The Age and Origin of Karez Systems of Silk Road Oases around Turpan, Xinjiang, P.R. of China

Abstract

Age and origin of ancient famous Karez water systems in the oases of the Turpan Basin are open questions in geoarchaeological and historical research. Four hypotheses exist: (a) invention during Han dynasty more than 2000 years ago, (b) transfer of technology from Persian Qanat's more than 3000 years ago, (c) independent invention of local Uyghur people in the 15th century, and (d) late invention during the Chinese Qing dynasty (19th century). Our study dates, for the first time, 8 Karez systems by 14 C from plants buried during the formation of Karez mounds, and interviews in order to record oral tradition. We found that the oldest investigated Karez systems originated in the Uyghurian Huihe dynasty (790-1755 AD), which coincides with the oral tradition. A second phase may have occurred during late Huihe/Qing dynasty (after 1755 AD), which may explain why information and the Uygurian term "Kan er jing" went down in historic Chinese records. In conclusion, hypothesis (d) that oldest Karez systems were built during Qing dynasty has to be rejected because they are at least 600 years old. Instead, during the 3rd Chinese expansion in the 19th century AD the Karez system expanded and got maintenance. A review of regional palaeoclimatic proxies suggests that the origin and the maintenance of the Karez systems took place rather in more humid periods than in more arid ones. However, more research is needed on other Karez systems to test the pending hypotheses of a much older age.

Sustainability of Underground Hydro-Technologies: From Ancient to Modern Times and toward the Future

“…In spite of the fact that the Turpan karez system represents a very sustainable way of water harvesting, under present conditions it is sentenced to dry out in a short time. Its restoration can only be implemented by considering the total hydrological system of the depression (precipitation, evaporation, infiltration, water table) and respecting sustainable values of groundwater subtraction [70].…”

“…Karez lines (in blue) of the Turpan basin, distributed along the southern slopes of the Bogda-Ula mountains. In the last 50 years, the number of karez active systems decreased from 1000 to 480[70].…”

“…Scale model of the entire karez system of the Turpan basin, from the piedmonts of the Bogda-Ula mountains in the north to the colonized plain 20-50 km far in the south[70].…”

On the Paleo-climatic/Environmental Impacts and Socio-Cultural System Resilience along the Historical Silk Road

“…Experience of extreme climate conditions can increase opportunities for learning and innovation, e.g. local people developed hydraulic systems of water-sediment separation at the mountainous Tea-Horse Road region that effectively mitigated flood hazards (Xu et al 2019), and the Karez system in the dry Asian regions is a great human creation that survives social development for thousands of years (Mächtle et al 2019). The study from Panyushkina et al (2019) shows that Saka people of the Iron Age employed extensive ravine agriculture on alluvial fans and that they were able to apply simple flow control structures, which certainly reduced water constrains to agricultural expansion in the Lake Balkhash Basin.…”

Assessing water distribution and agricultural expansion in the Cele Oasis, China

“…Relied upon by traders and traveling merchants for water, these oases served a vital role in supporting shared economic prosperity between Asian and Western European civilizations. In this period of trade and discovery, oases were not just important watering stops for travelers, some also were population centers of a mix of ethnic cultures near the region (Lawler 2009;Mächtle et al 2019). Even today, the oases serve a vital role in China's economy and the indigenous population, yet they are not necessarily the same oases as before.…”