Speel Arm extends generally northeast for 9 miles (14.5 km) from the head of Port Snettisham to the mouth of the Speel River, and is the site of a hydroelectric facility powered by water from Crater Lake and Long Lake, about 95 miles (153 km) northeast of Sitka and 30 miles (48 km) southeast of Juneau, Alaska. Port Snettisham was discovered by Lieutenant Joseph Whidbey in 1794 and named by Captain George Vancouver for the village of Snettisham in Norfolk, England. Speel River was named in 1888 by Lieutenant Commander Charles M. Thomas who commanded the USC&GS Carlile P. Patterson from 1887 to 1889 for the U.S. Coast and Geodetic Survey while mapping parts of the Southeast Alaska coast. The predominant rocks surrounding Speel Arm are quartz diorite of the Coast Range batholith and gneisses and schists of the metamorphic complex belt lying adjacent to the batholith. The Speel River is a braided sediment ladened stream that starts at the outlet of a proglacial lake formed by the retreating Speel Glacier and ends in mudflats at the head of Speel Arm. In 1948, the river flowed for 11 miles (18 km) from a braided outwash plain and drained a watershed of about 144,640 acres (58,534 ha). In 1984, the glacier had retreated 2.1 miles (3.4 km) creating a proglacial lake 1.4 miles (2.2 km) long. In 2022, the glacier has retreated another 2.3 miles (3.6 km), crossing the border into Canada, and lengthening the lake to 4.4 miles (7 km).

Port Snettisham is the traditional territory of Tlingit T’aaku Kwáan and there were several historical villages and fish camps along the shore at the time of first contact with Europeans in the 18th century. In 1895, a gold and silver mining camp was established on the south shore of the bay at the site of a village called Sit’ku. In 1899, the Alaska-Snettisham Gold Mining Company began operations on the Friday and Crystal mines. The Friday mine eventually had two tunnels of 750 feet (229 m) and 600 feet (183 m) long. In 1900, a 5-stamp mill was built. The ore contained mostly pyrite and magnetite which made extraction of gold difficult. The Crystal mine with 2,300 feet (700 m) of underground working was located 1.5 miles (2.4 km) from the wharf at Snettisham and was independently mined from 1901 to 1903 producing $25,000 of gold. In 1903, the mine was optioned to the Alaska-Snettisham Gold Mining Company and the ore was trammed to a 20-stamp mill at the Friday mine. The ore was exhausted by 1905 and the company discontinued all operations. Other businesses at Snettisham village included a salmon cannery started in 1900 and operated by Taku Fishing Company and sold to Pacific Packing and Navigation Company in 1901, and a paper pulp mill started in 1917. The village had a post office from 1900 to 1912 and it remained inhabited until 1926.

The Snettisham hydroelectric power plant at sea level is fed by water drained from two alpine lakes negating the need for a traditional dam. The elevation of Crater Lake is 1,022 feet (318 m) and Long Lake is at 814 feet (248 m) and both watersheds occupy deep glacially scoured troughs surrounded by steep glacier-clad mountains in the Tongass National Forest. The lakes are in the maritime climate zone with typically cool wet weather. The high divides of their respective basins form a barrier to storms from the North Pacific Ocean, providing an orographic effect and causing unusually high precipitation. The average annual precipitation is about 140 inches (356 cm) per year at the Snettisham power plant and is estimated to be 230 inches (584 cm) per year at Crater Lake. In 1967, construction began on the Long Lake hydroelectric project by the U.S. Army Corps of Engineers that included a power tunnel 8,400 feet (2,560 m) long to deliver water from the lake to the turbines at sea level in Speel Arm, a remote camp, a boat slip, an airstrip, and a high voltage transmission line 44 miles (71 km) long to deliver 47.2 megawatts of power to Juneau. In 1990, another tunnel was bored from nearby Crater Lake and the additional water powers a turbine contributing an additional 31 megawatts. The combined 78.2 megawatts provides approximately 65% of the power for the Alaska Electric Light and Power Company of Juneau. The power station also supports the Snettisham Fish Hatchery which is owned by the State of Alaska and operated by Douglas Island Pink and Chum. Read more here and here. Explore more of Speel Arm and Port Snettisham here: