Valmiki Ramayana Aranya Kanda Sarga 16 Shloka 24

साम्प्रतम् now, बाष्पसञ्छन्नसलिलाः waters covered with vapour, रुतविज्ञेयसारसाः inferred from the cackling of swans, सरितः river, हिमार्द्रवालुकैः with sands drenched with snow, तीरैः river banks,भान्ति appear.

Now the rivers are not visible as the waters are covered with vapour. They are only inferred through the cackling of swans and the sands of the bank moistened with dewdrops.