271 Mr. Tim Cass Water Resources Specialist San Diego County Water Authority 321 Fifth Avenue San Diego, CA 92103-4100 Dear Mr. Cass: Draft Environmental Impact Report for the Gregory Canyon Landfill The Metropolitan Water District of Southern California (Metropolitan) acknowledges receipt of your facsimile transmittals dated March 11 and March 17, 1999, detailing draft responses and comments to the prepared Draft Environmental Impact Report for the Gregory Canyon Landfill, dated January 1999. The Gregory Canyon Landfill project includes the construction, operation, and final closure of a Class III landfill, with a 30 million ton capacity, primarily located south of State Route 76, approximately three miles east of Interstate 15 in northern San Diego County. The proposed site is located adjacent to, and south of, the San Luis Rey River. San Diego Pipelines Nos. 1 and 2 and the approved San Diego Pipeline No. 6 traverse the proposed project site in a north-south direction. Although those portions of the existing and future San Diego pipelines that may be directly impacted by the proposed landfill are within the jurisdiction of the San Diego County Water Authority, a segment of each of the pipeline facilities within the proposed "open space" mitigation area is under the jurisdiction of Metropolitan. Metropolitan appreciates the opportunity to respond to the Draft Environmental Impact Report (DEIR) and your efforts to have us participate in the North County Landfill Working Group. We believe that this working group has been instrumental in consolidating and coordinating the concerns of the local and regional water districts potentially impacted by the proposed project. Metropolitan also has had the opportunity to review your draft comments to the submitted DEIR and fmd them to be detailed in their review of relevant sections of the report. As an alternative to detailing our comments to each relevant section of the report, we have tried to classify our principal concerns and then relate them to relevant sections of the report. The following discussion supports our determination that the DEIR is inadequate and Mr. Tim Cass Page 2 does not comply with the California Environmental Quality Act (CEQA) because the significant impacts to the regional water distribution system were not accurately presented or were insufficiently dismissed as being less than significant. These actions are not in compliance with Section 15064 of the State CEQA guidelines. Primarily Metropolitan is concerned with the following principal items: 1. 2. 3. Protection of the existing San Diego Pipelines Nos. 1 and 2 Protection of the Pala Basin aquifer Protection of the approved San Diego Pipeline No. 6 alignment through the planned landfill site 1. Protection of existing facilities: The statements in the Executive Summary (Page ES-6), the Compatibility With Existing Land Uses (Section 4.1.3.4) and the exposure of environmental protection controls to potential failure (Section 4.2.3.6) all indicate that the project has been designed to protect the SDCWA First Aqueduct (San Diego Pipelines Nos. 1 and 2). Therefore, the report concludes that relocation of the First Aqueduct is not considered to be a component of the project and a potential relocation option is only being included to cover a potential interest by SDWCA in relocating the pipelines. These statements are inconsistent with established guidelines for the protection of major water distribution facilities. Proposition C requires that the "project will include work required to protect the San Diego Aqueduct pipelines to the extent and in the manner required by the San Diego County Water Authority." As presently designed, the proposed landfill project does not and can not protect the pipelines for the following reasons: (a) The footprint for the proposed landfill lies along the eastern easement boundary of the San Diego First Aqueduct. At a number of locations the pipelines are located above and within the drainage tributary area of the proposed landfill. This condition is detailed on Sheet 23 of 24 of the . 100-Year Developed Condition Hydrology Map, Volume 1 - Appendix G of the Technical Appendices. These existing pipelines coupled with the future San Diego Pipeline No. 6 are subject to catastrophic failure and are located less than 100 feet west of the proposed landfill. Should these pipelines fail, either due to a seismic event, a rupture caused by blasting to Mr. Tim Cass Page 3 excavate the landfill or for excavation purposes within the borrow area, or due to leachate corrosion of the pipe material, the discharge from these pipelines could completely overwhelm the proposed peripheral drainage system. Section 4.4.3.2 indicates that the perimeter storm drain system along the west side of the proposed landfill has been "designed to handle peak flows that would occur under a combination of 100-year flood conditions plus discharge from the adjacent SDCWA aqueduct.... The current design features are built to protect the landfill from the catastrophic failure of the existing Pipelines 1 and 2, and the future Pipeline No. 6. For more detailed calculations, see Appendix H." Unfortunately, Appendix H only includes a Preliminary Bridge Report from Nolte and Associates, Inc., dated February 25, 1998, and makes no reference