NANNING, April 22 (Xinhua) -- When sunlight floods the mountains around the village at noon, Lan Aiyan, a 23-year-old Yao woman in Dahua Yao Autonomous County, south China's Guangxi Zhuang Autonomous Region, decides to start with her laundry.

However, after the washing machine discharged a round of wastewater, Lan felt a twinge of guilt and went on to complain that the machine consumed too much water.

"I use the water from my neighbors' water tank and dare not waste too much," she said, noting that her family's water tank had just been built a week ago, and now she is more eager for rain than ever.

To Lan, born and raised in the mountainous region, the water tanks of her village mean a lot.

Lan's village is located in the northwest of Dahua county, with the landscape marked by typical karst topography with its dense stone peaks and many depressions.

In 2009, an area of about 486 square km centered on Lan's town obtained the qualification of national geopark because of its unique high peak-cluster depressions.

This is the only large-scale karst national geopark that features high peak-cluster depressions in China, and it is also the deepest karst depression area in the world, according to a comprehensive geological investigation report published by the Guangxi institute of regional geological surveys in 2007.

The report said that in the core region of the national geopark with an area of 251 square km, which covers Lan's village, there are more than 5,000 mountain peaks of over 800 meters in height, 1,326 depressions of different depths and only 324 of them are inhabited.

The geopark belongs to a subtropical zone enjoying a humid and hot monsoon climate with abundant rainfall. Its average annual rainfall ranges from 1,249 mm to 1,673 mm, according to the local meteorological bureau.

Nevertheless, the lack of drinking water and poverty had plagued the local residents from generation to generation in the past.

In 2015, all the 10 administrative villages under Lan's township were identified as poor villages, with a total population of 19,118 and a poverty-stricken population of 10,681.

"We have a very long rainy season here, but we are unable to store water as the surface water infiltrates too fast," Lan said. "Generally, when it rains heavily here, lots of rainwater pours down from the mountain but disappears soon at the bottom of the depressions."

In order to store drinking water, people here had to build water tanks halfway up the mountain near the village in years past. As an area of serious rocky desertification, they can even obtain stone materials locally for the construction.

"During the dry season there isn't enough water in the tank, and we must gingerly use water," Lan said. "After washing, the water is used to feed livestock, such as cattle and sheep."

The water tanks built in the past are often small in capacity and leak easily because they are built from rubble, she added.

Compared to other villages in the geopark, Lan's village is lucky to have a karst cave with water all year round, which can supply water in the dry season. But villagers need to climb over the mountains to fetch water to drink.

Lan Zhike, 40, has vivid memories of the hardships of carrying water back from the cave. "I must go out at dawn and go back and forth twice in the morning, otherwise there will be no time to do farm work that day," he said.

"It is just about two km away, but walking on the mountain road is difficult, especially when you are carrying two buckets of water," he said. "You screw it up if you accidentally fall down."

To solve the shortage of drinking water, the local government launched a campaign to build cement water tanks with a larger capacity for the villagers.

Since 2015, the township government has offered more than 31 million yuan (about 4.4 million U.S. dollars) of subsidies to help the villagers built 2,069 water tanks, and more than 2,000 households and 11,000 people have benefited from the campaign.

Moreover, the government has also provided subsidies for the local families to install water purifiers and coverings on their water tanks, in order to ensure the water quality.

After four years of fighting against poverty, the poverty-stricken population in the township dropped to 1,322 at the end of 2019.

"When my water tank fills with water, I will audaciously take a bath," Lan Aiyan said, noting that the thousands of water tanks scattered in the mountains is one of the most beautiful sights in the national geopark.