Valmiki Ramayana Yuddha Kanda Sarga 4 Shloka 60

सततम् continuously, सेनायाम् all the army, उत्तरन्त्यम् latter, नदीस्रोतां सि the flow of water in the river, च बहुयोजनम् and several miles, विपरीतवत् as if excessive flood like, सस्यन्दुः flowed

When the army was continuously crossing the river, later (after they crossed) the water flowed excessively like flood.