to perimeter or peripheral drainage designs. Section 3.4.3.1 states that "the perimeter drainage channel along the west side of the landfill will be designed to accommodate discharge that could occur from a break in the existing water aqueduct (Pipelines 1 and 2), as well as the potential future Pipeline No. 6." Although the report fails to detail the design of the proposed perimeter channel, details that do exist clearly indicate that the proposed channel will be unable to accommodate the potential flows from San Diego Pipeline No. 6 (Section 5.1.5.4 details a potential San Diego Pipeline No. 6 flow of up to 636 cfs) regardless of potential additional flows from San Diego Pipelines 1 and 2, and/or a 100-year storm event. The risks associated with having high pressure large capacity water pipelines directly above a proposed landfill are unwarranted. Proposals to excavate the landfill site through the use of blasting will only contribute to the concerns. The Phase IV Excavation Plan as shown on Exhibit 3-23, details a proposal to excavate approximately 23,000 cubic yards of rock, adjacent to the pipelines and above the active landfill. Section 4.6.3.4 states that vibrations as a result of blasting could potentially affect the integrity of the aqueduct, including stability and structural soundness. Clearly, this level of assurance is unsatisfactory. Should the pipelines break, they will discharge both down the slope, and depending upon the internal pressure of the pipeline, discharge into the air potentially for hundreds of feet. With local prevailing winds or a specific type of pipeline rupture, the column of water could be directed on to the Mr. Tim Cass Page 4 landfill. The rupture would also tend to wash away surrounding soil from the pipeline, causing a complete failure of the line. The peripheral channel is clearly not designed to accommodate the potential flows from a ruptured pipeline. As a result, the discharge flows have the potential to seriously compromise the structural integrity of the landfill, completely overwhelming any future drainage system. Should one or all of the pipelines fail above the proposed landfill, the potential exists for the resultant water flow to carry refuse out into the Pala Basin of the San Luis Rey River, thus compromising the water quality of a strategic groundwater resource in northern San Diego County. It is Metropolitan's contention that any proposal which would include a provision for retaining large diameter high-pressure water pipelines critical to the health and welfare of San Diego County, within the drainage tributary area of a landfill, within 100 feet of the landfill, and subject those same pipelines to impacts from adjacent explosions, should be seriously questioned. As presently detailed, the proposed project would likely compromise the existing and future pipeline facilities. (b) Section 3.5.3 of the report indicates that up to 9,000 gallons of leachate may be generated each day. "Any leachate recovered from the system will either be utilized on-site, transported...." Proposals to spray leachate as a dust suppression proposal on the active landfill could have serious consequences for the structural integrity of the aqueduct and for the water quality within the aqueduct Considering that the proposed landfill abuts the existing aqueduct right-of-way, coupled with potential for wind gusts in the area, it is highly that leachate being used for dust control purposes, as proposed in the DEIR, will be dispersed over the aqueduct right-of-way. Since San Diego Pipelines Nos. 1 and 2 are treated water pipelines, we understand that there are little or no opportunities for intercepting or analyzing water quality before the water reaches the customer. Due to the high amount of harmful chemicals in leachate, which are partially detailed Volume 1 - Appendix G of the Technical Appendices, the introduction of leachate into the right-of-way of the San Diego Pipelines Nos. 1, 2, and 6 should be considered unacceptable. Mr. Tim Cass Page 5 (c) Volume 1 - Appendix F of the Technical Appendices details a geophysical study of the potential borrow areas proposed as an integral segment of this project. Borrow Area B is clearly identified in a drawing titled "Gregory Canyon Landfill, Figure 1." The proposed borrow site has an area of 1,889,160 sq. ft., with an anticipated depth of up to 150 feet, with a proposed extraction of 3.2 million cubic yards. Borrow Area B is underlain by a very thin mantle of residual soils (1 to 5 feet). Figure 1 also clearly identifies the existing aqueduct easement. The proposed Borrow Area B is shown to substantially overlay the existing aqueduct easement. Metropolitan and SDCWA have plans for the approved San Diego Pipeline No. 6 through the subject area. The pipeline alignment is immediately west of, or within the existing San Diego First Aqueduct right-of-way. The Final EIR for the San Diego Pipeline No. 6 Project was certified by Metropolitan's Board of Directors on June 15, 1993, and is available to the County of San Diego Department of Environmental Health for review. The alignment of the approved San Diego Pipeline No. 6 and the proposed location of Borrow Area B appears to be incompatible. San Diego Pipeline No. 6 would intersect a considerable portion of the proposed borrow