Water levels in southern Africa’s Lake Kariba have dropped to 12 percent of capacity, the authority in charge said on Tuesday, raising concerns about severe power rationing in Zimbabwe and Zambia.

Both countries rely heavily on the Kariba dam for electricity.

The levels were 477.25m above sea level on Monday, just two metres above the point their working capacity, the Zambezi River Authority, which manages the lake for Zambia and Zimbabwe, said on its website.

“The Kariba Lake was created and designed to operate between levels 475.50m and 488.50m,” it said.

The dam was 12 percent full on Monday compared with 53 percent on the same date last year, underscoring the severity of a prolonged drought that threatens crops across the Southern African region where the United Nations has warned that 14 million people face hunger.

Zambia asked South Africa last week for up to 300 megawatts (MW) of emergency power to ease an electricity crunch that has hit mining companies already grappling with a slide in global copper prices.

Meanwhile, on Monday, water flow measurements from the famed Victoria Falls, a major tourist site, were recorded at 492 cubic metres per second, close to the historic low of 390 cubic metres per second posted in the 1995/96 season, its authority said.

Zambian power companies and mining firms in August 2015 agreed to cut power supply to the mines by 30 percent due to a power deficit which rose to 985 MW in September from 560 MW in March.