Answer:
The image of "springs of water" presents how important Rachel's arrival was to Lyddie. She found happiness and life again, amidst the bustle and ordinary life in the mill. Rachel is like a fresh spring of water in the desert, in Lyddie's desert life.
Step-by-step explanation:
Katherine Paterson's "Lyddie" revolves around the character of Lyddie, a thirteen-year-old girl who worked hard to bring her family back to stability and unity. And through that goal, she learned how to be determined and persevere despite any odds that might come along the way.
Rachel is the younger sister of Lyddie who had previously been with their mother. But now, she had been brought back to Lyddie at the mill, which Lyddie finds it hard to manage. She is already in a tight spot, working hard to try to get enough money. And here is another mouth to feed, making Lyddie feel like giving up. But then, she realized "how dry her life had been before Rachel came". The author used a simile "springs of water" to describe the impact of Rachel on Lyddie, with the image of water found in the desert.
This image shows how important, significant, and good it was for Lyddie to have her sister. In the literal sense, water is always a sign of hope in a desert. And on the metaphorical level, Rachel seems to bring back happiness and bring Lyddie back to life.