site. Due to the geophysical characteristics of the proposed borrow site, the use of explosives is considered a necessity and is included in the Gregory Canyon Landfill DEIR. The DEIR indicates that the SDCWA has adopted the blasting criteria provided in the United States Bureau of Mines RI 8507 report. This report details a total allowable transverse displacement of up to 2 inches per second with a blast frequency of 40 Hz, reducing to 0.50 inches of blast frequencies of 10 Hz. Section 4.6.1.6 indicates vibration levels of over 14 inches per second at instrumentation locations 100 feet from the test blast locations, although they caution that open-face blasting should reduce this peak motion by nine times. Table 4.6-9 details the minimum blast distance from the aqueduct that is necessary to meet the Bureau of Mines RI 8507 standards. Since this distance is a minimum it is factored by 1.5 to arrive at a recommended distance. These recommended minimum blasting distances from the aqueduct range from 132 feet for blast frequencies of 40 Hz to over 750 feet for blast frequencies of 5 Hz. These values are tabulated for openblast only. It is also highly likely that some charges will be fired in confined environments, for example, to open up holes, etc. Minimum distances necessary for charges fired with a high degree of containment would be significantly larger. Considering the long distances recommended by the reports which were commissioned by the project proponent, and the proposed plans which detail pipelines adjacent to a landfill footprint and intersecting a proposed borrow pit, both of which incorporate blasting, any proposal to retain the existing or future pipelines in such an inhospitable area should be wholly unacceptable and incompatible with the existing land use. The proposed relocation alignment, as detailed in Section 3.4, Exhibit 311, does not include any provisions for relocating around the proposed Borrow Area B and is therefore also incompatible with existing land uses. (d) The proposed San Luis Rey River Bridge would channel river flow, increase river velocity due to the channelization and scour of the river bed, and therefore, potentially exposing the existing San Diego First Aqueduct. No study on the change in river configuration and the potential effects or impacts of such a change are included in the report. Our determination indicates that protection of the pipelines with the construction of a weir structure, or relocation of the pipelines to a new crossing, should be given consideration. (e) The DEIR details a proposed landfill access road over the existing San Diego Pipelines Nos 1 and 2. It is proposed that a concrete slab will be installed to accommodate the proposed traffic loads. Since the access crossing is proposed in an area with alluvial fill material, there exists the potential that a protective slab may not be able to assist in resisting settlement concerns. The protective slab may require supporting piles, drilled to the depth of bed rock, or as an alternative the pipeline should be relocated. (f) The DEIR proposed a leachate collection tank immediately upstream of the existing and future San Diego Pipelines. The tank is proposed to have a capacity of 10,000 gallons. Section 3.5.3 indicates that the maximum daily leachate generation rate is approximately 9,000 gallons. Such leachate will either be utilized onsite, transported away or injected into a Mr. Tim Cass Page 7 flare system for destruction. Should the landfill be closed for only one day, the capacity of the collection tank for leachate may not be adequate. Due to the close proximity of the existing and future pipelines to the leachate collection facility, the location of the leachate collection facility upstream of the existing and future pipelines, the lack of any protective berms around the leachate facility, the high traffic at the collection tank in order to continually ensure the leachate is removed promptly and the high corrosiveness of leachate on concrete pipelines, it would appear that the potential exists for leachate to be accidentally spilled in the direction of the pipelines. Since these pipelines are treated water pipelines with little or no facilities for intercepting contaminants, every effort should be made to ensure protection of the existing pipelines or relocation of the collection tank and/or existing and future pipelines. 2. Protection of the Pala Basin Aquifer: As identified in the Summary Table, on page ES-12, the proposed mitigation (MM4.3-1c) for production wells (nos. 34, 41, and 42) that might become contaminated is not sufficiently assessed in the DEIR. The possible menu of measures (e.g., pump-and-treat, bio-remediation, air-sparging, in-place reactive treatment) may not remedy the contaminated situation immediately, hence resulting in a potentially significant hydrogeologic impact to the Pala Basin Aquifer. As noted in the State CEQA Guidelines (Section 15126.4) "if a mitigation measure would cause one or more significant effects in addition to those caused by the project as proposed, the effects of the mitigation measure shall be discussed....." Additionally, as indicated earlier, the presence of blasting in the immediate vicinity of existing and planned high capacity and high pressure water transmission pipelines could lead to a catastrophic failure of the pipelines. Should one or all of the pipelines fail above the proposed landfill, the potential exists for the resultant water flow to carry refuse out into the Pala Basin of the San Luis Rey River, thus compromising the water quality of a strategic groundwater resource in northern San Diego County. 