STATE OF CALIFORNIA, PETE WILSON,
Governor
March 6, 1998
RE: Variance Request #42 - Relocation of the following block and check valves on Alameda Street near the Dominguez Channel crossing of the Pacific Pipeline Project(Segment 5):
• Block valve from station number 6132+57 to 6118+05 (a distance of approximately 1452 feet north and upstream of the original block valve location).
• Check valve from station number 6143+84 to 6160+68 (a distance of approximately 1684 feet south and downstream of the original check valve location).
Dear Mr. Shauers:
We have reviewed the above-referenced variance request and approve your request, based on the following factors:
- In accordance with Mitigation Measure SS-29**, valves shall be installed along the pipeline alignment at "environmentally sensitive areas, areas of liquefaction/faulting/scour, and at pump stations." The subject valves have been incorporated into the project design to minimize the amount of oil that could enter the Dominguez Channel and eventually the San Pedro Harbor in the event of a spill and potentially impact the biological and hydrological resources of the channel and harbor.
- The valve relocations have been requested to accommodate the Alameda Street widening project, currently completed within the Dominguez Channel area. In a letter dated March 3, 1998 from the County of Los Angeles, Department of Public Works, the "proposed relocation of the valves must fall outside a section of the road that has been newly paved. Please be advised, the County of Los Angeles has a moratorium prohibiting excavation within two years of newly paved streets."
- The Dominguez Channel at the Alameda Street crossing is approximately five miles from San Pedro Harbor. The channel from the Alameda Street crossing to San Pedro Harbor is concrete lined (CPUC 1993), although silt has deposited on the channel bottom. Dominguez Channel is subject to tidal influence, but its flow is contingent upon rain events. The habitat in the Dominguez Channel has been substantially altered through channelization. No suitable foraging, roosting, or nesting habitat for wildlife species exists along or immediately adjacent to the proposed right-of-way (CPUC 1993).
- The original valve locations would have allowed a maximum of 638 barrels of oil to be released if the pipeline were to break (413 barrels from complete draining and 225 barrels from continued pumping). The proposed valve relocations would increase the amount of the oil available between the two valves by 1218 additional barrels; 1856 barrels total. The new site for the block valve is approximately 1860 feet from the center of the Dominguez Channel. The proposed check valve relocation site is approximately 2403 feet from the center of the Dominguez Channel.
- CPUC was concerned about the potential increase in "drainable" oil in the case of an accidental release at or very close to the Dominguez Channel. However, subsequent survey of the two proposed new valve sites and the original sites indicated that based on the specific topographic features of these locations, the relocation of the valves would not affect the total spill size that could enter the Dominguez Channel.
- The surveys conducted by the PPSI engineers indicated that the elevation of the installed pipe at the northern edge of the channel is 18.96 feet above mean sea level at the top of the pipe. At the revised block valve location, the elevation at the top of the pipe would be 15.63 feet above mean sea level. The elevation at the top of the pipe between the northern edge of the Dominguez Channel and the revised block valve location is at all points below the 18.96 feet elevation at the edge of the channel. Given the drop in elevation from the northern edge of the Dominguez Channel to the revised block valve location, crude oil would flow away from the Dominguez Channel in the event of a pipeline rupture, if the rupture were to occur to the north of the channel.
- The check valve location would be placed on the south side of the Dominguez Channel. The elevation of the installed pipe at the southern edge of the channel is 19.06 feet above mean sea level at the top of the pipe, while the elevation at the top of the pipe at the revised check valve location would be 9.67 feet above mean sea level. The elevation at the top of the pipe between the southern edge of the Dominguez Channel and the revised check valve location is at all points below the 19.06 feet elevation at the edge of the channel. Given the drop in grade from the southern edge of the Dominguez Channel to the revised check valve location, crude oil would flow away from the Dominguez Channel in the event of a pipeline rupture, if the rupture were to occur to the south of the channel.
- A rupture at the Dominguez Channel crossing, between the northern and southern edges would result in the release of crude into the channel. However, because of the drop in elevation of the pipe to the north and south of the channel, the relocation of the block and check valves further to the north and south, respectively, would not increase the volume of crude that could enter the channel if a rupture were to occur between the northern and southern edges of the channel. Therefore, no increased impact to the biological and hydrological resources of the Dominguez Channel would occur as a result of the block and check valve relocations.
- The following measures shall be implemented:
- All applicable mitigation measures for the project shall be implemented at the subject location.
- Written approval from the California State Fire Marshal shall be provided to the CPUC Lead Environmental Monitor prior to the construction of the subject valves.
- Sunday construction at the subject valve locations shall be allowed on Sunday, March 8, 1998.
- Implementation of this variance in accordance with the provisions noted above shall be verified on a random basis by a CPUC/ANF Environmental Monitor.
The number, type, and location of valves as proposed by PPSI in their project description in the EIR/EIS document is one of the significant parameters considered by decision makers in approving this project. Relocations are only allowed if imposed by unanticipated natural conditions, and only if no additional impacts are predicted.
The approval of Variance Request #42 is based on the applicable facts related to the subject valve relocations. This approval does not establish a precedent for the approval of future valve relocations, if so requested, since each request must be analyzed based on its own extenuating circumstances.
Sincerely,
