Line Section (LS)-9 Joint # 51580 Anomaly repair

Line Section (LS)-9 Joint # 51580 Anomaly repair

The purpose of the project is to repair an anomaly on joint number 51580 on Line Section 9 that is located in an unnamed irrigation canal in Upper Jones Tract in San Joaquin County. The irrigation canal is adjacent to the Mokelumne Aqueduct, approximately a half mile west on the confluence of Trapper Slough and Whiskey Slough. Aerial photography shows likely hydrological connection with Middle River about 4.5 miles west. However, the connection is obscured by an earthen levee, suggesting that a culvert or irrigation pump draws water into the canal from the river. The irrigation canal appears to be terminal, discharging into a nearby agricultural field. The unnamed irrigation canal is an approximately 15 foot wide constructed channel with no adjacent wetlands on either bank. Active agriculture are approximately 200 feet south of Line Section 9 and an elevated railroad is approximately 250 feet north. The 10 inch pipeline by Kinder Morgan Energy Partners, L.P. is used to transport refined petroleum products from Concord to Bradshaw, California. Excavation is typically required to visually inspect, and, if necessary, repair areas of the pipeline where anomalies were detected. To verify the anomaly features on the above named pipe section, a portion of the canal must be dewatered to allow for excavation and inspection of the pipeline. The site is perpendicular to a culvert crossing and access road where staging, lay down, and equipment operation will occur. A coffer dam approximately 20 feet long by 10 feet wide will be installed in a portion of the canal using sandbags, sheet piling, and/or a shoring box, and trench shoring. During construction, water will not be fully obstructed, but allowed to pass along the west half of the canal. Approximately 12 cubic yards of soil will be excavated from this area to inspect and repair the pipeline. After the coffer dam is installed, the hole will be dewatered to an upland area adjacent to the site using gas-powered pumps. De-watering pumps will be placed in plastic secondary containment basins and spill kits will be available on-site. The pipeline will be excavated using a standard rubber-tired backhoe and soil stockpiled on the road adjacent to the canal. After the pipeline inspection and potential repairs have been completed the excavation will be backfilled and the coffer dam removed. Upon completion of the project, the site will be restored to pre-existing conditions. Issuance of a Streambed Alteration Agreement Number 1600-2008-0388-3 is pursuant to Fish and Game Code Section 1602.

San Joaquin