plans have on state parks?

    The environmental impact analysis for Delta Conveyance has not yet started. Mitigation plans have not been developed for the program, and restoration locations have not been identified. Preliminary mitigation and restoration information will be developed during the CEQA environmental analysis process. The environmental analysis is intended to identify potential impacts and, where feasible, potential mitigation for those impacts. DWR will assess potential impacts to state parks through the CEQA environmental analysis process. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Can you provide information about harmful algal blooms?

    DWR will evaluate the potential for harmful algal blooms through a comparison of conditions with and without implementation of the project and alternatives. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • DWR’s boring data should be released to SEC members without a PRA.

    The geotechnical data currently being evaluated consist of summary reports, well drilling reports and/or soil investigations by DWR (including flood projects), Caltrans and other state agencies. These data files include confidential personal information (e.g., property owner names). Due to the confidential nature of these files, most of the individual well logs and soil borings cannot be released. Soil boring data was provided for several locations in previous conceptual engineering reports for canal alignments in the eastern and western Delta and a central-Delta tunnel alignment. Soil boring data was also summarized in the following reports as part of previous studies:

    • Draft Phase I Geotechnical Investigation – Geotechnical Data Report – Isolated Conveyance Facility West, 07-12-2010, DWR.
    • Draft Phase I Geotechnical Investigation – Geotechnical Data Report – Isolated Conveyance Facility East, 07-12-2010, DWR.
    • Draft Phase II Geotechnical Investigation – Geotechnical Data Report – Pipeline/Tunnel Option, 08-22-2011, DWR.


  • How far upstream and downstream will the levees be affected and what kind of mitigation will be used? How do changes to the East Bank affect the West Bank, and what kind of mitigation will be used?

    Hydrodynamic modeling has not yet been conducted. However, it is expected from previous modeling that the intake structures would not materially impact the water levels in the river during high flows. The project may reduce water levels at some time periods. Water level impacts are expected to be below the USACE threshold for action. Therefore, levee improvements for water level impacts upstream of the structures would not be expected to be necessary. Hydrodynamic modeling is also planned to be conducted to evaluate more localized erosive conditions, which could lead to the need for slope protection on some locations along the levees. Those impacts are expected to be limited to a few hundred feet or less upstream and downstream of the intake sheet pile training walls.


  • Will the dewatering process create odors?

    The largest extent of dewatering flows on the Delta Conveyance program construction sites would probably be from the vertical tunnel shaft locations, which would extend less than 200 feet below the ground surface. During design, soil investigations would be conducted that would include observations of groundwater levels and odors from the borings. If odors, especially due to high sulfide constituents, are present during soil investigations, the on-site dewatering treatment process would include methods to minimize noxious odors on adjacent properties.


  • What can be done with soil to create habitat projects due to legacy mercury?

    All soils excavated during construction, including reusable tunnel material (RTM), would be tested for the presence of constituents, including mercury. The concentration of these constituents would be compared to criteria developed by the SWRCB, Regional Water Quality Control Board, California Department of Fish and Wildlife and U.S. Fish and Wildlife Service prior to use in habitat projects as well as any other disposal proposal. For soils with constituent concentrations higher than allowed criteria, soil treatment could be used to remove specific constituents, or other disposal plans would be developed.


  • Do soil conditioners aggravate the methylenation of mercury?

    The addition of soil conditioners (surfactants) is not anticipated to increase methyl mercury in the RTM.


  • What is air pollution from truck traffic and cement construction?

    DWR will be analyzing air quality in the environmental review. This comment could be related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Do soil conditioners need to be removed from the soil before it is reused?

    Soil conditioners would only be removed from the RTM if determined to be necessary as part of the testing program. Generally, the expected concentrations of conditioners in the RTM would not affect whether RTM would be available for reuse or disposal.


  • How is the safety of the soil determined?

