I guess this means they got the spillway gate(s), which had been damaged by Hurricane Maria, working again. From The Associated Press, 11:01 PM EDT. September 23, reporting from Guajataca, Puerto Rico:
In northwest Puerto Rico, people began returning to their homes after a spillway eased pressure on [Guajataca] dam, which had cracked after more than a foot of rain fell in the wake of the hurricane.
A dam upstream of the towns of Quebradillas and Isabela in northwest Puerto Rico [Guajataca] was cracked but had not burst by Saturday night as water continued to pour out of rain-swollen Lake Guajataca.
Governor [Ricardo Rossello] said there is "significant damage" to the dam and authorities believe it could give way at any moment. "We don't know how long it's going to hold. The integrity of the structure has been compromised in a significant way," Rossello said.
Some residents nonetheless returned to their homes Saturday as the water levels in the reservoir began to sink.
"There were a lot of people worried and crying, but that's natural, because the reservoir was about to break through," said Maria Nieves, 43. "They couldn't open the spillway until later in the night."
The 345-yard (316-meter) dam, which was built around 1928, holds back a man-made lake covering about 2 square miles (5 square kilometers). More than 15 inches (nearly 40 centimeters) of rain from Maria fell on the surrounding mountains.