The channel axis is broadest at the northern and southern ends of the study region, narrowing and shoaling within the channel axis bend south of Croton Point. A field of muddy sediment waves is present within the channel axis deposit at the southern end of the area. This field is 300-400 m wide, 3.3 km long and extends onto the western channel bank. The western half of the channel axis
Figure 5.11. Summary map of the Area 1 showing the distribution of oyster reefs and areas of finer and coarser sediment. The coarser sediments are generally restricted to the channel while the oyster reefs are primarily on the margins.
corresponds with a 100-300 m wide region of moderate to high backscatter. Sub-bottom data show that sediment layers which are truncated at the riverbed coincide with this high backscatter zone, indicating active erosion within this portion of the channel axis. South of the channel bend, the eastern half of the channel axis is covered with a linear band of low backscatter sediments which may be redeposited sandy silts from the east channel bank. Finer grained sediments are also present within the channel bend where they appear to cover coarser channel axis sediments.
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