    The soil material coming out of the tunneling or shaft excavations would be conveyed to a material classification area where it would be placed within smaller segregated areas. These areas would be tested to identify critical constituents related to the disposal or reuse of the RTM, including constituents that would identify the RTM for hazardous materials and contamination. Laboratory results would be used to define the appropriate, preapproved storage, reuse or disposal locations.


  • What is done with saltwater that is brought to the surface?

    The dewatering water would be tested to determine if on-site treatment would be required prior to reuse or removal from the site. The treatment could range from removal of sediment to removal of other constituents. If the salinity is too high for on-site reuse or discharge to a receiving water body, on-site water treatment could be considered or the water would be discharged to a permitted disposal facility that allowed for discharge of water with the high salinity. During design, soil investigations would be conducted that would include observations of groundwater levels and quality.


  • Is RTM subject to waste discharge requirements?

    DWR’s environmental review process will evaluate permitting requirements for the proposed project. Placement of the RTM at the construction site for either temporary or long-term storage may require compliance with specific measures in the Storm Water Pollution Prevention Plan, a type of waste discharge permit issued by the SWRCB and Regional Water Quality Control Boards.


  • Will the SEC members receive information about the soil and water testing program once it has been determined?

    Initial soil investigation methods were proposed and are being evaluated through a Draft Initial Study/Mitigated Negative Declaration (published in November 20, 2019) by DWR. Water quality testing programs have not been developed at this time.


  • How frequently will HAB data be reported, and how accessible will it be to the public?

    Harmful Algal Blooms (HAB) data currently are not included in most Stormwater Pollution Prevention Plan construction permits. Historically, analysis for potential for algal blooms in the Delta relies on operational assumptions, including diversion patterns at the north and south Delta intakes, that will be evaluated in the EIR. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • If the top of the tunnel is about 100 feet below the surface, will these depths still be in the range of human habitation considering the deposition of the Delta over the years and sea level rise?

    The environmental impact analysis for Delta Conveyance will include evaluation of cultural resources, including potential areas with human habitation. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • What is the subsidence potential for hitting various unknowns such as sand lenses?

    During the design phase, soil investigations would identify soil types and groundwater pressures by location to allow for planning of adequate soil conditioners and TBM face pressures. Control of the amount of ground loss through the TBM face would be an important factor in controlling the ground surface and reduce the potential of ground surface settlement. Conditioning of excavated soil would help to control movement of material through the screw auger. The TBM operator would coordinate the TBM advance rate with the amount of material moving through the screw auger and onto the transfer conveyor.


  • Where are the alternatives that are being suggested in scoping meetings?

    Alternatives are developed by DWR as part of completion of the EIR in accordance with CEQA, including consideration of scoping comments. Scoping comments will inform the development of alternatives. At this time, DWR has only asked DCA to evaluate the proposed project corridors specified in the NOP. Because it is more cost-effective to evaluate different flow capacities at one time, DWR also asked DCA to evaluate a flow capacity of 6,000 cubic feet per second (cfs) and three different flow capacities as alternatives (3,000; 4,500 and 7,500 cfs). However, it is not a commitment that the alternate flow capacities will be analyzed in detail as alternatives.


  • Heritage would be an important factor to add to the siting ranking criteria. In one of the previous meetings a comment was made about staying out of environmental considerations. How can at least some high-level aspects of environmental considerations be completely disregarded in the ranking of potential sites?

    “The DCA siting analyses presented at the SEC are focused on design and construction considerations of physical facilities. Environmental considerations will be evaluated as part of CEQA and may require iterative review of sites through the engineering siting studies.

    The EIR will describe impacts to the physical, biological and human environment, including considerations for heritage uses, related to construction and operation of the proposed project and the alternatives as part of the EIR. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.”


  • How long would it take a salmon fry to move past ¼ mile of intakes and how many times would that fry have to swim back out of the flow? Is it possible that the outgoing tide at the lower end of the screen will be full of dead fish that didn’t have the stamina to continue swimming for the entire length of the intake, and how has that been factored into the design?

