In the past, water was taken from the reservoir via low-level channels. The water had a high turbidity level, but the silt it carried in fact helped increase the fertility of farmland. But if the water fed into a water treatment plant is too turbid, the plant will be choked and stop working.
過去由底層取水道取水，濁度高、夾帶泥沙反而能增加農田的肥沃度，但如今濁度太高的原水進入淨水廠，卻會立刻癱瘓淨水廠。