In Ukraine, the river's width ranges from 60 to 250 metres (200 to 820 ft), with its average depth being 3 m (10 ft). The mean annual discharge at its mouth is 360 m3/s (13,000 cu ft/s).[1] The river freezes over from early December to early April, and is navigable fromNovhorod-Siverskyi to its mouth, a length of about 535 km (332 mi).[1]
The water level of the river reached its lowest recorded point in 140 years in June 2020. This water level was 5 m (16 ft) below normal for that time of year.[2]
The Desna originates in the Smolensk Heights ofSmolensk Oblast,Russia. The river's source lies inYelninsky District, east-southeast from the city ofSmolensk and not far fromYelnya in a forest near the village of Naleti. The Desna then flows south through a low and swampy valley toward the city ofBryansk, where the river's right bank rises.
After its confluence with theSeym near the Russian-Ukrainian border, the river then widens, splitting into numerous smaller branches. Its right bank declines again near the city ofChernihiv, and again near one of its tributaries, theOster, where the Desna continues its course through a low, muddy plain until it finally reaches its mouth nearKyiv at the Dnieper River.
Кудрявцев, Д. (1893)."Десна[, приток Днепра]" [Desna, a tributary of the Dnepr].Энциклопедический Словарь Ф.А.Брокгауза и И.А.Ефрона [Brockhaus and Efron Encyclopedic Dictionary] (in Russian). Vol. XА [20]. С.-Петербургъ [St. Petersburg]: Ф.А. БРОКГАУЗЪ (Лейпцигъ), И.А.ЕФРОНЪ (С.-Петербургъ). pp. 482–485.
