was exceptionally dry winter—and the maximum value corresponds to June 1959 and was The diagram below contains mean values of monthly average discharges calculated on the base of a 52-year-long period of observations at hydrological station "Bolshoy Porog". Seventy-three per cent of the entire annual water yield occurs during the spring–summer season. The amplitude of the water-level variations in the lower stream of Nizhnyaya Tunguska is the highest among all notable rivers of Russia. At narrow places in the river channel, ice jams during its seasonal drift, and this creates temporary dams that block normal water flow and raise water levels up to above the mean value. The summer break-up and drifting of ice passes very violently; it leaves traces in the form of torn-apart uprooted trees and polished rocks. During some days of spring freshets the river's discharge can peak at , and it supplies 50 to 60 per cent of the water volume to the lower stream of the Yenisey in the time of its seasonal inundation. Economy The channel of Nizhnyaya Tunguska with its tributaries constitutes dense network of rivers and creeks which creates convenient summer pathways through the wide rifted valley of Eastern Siberia. Historically, the river was used as a route for the fur trade, fishery, for transportation of goods and mineral resources. Hunting and fur trade is still a significant part of the local economy. Shipping Navigation on the river is difficult because of a number of rifts, rapids and whirlpools. The passage of large ships and barges is possible during the spring inundation, and rainy weather during particular years allows short periods of navigation at the end of summer or the start of autumn. The most problematic for the safe navigation of ships are the rapids "Bolshoy", which are from the river's mouth. In 1927 the first steamship passed this rapids and it is considered to be the start of modern navigation on the river from Turukhansk to Tura. As of 2010 the shipping routes of Yenisey River Steamship Lines () includes the village Kislokan, from the estuary. Timber rafting is possible throughout entire course of the river. It was suggested (and some research was done) in 1911 to build a canal joining the Lena and Nizhnyaya Tunguska rivers in the neighbourhood of Kirensk. Near this locality the rivers are separated by no more than , but here the Nizhnyaya Tunguska is not