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distribution curves and/or Atterberg limits ; and suspended sediment-settling time curves representing the finest-grained sample from each boring location . The recommended inlet operation strategy, based on the sediment data presented above, reflects a poorly graded mix of fine sand and silt-sized particles . This strategy makes no attempt to segregate material grain-size fractions by inlet manipulation, although some segregation will occur naturally as a result of differential settling behavioras described above . To minimize the mounding ofthe coarsest sediment fraction and to distribute the deposited material more uniformly, the inlet pipeline should be repositioned during dredging operations. This will require extending the pipeline and resting each extension on the sediment mound formed at the previous position. A minimum distance of 100 ft must be maintained between the inlet and the inside toe of the dike to preclude erosion or undercutting the interior dike slope. This strategy will also reduce the concentration of the finest sediment nearest the weirs as each deposition mound captures a portion of the silt- sized particles. (With a fixed discharge position , these particles would continually wash from the mound . ) The resulting deposition pattern should maintain a consistent slope from inlet to weir, should minimize dead zones and channelization, and should reduce the requirement for grading the deposited material to reestablish the desired 0 . 2% slope between successive dredging operations . 3. 2. 1 Monitoring Related to Inlet Operation During active dredging operations, several monitoring procedures related to inlet operations will be required . Ponding depth , as previously mentioned , is a critical parameter for maintaining acceptable containment basin performance. Increased ponding depth improves the basin 's solids retention performance by increasing retention time. However, under saturated foundation conditions, unbalanced hydrostatic forces resulting from too great a ponding depth can lead to slope instability, slumping, and the potential for dike failure. Indications of impending dike instability" include evidence of seepage related to piping and foundation saturation at the outer dike toe and small-scale slumping. Obviously, such conditions must be avoided. Therefore, ponding depth should be increased above the 2-ft minimum mean depth only under close monitoring by visual inspection of dike integrity. As discussed in Section 2 .2.2 , a 2-ft mean ponding depth corresponds to a 2 . 8-ft depth at the weirs as a result of the initial slope of the basin interior. If no effluent is released at the weir, the output of an 18- in . dredge (i . e. , 3 , 560 cy/hr slurry at a 20/80 solids/liquid mix, or 2,848 cy/hr liquid) will produce an increase in ponding depth of about 2 . 1 in ./hr and a rise in the water 29