20 |
|
Limit of dredged area |
|
21 |
|
Dredged channel or area with minimum depth regularly maintained |
|
22 |
|
Dredged channel or area with minimum depth not regularly maintained and year of latest survey |
|
24 |
|
Depth at chart datum, to which an area has been swept by wire drag. The latest date of sweeping may be shown in parentheses |
|
25 |
|
Unsurveyed or inadequately surveyed area; area with inadequate depth information |
|