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EXHIBIT A <br /> a ,y' "" <br /> �C <br /> Engh, on...Working Wonders With Wider' <br /> May 25, 2010 <br /> 7967A.10 <br /> City of Pleasanton <br /> 200 Old Bernal Avenue <br /> Pleasanton, CA 94566 <br /> Attention: Mr. Huy Ho <br /> Subject: S -6 Lift Station Replacement - Additional Scope Work <br /> Dear Huy: <br /> After a lengthy design process, we are excited to move forward with the City in the construction <br /> of the new S -6 Lift Station, which will improve both the reliability and capacity of its respective <br /> service area. As we have previously mentioned, Carollo has provided additional services <br /> beyond our original scope of work, and while we have attempted to bring the costs in under our <br /> total original budget, items beyond our control have contributed to this request for a contract <br /> amendment. Following is a list of the more significant items that have increased the effort on <br /> this project: <br /> • Design around the existing generator to reuse City -owned equipment: Rather than <br /> replace the diesel generator, as assumed in the original proposal, the existing generator <br /> was incorporated into the design. To minimize the chance of any problems associated <br /> with the emissions of the existing generator, which would make its replacement more <br /> cost effective, Carollo coordinated with the Bay Area Air Quality Management District <br /> (BAAQMD) to clearly understand the rules that would trigger a new review. The result of <br /> this coordination was a design around the necessary construction sequence, including a <br /> staged design of the Control Building. Reusing the existing generator is estimated to <br /> save the City approximately $100,000 in construction cost. <br /> • Modify electrical power feed design to reduce safety concerns: As included in our <br /> proposal and discussed during early design meetings, the electrical switchgear was <br /> designed based on being fed from both ends with an open tie - breaker to allow for <br /> maintenance. However, based on later review comments from the City that identified <br /> potential safety concerns, the design was revised to power the switchgear from only one <br /> end. The revised approach will require the entire pump station to be shut down in order <br /> to perform maintenance on the switchgear, but will reduce the potential for someone to <br /> shut down power to one side of the switchgear and mistakenly assume the entire <br /> equipment is de- energized. The City does not currently have any other double -ended <br /> switchgear equipment; eliminating it from this project reduces the risk of safety incidents. <br /> • MCC layout and various instrument revisions to match other City facilities: After <br /> the 90% design was completed, revisions to the motor control center layout and other <br /> design components, primarily focused on electrical and instrumentation, were made so <br /> that the pump station would match other City facilities. This design change will benefit <br /> the City through reduced maintenance efforts due to staff familiarity with the <br /> components. <br /> 2700 Ygnacio Valley Road, Suite 300, Walnut Creek, California 94598 <br /> P. 925.932.1710 F. 925.930.0208 <br /> pw: / /CarollolDOcun otsICieoVCA/ PIeasanIouw% 7A10 /Correspondence&Cllent/HOOI.tlau (A) carollo.com <br />