How did Bright Morning feel when she heard the river running?

Bright Morning is the main character and narrator in Scott O'Dell's 1970 novel entitled Sing Down The Moon. Bright Morning is part of the Navajo (spelled Navaho in the novel) tribe. The novel is set in 1864, and it is a wonderful portrayal a difficult part of American history. I love getting a glimpse of Navajo life, as well as seeing a historical event from the perspective of those who were victimized. It is a Newbery Honor award winner, as well.
It is beautiful to see the characters' relationship to nature in this novel. They depend on nature, and they revere it as well. Nature is often depicted as having a sort of supernatural power. For example, when her brother shoots the six prong deer and was singing with happiness because of this, lightning struck him and he died. Bright Morning believes this happened because the gods do not like to see people showing happiness by singing and they punish those who do not obey. 
When Bright Morning hears the river running in chapter one, she says she felt like singing. She said she wanted to leap and dance with joy because hearing the water of the river rushing is a sign that spring has begun. The first line of the novel indicates that spring came early that year, so hearing the river run when she did would have been somewhat of a surprise, as well. She describes it in the following way: 

The day the waters came was a wonderful day. I heard the first sounds of their coming while I lay awake in the night. At first it was a whisper, like a wind among the dry stalks of our cornfield. After a while it was a sound like the feet of warriors dancing. Then it was a roar that shook the earth. I could hardly wait until the sun rose.

A little later, she describes her feelings about the river running and the sounds and sights of spring:

I felt like singing. I wanted to leap and dance with joy, yet I stood quietly and watched the river running between the greening cottonwood trees, for I knew that it is bad luck to be so happy.