Complex sentence: Most of the lands were possessed by the city which collected grazing taxes on its lands, the oasis had approximately 1000 ha of irrigable land, in addition to the lands of the countrysides, where the Palmyrenes built dams and irrigation systems such as the Harbaqa Dam.
Split into simpler sentences: Most of the lands were possessed by the city, which collected grazing taxes on its lands. The oasis had approximately 1000 ha of irrigable land, in addition to the lands of the countrysides, where the Palmyrenes built dams and irrigation systems such as the Harbaqa Dam.