Transmission Line Replacement. The installation of the new 24‐inch pipe will be done so through the use of a Horizontal Directional Drill (HDD) to avoid impacts to Xxxxx Creek waterway and sensitive habitat within the Xxxxx Creek Historic State Park. Pipeline replacement would require entry and exit pits to be excavated for the proposed HDD that would be approximately 15 feet wide by 30 feet long and 10 feet deep. The HDD for the pipeline installation would be installed at a maximum depth of 48 feet deep at the point where the new pipe would cross under Xxxxx Creek using an angled drill with a round‐shaped drill bit to dig the bore hole. No impacts to the bed and bank of Xxxxx Creek would occur. An excavator and backhoe will be used to excavate the exit and entry pits for the HDD. The new pipeline will be strung to the north of the HDD exit point off of Miwok Avenue that will require approximately a 50‐foot‐wide by 2,800‐foot‐long workspace for pipeline pull‐back and stringing. Construction crews will deliver the pipe in segments and the pipe will be laid out on rollers. Crews will then begin coating the pipeline and weld the pipe segments together. Welds will be x‐rayed to ensure welds are properly conducted. The new pipe installed will be hydrostatically pressure‐tested (hydro‐ tested) to ensure pipe integrity before the line is brought into service. Hydro‐testing, which is the industry standard for testing pipelines and pressure valves, is a method of verifying the maximum operating pressure and ensuring the integrity of a pipe. Test water for the hydro‐test would be trucked to the work area from a municipal source. Hydro‐testing would occur within the project workspace adjacent to Miwok Avenue. Once the pipe is filled, the water pressure would be slowly raised to the appropriate test pressure for a minimum of 8 hours. At the end of the test, the piping would be emptied of water and the water would be collected into liquid storage tanks, such as Xxxxx™ Tanks, staged within the project workspace. After hydro‐testing is completed, the test water would be hauled offsite to an appropriate disposal site or used onsite for dust control. If hydro‐test water will be used for onsite dust control, free standing water would not be allowed to collect onsite, and water would not be allowed to enter any waterways or drainages. Once the new pipe has been successfully hydro‐tested, crews will string out the pipe using side‐ boom cranes. The HDD process would be accomplished with a drill rig that sit...
