Iraq Rivers and Morphology

By | December 19, 2021

As regards the geological structure, it should be noted that the course of the two twin rivers that cross it filled the furrow dividing the flat archaic plate of the Arabian peninsula with the enormous pile of alluvium here continues, with changed direction, the Armenian-Anatolian mountain ranges. The change of direction (from O.-E. to NO.-SE.) corresponds to the widening of the eruptive masses that extend over the middle course of the two rivers and force them to diverge. In S. the influence of the corrugation, more than in the presence of tectonic disturbances, becomes evident in the emergence that on the Cretaceous-Eocene basement the Cenozoic sandstones from which the group of Gebel Makhūl and Gebel Ḥamrīn result; through this the Tigris passage opens with a small erosion gorge, marked on the bottom by rapids. The mountainous areas that form the northern part of the Mossul region consist mainly of nummulitic limestones, alternating with various igneous rocks and above all with basalts and serpentines, and with crystalline schists, deeply carved by the streams that descend to the Tigris (Khābūr and Gran Zāb). Their height exceeds 3000 meters in several places and the whole landscape has harsh shapes, as shown by the fact that the transit towards the finite sectors (Turkish and Persian) is possible only through a few rather high passes. Towards the West, a small strip of Gebel Singiār (835 m.) Reenters within the Iraq, which the border with Syria divides in two; on the other side, the detected margin continues no less impervious and sublime (Boz Dāgh, 3672 m.; Tepe Khān 2793 m.) along the Persian border up to Khūzistān, where Kārkhah and Qarūn manage to open the way towards the Shaṭṭ al-‛Arab. This belt of mountains, also given the prevalence of limestone, functions as a water reservoir with respect to the plains below, whose agricultural-pastoral economy completes no less with transhumance than with the presence of a more or less dense sedentary population. For Iraq geography, please check

The rest of the country to the West of the Tigris is instead in the domain of nomadism, constituted as it is by desert or steppe: the first on the right of the Euphrates, the second essentially in the wide triangle (with apex at the Shaṭṭ al- ‛ Arab) that the two major rivers lap on the sides (the base is represented here by the long, straight Syrian border between Abu Kemāl on the Euphrates and the Wadi Suwaidiyyah, where it flows into the Tigris) and circumscribe in an island fashion, as it is precisely defined by the Arabs (al-Giazīrah). Morphologically more varied than the simplicity and monotony of its vegetal landscape, al-Giazīrah assumes, within the confines of Iraq, the characteristics of the classic halophilous steppe, all the more clear the more one progresses towards Baghdad and away from the Mediterranean. uidian which are all lost in salt pools and lakes, before reaching the river, even the long Tharthar, which also goes a short distance from Ramādī, and only in a few places the Bedouin nomads who cross the region know they can find, in the wells , the water needed by livestock. On the other hand, both major rivers run here embedded with respect to the level of the surrounding plains, so that the benefit of irrigation remains limited to more or less extended stretches of their beds. On the other hand, even before reaching the point where the Tigris and Euphrates are closest to each other, the sides of the two valleys become depressed until they gradually merge with the flat strips of steppe or desert that fringe them.: the waters, no longer contained within the rain of the eaves, wander in meanders, continuously shifting their course. The steppe gradually gives way to hills and the plain, previously bare and without trees, comes to life with the appearance and crowding of palm trees that set the tone for the landscape and announce the warm, fertile land of Babylon.

The whole region between 34 ° N. (approximately), the mountainous margin of Pusht-i kūh to the East., the crystalline base of the Arabian desert to the West and the Persian Gulf is geologically recent alluvial construction, but not due, as one might believe, only at the work of the two major rivers. Together with the Tigris and the Euphrates, the streams coming from the two opposite ends (E., O.) of the gulf have worked here, and in no lesser proportions: the Bāṭin, now reduced to a simple wadi, and the Kärkhah-Qārūn, which ended up also joining the Shaṭṭ al-‛Arab. The deltas of these two river currents, of which the second load of the copious food of floods torn from the Zagros, have gradually isolated from the sea behind them a lacustrine area (hot lake) that the waters of the Euphrates and Tigris are gradually filled and continue to fill: of the two rivers, in fact, the second carries only a small fraction (perhaps a tenth) of its solid tax to S. of al-Qurnah, while the first deposits it all, before joining al Tigris, in the lakes of Shināfiyyah and Hammār. Naturally the hydrographic conditions of the delta present the same instability that is found more or less in similar areas, but here made even more complex by human intervention, which has had from very ancient times to try to correct the mobile play of the forces of nature for its own benefit. But when we ignore particular issues, it is easy to realize that, in substance, even for the territory of the delta the best settlement conditions occur in the vicinity of the two major currents, where irrigation, here no less essential than in Egypt, it was and remains smoother; and this explains the distribution of the ancient and very ancient inhabited centers, all arranged, like the modern ones, on the banks of the two great rivers, or rather of those which, period by period, were the paths followed by the waters in their changing flow towards the sea. The upper section of this territory, north of the el-Ḥayy canal, still maintains, in essence, the saline steppe characteristics that distinguish the landscape upstream of Baghdad, except that the spring floods, and the greater ease of irrigation allow, at least for short periods of the year, the development of crops (barley, millet, hard, wheat); if even most of the area remains the domain of nomadic shepherds, the marginal strips sprinkled by the waters of the rivers and canals that are deduced form a border of green around the yellowish moor of the treeless plain. These conditions change proceeding towards S. As the slope decreases, the river currents become more sluggish and stagnate in marshes or branch out, lingering in meanders; at the same time the frequency and the danger of floods are decreasing. Beyond the plain of Tello and the marshes that precede the joining of the two twin rivers in the Shaṭṭ al-‛Arab, palm cultivation becomes dominant, but cereals and cotton also find ideal conditions for development, especially the latter, on which the hopes of those who believe the country’s fortune are assured by a renewed arrangement of the water system. Thanks to this arrangement, which includes a series of barriers not only on the Euphrates and Tigris, but also on the most important of the tributaries, the Diyālā, and the creation of catchment basins to avoid the damage of the floods (Lago al- Ḥabbāniyyah for the Euphrates, Āqarqūf for the Tigris), other arable land upstream of the Baghdād area, and especially on the left of the Tigris, could be put into value, where the riches of the subsoil have already brought about a promising awakening. As far as theoretical calculations are concerned, it is certain that the possibilities appear conspicuous, even if limited to 15-20 thousand sq km. that it is certain to be able to reclaim in the lower delta area: cereals, cotton, legumes, tropical fruit and dates will be able to allow, with appropriate rotations, highly profitable products.

Iraq Rivers