Hreód-wæter

According to the Old English Dictionary:

es;

hreód-wæter

n. Fenny land where reeds are growing :-- Ðá wæs ðæt land eall swá wé geférdon ádrigad and fien and hreádwæteru palus erat sicca et ceno habundans, Nar. 20, 23. hreod-wæter