    The fish passage time across the intakes would depend upon the flow velocity in the Sacramento River, depth of the water and fish swimming patterns across the river and along the river banks, which varies by fish species. The intake would be designed and permitted in accordance with design criteria established by fish biologists for the National Marine Fisheries Service, U.S. Fish and Wildlife Service and California Department of Fish and Wildlife. The permit is likely to include many items, such as requirements for fish refugia along the intake structure to provide a space without fish screens to allow fish to rest. During the permitting process, fisheries biologists will be analyzing the effects of the intake structures and screens on a range of fisheries species, including Delta smelt, salmon and steelhead. This comment is related to the scope of DWR’s EIR and other permitting processes; please consider submitting this comment through DWR’s CEQA scoping process.


  • Do any of the images or videos shared show tunneling through peat soils?

    The demonstrations shown likely did not show peat soils. For the Delta Conveyance tunnel, based upon existing available geotechnical information, peat soils would not exist at the depths of the tunnel excavation (approximately greater than 100 feet below the ground surface).


  • How does the project team know about the soil composition at the depths of the tunnel, which is over 100 feet below the surface?

    “The geotechnical team has collated data from soil borings conducted not only for the prior project but from other construction projects across the Delta, including design documents for roads, bridges and levee improvements. Based on this data, there is a reasonable understanding of the depth of the competent soils. While there is still some information that needs to be obtained, it appears that the tunnel would not be constructed in peat soils.

    Additional geotechnical information would be collected prior to the completion of design. If peat soils occurred at depths considered for the tunnel, the design would be modified to lower the tunnel to competent soils below the peat soils.”

Facilities


  • Regarding flow at the intake: At the last meeting someone asked about negative or reverse flow in the river at the intake. There was an instant response of, “No, never negative,” but I wonder what that looks like at high or low tide. That is a big issue out here, and I personally would like to understand those flows at the intake during the complete tide cycle, i.e., top, bottom, half tide rising (flooding), half tide falling (ebbing). At full “take” what are the flows just above, just below and going out of the system? I assume that just below there is always a positive downstream cfs there even when it is peak flooding. Specific numbers like that would help. It would probably be good to measure during the driest drought time, low river flow. If we can get those flows, I can put stuff like that to bed when talking with people.

    The project would not significantly impact the magnitude of reverse flows that would already occur in the river/Delta system.

    The project would divert water until the tidal flow in the river approaches a preset minimum outward flow rate (i.e., towards the ocean). The diversion rate would be reduced proportional to the reduction in the outward river flow rate as the tide comes in. At some preset minimum outward river flow rate, diversions would be stopped by closure of the intakes. In summary, the project would only divert at the maximum capacity when the river flow rate exceeds a specific high preset outward flow rate. The diversion rate would be reduced in steps as the outgoing river flow rate declines and would stop completely if the outward river flow rate reaches the preset minimum rate prior to a dominant incoming tidal flow rate.

    Flow histograms illustrating the river and diversion flow rates across tidal cycles will be generated from an extensive modeling process as part of the preparation of the EIR.


  • What constitutes a recreational facility in terms of representing sensitive receptors?

    The map presented at the December Stakeholder Engagement Committee meeting was prepared with information collected in past studies. The recreational areas shown on that map included fishing marinas, parks and wildlife viewing areas that could be affected by noise, light and air quality emissions. The database used for this map also included support facilities for the recreation areas, such as power poles. The database has been updated using information from California state agencies, and the updated map with recreational facilities was presented at the February 26, 2020, Stakeholder Engagement Committee meeting.

    The database has been updated, and a map including public schools, hospitals, fire stations and local law enforcement was developed to represent sensitive receptors. It was presented at the February 26, 2020, Stakeholder Engagement Committee meeting. A separate map with publicly available marinas, boat launches, refuges and habitat preserves has been completed and was presented at the February 26, 2020, Stakeholder Engagement Committee meeting.


  • Is there a map reflecting existing water infrastructure and facilities such as intakes, diversion works and conveyance facilities?

    This map was presented to the SEC during the February 12, 2020, meeting.


