02-17-2012 BPU RPT 04 - Laserfiche WebLink

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RIVERSIDE PUBLIC UTILITIES Board Memorandum PUBLIC UTILITIES BOARD OF PUBLIC UTILITIES DATE: February 17, 2012 ITEM NO: 4 SUBJECT: AGREEMENT FOR PROFESSIONAL ENGINEERING SERVICES FOR THE MOCKINGBIRD CANYON LAKE DREDGING PROJECT ISSUE: Thatthe Board of Public Utilities consider approving a Professional Services Agreement with MNS Engineers Inc. in a not-to-exceed amount of $249,858 for engineering and surveying services for the Mockingbird Canyon Lake Dredging Project. RECOMMENDATIONS: That the Board of Public Utilities: 1. Authorize the capital expenditure in the amount of$209,858 for Work Order No. 1111607 for the Mockingbird Canyon Lake Dredging Project; and 2. Approve a Professional Services Agreement with MNS Engineers Inc., of Ventura, California, in a not-to-exceed amount of $209,858 for engineering design and surveying services for the Mockingbird Canyon Lake Dredging Project. BACKGROUND: The Mockingbird Canyon Lake (Lake) was formed in 1913 by the U.S. Army Corps of Engineers and the Gage Canal Company(Gage Co.)with the construction of the Mockingbird Dam, California Department of Water Resources Division of Safety of Dam (DSOD), Dam Number 81-003. The City of Riverside (City) acquired the Lake in 1964 with the acquisition of Gage Co. The Lake is operated by Gage Co.and captures storm water flow utilized within the Gage Canal delivery system. Overtime, as storm events occur, sediment is transported from the surrounding tributary area and deposited in the Lake. As discovered during the post December 2010 storm investigation,the capacity of the Lake has drastically decreased due to deposited sediment. Staff conducted extensive research on the Lake and were unable to find any evidence that the Lake had been previously dredged since its construction in 1913. Furthermore, the post December 2010 storm investigation revealed that sediment had reached a level that impeded flow out of the reservoir's sole drainage structure, thereby, threatening the reservoir's operational integrity and ability to maintain a safe water level. This project will evaluate the amount of sediment deposited within the Lake through aerial and bathymetric surveys and develop a preliminary design report to dredge the Lake and restore it to a safe operating capacity. Consultant Selection Staff issued a Request for Proposals (RFP) to several different engineering firms with experience in the bathymetric surveying and dredging engineering design. Proposals from three different engineering firms were received, as summarized in the following table: