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WASTE DISCHARGE REQUIREMENTS GENERAL ORDER -� <br /> US ARMY CORPS OF ENGINEERS <br /> PORT OF STOCKTON <br /> MAINTENANCE DREDGING STOCKTON DEEP WATER SHIP CHANNEL <br /> CONTRA COSTA,SACRAMENTO, & SAN JOAQUIN COUNTIES <br /> turning basin where it is 970 feet wide. The 36.7 miles of waterway will be dredged to <br /> maintain an average depth of 35 to 36 feet from channel mile 4.4 to channel mile 39.3 and <br /> from Mile 40.2 to Mile 41.0; and 40 to 41 feet from Mile 39.3 to Mile 40.2 along the channel. <br /> A conventional clamshell dredge and barge may also be used for limited dredging in the <br /> vicinity of utility crossings and to remove large debris. <br /> 6. Following excavation, dredged sediment will be transported by pipeline, barge, or hopper <br /> dredge for settling and disposal onto one of the upland disposal sites on Roberts or Spud <br /> Islands or at the Stockton Disposal Site. See Attachment "A". The settling ponds at each of <br /> the DMD sites are designed to remove a significant portion of suspended material. The <br /> settling pond design has shown to be effective in the Sacramento Deep Water Channel <br /> Dredging Projects regulated by Order No. 88-143. Return water will be discharged to the San <br /> Joaquin River, at locations shown on Attachment "A". Presently, the disposal sites have a <br /> combined useful capacity of 4,470,000 cubic yards with the following capacity at each of the <br /> DMD site locations: <br /> DMD Site Maximum DMD Capacity Approximate Location <br /> Roberts Island Disposal Site#1 - 2,200,000 cubic yards Channel mile 36 <br /> Roberts Island Disposal Site#2 - 1,400,000 cubic yards Channel mile 34 <br /> Spud Island Disposal Site - 150,000 cubic yards Channel mile 32 <br /> Stockton Disposal Site - 720,000 cubic yards Channel mile 40 <br /> 7. The General Orders' Report of Waste Discharge estimates the rate of dredged spoil and return <br /> water discharges during a typical dredging operations to be as follows: <br /> Average Dredge Material Disposal: 5,000 to 8,000 cubic yards per day <br /> Return Water Average Flow: 8.7 million gallons per day (mgd) <br /> Return Water Maximum Flow: 9.7 mgd <br /> 8. The Discharger performed analytical analyses of river sediments to determine what the <br /> anticipated sediment quality could be during maintenance dredging projects. The following <br /> sediment constituents and average concentrations were found: <br /> Constituent Average Concentration. mgkQ <br /> Arsenic 4.5 <br /> Copper 88.9 <br /> Lead 6.4 <br /> Mercury 0.1 <br /> Thallium 0.6 <br /> Zinc 40.5 <br />