Chongqing expands access to drinkable karst water

CHONGQING — A team from Chongqing's geology and mining authority has improved techniques to achieve a major breakthrough in karst groundwater exploration and drilling in the municipality.

The step forward has helped secure water supplies for thousands of residents, including students at a primary school in Xiushan county, which had chronic water shortages.

"The school will have easy access to wells to get drinking water in the future," cheered teachers and students when hearing the news.

Chongqing in Southwest China has vast mountainous and hilly areas, with prominent karst landforms and abundant water flowing through the city, said Du Chunlan, a senior engineer of hydraulic and environmental geology of the geological team. But it is difficult to develop and utilize water in the municipality.

The karst area of Chongqing is close to 30,000 square kilometers, accounting for one-third of the city's jurisdiction area, according to a report by Science and Technology Daily.

There are a large number of pipes and huge corrosion cracks and pores in the rock strata, and precipitation is quickly converted into groundwater.

Previously, it took about 30 days to drill a well in the karst areas due to the complex geological structure, said Lyu Yuxiang, deputy chief engineer with the geological team. Water shortages in such areas often occur in summer.

"We can't bear people waiting such a long time," Lyu said.

The team of engineers improved the drilling technique to promote efficiency. The new technique shortens the average duration of drilling a hole to three days, operating at the rate of more than 20 meters per hour.

The karst region has an uneven distribution of water resources, Lyu said. The transport and accumulation of karst water has been a challenging issue for a long time.

The success rate of drilling for water used to be only about 30 percent in karst regions.

The geological team has been engaged in water exploration and drilling since 2006, and it has improved the success rate to 70 percent.

The team has analyzed and summarized the accumulation of karst groundwater, the karst water storage structure and water exploration in southeastern and northeastern parts of Chongqing. It has also identified 26 water-rich blocks in the city's karst areas.

The team's achievements have also enriched the field of hydrogeological theory and provided a reference for exploiting karst groundwater.

Up till now, the geological team has set a water exploration standard in the karst areas of Chongqing, conducted 13 karst water supply demonstration projects, drilled 68 wells and made drinking water easily accessible for more than 80,000 people.

Xinhua