COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

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