Design for Initial Storage 



40. First, consider a site that will hold 100,000 cu yd of dredged 

 material. Because this material has the tendency to bulk (increase in vol- 

 ume) , the amount of material to be dredged will be less than 100,000 cu yd, 

 The equations used are as follows: 



(1 - FC)(1 + e ) 

 BF = FC + - 



l+. ± 



G x 1,000 



where 



BF = bulking factor 



FC = percent coarse grain 



e = dredged material final void ratio in CDF 



e. = initial void ratio, estuary sediment 



G = specific gravity 



C = design solids concentration 



= 221 x T * (upper estuary composite) 

 A bulking factor of 1.59 was determined, yielding 64,000 cu yd of sediment to 

 be dredged for this site. If an available site will hold 300,000 cu yd of 

 material, 205,000 cu yd of sediment with a bulking factor of 1.46 can be 

 dredged. The bulking factors differ because the dredging times were 80 days 

 for a bulking factor of 1.59 and 256 days for a bulking factor of 1.46. The 

 dredging time is then divided by 2 to obtain the average dredging time or T . 

 This procedure is done by trial-and-error. The results are particularly sen- 

 sitive to the initial voids ratio, which is calculated from the water content 

 of the in situ sediment. 



Predicted Effluent Suspended Solids Concentrations 



41. After the dredged material has been dredged and placed in the con- 

 tainment area, solids that have not settled by gravity will remain suspended 



29 