  • Would it be possible for the upcoming packet to get a map with the alignment for the tunnel that has the following? 1) Highways, railroads — any major infrastructure that is easy to label. It needs a few more markers for users. 2) A legend for miles. 3) Names of the islands through which it passes and refuges — public boat launches if time permits. My request is for readability.

    All maps presented since January 2020 at the Stakeholder Engagement Committee meetings include major highways, railroads, legend in miles and names of the islands. A separate map with publicly available launches, refuges and habitat preserves has been completed and was presented at the February 26, 2020, Stakeholder Engagement Committee meeting.


  • Can we have the GPS coordinates of the three favorable intake sites?

    “The approximate GPS coordinates for the intakes described at the January 22, 2020, SEC meeting are provided below. As discussed in the January 22, 2020, SEC meeting, the intake sites are preliminary and sites may shift in location. These coordinates are for informational purposes only and are at the approximate center of the intake sites.

    Intake Latitude Longitude
    Intake 1 38.406611 -121.51307
    Intake 3 38.380871 -121.518795
    Intake 5 38.349012 -121.532294


  • Is there a possibility that the geotechnical reports DWR is currently conducting could change where the intakes are located?

    It is possible that geotechnical conditions may result in minor adjustments to facility locations within currently identified intake sites; however, major changes are not anticipated at this time.


  • How will this facility be kept operational once it is constructed considering the amount of dewatering that needs to occur?

    After construction, the water level in the facility would be higher than the surrounding groundwater. Also, the site would be surrounded by a slurry cutoff wall. Based upon existing geotechnical information, it is anticipated that the slurry walls would be extended to clay lenses to essentially isolate the site from surrounding surface water and groundwater. Dewatering would be expected to be a more significant issue during the early construction phases than during the operation phases. DCA is currently evaluating the estimated dewatering needs to maintain groundwater levels suitable for construction. DCA is also currently evaluating estimates for operational dewatering needs, which will be limited to periodically dewatering the basins for infrequent maintenance. At this time, only limited geotechnical data is available near the intake sites. Additional geotechnical investigations would be completed prior to design. Final determinations for protecting the sites from seepage into or out of the site and to quantify the dewatering needs would be revised following the geotechnical investigations.


  • Will the sediment basin be lined and, if not, will the basins be in groundwater from 4 or 5 feet below existing ground level and below? Does DCA expect the slurry walls to keep them out of the groundwater?

    The bottom of the sedimentation basins at the intakes would be located below the groundwater elevation. As described at the January 22, 2020, SEC meeting, the intakes, including the sediment basins, would be surrounded by a slurry wall. Slurry walls would serve to isolate the sediment basin volume from the surface water and groundwater to minimize the potential for seepage either into or out of the sedimentation basin. Based upon the geological information available for the intake locations, it appears that there are adequate clay lenses below the bottom of the sedimentation basin to isolate the intakes from surrounding groundwater. Therefore, it is currently not anticipated that the basins would require lining except for placement of riprap along the sides. Additional geotechnical investigations would be completed prior to design. The determination to provide linings for the basin would be based upon the additional geotechnical investigations.


  • Will there be discussion about the flow capacity used, and will it be pressurized or not pressurized?

    The NOP described the project with a capacity of 6,000 cubic feet per second (cfs) with a possible range in capacities of 3,000 to 7,500 cfs. At this time, DCA is considering tunnel sizing design criteria for gravity flow from the intakes to the pumping plant near the Southern Forebay. DCA is not considering design criteria for pressurized flow in the tunnel.


  • Is the corridor that was proposed through the Deep Water Ship Channel with an intake near Rio Vista still a possibility?

    DWR did not identify the corridor through the Deep Water Ship Channel as part of the proposed project in the NOP. However, this approach may be considered as an alternative. These types of alternative concepts should be submitted to DWR through the scoping process for consideration during the alternatives formulation process.


  • How much water is being pulled out and from where?

