2014-069 - Final Environmental Impact Report No. 2014-01

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HARBOR BLVD. MIXED USE TRANSIT CORRIDOR PLAN FINAL FIR CITY OF SANTA ANA 5. Environmental Analysis UTILITIES AND SERVICE SYSTEMS 5.14.1.2 WASTEWATER TREATMENT AND COLLECTION Wastewater Treatment The Orange County Sanitation District (OCSD) provides wastewater treatment for the project site Reclamation Plant No. 2 is adjacent to the Santa Ana River and approximately 1,500 feet from the Pacific Ocean in Huntington Beach. This plant provides a mix of advanced primary and secondary treatment. The plant receives raw wastewater through five major sewers. Approximately 33 percent of the influent receives secondary treatment through an activated sludge system, and all of the effluent is discharged into the ocean disposal system. OCSD's treated wastewater is discharged through a 120 inch outfall at 200 feet below sea level and nearly five miles offshore. Current capacity for Reclamation Plant No. 2 is 168 mgd of primary treated wastewater and 90 mgd of secondary treated wastewater. The current average flow is 151 mgd; thus, remaining capacity at this plant is approximately 17 mgd. Expansion plans by OCSD are ongoing and designed to address the incremental increase in sewage generation as a result of a new development. The secondary treatment capacity at this plant is currently being increased by 60 mgd for a future total capacity of 150 mgd. Wastewater Collection City sewers discharge into Orange County Sanitation District (OCSD) trunk sewers. One OCSD trunk sewer passes along the Santa Ana River next to parts of the east site boundary; the next nearest OCSD trunk sewer to the site is in Newhope Street west of the site. The majority of sanitary sewer pipes in the city are vitrified clay pipe and range in size from 8- inches to 15- inches in diameter. Existing pipes within the project area are mapped on Figures 2.3A and 2.3B of the Sewer Study included as Appendix J of this EIR. The project area is within Sewer Basin 1 where the majority of the pipe was previously modeled (IBI 2014). Several existing city sewer segments in the project site are undersized based on Orange County Sanitation District (OCSD) sizing requirements, particularly in 5u' Street, Washington Avenue, Green Drive, and McFadden Avenue. It should be noted that this is a design consideration and does not reflect the actual flow in the pipes as compared to pipe capacity. 5.14.1.3 STORM DRAINAGE SYSTEMS The majority of the project area is developed with only a few vacant lots remaining. The project area consists of predominantly impervious areas with a few back lots that are unpaved where cars are stored. The existing runoff coefficient for the project area was calculated to be approximately 70 percent (1131 2013). Lots in the project area surface drain to Harbor Boulevard and other side streets and the runoff is captured and conveyed in the storm drain systems. Run -off is managed by a combination of closed and open drainage channels. A 90 inch reinforced concrete pipe crosses Harbor Boulevard at Washington Street. A second large closed drainage system is located midway between 1st and 5th Streets. All drainage ultimately discharges into the Orange County Flood Control Channel (see Appendix F). Boyle Engineering prepared a Drainage Engineering Report in 1993 for the entire City of Santa Ana. The results of the report for the existing drainage system in the project area are provided in Table 5.144. The Page 5.14 -8 PlaceWorkr