3. San Diego Pipeline N. 6 The proposed landfill project will also have a significant impact on the San Diego Pipeline No. 6 Project. San Diego Pipeline No. 6 is ajoint project between Metropolitan and the San Diego County Water Authority. The project consists of approximately 6.5 miles of 9-foot diameter tunnel and 24 miles of 9- to 10-foot diameter pipeline. The Mr. Tim Cass Page 8 Final Environmental Impact Report (FEIR) for the project was approved by Metropolitan's Board of Directors in June 1993. Pursuant to CEQA, Metropolitan is the lead agency and the Authority is a responsible agency. The Authority's portion of the project, and its responsibility begins south of the Mount Olympus Tunnel portal and north of Pala Road, in the vicinity of the abandoned Lucio Dairy, The Authority's portion of Pipeline 6 will generally follow the alignment of San Diego Pipelines 1 & 2 through the proposed landfill and borrow areas, and thus could be impacted significantly by the proposed project. The proposed open space area north of the San Luis Rey River is incompatible with Metropolitan's proposed Mount Olympus Tunnel south portal. The south portal of the Mount Olympus Tunnel, a critical component of the project, is located in the small canyon north of Pala Road and just west of San Diego Pipelines 1 & 2. This portal site will be the tunnel contractors main base of operations for approximately four years, and will remain as a permanent access point for operations and maintenance of the tunnel. The Gregory Canyon Landfill DEIR only addresses the Authority's pipeline alignment portion, indicating that the pipeline can be located up to 1000 feet west of the existing pipeline corridor. There is no such flexibility identified in our FEIR with regards to the tunnel portal. The landfill project proponent must include Metropolitan's portion of San Diego Pipeline No. 6 including the planned tunnel portal site, as a related project in its DEIR with respect to potentially siginificant cumulative impacts to regional water supplies and water distribution systems. Otherwise, the Gregory Canyon Landfill DEIR does not comply with CEQA and the State CEQA Guidelines with respect to cumulative impact analysis. In addition to the specific concerns relating to the protection of San Diego Pipelines Nos. 1 and 2, the acknowledgment of the approved San Diego Pipeline No. 6 project and the potential threats to the Pala Basin aquifer, Metropolitan also notes that the DEIR incorrectly references the location for the change in operations and maintenance responsibilities for the various San Diego pipelines. Section 4.15.3.1 of the DEIR incorrectly states that the "SDCWA maintains two aqueducts (First and Second) from the point at which they leave the Riverside County line." The subject section also states that "agency control over the Aqueduct in the project site lies with SDCWA whose jurisdiction begins at the Riverside County border. North of the Rainbow area, the Metropolitan Water District (MWD) operates the First Aqueduct." Mr. Tim Cass Page 9 Our records indicate that the terminus for Metropolitan's jurisdiction of the First Aqueduct does not end at the Riverside County line or north of Rainbow, but potentially just within the proposed "open space" area north of the San Luis Rey River. In addition, Metropolitan and the SDCWA have plans for the approved San Diego Pipeline No. 6 through the proposed project site. The location of the Mount Olympus Tunnel portal site is shown to be north of, and adjacent to, State Route 76, within the proposed project site. Metropolitan's operation and maintenance responsibilities for the approved San Diego Pipeline No. 6 will terminate at this portal site. Section 6.4.2.1 of the Gregory Canyon Landfill DEIR also incorrectly identifies the name and ownership of the aqueduct with traverses the alternative potential landfill site at Aspen Road. The first and fifth paragraphs should be corrected to indicate that the pipelines are San Diego Pipelines 4 and 5 rather than San Diego Pipeline No. 1, and that they are owned, operated and maintained by Metropolitan rather than SDCWA. Per your request in your March 17, 1999 transmittal, Metropolitan is also submitting comments to the DEIR to the San Diego County Department of Planning and Land Use. These comments are abridged to reference only concerns related to impacts from the proposed landfill on those existing and approved pipelines and tunnels which are specifically Metropolitan's responsibility. The comments contained herein are being forwarded to SDCWA for your review and consideration in conformity with our participation in the North County Landfill Working Group. Should you have any questions or require additional information, please contact Mr. Leslie Barrett of our Project Management Branch at telephone (213) 217-6245, or at e-mail lbarrett@mwd.dst.ca.us . Very truly yours, Original Signed by Laura J. Simonek Principal Environmental Specialist LJB /Zg•