The so-called two-river basin refers to the area where the Tigris River, the Euphrates River and their tributaries originate from the West Asia Mountain and Zagros Mountain. The two rivers meet and separate almost near Baghdad, and they don't meet until about 80 kilometers from the Persian Gulf. Seen from below Baghdad, the fertile alluvial plain caused by the two river basins is the place where the ancient civilizations in the two river basins were bred and grown. The southern half of this alluvial plain was called Sumer in ancient times, the northern half was called Akkad, or Babylon, and the northern part of Babylon became Assyria.
Mesopotamia plain is an alluvial land with plenty of water in a dry environment. The water source of the two rivers is the snow in eastern Turkey, and their annual flooding degree depends on the speed of snow melting, and the flooding time is generally from April to June. The distance from the water source to the delta is short, so the alluvial is more intense. When the two rivers flow through a large swamp, the river water evaporates a lot, and when they reach the estuary of the delta, a lot of salt is deposited, so there has always been a problem of salinization in the Mesopotamian plain. The middle part of the Euphrates River bed is higher than the surrounding area, and the flooded river will stay in the adjacent flooded basin for several weeks, so a lot of salt is deposited in the basin. In order to maintain soil fertility, people in the two river basins need to establish irrigation networks to control river floods. Without maintenance, if the river overflows, the plains in the two river basins cannot be cultivated. There was abandoned land in Mesopotamia in history, and the center of ancient civilization moved northward, from Sumer to Akkad, and then to Assyria, all of which were related to abandoned land. In northern Mesopotamia, rivers are more winding because the north is mountainous. With the passage of time, the river course has changed. From the late uruk to the third Ur Dynasty, residents mainly concentrated in the delta, but with the intensification of salinization in the south, residents gradually moved northward.
Without advanced water conservancy technology, it is difficult to maintain the irrigation network in the northern valley area. With the continuous improvement of water conservancy technology, the empire invested a lot of manpower and material resources to build water conservancy, and the north gradually became the political, economic and cultural center. The problem of salinization in South China is becoming more and more serious. In a period of time, the output of crops has dropped by half, but the number of seeds needed has more than doubled. Long-term continuous farming without proper fallow has accelerated the process of salinization; Perennial irrigation keeps the groundwater level at a high level, and the salt cannot be washed away and stays on the upper surface. An important consequence of salinization is that people keep moving northward, from Sumer to Akkad to Assyria, and the delta region has never recovered its former glory.
Second, the influence of geographical environment on ancient Egyptian civilization
Ancient Egyptian civilization originated from a vast desert area in northern Africa. The Nile flows from south to north, leaving a long and narrow valley corresponding to the desert areas on both sides. Valleys and deserts constitute an integral part of the living environment of ancient Egyptians. Egypt is geographically isolated, with deserts in the east and west and the Mediterranean Sea in the north. This isolation made it difficult for ancient Egyptians to communicate with other countries, but on the other hand, it also made Egypt not easy to be invaded by foreign enemies, which was conducive to maintaining the continuity of civilization. Herodotus said, "Egypt is a gift from the Nile." This sentence highly summarizes the significance of the Nile to ancient Egyptian civilization. It can be said that in the arid desert of North Africa, there would be no Egyptian civilization without the Nile. The Nile originates from Lake Victoria in central Africa and has two main tributaries: the White Nile and the Blue Nile. The water volume of the White Nile is relatively stable. The Nile is more than 6,000 kilometers long, and it is 1000 kilometers in Egypt. When it flows through Cairo, it divides into five tributaries and flows radially into the Mediterranean Sea. The ancient Egyptians called the Nile Delta "Lower Egypt", the narrow area south of Cairo "Upper Egypt", and the king of ancient Egypt called himself "King of Upper and Lower Egypt", which reflected the geographical differences between the river valley and the delta.
