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 Russian name ‘Zaliv Glubokoy’ published in 1848 on hydrographic charts. Peril Strait separates Chichagof Island to the north from Baranof Island to the south. The name is a translation from the Russian ‘Proliv Pogibshiy’ and originates from an incident reported by Captain Yuri F. Lisianski in 1799 when a large number of conscripted Aleut sea otter hunters perished from paralytic shellfish poisoning after eating mussels collected from the strait. Deep Bay is the estuary for an unnamed stream that starts from an elevation of roughly 1800 feet (549 m) on Chichagof Island and flows generally southeast for 6 miles (10 km), draining a watershed of 11,958 acres (4,939 ha). The watershed is underlain by an igneous intrusion that developed during the Oligocene and Eocene and consists mostly of granodiorite, granite, and tonalite.

The western side of Baranof Island, Peril Strait, and the southwestern portions of Chichagof Island, and the myriad islands and bodies of water between these locations are the traditional territory or kwaan of the Sheey At’iká Tlingit. The name is descriptive and means ‘outside edge of the tribe’. Geological evidence indicates that this area was covered by glacial ice with broad-scale ice retreat starting around 13,000 years ago. The archaeological record suggests that the earliest humans traveled by boat and inhabited this land 10,000 years ago focusing food gathering efforts on intertidal and nearshore environments with fishing and shellfish harvests being the mainstay of subsistence. Salmon were increasingly harvested with the introduction of fish weirs sometime before 3,000 years ago. Many of the traditional geographical sites known to modern Tlingit people through oral histories date to roughly 1,500 years ago. By the time of European contact, the Northwest Coast culture was fully in place and marked by permanent or semi-permanent village life, intensive resource production and storage, and hereditary social inequality.

The stream draining into Deep Bay is characteristic of many coastal streams in Southeast Alaska that 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. Mixed semi-diurnal tidal flooding perfuses the marsh with organics and nutrients. Post-glacial rebound in general, and sediment trapping by marsh vegetation in particular, gradually elevated the marsh allowing for a succession of plants less tolerant of tidal immersion. Read more here and here. Explore more of Deep Bay and Peril Strait here: