Rock desertification is a serious ecological geological problem in the broad karst area of southwest China, which covers about 540,000 km². It brings about poverty to local people. The rehabilitation of such poor region is one of the major target in China’s << Agenda 21>>, and a part of the governmental drive to develop middle-west part of the country.

During 1978-1982, a research group of the Institute of Karst Geology, Chinese Academy of Geological Sciences went to a typical site of rock desertification, the Luota township of Longshan county, Hunan province (Fig.1) to carry out karst hydrogeological survey, and look for rehabilitation measures. The township had a population of about 10 thousand living under the state poverty line. It covers 119.07 km² underlain by Permian and Triassic carbonate rocks. The area is on the transitional slope zone between Guizhou plateau (1200m asl in general) and Hunan Basin( 100m asl in general), and characterized by multi-level plateaus dissected by deep gorges. There are 737 hectares of terraced farmland scattered on slopes 1000m-600m asl, which suffered from drought because of leakage in the underlying intensively karstified carbonate rocks, even though there are remarkable rainfall of about 1400mm annually.

Fig.1, The location of Luota township

Fig.2, Aqueduct on 1000m asl, Luota,Hunan, above it is the plantation and doline-reservoir building zone, below it is the terraced farmland

Through systematic geological and hydrogeological mapping, caving, tracing test, hydrological and meteorological monitoring works, 51 underground streams larger or smaller with a total length of 82 km were identified. The total karst water resources are estimated to be 120 million m³/a. Moreover, the area is found to be rich in coal, limestone and hydropower resources. The latter is also related to karst underground streams.

The rehabilitation works in the past 15 years turned out to be successful. It started from re-arrangement of land use, i.e, plantation on the slope above 1000m asl (Fig.2) for ecological rehabilitation, and building reservoirs in dolinen (Fig.3) in this zone for irrigating the terraced ricefield below 1000m asl. The harvest from the ricefield grows up remarkably after the irrigation system putting into use, and provides food for local peopple more than enough. After irrigation use, the water returns to the underground stream again in a lower level. There, the hydraulic gradience is still high, and hydropower station was built to provide electricity not only for their own use , but also for neighbouring township and making money. Besides, Luota people take the advantages of their coal and limestone resources to develop cement and coal industry. On plateaus with different elevations, fruits and some herb medicines(such as Eucommia Ulmoides) are planted in accordance with the local climate and soil conditions.

Fig.3, The Baxiandong doline-reservoir constructed by damming a swallet hole, showing low water level in dry season. The water is conducted into the aqueduct in Fig.2 through a natural undergroung course

The comprehensive developments have not only helped Luota people overcoming proverty problems, but also changed Luota’s ecological system into a more rational cycle.

Comments and suggestions to Webmaster,
Copyrights by Karst Dynamics Laboratory and Network Center of Guangxi Normal University,
1995-1999. All rights reserved.