The researchers studied ways to improve the water quality of Lake Yangchenghu in China by using a computer model. They looked at three different methods to reduce nutrients in the lake: cutting down on nutrients coming in, increasing water flow, and changing where water enters the lake. They found that reducing nutrient levels in the water was the best way to control algae growth. Increasing water flow didn't help much unless the water brought in fewer nutrients. Changing where water enters the lake could improve water quality in some areas but make it worse in others.