The regular flooding of the Nile brought a lot of fertile soil to this valley, making it a paradise for ancient Egyptians. Every July, the water level of the Nile rises gradually, overflows the riverbed and flows into the valley. It reaches its climax in September every year. The whole valley was submerged in the river, and the river receded, leaving a layer of silt, which is rich in phosphate and humus and is fertile ground for crop growth. Because rivers regularly flood most of the time and bring natural fertilizers in time, the agricultural development in this area has unique conditions. The Nile not only provides favorable conditions for agriculture, but also avoids the salinization of the two river basins. After the harvest, it was followed by several months of drought, which prevented the problems of waterlogging and salinization. In addition, due to sediment deposition, the ground on both sides of the river rises, and the river overflows slowly along the river instead of breaking through the bank, forming many small ponds in the process. In the wet season, these small ponds can store a lot of water, which flows back in the dry season. On the one hand, it can make the soil fully absorb water and avoid the problem of salinization, on the other hand, it can supplement irrigation.
Although the desert can't make the ancient Egyptians survive, the resources in the desert have great attraction to the ancient Egyptians. The western desert is relatively flat, and there are several oases that produce some precious stones. The influence of the western desert on the ancient Egyptians is limited to this. The eastern desert is close to the life of ancient Egyptians. There are many mountains and rich stones here, and most of the stones used by ancient Egyptians to build pyramids were obtained from here; The eastern desert and the southern desert are also rich in gold deposits, which are the most attractive places for ancient Egyptians. The exploitation of various mineral resources in the desert is an important link in the economic life of Egyptians. Without the desire and courage to actively develop the desert, there would be no miracles of the pyramids and Karnak temples, and other achievements that surprised future generations.
Third, the influence of geographical environment on ancient Greek civilization.
The hometown of the ancient Greeks includes both the Balkans surrounded by the Aegean Sea and other areas around the ocean. There are many islands in the Aegean Sea, which have become stepping stones for the ancient Greeks to expand outward. The eastern part of the Greek peninsula is more developed than the western part. One of the important reasons is that the eastern coastline is tortuous and navigation conditions are good. Moreover, the developed areas of ancient civilizations facing the East have the conditions to learn from the achievements of Egyptian and Western Asian civilizations and conduct various exchanges with them. Located on the peninsula, the isthmus of Corinth extends the immovable coastline, forming several independent islands and pushing them into the embrace of the sea, making the important commercial centers in ancient history concentrated in the East.
The Greek Peninsula is mountainous, and a series of rugged mountains separate Greece from the northern Balkan Peninsula, and the northern part becomes Macedonia. The mountains on the Greek peninsula are not high, the highest is only 10,000 feet, but they are steep and difficult to climb, which makes southern Greece free from the invasion of northern nationalities, which is also one reason why ancient Greece can form city-state politics. There is no great plain in the Greek peninsula, and there is no big river conducive to agricultural irrigation and transportation, so agriculture is not very developed. The coastline of Greece is rather tortuous, and almost all the city-states are less than 40 kilometers away from the coastline. For the Greeks at that time, the only mode of transportation on the peninsula was rugged dirt roads, which were slow and expensive. It was often windy at sea and there were many pirates, so it was not safe to go by sea, so most people in Greece at that time didn't want to go out, which may be part of the reason why Greece formed city-state politics. The Greek Peninsula is rich in mineral resources and developed earlier. Greece has a Mediterranean climate, with wet and rainy winters and dry summers. There is only snow in the mountains in winter, and it hardly snows in other places, but there will be strong winds and cold weather. The annual rainfall varies greatly, and the agricultural harvest is unstable, sometimes good and sometimes bad. The Greeks themselves think that the local climate is the most ideal in the world except for occasional natural disasters. Aristotle believes that the climate determines people's political destiny, and the weather in Greece is neither too hot nor too cold, which is good for the physical and intellectual development of Greeks. They can remain free and create the best political system. If they can keep political unity in their own hearts, they can conquer the whole world.
To sum up, the geographical environment restricts the emergence and development of ancient civilization to a certain extent. The reason why West Asia has such a civilization, Egypt has such a civilization, and Greece has a different civilization from them, which has a lot to do with the geographical environment. Why the pyramids appeared in Egypt instead of Greece, and why city-state politics prevailed in Greece instead of West Asia, has a certain relationship with the geographical environment.