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Page 3 of 5 <br />City of Redwood City 1017 Middlefield Road, Redwood City, CA. 94063 Tel: 650-780-7000 www.redwoodcity.org <br />ANALYSIS <br />The single most important factor in effecting a levee repair is isolating the work area. Given the <br />inaccessibility of the repair location, traditional construction methods become much more complex and <br />expensive. Thus, staff reached out to multiple manufacturers of water-filled cofferdams, the type of <br />products necessary to complete the repair. Ultimately, only one product was large enough to be viable in <br />this situation. That manufacturer recommended that Dixon Marine Services, a Bay Area contractor that <br />has completed multiple similar projects around the Bay, install the system. <br />Staff worked with Dixon Marine Services on a repair plan, based on the approved geotechnical design, <br />and in conjunction with the contracted biological consultant. The completed repair represents the most <br />efficient and expedient solution to restore the levee protection and to get the Bay Trail back into service <br />safely. <br />Staff coordinated closely with all parties involved, including the contractor, consultants, suppliers, and <br />property owners to ensure the repair proceeded as expeditiously as possible. However, due to the unique <br />and remote nature of the breach location, the construction activity for the repair required more time than <br />anticipated. This resulted in several days of additional biological monitoring being required, and the <br />additional consulting costs. As of preparation of this staff report, an amendment to the Agreement for <br />Services with Montrose Environmental Solutions, Inc. to cover these additional costs was in process. <br />As of August 22, 2024, the repair work has been completed to the satisfaction of City staff. Therefore, <br />staff recommends acceptance of the project and approval of the emergency action for the repair. The trail <br />was formally reopened on September 10, 2024, after Public Works crews performed some additional <br />maintenance work along other sections of the closed trail. <br />This is the first time that the City has experienced a specific levee failure, especially in such an inaccessible <br />location. Based on the lessons learned, the Engineering & Transportation Department is working to <br />implement on-call contracts for the geotechnical design and environmental monitoring support that is <br />necessary for such repairs. Having such contracts in place would expedite the repair timeline, and <br />potentially reduce the cost of the support work for such a repair. <br />6.C. - Page 3 of 5 <br />74