Seym (river)

{{short description|River in Russia and Ukraine}}

{{Infobox river

| name = Seym

| native_name = {{native name|ru|Сейм|paren=omit}}

| image = Sejm in bupel.jpg

| image_caption = Seym at Bupel in Kursk Oblast

| mapframe = yes

| mapframe-zoom = 6

| source1 = near Morozovo

| source1_coordinates = {{coord|51|09|50|N|37|13|58|E|region:RU}}

| mouth = Desna

| mouth_coordinates = {{coord|51|27|34|N|32|33|50|E|source:kolossus-ruwiki|display=it}}

| subdivision_type1 = Regions

| subdivision_name1 = {{RUS}}: Belgorod, Kursk
{{UKR}}: Sumy, Chernihiv

| length = {{convert|748|km|abbr=on}}

| source1_elevation =

| discharge1_avg = 99.6 m³/s

| basin_size = {{convert|27,500|km2|abbr=on}}

| progression = {{RDesna}}

| tributaries_left = Reut, Vyr

| tributaries_right = Tuskar, Svapa, Kleven

| extra =

}}

The Seym or Seim ({{Langx|ru|Сейм}}; {{Langx|uk|Сейм}}) is a river that flows westward in Russia and Ukraine. It is {{convert|748|km}} long (250 km within Ukraine) and its basin area about {{convert|27500|km2}}. It is the largest tributary of the Desna.{{cite book|url=http://www.kmf.uz.ua/hun114/images/konyvek/Izsak_Tibor_Ukrajna%20termeszeti_foldrajza.pdf|title=Ukrajna természeti földrajza|format=pdf |pages=95| author=Izsák Tibor|publisher=II. Rákóczi Ferenc Kárpátaljai Magyar Főiskola|year=2007|accessdate=2019-05-05|language=hu|archive-url=https://web.archive.org/web/20130228072653/http://www.kmf.uz.ua/hun114/images/konyvek/Izsak_Tibor_Ukrajna%20termeszeti_foldrajza.pdf|archive-date=2013-02-28|url-status=dead}}{{cite web|url=http://okt.kmf.uz.ua/ftt/oktat-ftt/Foldrajz_szak/Ukrajna_termeszeti_fodrajza/szotarukrfoldr.pdf|title=NÉVJEGYZÉK-SZÓTÁR az UKRAJNA TERMÉSZETI FÖLDRAJZA tantárgyhoz|publisher=II. Rákóczi Ferenc Kárpátaljai Magyar Főiskola|accessdate=2019-05-05|format=pdf|language=hu|archive-url=https://web.archive.org/web/20190404180651/http://okt.kmf.uz.ua/ftt/oktat-ftt/Foldrajz_szak/Ukrajna_termeszeti_fodrajza/szotarukrfoldr.pdf|archive-date=2019-04-04|url-status=dead}}{{cite web|url=http://bse.sci-lib.com/article100794.html|title=Сейм (река)|publisher=Большая Советская Энциклопедия|accessdate=2019-05-05|language=ru}}{{cite web|url=http://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CS%5CE%5CSeimRiver.htm|title=Seim River|publisher=Encyclopedia of Ukraine|accessdate=2019-05-05|language=en}}

Places on the river include Kursk, Kurchatov,{{cn|date=August 2024}} Rylsk, Glushkovo,{{cite news|url=https://www.canberratimes.com.au/story/8733023/ukraine-destroys-bridge-in-russias-kursk-region/ |title=Ukraine 'destroys bridge' in Russia's Kursk region|work= Canberra Times|date= 16 August 2024}} Putyvl, Baturyn, and the junction with the Desna, which continues west and south past Chernihiv to Kyiv.{{cn|date=August 2024}}

In September 2024, during the Russian invasion of Ukraine, Ukrainian officials accused Russia of polluting the river by dumping sewage from a sugar factory in Tyotkino, Kursk Oblast, resulting in environmental damage estimated at about Hr 186 million ($4.5 million) in Chernihiv Oblast that included a decrease in oxygen levels and fish kills downstream.{{cite news|url=https://kyivindependent.com/russia-polluted-seim-river/ |title=Ukrainian river polluted by factory sewage in Kursk Oblast, PM says |work= The Kyiv Independent|date= 10 September 2024}}

The river also serves cooling water for the Kursk Nuclear Power Plant in Russia.