Indians, and Hindus to be specific, have a ton of traditions, rituals, and practices. And one of the many is praying to rivers. Since time immemorial rivers have been the lifeline of people and communities, giving them water, sustaining their crops, and even their life. And so with time, the rivers and water bodies came to be reverred as a life-giving force. In many cultures, rivers are also seen as deities or as manifestations of goddesses.
And in Hinduism, rivers are seen as personifications of Goddesses. Be it Maa Ganga, Maa Yamuna, or else.