Abstract
The landscape of the middle course of the Syrdarya is scattered with numerous oases that prospered between the first and the eighteenth centuries ad. Some of them, like those of the Turkestan oasis (Yasi-Turkestan and Sauran) are characterized by complex and autochthonous water supply systems that relied on the use of groundwater and the digging of karez (wells). Others, like the ones of Otrar on the Arys delta, and Baltakol and Chiili on the Syrdarya branches, are based on the implementation of large irrigation canals fed by flood and active waters. Today most of the ancient landscape has been reduced to a semi-desert, the medieval towns are in ruins, and the ancient irrigation systems are out of use.The aim of this paper is to underline the wide issues related to the management of such large sites, and to report about the smaller-scale conservation activities carried out in that perspective as part of the UNESCO/Japan Trust Fund project for the Preservation and Restoration of the Ancient City of Otrar (2001–04). Detailed description is given on the conservation of a fired brick mosque of the fourteenth to fifteenth century ad and on the problematic interventions carried out before perestroika.