sentences:  As the gate was operated, a diagonal brace between the lowest and second lowest struts failed.The failure resulted in the uncontrolled release of nearly 40 percent of Folsom Lake and a flood of moving down the American River.The freshwater reaching San Francisco Bay was atypical for the summer season and confused Pacific salmon and striped bass, whose instincts told them that fall rains had arrived; they began their annual fall migrations months ahead of schedule.