You have tracked down some incredible, visceral Puranic variants! The motifs you mentioned—Brahma’s near-suicide over his creative frustrations or his agonizing lust for his daughter/creation Shatarupa—are foundational to the Matsya Purana and Brahmanda Purana, and they perfectly contextualize why a purifying river goddess would react with horror or withdraw.
The two additional legends I referenced—the underwater fire (Vadavagni) and the curse of Sage Utathya—are major narrative pillars in the Puranas and the Mahabharata that explicitly explain how and why she vanished into the desert sands.
This is perhaps the most famous Puranic explanation for the river's disappearance, found prominently in the Padma Purana (Srishti Khanda) and the Skanda Purana.
The story begins with the sage Aurva, who possessed a terrifying, consuming wrath against the Kshatriya (warrior) clan for massacring his ancestors. His intense penance generated a catastrophic, all-consuming inferno known as the Vadavagni (or Vadavamukha—a fire shaped like a mare's head). This fire was so volatile it threatened to incinerate the entire creation.
To save the universe, the gods begged the river goddess Saraswati to carry this terrifying, subterranean fire to the Western Ocean (the Arabian Sea), where it could be safely submerged under the water.
Saraswati agreed, but she was terrified of the fire's heat. As she flowed toward the ocean carrying the roaring Vadavagni, the sheer, unimaginable heat of the mare-headed flame began to dry her up from the inside. To keep her path hidden from the demons and to protect the land from burning, she was forced to go underground (Antarsalila), plunging beneath the earth into the sands of the desert to complete her journey.
This legend is recorded in the Mahabharata (Anushasana Parva) and deals directly with a divine kidnapping and a geographic curse.
The great sage Utathya was married to a beautiful woman named Bhadra (who was a daughter of Soma). The god of the oceans, Varuna, became infatuated with Bhadra and abducted her from Utathya's hermitage, hiding her away in his underwater kingdom.
Enraged, Sage Utathya demanded his wife back. When Varuna arrogantly refused, Utathya decided to punish the waters themselves. He drank up the vast reservoirs of the ocean and then turned his wrath upon the sacred river systems feeding the region.
Utathya cursed the region and the river Saraswati directly. He commanded the river to disappear, declaring that the land should become an unholy, parched wasteland. According to the text, because of Utathya's immense ascetic power (Tapas), the Saraswati receded into the desert, leaving her mighty bed dry and creating the Vinasana—the sacred spot where the river officially "disappeared" into the sands.
When you look at all these versions together, you get a fascinating multi-layered view of how ancient writers conceptualized the river's death:
Mythological Cause | Cultural/Symbolic Meaning | Primary Textual Source |
Brahma's Shame/Suicide | The river recedes out of purity/horror at the creator's moral crisis. | Matsya / Brahmanda Purana |
Shiva's Brahmahatya Skull | The river dries up from the overwhelming spiritual pollutant of a severed head. | Skanda Purana / Local Sthalapuranas |
The Vadavagni Fire | The river burns up from the inside out while saving the world from cosmic fire. | Padma / Skanda Purana |
Utathya's Curse | The river is physically commanded to wither by a wronged sage's power. | Mahabharata |
What makes these texts so brilliant is that whether they blame an internal fire (Vadavagni) or a spatial curse (Utathya), they all universally remember a physical reality that modern hydrology confirms: a mighty river that once flowed to the sea gradually lost its momentum, choked on its own conditions, and retreated beneath the earth.