The arrangement of the mountainous reliefs, in the central part of the territory, conditions the radial structure of Moroccan hydrography. Towards the interior various watercourses (Ziz, Guir etc.) descend, which, due to being insufficiently fed, are lost in the desert and therefore re-enter the vast endorheic area of the interior of northern Africa, however, giving life to a whole series of oases. The streams that descend to the sea, thanks to the relatively abundant rainfall on the external mountain slopes, have a much greater development, but an absolutely torrential regime due to the great irregularity of rainfall. The long lean summers, culminating in September, are followed by abundant and full coursesviolent but short, due to the winter rains. They also carry out an intense erosion and deposit action; they are therefore characterized by deep gorges, frequent landslides, imposing dejection fans and abundant detrital material, which clutters the river beds. The main river is the Oum-er-Rbia, which originates in the Middle Atlas and flows into the Atlantic just N of El-Jadida after crossing the Chaouia plateaus. The other major waterways on the Atlantic side are the aforementioned Sebou, Tensift and Souss. In the southwestern sector of the country develops the Draa, an Atlantic river as far as its mouth is concerned (however it reaches the ocean only in the wettest years) but Saharan by origin since it originates from the internal side of the High Atlas; it is theoretically the longest river (approx. 1200 km) in Morocco, but the middle and lower reaches are normally dry. The main tributary of the Mediterranean is the Moulouya, which flows between the ranges of the Middle and High Atlas.
Despite the profound Arabization of the country, according to threergroup, the Moroccan population is still partly made up of the Berber ethnic group (45%), which has been preserved in all its purity in the most secluded mountainous regions of the interior; the Arabs, who arrived here in the century. VII, are 44%. The other groups, overall, are 11%. However, given the difficulty if not the impossibility of distinguishing the Arabs from the Berbers most of the time, we often speak generically here of Arab-Berber populations. In the region of the Anti Atlas there was also a black-African infiltration, which gave rise to interbreeding with the Berbers. Characteristic was also the Jewish immigration, particularly intense between the sec. XIV and XVII. The first half of the century XX had seen the immigration of about 300,000 Europeans, but these, after the cessation of the French and Spanish protectorates, returned in large numbers to Europe, or took the road to America. At the same time, many Jews also left Morocco for Israel, other European countries and North America. The Moroccan population grew in the century. XX with a very high rate, due to the improved living conditions: in 1931 it was 6 million residents, almost doubled in 1961 and more than quadrupled in 2000. Population growth, for a long time among the highest in the world, fell to 1.3% (2015-2020). The population density is 78.40 residents/km². The highest demographic values are recorded in coastal areas, in particular in the Tangier area and in the hinterland of Casablanca. Proceeding inwards, the density decreases but to an unequal extent, according to the economic possibilities of the various areas, until reaching semi-desert values in the Saharan region and in the eastern sector of the country. Where climatic conditions and soil fertility allow it, the population is sedentary and lives gathered in villages but also in scattered houses; in the poorest and most arid areas, where economic activities are closely linked to pastoralism, that is, in much of the southern section of the country, the population lives in tents and constantly moves in search of ever new pastures for cattle.
Characteristic are in the High Atlas the fortified villages (ksar) in defense of the raids that once carried out the nomads of the Sahara. L ‘ urbanization affects more than half of ab. (in 2017 it was 61.9%), which for almost a third are concentrated in Casablanca (or Dar-el-Beida), a modern industrial, commercial and port metropolis, which developed dramatically from the early years of the century. XX. Morocco also boasts 4 “imperial” cities: Rabat, today’s capital, Fès, Marrakech and Meknès; they are ancient Islamic cities, which arose in different eras as seats of the central government of the different dynasties that took turns in power, which developed as lively market centers and then also as industrial and tourist centers. Of great interest is the structure of these cities and some other minor ones: in Morocco, in fact, Islamic urbanism has developed its most characteristic models (especially in Fès and Marrakech it is still intact) with the walls, the souk or market, the mosques, the casbah or citadel, the mellah or Jewish quarter; next to the medina, or ancient city, normally on a completely distinct area, residential neighborhoods of a European type arose in the colonial age, which developed autonomously, thus respecting the extraordinarily suggestive character of the original center. Tangier is an ancient city, in an excellent position on the Strait of Gibraltar, which thanks to the status of an international city was a very flourishing banking and financial center; today it is regaining importance as a maritime port (the outlet in particular of the Rif region) and as a climatic-seaside resort. Other important cities are Salé, almost joined to the capital, Tétouan, former capital of Spanish Morocco, the Atlantic ports of Safi and Kénitra, and Oujda, an important railway hub near the border with Algeria.