Figure 15. Maximum extent of sediment plume with bucket release rate of 2 percent for Fox Point Reach North (FPRN) and Central (FPRC) sites and Fuller Rock Reach Central (FRRC) site over the 3-day simulation time.

ERDC TN-DOER-E12

July 2000

Figure 15. Maximum extent of sediment plume with bucket release rate of 2 percent for Fox Point Reach

North (FPRN) and Central (FPRC) sites and Fuller Rock Reach Central (FRRC) site over the

3-day simulation time. Plan view shows release point, channel geometry and maximum

concentrations (mg/L) at 8-10 m (26-33 ft) depth. Vertical section shows distribution of

maximum concentrations (mg/L) over depth along dashed section line shown in plan view.

Concentration contours correspond to ranges in the Newcombe-Jensen (1996) fisheries impact

model

The dredging sites were selected to be representative of locations along the length of the channel

from the Fox Point Reach to the Rumstick Neck Reach where dredging will occur. The model

simulated the release of material over the water column individually from three separate sites and

then from two and three sites simultaneously. Three release rates of 1.5, 2, and 4 percent of the total

dredged material were used to simulate the effects of different types of buckets and barge filling

protocols. Only a release rate of 2 percent was used in the simulation of dredging plumes created

simultaneously from more than one site.

In general, the resulting TSS concentrations in the water column were highest in the Fox Point Reach

and lower at the southern sites. This was due to the increased availability of diluting water at the