    In the Notice of Preparation (NOP), DWR identified that the proposed project could divert up to 6,000 cfs with two intake facilities. These intake facilities are indicated on the NOP map along the Sacramento river between Freeport and the confluence with Sutter Slough. DWR would not be seeking new water rights for these diversions but would apply to the State Water Resources Control Board for a change in the point of diversion for its existing water right.


  • Have there ever been three intakes of a similar size using tee screens within the same proximity on the same river?

    Intake fish screens constructed along the Sacramento River near the city of Sacramento or in the Delta were smaller than the intake fish screens being considered for the Delta Conveyance program.


  • Would construction of the maintenance and reception shafts use the same staging areas (e.g., parking lots, roads, etc.) as the launch shafts?

    The locations of the maintenance, reception and launch shafts would be in separate locations, so access, support and staging facilities would also be separate.


  • Are the safe haven shafts included as part of the planned components, or are they only created in case of emergency?

    In the previous project, “safe haven” shafts were identified to allow for maintenance and repair of the tunnel boring machine outside of the tunnel. These shafts are referred to as “maintenance shafts” in the Delta Conveyance program.


  • In order to provide adequate comments on any questionnaires or proposed siting, we need actual maps and coordinates. Stakeholders primarily want to know if it the project comes through their property.

    Locations of potential facilities, at this time, were presented at the March 11, 2020, SEC meeting. However, these locations could change in the future.


  • Are the launch shafts about 100 acres?

    The size of the tunnel launch shaft construction area would be based upon the drive length between the launch shaft and the reception shaft because the launch shaft location would include area for tunnel segment storage, RTM testing, RTM dewatering and treatment and RTM storage. The longer drives would need more area for tunnel segment storage and RTM handling and storage. For each launch shaft, the area could range from 250 to over 400 acres.


  • Are the maintenance and retrieval shafts about 10 acres?

    The maintenance and reception shaft construction areas would be approximately 10 acres in size.

 

Other


  • Can you provide clarification about how DWR will reflect and characterize SEC participation in the EIR?

    See attached memo.


  • At the last meeting, a letter from a member was shared that said the intakes at these locations could not be approved by the Water Resources Control Board and Delta Stewardship Council during the WaterFix project. What has changed since the previous project to make the proposed intake sites viable?

    This statement does not accurately reflect the history of the California WaterFix project. During the previous California WaterFix project, the evaluation of the application for Change in Point of Diversion to the State Water Resources Control Board (SWRCB) and the appeal of the Certification of Consistency by the Delta Stewardship Council were not completed because the California WaterFix project was withdrawn. Although there were many questions discussed in hearings conducted through these processes and requests for additional information, the change petition and Certification of Consistency process did not make final findings regarding the previous project. As the Delta Conveyance program continues, new water rights applications and Certification of Consistency, as well as many other permit applications, are expected to be prepared for review by the regulatory agencies.


  • It would be important to put the ITR into context, including how the ITR is the opinion of one group of people.

    The ITR report is merely a single data point. As such, it is being considered with the evaluation results of many design, construction and operations considerations. The ITR report only considered a subset of the engineering and geographical issues relevant to tunnel construction activities, as noted by several tunnel construction contractors and tunnel manufacturers, and does not represent detailed conclusions about Central or Eastern Corridor options. Moreover, the ITR expressly did not consider other relevant environmental factors that will be considered through the CEQA process.


  • Is there an option to have more intakes with a smaller capacity?

    DWR identified three intake locations and a range of capacities to be considered in the NOP and asked DCA to develop plans for these options. This comment considering additional options is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.

 

Safety


  • How will first responders be informed of all the construction and be able to respond to emergencies that occur in the tunnel?

    Due to the lengths of the tunnel drives and the locations of the potential construction sites, first responders could be required to be located at most of the construction sites to provide response in the required time limits. With or without on-site first responders, all fire, police, ambulance and hospitals in the area would be notified prior to and during construction of major construction activities and potential traffic considerations along roadways. The environmental impact analysis for Delta Conveyance will include evaluation of emergency services. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Is the project subject to the jurisdiction of the Mine Safety and Health Administration (MSHA)?

