Complex sentence: A restoration project in the 1970s had to sacrifice roughly half of the seating capacity because of instability; in 1981 a burst storm drain washed away the scoreboard and the bayward end zone of the football field.
Split into simpler sentences: A restoration project in the 1970s had to sacrifice roughly half of the seating capacity because of instability. In 1981 a burst storm drain washed away the scoreboard and the bayward end zone of the football field.