Irrigation of Egypt
Hydraulic engineering river, the natural flows of the rivers using different methods engineering and hydraulic structures, providing navigation, flood fighting, hydropower, hydro, water and environmental protection — always accompanied human history in its entirety, but had particular significance in the history of Ancient Egypt and partly Ancient Rome.
Among the countries with highly developed irrigation systems Egypt, Iraq, Syria, Turkmenistan and Uzbekistan. In hot dry areas of these countries, the lands, annually flooded flood waters of the rivers, having first centers of agricultural culture. Seeds were sown during the decline in water deposited silt, which allowed them to cultivate plants without soil treatment. Thus was born the primitive form of irrigated agriculture — hoe farming. The natural regime of rivers, or failed to ensure the annual flooding of the same areas, or lead to excessive flooding. Therefore, ancient farmers protect the land by ramparts or filed the water to them through the channels — a primitive system of flood irrigation. Large irrigation systems started to be created in the slave society. Therefore, the largest irrigation system occurred in the conditions of slave-holding States of Egypt and Rome.
The main methods of irrigation include:
¾ in furrow irrigation water supplied by a pump or from an irrigation canal;
¾ spray of water from a specially laid pipes;
¾ spray irrigation — irrigation of tiny drops of water to control the temperature and humidity in the atmospheric surface layer;
¾ ground (subsurface) irrigation — irrigation by supplying water directly to the root zone;
¾ irrigation Firth — one-time spring deep soil moisture runoff to local waters.
¾ irrigation — irrigation using self-propelled circular system or frontal type.
1 Irrigation of Egypt
The spread of irrigation in Ancient Egypt is inextricably linked with its natural features. Characteristic physiographic features of Egypt are defined so that on its territory flows the Nile river. The sources of the Nile are located in Equatorial Africa, he is sent to Egypt from the South and stretches for 1.5 thousand km, flows North into the Mediterranean sea. In Egypt the Nile has no tributaries, and volume of evaporation from the surface of the river greatly exceeds precipitation. In Egypt the beginning of the Nile flood occurs in June or July, in September, the flood reaches its highest point, during the winter months there is a gradual decrease of the water level, and in may the water level in the river sinking to the bottom. During the lowering of the water level is transparent, during the high water becomes cloudy due to rising from the bottom sludge.
On both sides of the Nile valley are the deserts. Located to the West of the plateau of the Libyan desert is part of the Sahara desert; its smooth surface stretches for hundreds of kilometers.
Located East of the Nile valley, the plateau of the Arabian desert rises gradually towards the red sea, breaking off a steep ledge. Here there are some mountain ranges with a height of 300-2150 m above.m.
The cool season in the region of Upper Egypt lasts from December to February. From April to October remains very hot weather with temperatures up to 42 ° C in the shade. In April and may, when blowing hot and dry Khamsin winds, frequent sand storms. Humidity increases in July, when the Nile begins spilling. In the district of Lower Egypt, especially in its coastal strip, the climate is predominantly Mediterranean. The cool season lasts from October to April. Summer begins in may and is accompanied by a significant increase in humidity. Egypt is located in a very arid zone, where rainfall is rare and irregular.
Thus, in the area of Upper Egypt precipitation sometimes falls for 7-10 years. The average annual rainfall in Cairo is 28 mm, and in Alexandria -190 mm.
The conqueror of Egypt AMR Ibn al-as in the VII century BC wrote that the wealth of a nation “comes from the blessed river which flows with the dignity of Caliph. There comes a time when all sources of the world should pay tribute to this Queen of rivers, which Providence has exalted high above all others: then the water rises, overflows above the riverbed, flood plain and leaves a fertile mud. Then all the villages are separated from one another. Only boats can pass between them and they were innumerable as the leaves on a palm tree. But then in their wisdom the river enters the boundaries defined her destiny, so that those who live near it, can gather wealth, which she gave to the mother earth. Thus, Egypt is a picture of the alternately dry