Full Public Notice Mitigation Plan Pipeline Project Terminal Plans
PROJECT DESCRIPTION: The applicant proposes to construct, install, operate, and maintain structures and equipment necessary for liquefaction and export of natural gas, including construction of a gas supply pipeline with compressor stations and attendant features, and a LNG terminal with marine facilities.
The applicant proposes to construct and operate a 10.2-mile-long, 30-inch-diameter pipeline that would provide natural gas to Texas LNG’s proposed natural gas liquefaction, storage, and export facility (Terminal). The proposed underground pipeline would interconnect with the Valley Crossing Pipeline currently being constructed by Enbridge, Inc. The pipeline would be collocated with the Valley Crossing Pipeline or SH48 for nearly its entire route. The pipeline would be installed using conventional open-cut methods. At two locations (mileposts 4.5, San Martin Lake, and 6.1, Bahia Grande Restoration Channel) the pipeline would be installed using the horizontal directional drill (HDD) method. The HDD contractor would monitor both the surface along the lateral route between the entry and exit points of the drill and the circulation of drilling mud throughout the HDD operation for indications of an inadvertent drilling mud release and would immediately implement corrective actions if a release is observed or suspected. Pipeline construction would require a 100-foot-wide construction right-of-way (ROW), additional temporary workspaces, and several temporary access roads, all of which are pre-existing. The construction ROW would be temporarily cleared of vegetation for pipeline construction, temporary storage of trench spoil, and the operation of heavy equipment. In areas of saturated soils or standing water, temporary timber construction mats would be placed to support vehicles and construction equipment. Excavated trench spoil would be deposited in wetlands adjacent to the trench within the construction work area. Typically, the trench would be sufficiently deep to provide for a minimum of three feet of cover over the pipeline. In certain areas, such as road or buried utility crossings, deeper burial would be required. Once the pipeline is installed the trench would be backfilled and any excess subsoil would be removed from wetlands. A 25-foot-wide permanent maintenance ROW is proposed.
Terminal features include: gas gate station and interconnect facility; pretreatment facility for carbon dioxide removal and dehydration; turbo-expander for pentane plus heavy carbon removal; a Liquefaction Plant consisting of two liquefaction trains and ancillary support facilities; two approximately 210,000 m3 aboveground full containment LNG storage tanks with cryogenic pipeline connections to the Liquefaction Plant and berthing dock; an LNG carrier berthing dock capable of receiving LNG carriers between approximately 130,000 m3 and 180,000 m3 in capacity; a permanent material offloading facility (MOF) to allow waterborne deliveries of equipment and materials during construction and mooring of tug boats while an LNG carrier is at the berth; thermal oxidizer, warm wet flare, cold dry flare, spare flare, acid gas flare, and marine flare; and administration, control, maintenance, and warehouse buildings and related parking lots; electrical transmission line and substation, water pipeline, septic system, natural gas pipeline, and stormwater facilities/outfalls. Marine facilities at the Terminal would include a deep-draft LNG carrier berth and dock, an MOF, a 2,000-foot-diameter turning basin, and rip-rap slope protection. Approximately 1,792 feet of an abandoned underground 4-inch-diameter gas gathering line paralleling the Brownsville Ship Channel would be removed. A mechanical dredge may be used to dredge near installed pilings. Hydraulic pipeline dredges would be used to construct and maintain the proposed marine terminal/turning basin to a depth of -43 feet mean lower low water plus -2 feet of allowable overdepth, removing 3.9 million cubic yards of material. Dredged material would be placed in existing upland dredged material placement area (PA) No. 5A and/or No. 4A. Some dredged material may be placed on the Terminal site to raise the grade. Sediment is expected to accrete within the constructed marine facilities at a rate of 50,000 cubic yards annually, and a maintenance dredging cycle of 3 to 5 years is expected.
Approximately 74.3 acres of waters of the U.S. (WOUS) would be permanently impacted and 8.9 acres temporarily impacted for construction of the Terminal. The 74.3 acres of permanently impacted waters includes approximately 33.8 acres of openwater habitat between the terminal property boundary and the northern edge of the Brownsville Ship Channel, 40.3 acres of tidal mudflat, and 0.2 acres of palustrine emergent wetlands.