    MSHA has jurisdiction over mines (i.e., places where minerals are extracted) and related facilities. This does not include water conveyance tunnels (MSHA Program Policy Manual, Section I.4-1). The proposed project would not qualify as a mine.


  • The proposed project is a 40-foot diameter TBM that is tunneling 40 miles. There may be four TBMs, but the process is the same. What happens if the TBM gets stuck? What about safety in the tunnels?

    There will be multiple TBMs on the project, and they are all expected to use a pressurized face method of excavation (i.e., earth pressure balance and/or slurry shield TBMs). Maintenance shaft spacing would be about every 5 miles and would be sized to allow for major repairs of the TBM at those locations, if necessary. Because the TBM would have major maintenance reviews and repairs approximately every 5 miles, it would not require major repairs between the shafts. The specifications would also require that many of the major TBM parts; like the main bearing, seals and other parts; would be replaceable from within the tunnel in case some repairs are necessary between shafts. This approach is actually more conservative than that recommended by the ITR. Worker safety in tunnels is dictated by the regulations provided under Cal/OSHA’s Tunnel Safety Orders, which are very prescriptive in terms of the working conditions for such essential items as adequate ventilation, illumination, ingress/egress and other items to comprehensively address worker safety.

Transportation/Traffic


  • Can you provide the truck trip estimates for operational traffic for hauling away sediment?

    The estimated amount of sediment to be removed at the intakes will be calculated following the completion of the EIR operational modeling. When the sediment volumes are calculated, the number and frequency of trucks needed to haul sediment during operations will be calculated.


  • Can the informational materials please represent barge and rail trips as round trips?

    All data related to barge and rail trips presented to the Stakeholder Engagement Committee have been described as “round trips.” Future presentations will include the specific units.


  • Is it feasible to use barges at all, since opening the bridges stops the traffic in both directions?

    The environmental impact analysis for Delta Conveyance will include evaluation of road traffic on operable bridges to allow for barge traffic. This comment is related to the scope of DWR’s EIR; please consider submitting this comment through DWR’s CEQA scoping process.


  • Is new rail siding needed on existing rail lines if rail is used, or will DCA build a spur to the launch sites?

    Currently, DCA is considering construction of railyards adjacent to the railroad tracks at locations along the Interstate 5 corridor. Materials would be moved on conveyors and/or trucks from the new railyards to and from the tunnel launch sites. At the tunnel launch shafts in the southern Delta, DCA is considering extension of the new sidings to the tunnel launch shaft sites. Any changes would be subject to environmental review.


  • Does the slide showing truck trips per day reflect the number for one shaft or for multiple shafts? Are all of the shafts constructed simultaneously or is their construction staggered?

    The data in the presentation was shown for one launch, maintenance or reception shaft site. The launch shafts would be located approximately 15 miles from the reception shaft with maintenance shafts located approximately every 5 miles between the launch and reception shafts. Several tunnel boring machines could be operating at launch shafts simultaneously; however, the schedules have not been completed at this time.


  • Has DCA determined if these trestle bridges would be a hazard for either the trains or the workers in the dig areas? Will the TBM be tunneling under the bridges?

    The tunnel alignment would be constructed more than 120 feet below the ground surface, including foundations of trestle bridges. Prior to the completion of design, geotechnical field investigations would identify the soil types and locations as well as the groundwater pressures along the entire alignment, including areas of concern such as levees and bridge foundations. Based upon the results of the geotechnical information, the TBM operator would control the rate of boring to minimize changes in the soil structure above and below the TBM.


  • Where would barges be parked at nights and on weekends?

    The DCA team includes barging specialists. The DCA is developing barge landings as well as rail-served material depots to reduce truck traffic. The plans being developed by DCA will include areas where barges are staged to allow loading and offloading at the landings. This information will be provided at a future SEC meeting.

Tunneling/RTM

Coming soon

June 17, 2021
June 17, 2021

Q & A Library

Do you like it?
Read more