Grass grids safeguard power transmission in NW China desert

YINCHUAN, June 1 (Xinhua) -- Looking at the southwest edge of the vast Maowusu Desert from above, one would not expect to see a green corridor of vibrant vegetation stretching across the wasteland.

The spectacular 25-km corridor, paralleling an array of high voltage transmission towers, lies in northwest China's Ningxia Hui Autonomous Region.

The towers, part of China's west-to-east power transmission program, have been safeguarded by the vegetation mainly consisting of grass and shrubs, which stabilize the sand and reduce desert-induced damage.

The infrastructure is also part of the world's first 660-kilovolt direct current power transmission project. Operational in 2011, the project has transmitted over 330 billion kWh of electricity from the country's resources-rich west to the more developed, power-thirsty east.

"In the past, it was all moving sand here and we couldn't drive in. We had to walk near the towers and patrol in the desert on foot," said Bai Lu, an employee of the State Grid Ningxia Ultra-high-voltage Electric Power Co., Ltd.

Besides, challenges such as accumulated sand burying tower legs or tower foundation exposure due to backfill soil being blown away by winds also increased the difficulty of the maintenance work.

"At that time, most of our efforts were focused on maintaining foundations of transmission towers in the desert, otherwise there would be a risk of the towers falling," Bai added.

To tackle the challenges, the company Bai works at launched a campaign in 2012 to stabilize sand dunes along the transmission lines.

"We were lacking in experience at first, and the survival rate of grass and trees planted was low. We consulted with the forestry department later to jointly roll out a plan for sand stabilization," said Yan Nanzheng, deputy general manager of the company.

We have transformed the drifting sand dunes into fixed or semi-fixed sandy land by setting up grass grids, and then planted seedlings of Caragana korshinskii Kom and sowed mixed seeds of Artemisia desertorum Spreng and other species in the grids to restore vegetation under the towers, Yan added.

The company also used drones to survey the grass grids to improve the efficiency of the restoration work. In the past decade, the campaign has added 1,446 mu of grassland (about 96.4 hectares) to the area.

The areas once afflicted by sand-related disasters have been transformed to fixed sandy land, with weaker sand storms and signs of life emerging, said Bai.

"Wild animals can be seen now and then during the patrol work," Bai said, adding that the transmission failure and the operation and maintenance pressure have been greatly reduced.