55A - SAN LORENZO SEWER LIFT STATION

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EXHIBIT "B" TETRA TECH MEMORANDUM TO: Steve Worrall, City of Santa Ana FROM: Tom Epperson, Tetra Tech JOB TITLE: San Lorenzo Sewer Lift Station PROJECT NO: City No. 06 -3510 / EIR No. ER- 2011 -04 SUBJECT: Response to January 13, 2012 Comment Letter from Silverstein Law Firm DATE: February 2, 2012 The following are our responses to several of the items which hopefully will assist the City in preparing the final response to the City Council. Section II Purpose of Project is stated in EIR S.2.2. The key objectives are listed in S.2.2 and further highlighted below: • Existing lift station was last upgraded in 1989; pumps rebuilt in 2007; other mechanical equipment and associated piping were not. Mechanical and electrical equipment are old and difficult to maintain in proper operating condition. • Existing lift station (dry pit containing mechanical equipment) is located in Bristol Street within manhole. Requires closure of a travel lane and disruption of traffic on Bristol to perform routine maintenance. To perform maintenance, crews must perform confine space requirements and descend 15 foot ladder carrying tools and equipment. All mechanical equipment is located within a below -grade 12 -foot diameter manhole, so work area is tight and cramped. • Proposed lift station is located outside of roadway right -of -way; located within a building; stairway is provided to dry pit; dry pit has sufficient space for maintenance (room is five times bigger). • Existing lift station has only two pumps while proposed lift station has three pumps which improves reliability. The proposed lift station wet well has three times more capacity than the existing lift station wet well. The response time to an emergency is much quicker with the new lift station due to ease of access (no traffic control set- up /confine space issues /etc) and the mechanical equipment being located within a building. Due to the faster response time, additional pump, and larger capacity wet well, the new lift station reduces the potential of a sewer spill. • Existing lift station electrical panels are located within Bristol parkway (back of sidewalk and exposed to elements). Being located within public right -of -way of an arterial, they are susceptible to catastrophic damage by an out -of- control car and public vandalism. Proposed lift station electrical panels will be located within a building (safe and secure). • Existing lift station is located within a roadway which has tendency to flood. Proposed lift station is designed to protect the electrical facilities and dry pit from flooding (located at an elevation that is higher than relief elevation to street). C:\Documents and Settings\nmitre \Local Settings \Temporary Internet Fil es \Content.Outlook \VDSN8UCB \santa ana memo on silverstream letter - TetraTech (FINAL 2012- 02- 02).DOC 55A -131