1300 W MARINE VIEW DR 2018-01-19

failure of any component of the dewatering system- The Contractor shall assume all responsibility for any damage or claims resulting from dewatering. Any testing or pumping the Contractor may wish to perform to assure a properly functioning dewatering system shall be at the Contractor's own cost. Design and construct the dewatering system such that foundations soils (natural or engineered) will not be subject to fines removal upon pumping. Monitor discharge from all parts of the system to insure that the discharge water does not contain sand. Provide all of the equipment and fitting for monitoring sand content- Monitoring for sand content shall be performed for each dewatering discharge point on a regular basis. All groundwater pumped and stormwater that is collected shall be collected in tanks, allowed to settle out sediment or filtered as necessary, and then discharged to roadside ditches. The turbidity of the discharged water shall not exceed 5 NTU's over background. If the turbidity exceeds 5 NTU's above background levels in the receiving water body, discharging must cease until the problem is corrected. Materials and sediments remaining in the tanks must be disposed of at a suitable landfill. ' The Contractor is responsible for monitoring the turbidity of the stormwater and the water from dewatering operations every two hours during working shifts. If dewatering water is pure and stable at the end of the it will not be required. The Contractor shall keep written records of all shift, off-shift monitoring of turbidity test results, maintain a test result file on-site for review, and provide test results to the City's onsite representative immediately after obtaining results of each test. The Contractor shall be responsible for all costs associated with the testing. When no longer required,completely remove all dewatering system elements with the exception of those monitoring wells so designated by the Engineer. The Contractor shall assume ownership and responsiblility for the disposal of all dewatering pumps, pipes, and other assorted system hardware. Employ the services of a licensed water well contractor for the well abandonment. System components removed from contaminated areas shall either be decontaminated or disposed of appropriately per Washington State Department of Ecology WAC 173-160- SECTION 7-093(8) OF THE STANDARD SPECIFICATIONS IS REPLACED BY THE f : FOLLOWING: ! 7-09.3(8) Removal and Replacement of Unsuitable Materials Whenever in excavating the trench for water mains, the bottom of the trench exposes peat, soft clay, 1 quicksand, or other unsuitable foundation material such material shall be removed to the depth of 18 inches or as directed by the Engineer and backfilled with "Foundation Material Class A"_ f ' All material removed from the trench shall be considered unsuitable and shall be loaded directly into trucks and hauled to a waste site obtained by the Contractor. Stockpiling of unsuitable material at the project site t a will not be allowed. 1 ` Any overexcavation not specifically authorized by the Engineer shall be replaced by the Contractor with Gravel Borrow, and compacted as specified above, at no expense to the owner_ SECTION 7-09.3(9) OF THE STANDARD SPECIFICATIONS IS REPLACED BY THE FOLLOWING: 7-09.3(9) Bedding the Pipe Unless otherwise specified on the drawing or directed by the Engineer, pipe zone material for water main pipe shall be as specified in section 7-09.2 of these specifications. J The pipe zone material shall be placed to a depth of at least 12" over the top of the pipe and 6" under the pipe. The pipe zone material shall be rammed and tamped around and under the pipe to 95 percent of the -� maximum dry density by the use of shovels or other approved hand-held tools, as to provide firm and UP3220-Div_7 Page SP 7-3 June 15,2005