Valmiki Ramayana Bala Kanda Sarga 43 Shloka 12

तस्याम् when that Ganga, विसृज्यमानायाम् was being released, सप्त seven, स्रोतांसि streams, जज्ञिरे were born, ह्लादिनी Hladini, पावनी Pavani, तथा and, अपरा another, नलिनी च Nalini, शिवजला: possessing auspicious waters, तिस्र: three, शुभा: auspicious, गङ्गा: streams of Ganga, प्राचीम् दिशं eastwards, जग्मु: had flowed.

As she (Ganga) was released, she branched out into seven streams. Three streams known as Hladini, Pavani and Nalini having auspicious waters and conferring prosperity flowed eastwards.