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CITY OF EVERETT SPECIAL PROVISIONS <br /> <br />3rd Ave Water Quality Facility Division 7 – STORM, SEWER, WATER September 12, 2024 <br />WO No. – UP 3775 SP – 184 <br />7-08.3 Construction Requirements <br />7-08.3(1) Excavation and Preparation of Trench <br />7-08.3(1)A Trenches <br />Revise the second paragraph in 7-08.3(1)A and to read as follows: <br />Excavate trench in accordance with COE Standard Drawing No 614. <br />Delete the second sentence in the third paragraph in 7-08.3(1)A and substitute the <br />following: <br />Contractor may excavate above the top of the pipe zone only as wide as <br />necessary to meet OSHA requirements. <br />7-08.3(1)C Bedding the Pipe <br />Delete the second and third paragraphs in 7-08.3(1)C and substitute the following: <br />Provide pipe zone bedding in accordance with COE Standard Drawing 614 and <br />615. <br />If the Engineer determines the material existing in the trench bottom is <br />satisfactory for bedding the pipe, then the bedding material specified in the <br />COE Standard Drawing 615 is not required, provided the existing material is <br />loosened, regraded, and compacted to form a dense, unyielding base. <br />Supplement 7-08.3(1) by adding the following: <br />7-08.3(1)D Trench Dewatering <br />(******) <br />This section specifies the definition, responsibilities and execution for dewatering <br />associated with trench excavation for pipes, manholes, catch basins, cleanouts, <br />side sewers and other buried utility work. Implement trench dewatering measures <br />where necessary or directed by the Engineer. Implementation shall include, but not <br />be limited to, the design, furnishing, installation, operation, maintenance, <br />monitoring, reporting and removal of dewatering systems to achieve proper <br />completion of Work performed under this Contract. <br />Prevent the flow of surface water runoff into the trench excavation. Control surface <br />water and other erosion control measures associated the Work in accordance with <br />8-01 of the Standard Specifications and modified in these Special Provisions. <br />Maintain groundwater level at or below the bottom of the excavation in all Work <br />areas during excavation, foundation preparation, pipe and structure installation and <br />backfilling. Trench dewatering shall sufficiently control groundwater to prevent <br />softening of the bottom of the excavations or formation of “quick” conditions or <br />“boils” during excavation. Use gravel or non-moisture sensitive trench backfill in <br />areas encountering groundwater. If foundation soils are disturbed or oversaturated <br />with water, then over excavate and replace the affected areas with suitable fill at no <br />additional cost to the Owner. Upon completion of dewatering operations, restore the <br />normal water table to its natural level in such a manner as to not disturb the pipe, <br />its foundation and structures. Contractor shall be solely responsible to control the <br />rate and effect of the dewatering in a manner to avoid all objectionable settlement <br />and subsidence. <br />Direct discharge flow from trench dewatering to a nearby sewer or storm drain <br />system unless otherwise directed by the Engineer. Obtain, at no cost, a Discharge <br />Authorization Permit from the City prior to discharging trench dewatering flows into <br />the City sewer or storm drain system. Control groundwater by trench dewatering <br />systems designed and operated to minimize turbidity of the discharged flow and to <br />prevent removal of the natural soils or imported fill.