Iran Morphology and Hydrography

By | December 16, 2021

1.1 Morphology

The territory, a central-western section of the largest Iranian region, is formed by a complex of other lands, whose distinctive geographical character emerges from the contrast between the mountain ranges that surround it on each side and the interior, a plateau divided into separate basins. of various sizes, without outflow to the sea and mostly steppe or desert. Leaving the Armenian highland, the Iranian reliefs open towards the SE, splitting into a series of divergent chains. AN are the complex mountain systems of Azerbaijan, marked by volcanism and subject to catastrophic earthquakes. Towards the E, the Elburz Mountains close the southern Caspian in a semicircle, a chain over 4000 m high which rises on a long and narrow northern coastal plain, with a series of volcanoes among which the majestic Damavand (5601 m) dominates. The Elburz continued E from the Kopet Dag mountains, a pleated chain, with a width of about 200 km and a height of about 3000 m. Further inland there are the mountains of Khorasan, divided into several chains, often discontinuous, which occupy a vast mountainous region, hollowed out by vast and fertile valley depressions (as in the S), densely populated, rich in crops (especially cereals, cotton, screw) and easy to move. Also to the South, the Iranian plateau is bordered by high mountains, which form an almost continuous arc: the Zagros Mountains, those of Fars and partially those of Makran. The former extend from Kurdistan up to the Fars region (where it is difficult to give them a precise limit) for about 1000 km and with an average width of 200; the highest altitude of the Zagros is in the north (Zard Kuh, 4548 m). The Zagros chains are succeeded towards the SE by those of the Fars, which, while repeating the general characteristics of the former, are less elevated and simpler: they gradually rise from the sea towards the interior. Beyond the node of Hormuz lies the Makran, a country of mountains arranged in a series of parallel chains which, following the coastline, connect towards the E with the mountains of Baluchistan. Other mountainous alignments affect the internal part of the Iran, and two of them, with very tormented tectonics and frequently accompanied by eruptive manifestations, cross it diagonally: the first, from Azerbaijan to Makran, it runs parallel to the Zagros with the highest peaks of Shir Kuh (4076m) and Kuh-e-Hazaran (4420m); the second, less elevated and more arid, with an approximately meridian direction, stretches from southern Khorasan to the reliefs of Baluchistan, forming a natural dividing limit with Pakistan. For Iran 2016, please check softwareleverage.org.

Between the marginal mountain ranges and the internal ones there are depressed areas, mostly independent of each other, and sometimes even significantly: they represent the real Iranian deserts; due to the differences in altitude and the influence of the nearby mountains, 3 in particular can be distinguished: first of all, the basins that still house a perennial lake (hāmūn), fed by one or more watercourses (as in the case of the Sistan, however, only partially included within the borders of the country); then the depressions, in a more advanced evolutionary stage than the previous ones, filled with all kinds of debris, coarse at the edges, minutes, which turn into salty marshes during the short periods of rain or into saline crusts in the dry season (the Kavir Desert, to the NW, a desert in the strictest sense of the term, devoid of any form of plant and animal life, except in oases); finally, the Desert of Lut to the SE, a sterile area, entirely filled and dried up, in which layers of clay and sand alternate with incrustations of salt where, in correspondence with the most pronounced depressions, it is formed in winter, due to the of the waters that descend from the nearby mountains of Kerman, a temporary salt lake, which does not bring any improvement to the environmental conditions, hostile both to stable human settlement and to vegetation in general.

1.2 Climate

The climate is generally arid, with the exception of a few narrow coastal strips where it turns into humid. Characteristics of the inland regions are the high summer temperatures, which are contrasted by very cold winters, the marked excursions, not only annual but also diurnal, and the extreme drought in summer. In general, it can be said that the western half of the country has better climatic conditions, being able to benefit from the rains that bring the last breaths of the westerly winds during the winter, while the eastern and southern portion is dominated by the seasonal rhythm of the monsoon with however, these effects are strongly limited by the external mountain barriers.

1.3 Hydrography

Morphology and climate condition Iranian hydrography. More than half of the territory sends its waters into closed basins through often discontinuous streams, or which even run out during their journey. The remainder has flowed out to the sea through streams of water that are in some cases copious, perennial or intermittent, but mostly very short, because they are hindered in their development by the arrangement of the reliefs they cross. Among the largest are the Diyala, the Karkheh, both tributaries of the Tigris, and above all the Karun, which, like the previous ones, has its source in the Zagros Mountains: the latter, after a distance of 700 km, can be navigated downstream of Ahvaz, flows into the delta area of ​​the Shatt al-Arab; also the Qezel Owzan (or Safid), the longest of the Caspian riviera if we exclude the Aras, a river that marks the border with Armenia and Azerbaijan, a function also performed by the Araks on the opposite bank. Then there are the tiny but numerous tributaries of the salty Lake Urmia, in Azerbaijan, a basin of variable dimensions according to the seasons.

Iran Morphology