The Karez Systems of Turpan (China) – Origin, Bloom and Heritage

olaf.bubenzer [at] uni-koeln.de (Olaf Bubenzer) ^a, Stefan Hecht ^b, Cheng-Sen Li ^c, Nicola Manke ^b, Bernd Kromer ^d, Qiang Zhao ^d, Bertil Mächtle ^b

^a Institute of Geography, University of Cologne
^b Institute of Geography, Heidelberg University
^c Institute of Botany, Chinese Academy of Science, China
^d Curt-Engelhorn-Zentrum Archäometrie, Mannheim
^e Turpan Prefecture Cultural Relics Bureau, Turpan                       

The poster presents results of sino-german research on the famous Karez irrigation systems in the oases of the Turpan basin (Autonomous Province Xinjiang, NW-China). The oldest known Karez systems are located in Iran and are dated to at least 2500 years before today. These underground-water carriers are also known, for example, from several other drylands of eastern and central Asia (“Karez”), Middle East (“Qanat”), and N-Africa (“Foggara”, “Khettera”). In the Turpan Basin, more than 1,100 Karez (Kan er jing) systems with around 60,000 hand-dug “shafts” are known. With regard to their origin four hypotheses exist:

1. The Karez were invented by people from mainland China during the Han dynasty (206 BC – 220 AD). In that case, Karez are more than 2000 years old.
2. The knowledge about water harvesting technique was transferred eventually along the silk roads from Persia after their first “invention”.
3. Local Uigur people developed the technology independently, with unknown age.
4. The Karez were invented first during the Qing dynasty (19. cent. AD), which means that the systems in the Turpan Basin are not older than 200 years.

In order to shed light on these hypotheses/questions, our team undertook joint fieldwork. Firstly, the most likely oldest Karez systems which are still in use, were identified based on interviews of local people. Secondly, we sampled 11 of these Karez systems spread over the Turpan Basin. From our experience in studying geoarchives, we expected remnants of plants which were buried during the formation of Karez mounds. Thirdly, applying radiocarbon dating technology, we got the time of death of the plants and hereby the formation age of each investigated mound. As Karez mounds grow over centuries by repeated maintenance, they are layered. These layers were also dated.

The poster presents first results. Although the question about the oldest Karez system cannot be answered totally up to now, our study showed that the applied methods work properly and confirms most of the information from oral tradition. Finally, the Karez systems and its origin in the Turpan basin are of high historical importance and are nominated as UNESCO Heritage (tentative list). More knowledge about the origin and maintenance history of these unique systems, which are recently highly endangered by groundwater recession and damage, will help in protecting them for future generations.