2. 1. Drowned River Valleys
Drowned River
Valleys
-are most extensively
developed along
coastlines with
relatively low and wide
coastal plains.
Chesapeake Bay which is
located on the mid-Atlantic
coast of the United States.

3. 2. Fjord-type Estuaries
Fjord-type Estuary
-are deep, U-
shaped coastal
indentures gouged
out by glaciers and
generally with a
shallow sill at their
mouths formed by
terminal glacial
deposits. The famous fjords of Norway

4. 3. Bar-built Estuaries
•shallow basins, often partly exposed at low tide
•enclosed by a chain of offshore bars or barrier
islands
•broken at intervals by inlets (thus insuring “a free
connection with the sea”
•Sometimes the sand bars are deposited
offshore, but in other instances the barriers may
represent former coastal dunes that have become
isolated by recent gradual rises in sea levels.
•In the former case the estuary develops from a
former marine area, while in the latter case it
develops on a flooded area of former coastal plain.

5. The “sounds” behind the “outer banks” of North Carolina
(Cape Hatteras National Seashore Park)

6. 4. Estuaries produced by
Tectonic Processes
Estuaries produced
by tectonic processes
-are coastal
indentures formed by
geological faulting or
by local subsidence,
often with a large
inflow of fresh water.
San Francisco Bay