SECTION 01 14 10 USE OF SITE PART 1 GENERAL ... - IDEAS-EC

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Amendment 0005Red Bluff Pumping Plant and Fish Screen Specifications No. 20-C07521. Describe cofferdam, construction sequence for cofferdam and adjacent earthworkand retaining walls, and other proposed methods for diversion and care of theSacramento River during construction:2. Plan shall consider both hydrologic variability in river flow rates and stages, andoperational water levels associated with operation of Red Bluff Diversion Dam,as referenced in Section 51 <strong>10</strong> 00 - Hydrologic Data. Cofferdam plan shall alsobe coordinated with relevant portions of removal of water plan.3. Include:a. Experience for cofferdam designer and installer. Include briefdescriptions for each of at least two previous successful projects ofcomplexity comparable to that required for this contract.b. Design elevation for cofferdam including design river stage return period,and freeboard allowance. Design elevation for cofferdam is the soleresponsibility of the Contractor, and shall be consistent with projectschedule.c. Provisions for worker egress and controlled flooding of the cofferdam inthe event river stages exceed the cofferdam design elevation selected bythe Contractor.d. Layout, description and materials for cofferdam including locations,depths and sizes for sheeting, bracing and other components. Thisincludes both temporary components as well as permanent components tobe left in place as part of the completed work.e. Methods, equipment, sequence and schedule for installation, maintenanceand removal of the cofferdam, including barges or temporary trestlesneeded to install the cofferdam, as well as repositioning of bracing orother elements over the course of construction.f. Design calculations and supporting data for cofferdam. Include adescription and profile of the geology, soil, groundwater conditions,stream/surface water conditions, anticipated leakage and control strategiesthrough sheet pile interlocks and floor surfaces, excavation anddewatering assumptions, and other pertinent characteristics.g. General construction sequence for adjacent site facilities, includingretaining walls, pumping plant and site earthwork to make sure theSacramento River and Red Bank Creek are prevented from floodingoutside the existing channels.h. Demonstrate compliance with requirements of water pollution control,streambed alteration, endangered species protection and other permitsfrom federal, state and local agencies.i. Methods and procedures for monitoring of cofferdam performanceincluding river stage, deflection, leakage and underseepage, with monthlyreview of data and field inspection by the cofferdam design engineerRemoving and Controlling Water During Construction31 03 33 - 4
Amendment 0005Red Bluff Pumping Plant and Fish Screen Specifications No. 20-C0752registered in the State of California. Include personnel list, schedules,equipment, reporting, system supplementation or revision, and otheroperations related to diversion and care of water.4. Design drawings, calculations, data, and other supporting design documents shallbe stamped by a Professional Engineer registered in the State of California.Monthly report of cofferdam inspection and review of monitoring data shall bestamped by same Professional Engineer who stamped the design.5. The plan may be placed in operation upon approval, but nothing in this Sectionshall relieve the Contractor from full responsibility for the adequacy of thecofferdam installation.D. RSN 31 03 33-3, Records:1. Cofferdam performance monitoring data and stamped monthly inspection reportsby cofferdam design engineer.2. Monitoring records required by permits.E. RSN 31 03 33-4, Bathometric Surveys of River:1. Topographic map with 1 foot contour intervals extending from face of fish screencofferdam location and for a distance of 200 feet upstream and downstream of thefish screen cofferdam and out into the Sacramento River a distance of 20 feetfrom the shoreline or from the face of the cofferdam, whichever is greater.2. Bathometric contours to be tied to contours above shoreline shown on the projecttopographic map.3. Provide electronic files of topographic map.4. Provide updated bathometric surveys of scour repair areas as specified.1.05 SYSTEM DESCRIPTION AND <strong>GENERAL</strong> REQUIREMENTSA. Design, furnish, install, maintain, operate, monitor, and remove facilities required fordiversion and care of the Sacramento River, removal of water during requiredexcavations and construction of facilities, and for controlled flooding of cofferdams,excavations, and structures below groundwater or the Sacramento River if necessary toprotect facilities from damage due to instability, uplift or excessive deflection.B. Comply with RSHS.C. Dewatering and unwatering operations are dependent on the construction methods usedand the sequence of excavation and construction operations used for work completion.D. Dewatering and unwatering requirements can be divided into two basic categories:1. Excavation and construction in the wet is where water is present in the area beingexcavated. The source of the water may be groundwater or seepage throughshoring or cofferdams. This applies to the forebay and fish screen area onlyRemoving and Controlling Water During Construction31 03 33 - 5
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SECTION 01 14 10 USE OF SITE PART 1 GENERAL ... - IDEAS-EC

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