Valmiki Ramayana Ayodhya Kanda Sarga 50 Shloka 17

क्वचित् at places, स्तिमितगम्भीराम् was deep and quiet, क्वचित् at places, वेगजलाकुलाम् perturbed due to fastflowing waters, क्वचित् at places, गम्भीरनिर्घोषाम् making majestic sound, क्वचित् at some place, भैरवनिस्वनाम् makes dreadful sounds.

Here the Ganga runs deep but quiet, there she looks perturbed due to fastflowing waters, here she flows with a deep groan and there with a dreadful roar.