
1) Belgian 1914 battle river 2) Belgian border river 3) Belgian canal 4) Belgian Canal connector 5) Belgian canals-connector 6) plant native to Belgium 7) Belgian frontline river 8) River in Belgium 9) Belgium stream 10) Brussels subway destination 11) Certain Flanders river 12) Crossword river 13) Early WWI battle site
Found on
https://www.crosswordclues.com/clue/yser

The Yser (IJzer, Yser) is a river that originates in French Flanders (the north of France), enters the Belgian province of West Flanders and flows into the North Sea at the town of Nieuwpoort. The source of the Yser is in Buysscheure (Buisscheure), in the Nord département of northern France. It flows though Bollezeele (Bollezele), Esquelbecq (Eke...
Found on
http://en.wikipedia.org/wiki/Yser

a river flowing from N France through NW Belgium into the North Sea: battles 1914–18. 55 mi. (89 km) long.
Found on
https://www.infoplease.com/dictionary/yser
No exact match found.