Search Results (3)

Karez systems are ancient hydraulic works that use underground waterways to divert water by gravity and have historically been popular in arid regions across Central Asia. Karez systems have undergone thousands of years of development and have been used for irrigation in 40 countries and regions worldwide. Although there are different opinions about the origin of karezes, the role and significance of karezes are similar. The Turpan Basin is a relatively closed inland basin in China, far from the ocean, with a very dry climate and high evaporation rates. However, due to the ice and snow meltwater of the Tianshan Mountains, the groundwater resources in the basin are abundant. Karezes are an important support for Turpan’s farming civilization and tourism culture and represent a great masterpiece of how people in arid areas have used the natural environment. This study used historical CORONA images to visually interpret the karez system in the 1970s and compared it with the karez system in 2020 to analyze the spatial distribution variation characteristics of the karezes. The impact of land use/land cover change on the karezes was also analyzed. The results showed that from 1970 to 2020, as the population grew, there was an increase in arable land and built-up areas while the water area decreased. In general, the increase in arable land and built-up areas, the decrease in water area, and the increase in the number of electromechanical wells have combined to reduce the number of karez systems. Based on the CORONA image from 1970, it is possible to visualize the shaft area that existed in 1970 but did not exist in 2020. Some karez shafts that existed in bare terrain areas in 1970 were truncated when the land use/land cover type changed to arable land. The area where the disappeared karez shafts were located is approximately 87.77 square kilometers. Through the study of the changes in the spatial distribution of karezes and the impact of land use/land cover change on karezes, this research provides a valuable reference for the construction of karez conservation areas or urban planning. The investigation of the distribution of historical karezes is of great significance for studying the changes in karezes and excavating the historical and cultural value of karezes. Full article

Historical hydraulic systems represent a significant part of landscapes and global heritage. However, from the second half of the 20th century onwards, substantial socio-economic as well as technological changes occurring worldwide have put them at risk of abandonment and, eventually, of disappearing. Recent studies and international conventions, including the ICOMOS-IFLA, framed historical hydraulic systems and water management techniques in a new dimension, not only as an element of the past to be preserved but an active element to achieve sustainable economic development and mitigate climate change. Those qanats or karez represented a major historical hydraulic sustainable solution for irrigation, providing a water supply, which during the last few decades, has been slowly replaced with modern, although polluting and unsustainable, technologies. Building on the recent ICOMOS-IFLA Principles Concerning Rural Landscape as Heritage and the recommendation provided by initial research, this paper aims to show how qanats can become: (1) an important local and regional cultural and natural heritage; (2) a valuable economic resource; (3) an environmentally friendly system that could at least partially replace the existing polluting solution (i.e., dams and other modern infrastructures). To achieve these goals, we propose a restoration or reuse approach for the qanat based on the necessity of multiple stakeholders at local and national levels using sustainable materials and respecting the different values as a heritage place. Our case study is the No-Ras qanat in North-western Iran. In the conclusion, we also illustrate the relevance of the aims and methods of this paper in the light of the United Nations Sustainable Development Goals. Full article

This paper investigates the impact of tube wells on the discharge and water table of the Quetta Valley aquifer and conducts a financial analysis of the solar photovoltaic water pumping system (SPVWP) in comparison with a typical pumping system for the Water and Sanitation Agency of Quetta’s (WASA) tube wells. Quetta Valley is dependent on groundwater as surface resources are on decline and unpredictable. The population of this city has exponentially increased from 0.26 million in 1975 to 2.2 million in 2017 which has put a lot of pressure on the groundwater aquifer by installing more than 500 large capacity tube wells by WASA and Public Health Engineering (PHE) departments in addition to thousands of low-capacity private tube wells. The unprecedented running of these wells has resulted in drying of the historical Karez system, agricultural activities, and the sharp increase in power tariffs. There are 423 tube wells in operation installed by WASA in addition to PHE, Irrigation and Military Engineering Services (MES), which covers 60% of the city’s water demand. The results will be beneficial for organizations and positively impact the operation of these wells to meet public water demand. For the two zones, i.e., Zarghoon and Chiltan in Quetta Valley, recommendations are given for improved water management. Full article