Central Outfall Sewer at 59th Street and 4th Avenue Project (Archived)

A Mitigated Negative Declaration/Initial Study (MND/IS) is available for review for the Central Outfall Sewer (COS) at 59th Street and 4th Avenue. The proposed project involves reconstruction of the existing COS located at the intersection of 4th Avenue and 59th Street in the City of Los Angeles. At this location, an obstruction in the sewer caused by a City storm drain, results in sewage back up in the 74th Street and Florence Avenue sewers. The proposed project would remove the obstruction by reconstructing both the sewer and the storm drain at this location. The proposed project would modify the COS as well as other sewers within the immediate project area. Activities associated with the project at COS would include restoring the invert, removing the existing transition structures and reinforced concrete box sewer, and installing a new approximately 6-foot high by 5-foot wide elliptical sewer. The project would also involve the reconstruction of the storm drain at the intersection of 4th Avenue and 59th Street. A siphon would be constructed using an approximately 30-foot long squash box with three chambers. Although the proposed project could have a significant effect on the environment (particularly during construction) related to hazards and hazardous materials, noise, and transportation and traffic, there would not be a significant effect as a result of the implementation of mitigation measures.

The MND was adopted by the City Council on May 2, 2012 and a Notice of Determination was filed with the Los Angeles County Clerk.

Initial Study Appendices

• Appendix A: Air Quality Worksheets
• Appendix B: Geology and Soils Technical Reports
• Appendix C: Noise and Vibration Worksheets