The basin of Lake Neyriz lies towards the north.

Here the famous Bendamir, and the Pulwar or Kur-ab, flowing respectively from the north-east and the north, unite in one near the ruins of the ancient Persepolis, and, after fertilizing the plain of Merdasht, run eastward down a rich vale for a distance of some forty miles into the salt lake which swallows them up.

This lake, when full, has a length of fifty or sixty miles, with a breadth of from three to six.

In summer, however, it is often quite dry, the water of the Bendamir being expended in irrigation before reaching its natural terminus.

The valley and plain of the Bendamir, and its tributaries, are among the most fertile portions of Persia, as well as among those of most historic interest.
The basin of the Deriah-i-Nemek is smaller than that of the Neyriz, but it is even more productive.