The city of Yazd is situated on the edge of the Dasht-i Kavīr in the Ardistān-Yazd basin, which stretches some 250 miles from near Kāshān to south of Bāfq. It lies at a height of 4,000 ft. West of Yazd, the Shīr Kūh massif rises to 13,370 ft. It receives considerable moisture including heavy snow but the rainfall of Yazd itself is less than 5 in. per annum. Near Yazd groundwater which originates in the Shīr Kūh mountains follows a northward slope from Mihrīz towards Ardakān. Before the sinking of semi-deep power-operated wells from about 1950 onwards, Yazd obtained its water from long qanāts originating in the mountains west of Taft and Mihrīz. The qanāts of the villages to the north-west of Yazd tap water in the highest elevations of the basins to the north-east. Some of these qanāts flow underneath Yazd, while a few originate in Yazd itself.