Kasnyku Falls is a waterfall on Kasnyku Creek, which flows about 1 mile (1.6 km) to Waterfall Cove on Baranof Island, approximately 23 miles (37 km) south-southwest of Angoon and 21 miles (34 km) northeast of Sitka, Alaska. The creek drains Kasnyku Lake from an elevation of 650 feet (198 m). The upper reach is a canyon filled with large talus blocks, where the stream flows underground for about 0.3 miles (0.5 km) to a small pond. The lower reach, below the pond, flows through a narrow canyon and finally cascades to sea level on Chatham Strait. Kasnyku Lake is 393 feet (120 m) deep, 1.7 miles (2.7 km) long, and 0.3 miles (0.5 km) wide, surrounded by a 2,944-acre (1,191 ha) watershed of deglaciated cirques within Tongass National Forest. Named in 1923 by the U.S. Forest Service, presumably for Kasnyku Bay. Kasnyku is a Tlingit name reported in 1895 by Lieutenant Commander Edwin K. Moore of the U.S. Navy on the U.S. Coast and Geodetic Survey steamer Carlile P. Patterson. Baranof Island, part of the northern Alexander Archipelago in Southeast Alaska, was named in 1805 by Captain Yuri Lysianskyi after Alexander A. Baranov, governor of Russian America and chief administrator of the Russian-American Company. Baranof Island is rugged, mountainous, and heavily glaciated, located within the Chilkat-Baranof Mountains section of the Pacific Border Ranges geological province. The northeast coast consists of rocks from the Chugach terrane—an accretionary wedge containing sedimentary rocks deposited by turbidity currents in a deep ocean trench, along with volcanic rocks from a subducting oceanic plate. The bedrock near Waterfall Cove is tonalite, an igneous intrusive rock, formed between the Late Paleocene and Oligocene periods, or 43 to 23 million years ago. This is primarily represented by the Kasnyku Lake pluton, which underlies about 64,000 acres (25,900 ha) of Baranof Island and extends to an unknown area under Chatham Strait.

The Tlingit people have occupied the rugged mainland and the Alexander Archipelago of present-day Southeast Alaska since at least 1000 AD. According to their oral tradition, their place of origin was near the Nass and Skeena rivers in present-day British Columbia. From there, they migrated northward, avoiding southward movement due to the warring Haida and Tsimshian tribes. The northern coastal strip had been inhabited for at least 10,000 years by an ancient people, possibly of Athabascan origin, who were assimilated by the Tlingit. Archaeological evidence suggests that Klukwan, one of the largest Tlingit settlements, was an Athabascan site as recently as 300 years ago. Russian fur traders explored the Alaskan coasts in the late 18th century. The Russian-American Company regulated settlements and facilitated the fur industry. In 1799, Russians established a fort at Sitka, leading to violent encounters with the Tlingit. Initially defeated, the Russians learned the Tlingit lived by the law of blood feuds. Frequent wars between clans of different tribes, often incited by insults, led to the development of sophisticated armament and tactics. Tlingit warriors wore armor made of hides and wooden slats, wielding heavy clubs, daggers, and bows and arrows. They later adopted European firearms. The Tlingit successfully maintained their independence from colonization, even as their interest in European products grew. In the 1830s, a devastating smallpox epidemic disrupted the social hierarchy by undermining the power of shamans and the aristocracy. The Alaska Purchase of 1867 further altered the social order by introducing distilled liquor. From 1870 to 1880, commercial fishing proliferated, providing jobs for the Tlingit. Tourism created a market for Native artifacts, arts, and crafts. By the late 19th century, Angoon offered jobs, schools, and churches, becoming the only permanent northern Tlingit settlement on Chatham Strait.

Southeast Alaska receives high levels of precipitation and features mountainous terrain, making it ideal for hydroelectric generation. Over the years, many communities have sought to harness this potential to meet their residents’ and businesses’ electricity needs. Communities with hydroelectric projects generally enjoy relatively low power costs. In contrast, those without such generation rely almost exclusively on diesel generators, resulting in comparatively high power costs. The rugged terrain and long distances between communities make transmission interconnections rare and expensive to construct. Potential hydroelectric sites have been explored on the east side of Baranof Island since 1929. One proposed site for hydroelectric power development is Kasnyku Lake. However, the lake’s current storage capacity is insufficient, necessitating the construction of a dam at the lake’s outlet above the Kasnyku Creek gorge to raise the water level by at least 100 feet (30 m). Water would be diverted through a tunnel bored on the north shore of Kasnyku Lake near the outlet, extending to tidewater at Ell Cove, just north of Waterfall Cove. This tunnel would be approximately 2,900 feet (884 m) long and would convey water to a powerhouse installation at Ell Cove through a penstock about 1,400 feet (426 m) long. Read more here and here. Explore more of Kasnyku Falls and Waterfall Cove here: