This power function describes the existing situation whereby the increasing sediment 

 shoaling or dredging volume will require increased O&M cost with time. 



Figure 12 indicates how the segments after the intersection (sta 15+000 - 21+000) with the 

 GIWW have cumulatively yielded larger amounts of material dredged. Figure 13 breaks down the 

 cumulative volume dredged for maintenance from the GIWW into sections for the years in which 

 most of the dredging has been performed. The years between 1986 and 1995 experienced the 

 most dredging activity. This observation is consistent with the increase in dredging 

 frequency and cost noted by the Galveston District. 



1.2E+06 



[11+000-13+000) 

 [13+000 - 15+000) 

 [15+000 - 17+000) 

 [17+000 - 19+000) 

 [19+000 - 21+000) 



O.OE+00 



1963-66 1967-70 1971-74 1975-78 1979-82 1983-86 1987-90 1991-94 



Elapsed Time (years) 



Figure 12. Cumulative volume dredged for maintenance from the MSC 



1.8E+05 



1.6E+05 



1.4E+05 



^ 1.2E+05 



S 



*1 l.OE+05 



a> 



S 8.0E+04 



"O 6.0E+04 



> 



4.0E+04 



2.0E+04 



O.OE+00 





Stations 



Figure 13. Volume of material dredged for maintenance from the GIWW 



16 



Chapter 2 Channel Shoaling 



