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HomeMy WebLinkAbout2006/08/01 Item 14 COUNCIL AGENDA STATEMENT Item 14 Meeting Date 8/1/2006 ITEM TITLE: Resolution Appropriating $550,000 from the available balance of the Trunk Sewer Capital Reserve Fund to the Salt Creek Sewer Interceptor (SW- 219) Project and authorizing the use of these funds and other available project funds to be used for the repair of damaged public infrastructure and the mitigation of potential future damages due to trench settlement and unforeseen subsurface conditions associated with the construction of the Salt Creek Interceptor Sewer SUBMITTED BY: Director of Public Works Operation# Acting Director of En?g.w REVIEWED BY: Interim City Manager d' (4/5ths Vote: Yes.xNo~ The 13.5 mile-long Salt Creek Interceptor Sewer, which is designed to serve existing and future development within the eastern Territories, was built between 2001 and 2004 in four construction phases at a total capital cost of $32 Million. Five miles of this major infrastructure element were constructed beneath Main Street between Interstate 5 and Heritage Road. Since the project's completion, a number of Sweetwater Authority's settlement-sensitive water services under-crossed by the sewer trench have unexpectedly and suddenly failed. These breaks are considered catastrophic and have resulted in costly repairs to both the water laterals and the street as well as inconvenience to local residents and disruption of business and travel along Main Street. Trench and pavement failures have also occurred in a number oflocations along Main Street east of Sweetwater Authority's service area. The proposed resolution would appropriate $550,000 from the Trunk Sewer Capital Reserve Fund to the Salt Creek Trunk Sewer Project, and further authorize the use of these funds and other available project funds to be used to pay for (a) one-half of Sweetwater Authority's cost to reinforce thirty-six settlement-sensitive water services under-crossed by the Salt Creek Interceptor Sewer; (b) localized pavement repairs along the entire sewer alignment within Main Street; and, (c) additional geotechnical investigation ofthe trench settlement problem and recommendations to mitigate settlement impacts to public facilities. RECOMMENDA nON: That Council adopt the resolution appropriating $550,000 from the available balance of the Trunk Sewer Capital Reserve Fund to the Salt Creek Sewer Interceptor Project (SW-219) and authorizing the use of these funds and other available project funds to be used for the repair of damaged public infrastructure and the mitigation of potential future damages of public infrastructure due to trench settlement and unforeseen subsurface conditions associated with the construction ofthe Salt Creek Interceptor Sewer. BOARDS/COMMISSIONS: N/A 14-1 Page 2, Item I ~ Meeting Date 8/1/2006 DISCUSSION: The project was designed and constructed by reputable consultants and contractors with oversight by City staff. The specified materials and construction methods followed accepted standards and industry norms for this type of a facility. Beginning a little more than two years ago, pavement failures and water lateral breaks began occurring within the trench limits of the Salt Creek Interceptor Sewer at various locations under Main Street, between Industrial Boulevard and Heritage Road. Most of the water lateral failures would be considered catastrophic as they occurred suddenly and unexpectedly, disrupted business and travel along Main Street, and required immediate and costly repairs. Water lateral failures have occurred primarily with 4" and larger diameter asbestos cement pipe and failures became more frequent during the 2004- 2005 rainy season, which was the third wettest rainy season on record. These failures have resulted in substantial damages to both Sweetwater Authority and City of Chula Vista facilities. City and Sweetwater Authority staff, with the support of consultants retained by both agencies, have identified the underlying cause(s) of the catastrophic failures that have occurred with several of Sweetwater Authority's water services under-crossed by the sewer trench. Both agencies' staffs have concluded the series offailures has resulted from migration of the underlying soils supporting the water laterals. This unanticipated soil migration likely stemmed from both groundwater transport and settlement within the trench backfill. Future failures of settlement-sensitive water services are likely to continue as these unforeseen conditions persist within and adjacent to the trench. Sweetwater Authority and the City have incurred several hundred thousand dollars to date in repair costs related to failure of asbestos-cement water services. Both agencies' staffs have concluded there is shared responsibility for these failures. Staff from both agencies has worked jointly to identify solutions to significantly reduce the risk of these catastrophic failures occurring in the future, as well as validate our understanding of the underlying failure mechanisms. Therefore, to prevent further failure of settlement-sensitive water services and to determine long-term solutions that will control trench backfill settlement in other areas, City staff has formulated the following recommended actions: >- Share the cost of replacing 36 settlement-sensitive water services that were under-crossed by the Salt Creek Interceptor Sewer. Staff s recommendation is based upon the following: · A large majority of the existing settlement-sensitive water services are asbestos-cement pipe over two inches in diameter and will fail if the underlying trench settles significantly or suddenly collapses. A very small number of PVC pipes over 2" in diameter will also be repaired because they are also susceptible to failure if a loss of underlying soil support occurs. 