Deep Bay is an estuary about 0.5 miles (0.8 km) across, located on the western shore of Peril Strait, on the southern coast of Chichagof Island, about 74 miles (119 km) southwest of Juneau and 29 miles (47 km) northwest of Sitka, Alaska. The name is a translation by the U.S. Coast and Geodetic Survey in 1882 of the name “Zaliv Glubokoy” published in 1848 on Russian hydrographic charts.

Many of the coastal streams in Southeast Alaska are relatively short, steep, and drain watersheds with very high precipitation. This causes large volumes of water and suspended sediments to be discharged into coastal estuaries. When the slope of the drainage basin suddenly decreases near sea level, the water velocity and turbulence can no longer suspend the sediment load and the material is deposited as an alluvial fan or delta.

Channels develop through the delta from tidal current reversals and differential rates of sediment deposition to create intricate meander patterns. Finer sediments are deposited at the edges of the plain where perennial sedges colonize and stabilize the substrate. Semi-diurnal tidal flooding perfuses the marsh with organics and nutrients. Sediment trapping by marsh vegetation may gradually elevate the marsh, allowing for a succession of plants less tolerant of tidal immersion. Read more here and here. Explore more of Deep Bay here: