The Ob provides irrigation, drinking water, hydroelectric energy, and fishing (the river hosts more than 50 species of fish). There are several hydroelectric power plants along the Ob river, the largest being Novosibirskaya GES. The navigable waters within the Ob basin reach a total length of . Novgorod established two trade routes to the Ob River, both starting from the town of
Ustyug. The Russian settlements of
Beryozov and
Obdorsk were founded towards the end of the 16th century on the lower reaches of the Ob, while
Surgut was founded on the middle course of the Ob. Until the early 20th century, a particularly important western river-port was
Tyumen, located on the
Tura, a tributary of the
Tobol. Reached by an extension of the
Yekaterinburg–
Perm railway in 1885, and thus obtaining a rail link to the
Kama and
Volga rivers in the heart of Russia, Tyumen became an important railhead for some years until the railway extended further east. In the eastern reaches of the Ob basin,
Tomsk on the
Tom functioned as an important terminus. Tyumen had its first
steamboat in 1836, and steamboats have navigated the middle reaches of the Ob since 1845. In 1916, there were 49 steamers on the Ob; 10 on the Yenisei. In the 1870s, the
navigability of the river was explored by
Christian Dahl, who was instrumental in opening up a direct trade route from central Siberia to Western Europe. In an attempt to extend the Ob navigable system even further, a
system of canals, utilising the
Ket, long in all, was built in the late 19th-century to connect the Ob with the
Yenisei, but soon abandoned as being uncompetitive with the
railway. The Trans-Siberian Railway, once completed, provided for more direct, year-round transport in the east–west direction. But the Ob river-system still remained important for connecting the huge expanses of
Tyumen Oblast and
Tomsk Oblast with the major cities along the Trans-Siberian route, such as Novosibirsk or
Omsk. In the second half of the 20th century, construction of rail links to
Labytnangi,
Tobolsk, and the oil and gas cities of
Surgut, and
Nizhnevartovsk provided more railheads, but did not diminish the importance of the waterways for reaching places still not served by the rail. A dam built near Novosibirsk in 1956 created the then-largest artificial lake in
Siberia, called
Novosibirsk Reservoir. From the 1960s through 1980s, Soviet engineers and administrators contemplated a gigantic project to
divert some of the waters of Ob and Irtysh to
Kazakhstan and the Soviet
Central Asian republics, replenishing the
Aral Sea as well. The project never left the drawing board, abandoned in 1986 for economic and environmental considerations. ==Pollution==