14-2 Page 3, Item I Y: Meeting Date 8/1/2006 · If left uncorrected, continued failure of these settlement-sensitive pipes is very likely, resulting in significant disruption and costly damage to adjacent public and private improvements, including, but not limited to, pavement, curb, gutter, and sidewalks. · City and Sweetwater Authority staff have identified a solution to the settlement-sensitive water lateral problem that essentially replaces them with a system consisting of stronger pipe and a reinforced concrete slab under the new pipe that is able to "bridge" across the trench's full width without underlying soil support. · The City and Sweetwater Authority will equally share in the costs of water lateral replacements within the framework of our existing and long-standing cost-sharing arrangement. Sweetwater Authority, as successor to California Water & Telephone Company, is bound under the terms and conditions of an existing agreement approved by City Council Resolution No. 1494 with said California Water & Telephone Company. Total lateral replacement costs are estimated to be between $600,000 and $800,000. Therefore, staff is requesting an appropriation of$400,000 trom the Trunk Sewer Capital Reserve Fund for this work. Use of these funds is limited to the planning, design, or construction of sewage collection and treatment facilities and water reclamation facilities, unless otherwise approved by a four-fifths vote of the City Council. It is staffs opinion that the use of this funding source is appropriate for the purpose requested because the need to perform this work is related to, and necessitated by, the construction of the Salt Creek Interceptor Sewer. The Sweetwater Authority's Board has approved funding for this work and has authorized its staff to bid the work. }- Timely repairs to the roadway are necessary to address hazardous roadway conditions, to halt damage to underground and surface improvements, and to prevent damage to adjacent facilities. Therefore, staff recommends hiring a paving contractor under a public works contract on an as- needed, time-and-materials basis to perform pavement repairs needed now and over a one-year contract period. Staff is requesting an appropriation of$200,000 for this work in FY2006-2007. Thereafter, staff will annually assess the need to repair pavement failure caused solely by sewer trench settlement and will include funding requests in the Department of Public Works Operations' annual operating budget specifically for this work. }- Further geotechnical investigation be performed during repairs to both the water laterals and the pavement failures to validate and better understand the failure mechanism(s) and to establish recommendations for remediation with a high potential for success though the following: · The geotechnical consultant and City staff will observe excavations within failure areas during Sweetwater Authority lateral replacements to better understand conditions in areas that have not yet failed (the cost for 80% of this consulting work is included in the cost for replacing 36 settlement-sensitive water services). 14-3 Page 4, Item~ Meeting Date 8/1/2006 . The geotechnical consultant will perfonn subsurface borings to establish the presence and elevation of groundwater in and adjacent to the trench along the sewer's full length. . The geotechnical consultant will detennine, if practical, the root causers) for the trench settlement and distress and to provide long-tenn methods for repair and control. . Staffis requesting an appropriation of $65,000 for this work. SALT CREEK TRUNK SEWER- PROJECT FUNDING STATUS Remaining Balance of Project Funds orig. rom Trunk Sewer Capital Res. (293) $ 390,000 Remaining Balance of Project Funds orig. from Salt Creek DlF. (553) $140,000 r otal Available Project Funds $ 530,000 Outstandine: EXDenditures to be funded from Trunk Sewer Fund (293) :::ity's share of Sweetwater Authority Sewer lateral Replacements $400,000 Pavement Repair along Main Street $200,000 :;eotech Study $32,500 ~ompletion of the remaining portion of the Auto Park Sewer $150,000' Un-reimbursed Staff Time $117,500' :;taff Time to complete project (Constr. Inspection & Wastewater Engineering) $40,000' SubTotal Outstanding Expenditures $940,000 Outstandine: EXDenditures to be funded from Salt Creek DIF Fund (553) :;eotech Studv $32,500 Project Fund Balance Additional Trunk Sewer Funds needed to complete the project ($550,000) Remaining Balance of Salt Creek DIF funds upon completion of project $ 107,500 · other anticipated expenditures that will impact fund 293 14-4 Page 5, Item N Meeting Date 8/1/2006 Decision Maker Conflicts Staff has reviewed the property holdings of the City Council and has found no such holdings within 500' of the property which is the subject of this action. FISCAL IMPACT: The Salt Creek Trunk Sewer project was funded primarily from two sources: Trunk Sewer Capital Reserve Fund (for that section of the pipeline considered a regional facility) and Salt Creek Gravity Basin Development Impact Fee (DIT) Fund (for that section of the pipeline which serves only the properties within the Salt Creek and W olfCanyon sewer basins). Approximately $32 million has been allocated to the project to date. Staff is requesting an additional total appropriation of$550,000 from the Trunk Sewer Capital Reserve Fund. Upon completion of the Geotechnical Study and obtaining a better understanding of potential failures along the pipe alignment, there will be additional funding requests to repair any future damage to public improvements caused by trench settlement. Future requests for allocations for this effort will be included in the Department of Public Works Operations' annual operating budgets for the foreseeable future. The approval of this request will not result in any impact to the General Fund. /rah K:\Pubhc Works OperationslAgenda Statements FY06\Salt Creek Sewer Lateral and Pavement Repairs 2.doc 14-5 RESOLUTION NO. 2006- RESOLUTION OF THE CITY OF CHULA VISTA APPROPRIATING $550,000 FROM THE AVAILABLE BALANCE IN THE TRUNK SEWER CAPITAL RESERVE FUND TO THE SALT CREEK SEWER INTERCEPTOR (SW-2l9) PROJECT AND AUTHORIZING THE USE OF THESE FUNDS AND OTHER AVAILABLE PROJECT FUNDS TO BE USED FOR THE REPAIR OF DAMAGED PUBLIC INFRASTRUCTURE AND THE MITIGATION OF POTENTIAL FUTURE DAMAGES DUE TO TRENCH SETTLEMENT AND UNFORESEEN SUBSURFACE CONDITIONS ASSOCIATED WITH THE CONSTRUCTION OF THE SALT CREEK INTERCEPTOR SEWER WHEREAS, beginning a little more than two years ago, pavement failures and water lateral breaks began occurring within the trench limits of the Salt Creek Interceptor Sewer at various locations under Main Street, between Industrial Boulevard and Heritage Road; and WHEREAS, most of the water lateral failures would be considered catastrophic as they occurred suddenly and unexpectedly, disrupted business and travel along Main Street, and required immediate and costly repairs; and WHEREAS, water lateral failures have occurred primarily with 4" and larger diameter asbestos cement pipe and failures became more frequent during the 2004-2005 rainy season; and WHEREAS, these failures have resulted in substantial damages to both Sweetwater Authority's and the City ofChula Vista's facilities; and WHEREAS, both the City and Sweetwater Authority ("agencies") staff have concluded that the series of failures has resulted from migration of the underlying soils supporting the water laterals; and WHEREAS, future failures of settlement-sensitive water services are likely to continue as these unforeseen conditions persist within and adjacent to the trench; and WHEREAS, Sweetwater Authority and the City have incurred several hundred thousand dollars to date in repair costs related to failure of asbestos-cement water services; and WHEREAS, the agencies' staff have worked jointly to identify solutions to significantly reduce the risk of these catastrophic failures occurring in the future, as well as validate their understanding of the underlying failure mechanisms; and WHEREAS, the agencies will share the cost of replacing thirty-six settIement- sensitive water services that were under-crossed by the Salt Creek Interceptor Sewer; and WHEREAS, as timely repairs to the roadway are necessary to address hazardous roadway conditions, staff recommends hiring a paving contractor under a Public Warks contract on an as-needed, time-and-materials basis to perform pavement repairs needed now and over a one-year contract period; and 14-6 WHEREAS, geotechnical investigation will be perfonned during repairs to both the water laterals and the pavement failures to better understand the failure mechanism(s) and to establish recommendations for remediation with a high potential for success; and and WHEREAS, approximately $32,000,000 has been allocated to the project to date; WHEREAS, staff is requesting an additional total appropriation of $550,000 from the Trunk Sewer Capital Reserve Fund; and WHEREAS, any requests for allocations to repair any future damage to public improvements caused by trench settlement will be included in the Department of Public Works Operations' annual operating budgets. NOW, THEREFORE, BE IT RESOLVED that the City Council of the City of Chula Vista does hereby appropriate $550,000 from the available balance of the Trunk Sewer Capital Reserve Fund to the Salt Creek Sewer Interceptor (SW-219) Project and authorizes the use of these funds and other available project funds to be used for the repair of damaged public infrastructure and the mitigation of potential future damages due to trench settlement and unforeseen subsurface conditions associated with the construction of the Salt Creek Interceptor Sewer. Presented by Approved as to fonn by ~<r<J\~~a~ Ann Moore " City Attorney Dave Byers Director of Public Works Operations J :/anomey/reso/finance\appropriation - Salt Creek Trunk Sewer SW -219 14-7